Results of the Simultaneous Combination of Ponatinib and Blinatumomab in Philadelphia Chromosome-Positive ALL

Abstract

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.In this analysis, we update our experience with the chemotherapy-free regimen of blinatumomab and ponatinib in 60 patients with newly diagnosed Philadelphia chromosome (Ph)-positive ALL. At a median follow-up of 24 months, the complete molecular response rate by reverse transcriptase-polymerase chain reaction was 83% (67% at the end of course one), and the rate of measurable residual disease negativity by next-generation clono-sequencing was 98% (45% at the end of course one). Only two patients underwent hematopoietic stem cell transplantation (HSCT). Seven patients relapsed: two with systemic disease, four with isolated CNS relapse, and one with extramedullary Ph-negative, CRLF2-positive pre-B ALL. The estimated 3-year overall survival rate was 91% and event-free survival rate was 77%. Three patients discontinued blinatumomab because of adverse events (related, n = 1; unrelated, n = 2) and nine discontinued ponatinib because of cerebrovascular ischemia, coronary artery stenosis, persistent rash, elevated liver function tests with drug-induced fatty liver, atrial thrombus, severe arterial occlusive disease of lower extremities, pleuro-pericardial effusion, and debilitation. In conclusion, the simultaneous combination of ponatinib and blinatumomab is a highly effective and relatively safe nonchemotherapy regimen. This regimen also reduces the need for intensive chemotherapy and HSCT in first remission in the majority of patients.

Trial registration: ClinicalTrials.gov NCT03263572.

Figure 1.. Consort Diagram

Abbreviations: ALL, acute lymphoblastic leukemia; CNS, central nervous system; CR, complete remission; DVT, deep venous thrombosis; HSCT, hematopoietic stem cell transplantation; MRD, measurable residual disease; PE, pulmonary embolism; Ph, Philadelphia chromosome. *The study was initially designed to treat older patients (age 60+ years). The early promising results led to amending the eligibility (August 2019) to include patients ≥18-year-old with newly diagnosed Ph-positive ALL. This one patient was screened before the amendment was implemented.

Figure 2.. (A) Event-free survival and (B) Overall survival.

Figure 2.. (A) Event-free survival and (B) Overall survival.