First Patient Achieves Remission With Subcutaneous Blinatumomab in Ultra-Rare MPAL

A WVU Cancer Institute team has achieved a global medical first in a clinical trial examining the efficacy of subcutaneous blinatumomab in treating one of the rarest and most aggressive forms of leukemia. The investigator-initiated Phase II clinical trial marks the first-ever use of a subcutaneous formulation delivery for blinatumomab in CD19-positive mixed phenotype acute leukemia (MPAL). The trial's first patient received the milestone blinatumomab dose on Jan. 16.

After only a single cycle of subcutaneous blinatumomab, the patient achieved complete remission with full hematologic recovery, including transfusion independence and the absence of the Philadelphia chromosome, an abnormal chromosome associated with certain types of leukemia. The therapy was exceptionally well tolerated and transitioned entirely to the outpatient setting after the first week. The patient is currently at home with outstanding performance status and preserved organ function as cycle two is prepared.

The first patient dosed in the trial was a 77-year-old woman with Philadelphia chromosome-positive, B/myeloid MPAL. The patient, who had tolerated treatment well, had transitioned to full outpatient care after the first week of treatment.

MPAL only accounts for one-to-three percent of acute leukemias diagnosed. Adults diagnosed with MPAL face a median survival rate often measured in months. There is no consensus among medical experts on treatment, and no FDA-approved, disease-specific therapies are currently available to address a critical, unmet need.

Blinatumomab (Blincyto®), a bispecific T-cell engager targeting CD19 has increased survival in patients in B-cell acute lymphoblastic leukemia. Treatment has traditionally required continuous intravenous (IV) infusion via pumps over a period of 28 days, prolonging hospitalization or home infusion. The WVU Cancer Institute-led trial is evaluating a subcutaneous formulation designed to deliver comparable therapeutic exposure without the burden of continuous IV administration.

The primary advantage of this new delivery method is the drastic reduction in chair time, which becomes virtually nonexistent; the only remaining limiting factor is the time required for the pharmacy to prepare the medication. Currently, blinatumomab is administered via continuous intravenous (IV) infusion, a process fraught with logistical and technical challenges. These include the frequent malfunction of infusion pumps and the necessity of coordinating with specialized infusion companies.

The simplicity of the subcutaneous regimen allows patients to receive an "under-the-skin" injection and return home immediately, with no weekend schedule required. Right now, there are very, very few community oncology practices that can handle the continuous infusion. This subcutaneous formulation will open the door for them so that they can serve their patients with MPAL.

This Phase II study (NCT07222579) will enroll up to 75 patients across three clinical cohorts, including newly diagnosed MPAL patients who are older than 75 years of age or unable to undergo intensive chemotherapy; patients in morphologic complete remission with measurable residual disease (MRD) positivity; and patients with relapsed or refractory MPAL.

The WVU Cancer Institute serves as the coordinating center for this multicenter trial, which is expected to open at approximately 15 sites across North America. Due to the extreme rarity of MPAL, enrollment is projected at one-to-three patients per site, per year. The WVU Cancer Institute is currently the only active enrollment site and is accepting trial participant referrals from across the globe.