Pemigatinib is a selective fibroblast growth factor receptor inhibitor. The medication’s new approval is based on results from the multicenter, open-label, single-arm FIGHT-203 phase 2 clinical trial. The trial included 28 patients with relapsed or refractory MLNs who had a median age of 65 years and weren’t candidates for, or had relapsed after, allogeneic hematopoietic stem cell transplants or treatments such as chemotherapy.
During the trial, patients received 13.5 mg of pemigatinib orally once daily until disease progression, unacceptable toxicity or until they were able to receive allogenic hematopoietic stem cell transplants. Fourteen of the 18 patients with chronic involvement of bone marrow with or without extramedullary disease (EMD) achieved a complete response (CR) (95% CI, 52%-94%). Two of the four patients with blast phase detected in the bone marrow with or without EMD achieved a CR, and one of the three patients with EMD only achieved a CR.
The complete cytogenetic response rate for all 28 patients (including three without evidence of morphologic disease) was 79%, or 22 patients (95% CI, 59%-92%).
“In patients with relapsed or refractory MLNs with FGFR1 rearrangement treated with Pemazyre in FIGHT-203, the high rate of complete response and complete cytogenetic response in patients with chronic phase disease and the high rate of complete cytogenetic response in patients with blast phase disease is clinically meaningful, especially in light of the lack of these specific responses with existing first-line treatments,” said Srdan Verstovsek, MD, PhD, the director of the Hanns A. Pielenz Clinical Research Center for Myeloproliferative Neoplasms and chief of the section for myeloproliferative neoplasms at The University of Texas MD Anderson Cancer Center, in Houston, and the principal investigator of the FIGHT-203 study.
The most common adverse reactions to pemigatinib, occurring in at least 20% of patients, were hyperphosphatemia, nail toxicity, alopecia, stomatitis, diarrhea, dry eye, fatigue, rash, abdominal pain, anemia, constipation, dry mouth, epistaxis, serous retinal detachment, extremity pain, decreased appetite, dry skin, dyspepsia, back pain, nausea, blurred vision, peripheral edema and dizziness.
Serious adverse reactions occurred in 53% of patients who received pemigatinib for MLNs with FGFR1 rearrangement. The most common serious abnormalities (≥10% grade 3/4) were decreased phosphate, decreased lymphocytes, decreased leukocytes, decreased platelets, increased alanine aminotransferase and decreased neutrophils.
Twelve percent of patients permanently discontinued the medication due to adverse reactions that included cardiac failure, multiple organ dysfunction syndrome, blood alkaline phosphatase increase and calciphylaxis.
Pemigatinib received accelerated FDA approval in 2020 for adults with previously treated, unresectable locally advanced or metastatic cholangiocarcinoma with FGFR2 fusion or other rearrangement.
—Clinical Oncology News Staff
—Based on press materials from Incyte and FDA.