Ponatinib, chemotherapy, and transplant in adults with Philadelphia chromosome-positive acute lymphoblastic leukemia.

Promising results have been shown with the combination of ponatinib and chemotherapy in adults with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). The PONALFIL (Ponatinib With Chemotherapy for Young Adults Ph Positive Acute Lymphoblastic Leukemia) trial combined ponatinib (30 mg/d) with standard induction and consolidation chemotherapy followed by allogeneic hematopoietic stem cell transplant (alloHSCT) in newly diagnosed Ph+ ALL patients aged 18 to 60 years. Ponatinib was only given pre-emptively after alloHSCT. Primary end points were hematologic and molecular response before alloHSCT and event-free survival (EFS), including molecular relapse as event. Thirty patients (median age, 49 years; range, 19-59 years) entered the trial. All exhibited hematologic response, and alloHSCT was performed in 26 patients (20 in complete molecular response and 6 in major molecular response). Only 1 patient died (of graft-versus-host disease), and 5 patients exhibited molecular relapse after alloHSCT. No tyrosine kinase inhibitor was given after HSCT in 18 of 26 patients. Twenty-nine patients are alive (median follow-up, 2.1 years; range, 0.2-4.0 years), with 3-year EFS and overall survival (OS) of 70% (95% confidence interval, 51-89) and 96% (95% confidence interval, 89-100), respectively. Comparison of the PONALFIL and the ALLPh08 (Chemotherapy and Imatinib in Young Adults With Acute Lymphoblastic Leukemia Ph [BCR-ABL] Positive; same schedule, using imatinib as the tyrosine kinase inhibitor) trials by propensity score showed significant improvement in OS for patients in PONALFIL (3-year OS, 96% vs 53%; P = .002). The most frequent grade 3 to 4 adverse events were hematologic (42%), infectious (17%), and hepatic (22%), with only one vascular occlusive event. The combination of chemotherapy with ponatinib followed by alloHSCT is well tolerated, with encouraging EFS in adults with newly diagnosed Ph+ ALL. Cross-trial comparison suggests improvement vs imatinib (clinicaltrials.gov identifier #NCT02776605).
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