Ponatinib Demonstrates Increased Efficacy vs Imatinib in Patients With Ph+ALL

The phase 3 open-label PhALLCON trial found ponatinib plus chemotherapy to be more effective than imatinib with chemotherapy in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL), according to results being presented during the February 2023 session of the American Society of Clinical Oncology (ASCO) Plenary Series.

BCR-ABL1 tyrosine kinase inhibitors (TKIs) are currently the standard of care for newly diagnosed Ph+ALL, but patients treated with first- or second-generation TKIs often develop resistance to treatment. Ponatinib, a third-generation TKI, was directly compared with the first-generation TKI imatinib for the first time in the PhALLCON study, according to an ASCO press release.

A total of 245 adult patients were randomized to receive either ponatinib or imatinib, with both cohorts also receiving reduced-intensity chemotherapy. At the data collection cutoff, 78 patients in the overall cohort were still receiving treatment. Among these patients, 41% were receiving ponatinib and 12% were receiving imatinib.

After a 12-week induction period, the proportion of patients with no detectable residual disease was 34.4% in the ponatinib group compared with 16.7% in the imatinib cohort (P = .0021). Event-free survival was not reached in the ponatinib group but was trending toward improvement at the time of data cutoff.

“These results provide confirmation that ponatinib plus chemotherapy is an effective, safe treatment option for individuals with Ph+ALL, an aggressive acute leukemia with a historically poor outcome,” Olatoyosi Odenike, MD, ASCO expert and director of the leukemia program at UChicago Medicine, said in a statement. “Future research comparing ponatinib to a second-generation TKI would help determine the best choice of TKI for these patients. Chemotherapy-free regimens incorporating TKIs in combination with antibody-based therapies are being actively investigated in this disease.”

Hematopoietic stem cell transplantation, adverse events, and inefficacy were the most common reasons for treatment discontinuation among trial participants. In both groups, adverse events and arterial occlusive events were similar.

“The potential benefit to patients who achieve this early deep response may be important to improve long-term survival outcomes,” lead author Elias Jabbour, MD, from the University of Texas MD Anderson Cancer Center, said in the statement. “The trial results indicate ponatinib as a potential standard of care for patients newly diagnosed with Ph+ALL.”

The findings will be discussed during the ASCO Plenary Series presentation taking place on Wednesday, February 15, 2023, at 3 p.m. ET.

Reference

Ponatinib more effective than imatinib for newly diagnosed Ph+ALL leukemia patients. News release. American Society of Clinical Oncology. February 14, 2023. Accessed February 14, 2023. https://old-prod.asco.org/about-asco/press-center/news-releases/ponatinib-more-effective-imatinib-newly-diagnosed-phall