Trial Outcomes & Findings for A Phase II Study of Pomalidomide in Myelofibrosis With Myeloid Metaplasia (NCT NCT00463385)

Last Updated: 2019-11-20

Results Overview

A clinical responder was defined as either: 1. A baseline red blood cell (RBC)-transfusion-dependent participant with a ≥ 56 consecutive day RBC transfusion-free period after the first dose of study drug, or 2. A baseline RBC-transfusion-independent participant with an increase in hemoglobin of 2.0 g/dL or more from baseline for ≥ 56 consecutive days in the absence of RBC transfusions, or 3. A participant with either a ≥ 50% reduction in palpable splenomegaly of a spleen that was ≥ 10 cm at baseline or a spleen that was palpable at \> 5 cm and became not palpable. Participants who discontinued the study early without achieving clinical response were counted as non-responders.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

88 participants

Primary outcome timeframe

Up to 168 days

Results posted on

2019-11-20

Participant Flow

Participant milestones

Participant milestones
Measure	Prednisone Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Overall Study STARTED	22	22	22	22
Overall Study Treated	22	22	19	22
Overall Study COMPLETED	0	0	0	0
Overall Study NOT COMPLETED	22	22	22	22

Reasons for withdrawal

Reasons for withdrawal
Measure	Prednisone Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Overall Study Other	4	3	6	4
Overall Study Adverse Event	5	8	4	2
Overall Study Lack of Efficacy	6	6	7	9
Overall Study Withdrawal by Subject	3	3	3	4
Overall Study Lost to Follow-up	0	0	0	1
Overall Study Death	2	1	2	0
Overall Study Missing	2	0	0	2
Overall Study 1 participant received commercial drug	0	1	0	0

Baseline Characteristics

A Phase II Study of Pomalidomide in Myelofibrosis With Myeloid Metaplasia

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Prednisone n=22 Participants Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg n=22 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone n=22 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone n=22 Participants Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Total n=88 Participants Total of all reporting groups
Age, Continuous	66.0 years n=5 Participants	68.0 years n=7 Participants	67.5 years n=5 Participants	69.5 years n=4 Participants	67.5 years n=21 Participants
Sex: Female, Male Female	8 Participants n=5 Participants	5 Participants n=7 Participants	7 Participants n=5 Participants	9 Participants n=4 Participants	29 Participants n=21 Participants
Sex: Female, Male Male	14 Participants n=5 Participants	17 Participants n=7 Participants	15 Participants n=5 Participants	13 Participants n=4 Participants	59 Participants n=21 Participants
Race/Ethnicity, Customized White	21 participants n=5 Participants	22 participants n=7 Participants	21 participants n=5 Participants	22 participants n=4 Participants	86 participants n=21 Participants
Race/Ethnicity, Customized Black	0 participants n=5 Participants	0 participants n=7 Participants	1 participants n=5 Participants	0 participants n=4 Participants	1 participants n=21 Participants
Race/Ethnicity, Customized Hispanic	1 participants n=5 Participants	0 participants n=7 Participants	0 participants n=5 Participants	0 participants n=4 Participants	1 participants n=21 Participants
Janus kinase 2 (JAK2) Mutation Negative	6 participants n=5 Participants	7 participants n=7 Participants	8 participants n=5 Participants	8 participants n=4 Participants	29 participants n=21 Participants
Janus kinase 2 (JAK2) Mutation Positive	13 participants n=5 Participants	11 participants n=7 Participants	10 participants n=5 Participants	9 participants n=4 Participants	43 participants n=21 Participants
Janus kinase 2 (JAK2) Mutation Missing	3 participants n=5 Participants	4 participants n=7 Participants	4 participants n=5 Participants	5 participants n=4 Participants	16 participants n=21 Participants
Eastern Cooperative Oncology Group (ECOG) Performance Status Grade 0	12 participants n=5 Participants	11 participants n=7 Participants	6 participants n=5 Participants	14 participants n=4 Participants	43 participants n=21 Participants
Eastern Cooperative Oncology Group (ECOG) Performance Status Grade 1	8 participants n=5 Participants	9 participants n=7 Participants	10 participants n=5 Participants	6 participants n=4 Participants	33 participants n=21 Participants
Eastern Cooperative Oncology Group (ECOG) Performance Status Grade 2	2 participants n=5 Participants	2 participants n=7 Participants	5 participants n=5 Participants	2 participants n=4 Participants	11 participants n=21 Participants
Eastern Cooperative Oncology Group (ECOG) Performance Status Missing	0 participants n=5 Participants	0 participants n=7 Participants	1 participants n=5 Participants	0 participants n=4 Participants	1 participants n=21 Participants
Myelofibrosis with myeloid metaplasia Subtype Agnogenic Myeloid Metaplasia (AMM)	16 participants n=5 Participants	16 participants n=7 Participants	16 participants n=5 Participants	13 participants n=4 Participants	61 participants n=21 Participants
Myelofibrosis with myeloid metaplasia Subtype Postpolycythemic Myeloid Metaplasia (PPMM)	3 participants n=5 Participants	4 participants n=7 Participants	4 participants n=5 Participants	2 participants n=4 Participants	13 participants n=21 Participants
Myelofibrosis with myeloid metaplasia Subtype Postthromocythemic Myeloid Metaplasia (PTMM)	3 participants n=5 Participants	2 participants n=7 Participants	2 participants n=5 Participants	7 participants n=4 Participants	14 participants n=21 Participants
Time Since Myelofibrosis Diagnosis	1.5 years n=5 Participants	0.6 years n=7 Participants	1.1 years n=5 Participants	1.7 years n=4 Participants	1.1 years n=21 Participants
Red Blood Cell (RBC) Transfusion Dependence Yes	12 participants n=5 Participants	10 participants n=7 Participants	9 participants n=5 Participants	12 participants n=4 Participants	43 participants n=21 Participants
Red Blood Cell (RBC) Transfusion Dependence No	10 participants n=5 Participants	12 participants n=7 Participants	13 participants n=5 Participants	10 participants n=4 Participants	45 participants n=21 Participants
RBC Transfusion Burden	2.0 units/28 days n=5 Participants	1.0 units/28 days n=7 Participants	0.0 units/28 days n=5 Participants	2.0 units/28 days n=4 Participants	1.0 units/28 days n=21 Participants

PRIMARY outcome

Timeframe: Up to 168 days

Population: Modified intent-to-treat (MITT), defined as the patients who had a confirmed diagnosis of Myelofibrosis with myeloid metaplasia (MMM), received at least one dose of study drug, and participated in the study for at least 56 days.

Outcome measures

Outcome measures
Measure	Prednisone n=20 Participants Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg n=17 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone n=19 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone n=21 Participants Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Percentage of Participants With a Clinical Response Within the First 6 Cycles of Treatment	55.0 percentage of participants Interval 31.53 to 76.94	23.5 percentage of participants Interval 6.81 to 49.9	21.1 percentage of participants Interval 6.05 to 45.57	47.6 percentage of participants Interval 25.71 to 70.22	—	—	—	—

SECONDARY outcome

Timeframe: Up to 336 days

Population: Intent-to-treat (ITT), defined as as all patients who were randomized, independent of whether they received study treatment or not.

Outcome measures

Outcome measures
Measure	Prednisone n=22 Participants Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg n=22 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone n=22 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone n=22 Participants Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Percentage of Participants With a Clinical Response Within the First 12 Cycles of Treatment	50.0 percentage of participants Interval 28.22 to 71.78	18.2 percentage of participants Interval 5.19 to 40.28	18.2 percentage of participants Interval 5.19 to 40.28	45.5 percentage of participants Interval 24.39 to 67.79	—	—	—	—

SECONDARY outcome

Timeframe: Up to 168 days

Population: Intent-to-treat population with a clinical response

The time to the first clinical response achieved within 168 days after the first study drug dosing date was calculated for participants who achieved a clinical response as: Start date of the first clinical response - the first study drug date +1. A clinical responder was defined as either: 1. A baseline red blood cell (RBC)-transfusion-dependent participant with a ≥ 56 consecutive day RBC transfusion-free period after the first dose of study drug, or 2. A baseline RBC-transfusion-independent participant with an increase in hemoglobin of 2.0 g/dL or more from baseline for ≥ 56 consecutive days in the absence of RBC transfusions, or 3. A participant with either a ≥ 50% reduction in palpable splenomegaly of a spleen that was ≥ 10 cm at baseline or a spleen that was palpable at \> 5 cm and became not palpable.

Outcome measures

Outcome measures
Measure	Prednisone n=11 Participants Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg n=4 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone n=4 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone n=10 Participants Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Time to the First Clinical Response	0.3 weeks Interval 0.1 to 15.6	8.0 weeks Interval 2.6 to 17.3	10.1 weeks Interval 0.1 to 20.0	1.2 weeks Interval 0.1 to 16.6	—	—	—	—

SECONDARY outcome

Timeframe: Up to 40 months

Population: Intent-to-treat population with a clinical response.

For RBC-transfusion-dependent patients, duration of response was calculated as the last day of response - first day of response +1, where the last day of response was the date of the first RBC-transfusion administrated at or more than 56 days after the response started. For patients who did not receive a subsequent transfusion after the response started, the end date of response was censored at the day of last hemoglobin assessment. For RBC-transfusion-independent patients, the duration of response was calculated as the last day of response - first day of response +1, where the last day of response was the earlier of the date of a hemoglobin increase of \< 2.0 g/dL and the date of a RBC transfusion at ≥ 56 days after the response started. For patients whose hemoglobin measurements were always ≥ 2.0 g/dL and never received a RBC transfusion after response started, the end date of the response was censored at the date of last hemoglobin measurement. Kaplan-Meier methodology was used.

Outcome measures

Outcome measures
Measure	Prednisone n=11 Participants Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg n=4 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone n=4 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone n=10 Participants Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Duration of First Clinical Response	3.7 months Interval 3.0 to 6.6	NA months Interval 4.7 to Median not estimable as only 1 patient progressed in this group	6.0 months Interval 2.3 to 9.8	10.6 months Interval 2.8 to 16.1	—	—	—	—

SECONDARY outcome

Timeframe: Baseline and Cycle 6 (168 days).

Population: Intent-to-treat patients with available data.

The FACT-An comprises the four subscales of the 27-item FACT-General Scale (FACT-G), Physical Well-being, Social/Family Well-being, Emotion Well-being, Functional Well-Being, and the Additional Concerns Anemia subscale. Questions are rated on a scale from 0 to 4, where higher scores indicate more impact on quality of life. * Physical Well-being consists of 7 questions, the subscale score ranges from 0-28; * Social/Family Well-being consists of 7 questions, the subscale score ranges from 0-28; * Emotion Well-being consists of 6 questions, the subscale score ranges from 0-24; * Functional Well-Being consists of 7 questions, the subscale score ranges from 0-28; * Anemia subscale consists of 20 questions, the subscale score ranges from 0-80; * Total FACT-An score ranges from 0-188.

Outcome measures

Outcome measures
Measure	Prednisone n=9 Participants Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg n=7 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone n=3 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone n=12 Participants Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Change From Baseline in Functional Assessment of Cancer Therapy-Anemia (FACT-An) Subscale and Total Scores Functional Well-Being subscale	0.9 units on a scale Standard Deviation 4.14	-2.1 units on a scale Standard Deviation 8.99	2.7 units on a scale Standard Deviation 3.06	2.5 units on a scale Standard Deviation 6.50	—	—	—	—
Change From Baseline in Functional Assessment of Cancer Therapy-Anemia (FACT-An) Subscale and Total Scores Physical Well-Being subscale	0.6 units on a scale Standard Deviation 1.50	0.4 units on a scale Standard Deviation 6.42	5.3 units on a scale Standard Deviation 4.04	2.3 units on a scale Standard Deviation 2.26	—	—	—	—
Change From Baseline in Functional Assessment of Cancer Therapy-Anemia (FACT-An) Subscale and Total Scores Social/Family Well-Being subscale	1.9 units on a scale Standard Deviation 3.08	-1.9 units on a scale Standard Deviation 2.59	1.7 units on a scale Standard Deviation 3.79	0.9 units on a scale Standard Deviation 6.84	—	—	—	—
Change From Baseline in Functional Assessment of Cancer Therapy-Anemia (FACT-An) Subscale and Total Scores Emotional Well-Being subscale	1.3 units on a scale Standard Deviation 3.32	0.0 units on a scale Standard Deviation 4.76	-0.3 units on a scale Standard Deviation 0.58	1.7 units on a scale Standard Deviation 3.47	—	—	—	—
Change From Baseline in Functional Assessment of Cancer Therapy-Anemia (FACT-An) Subscale and Total Scores Anemia subscale	1.2 units on a scale Standard Deviation 9.47	2.3 units on a scale Standard Deviation 21.34	19.3 units on a scale Standard Deviation 18.93	5.8 units on a scale Standard Deviation 8.85	—	—	—	—
Change From Baseline in Functional Assessment of Cancer Therapy-Anemia (FACT-An) Subscale and Total Scores Total FACT-An score	2.3 units on a scale Standard Deviation 12.42	1.6 units on a scale Standard Deviation 36.51	27.3 units on a scale Standard Deviation 25.74	11.4 units on a scale Standard Deviation 13.51	—	—	—	—

SECONDARY outcome

Timeframe: Baseline, Cycle 6 (168 days)

Population: Intent-to-treat participants with a clinical response and available hemoglobin values at each time point.

Change from Baseline in hemoglobin for participants with a clinical response within the first 6 cycles of treatment.

Outcome measures

Outcome measures
Measure	Prednisone n=6 Participants Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg n=2 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone n=8 Participants Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Change From Baseline in Hemoglobin Concentration for Responders	1.4 g/dL Interval -0.5 to 4.1	2.0 g/dL Interval 0.7 to 3.2	—	-0.1 g/dL Interval -1.9 to 3.9	—	—	—	—

SECONDARY outcome

Timeframe: Baseline, Cycle 6 (168 days)

Population: Intent-to-treat participants with no clinical response and available hemoglobin values at each time point.

Change from Baseline in hemoglobin for participants without a clinical response within the first 6 cycles of treatment.

Outcome measures

Outcome measures
Measure	Prednisone n=3 Participants Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg n=5 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone n=5 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone n=6 Participants Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Change From Baseline in Hemoglobin Concentration for Non-Responders	1.2 g/dL Interval -0.2 to 2.7	0.1 g/dL Interval -0.8 to 1.3	-0.8 g/dL Interval -2.0 to 1.9	0.5 g/dL Interval -0.3 to 1.0	—	—	—	—

SECONDARY outcome

Timeframe: Baseline and Cycle 6 (168 days)

Population: Intent-to-treat patients with available data.

Participants rated abdominal discomfort or pain over the previous week on a scale from zero to ten, where zero is no discomfort or pain and ten is the worst pain imaginable.

Outcome measures

Outcome measures
Measure	Prednisone n=10 Participants Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg n=7 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone n=3 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone n=12 Participants Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Change From Baseline in Likert Abdominal Pain Scale	0.3 units on a scale Standard Deviation 1.83	-1.0 units on a scale Standard Deviation 3.11	0.3 units on a scale Standard Deviation 1.15	-0.1 units on a scale Standard Deviation 1.68	—	—	—	—

SECONDARY outcome

Timeframe: Up to 336 days

Population: Intent-to-treat population with non-missing JAK2 Baseline assessment results. The number of participants analyzed indicates the number of participants with a positive or negative JAK2 result for each treatment group respectively.

Percentage of participants who achieved a clinical response, presented by participants with positive and negative janus kinase 2 (JAK2) V617F mutation results at Baseline.

Outcome measures

Outcome measures
Measure	Prednisone n=13 Participants Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg n=11 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone n=10 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone n=9 Participants Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Prednisone, Negative JAK2 n=6 Participants Participants with a negative JAK2 result at Baseline received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg, Negative JAK2 n=7 Participants Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone, Negative JAK2 n=8 Participants Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone, Negative JAK2 n=8 Participants Participants with a negative JAK2 result at Baseline received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Percentage of Participants With Clinical Response by Baseline JAK2 Assessment	46.2 percentage of participants	27.3 percentage of participants	30.0 percentage of participants	66.7 percentage of participants	50.0 percentage of participants	28.6 percentage of participants	12.5 percentage of participants	25.0 percentage of participants

SECONDARY outcome

Timeframe: From date of the first dose of the study drug until discontinuation or the data cut-off date (up to approximately 45 months).

Population: Safety population (all treated patients).

A serious AE (SAE) was defined as any AE which resulted in death or was life-threatening, required or prolonged inpatient hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or constituted an important medical event (events that may have jeopardized the patient or required intervention to prevent one of the outcomes listed above). The severity of AEs were graded according to National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE, Version 3.0) or according to the following scale: Grade 1 = Mild; Grade 2 = Moderate; Grade 3 = Severe; Grade 4 = Life-threatening; Grade 5 = Death. The Investigator determined the relationship between study drug and the occurrence of an AE as "Not Related" or "Related" (since the study was double-blinded, a patient receiving only prednisone could have an AE that was judged as related to pomalidomide, and vice-versa).

Outcome measures

Outcome measures
Measure	Prednisone n=22 Participants Participants received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg n=22 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone n=19 Participants Participants received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone n=22 Participants Participants received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received oral prednisone from Day 1-28 of each 28-day cycle for up to 3 cycles (84 days), 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day, and pomalidomide placebo tablets on Days 1-28 for up to 12 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, participants were discontinued from the study.	Pomalidomide 2 mg, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and prednisone placebo tablets on Days 1-28 for the first 3 cycles in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 2 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 2 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 2 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.	Pomalidomide 0.5 mg + Prednisone, Negative JAK2 Participants with a negative JAK2 result at Baseline received 0.5 mg oral pomalidomide daily from Day 1-28 of each 28-day cycle for up to 12 cycles (336 days), and oral prednisone tablets on Days 1-28 for the first 3 cycles, 1st cycle = 30 mg daily, 2nd cycle = 15 mg daily, 3rd cycle = 15 mg every other day in the Double-Blind Treatment Phase. After the completion of cycle 12 and upon unblinding, eligible participants continued to receive oral pomalidomide 0.5 mg daily, from Days 1-28 of each cycle. Participants could remain on study treatment in the Extension Phase until disease progression, unacceptable toxicity or voluntary withdrawal.
Number of Participants With Adverse Events (AEs) At least one AE	20 participants	21 participants	18 participants	21 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) At least one AE related to pomalidomide	15 participants	17 participants	16 participants	15 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) At least one AE related to prednisone	10 participants	10 participants	11 participants	5 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) At least one Grade 3-4 AE related to pomalidomide	6 participants	7 participants	11 participants	6 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) At least one Grade 3-4 AE related to prednisone	5 participants	2 participants	6 participants	3 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) At least one SAE related to pomalidomide	4 participants	6 participants	8 participants	3 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) At least one SAE related to prednisone	4 participants	3 participants	5 participants	3 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) AE leading to discontinuation of prednisone	5 participants	7 participants	2 participants	1 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) At least one Grade 3-4 AE	10 participants	14 participants	13 participants	15 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) At least one SAE	6 participants	10 participants	11 participants	8 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) AE leading to discontinuation of pomalidomide	7 participants	11 participants	5 participants	6 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) AE leading to a dose reduction of pomalidomide	0 participants	2 participants	1 participants	1 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) AE leading to a dose interruption of pomalidomide	5 participants	9 participants	9 participants	7 participants	—	—	—	—
Number of Participants With Adverse Events (AEs) AE leading to a dose interruption of prednisone	2 participants	8 participants	6 participants	3 participants	—	—	—	—

Adverse Events

Prednisone

Serious events: 6 serious events

Other events: 20 other events

Deaths: 0 deaths

Pomalidomide 2 mg

Serious events: 10 serious events

Other events: 20 other events

Deaths: 0 deaths

Pomalidomide 2 mg + Prednisone

Serious events: 11 serious events

Other events: 17 other events

Deaths: 0 deaths

Pomalidomide 0.5 mg + Prednisone

Serious events: 9 serious events

Other events: 21 other events

Deaths: 0 deaths

Serious adverse events

Other adverse events

Additional Information

Associate Director, Clinical Trials Disclosure

Celgene Corporation

Phone: 1-888-260-1599

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee The investigator shall have the right to publish and/or present study data provided that the investigator shall (i) furnish the sponsor a copy of any proposed publication or presentation generally thirty (60) days in advance of the submission, (ii) delete any confidential information of the sponsor, and (iii) delay submission for generally up to ninety (90) days to permit the preparation and filing of intellectual property applications or until sponsor gives its consent in a timely manner.
Publication restrictions are in place

Restriction type: OTHER