Eli Lilly Reports Strong 2025 Clinical Trial Results, Acquires Orna Therapeutics

Eli Lilly achieved positive outcomes for nearly all R&D key events in 2025, a rare set of results in the pharmaceutical industry, according to the company's chief scientific and medical officer. On February 9, the company agreed to purchase Boston area-based biotech Orna Therapeutics for $2.4 billion in cash.

Tirzepatide, a medicine approved for diabetes and weight loss, became the best-selling drug on the planet last year, knocking Keytruda, the cancer immunotherapy drug, off the throne. Tirzepatide is sold as Mounjaro for treating type 2 diabetes and as Zepbound for weight loss. Sales of tirzepatide have pushed Eli Lilly's stock 400% higher over the past five years.

The success rate for phase 2 studies is only about 50%, and it rises to 59% in phase 3, according to some data. Estimates do vary, and these rates are also not uniform across different therapeutic areas.

The majority of Eli Lilly's 2025 results were in weight management or diabetes. Eli Lilly's retatrutide, a next-gen anti-obesity medicine, performed well in a phase 3 study, as did orforglipron, an oral GLP-1 racing toward approval.

However, Eli Lilly also made solid clinical progress in other areas. The company's cancer medicine, Jaypirca, aced a phase 3 study and is well on its way to earning label expansions. In 2025, Eli Lilly also reported that its Alzheimer's disease medicine, Kisunla, is helping slow cognitive decline in a long-term study.

Orna is developing innovative medicines using circular RNA. These drugs can manipulate a patient's genes and/or cells to fight diseases, in particular autoimmune diseases like multiple sclerosis and rheumatoid arthritis. So far, these gene therapy medicines have treated a patient's cells in a lab before being reinfused into the body. Orna, however, is developing a therapy with the working name ORN-252 that allows the patient's body to generate the changes needed to fight the disease, rather than modifying them in a lab. It's called in vivo chimeric antigen receptor T-cell technology, and while it's still in early-stage development, the therapy appears to be very promising.

According to Eli Lilly's announcement of the acquisition deal, ORN-252 is "clinical trial-ready," which means it could still be several years away from commercial sales.

Just a day before the Orna announcement, the company announced it was paying $350 million up front to collaborate with a Chinese biotechnology firm to develop treatments for immune disorders and cancer, and in January it announced another billion-dollar deal with a German company to develop hearing-loss gene therapies.

Eli Lilly is investing in artificial intelligence, notably by building what will become the industry's largest AI supercomputer, among other initiatives. Eli Lilly hopes to leverage AI to accelerate drug development. The U.S. Food and Drug Administration announced last year that it was phasing out animal models in favor of other methods, including AI-based models.

The company is recording strong financial results, boasts a deep pipeline, and continues to reward shareholders with growing dividends and share buybacks.