FDA Approves Targeted Therapy for Rare and Aggressive Blood Cancer Following Promising Clinical Trial Results

Recent advancements in targeted cancer therapy have led to the FDA approval of a new drug for treating a rare, aggressive blood cancer, following promising outcomes from a multicenter Phase II clinical trial. The study, conducted by Stanford Medicine and published in NEJM Evidence, investigated the effectiveness of pemigatinib in patients with myeloid/lymphoid neoplasms (MLN) exhibiting rearrangements in the FGFR1 gene.

This subtype of MLN is notably lethal, with fewer than 50% of patients surviving beyond one year post-diagnosis. The disease can present as either chronic or acute (blast phase), and is characterized by constitutive activation of the FGFR1 protein due to gene rearrangements, leading to rapid disease progression and poor prognosis.

The trial enrolled 45 participants with this rare condition, making it an exceptionally challenging study due to the low incidence rate—fewer than 100 new cases worldwide annually. Participants received daily oral doses of pemigatinib, which specifically targets and inhibits FGFR1 activity. The responses observed were remarkable: nearly 75% of patients with the chronic phase experienced complete remission, with some able to undergo potentially curative stem cell transplants. These responses were durable, lasting months to years, with some patients remaining disease-free for over seven years.

In the acute blast phase, 18 patients showed responses, although these were typically shorter-lasting. Nevertheless, five patients in this phase were able to proceed to stem cell transplantation, highlighting the drug's potential as a bridge to definitive treatment. Side effects like elevated phosphate levels and mouth sores were manageable through dose adjustments.

The success of this trial led the FDA to approve pemigatinib for treating FGFR1-rearranged MLN in 2022, marking a significant breakthrough for a disease with limited treatment options. Experts emphasize that this targeted therapy not only offers hope for extending life expectancy but also provides a pathway to transplant, which might not have been feasible previously.

This research underscores the importance of genetic testing in rare cancers, guiding precision medicine approaches that can dramatically alter disease outcomes.

Source: https://medicalxpress.com/news/2025-08-clinical-trial-fda-drug-rare.html