The following article features coverage from the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting. Click here to read more of MPR‘s conference coverage.


Ponatinib plus blinatumomab resulted in high rates of complete molecular remission (CMR) among patients with newly diagnosed or relapsed/refractory Philadelphia chromosome–positive (Ph+) acute lymphoblastic leukemia (ALL), according to the results of a phase 2 trial presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting.1

Although the standard of care for Ph+ ALL results in a 5-year overall survival of up to 50%, relapse is common and are frequently driven by the T3151 mutation in BCR-ABL, Nicholas J. Short, MD, of The University of Texas MD Anderson Cancer Center in Houston, and lead author of the study, said.

High rates of remission occur with ponatinib or blinatumomab as single agents. The aim of this trial was to determine if the combination could achieve durable responses and reduce allogeneic hematopoietic stem cell transplant (HSCT).


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The single-arm, phase 2 trial treated 35 patients with newly diagnosed or relapsed/refractory Ph+ ALL or lymphoid accelerated or blast phase chronic myeloid leukemia (CML-LBC) with 5 cycles of blinatumomab and 30mg of ponatinib during cycle 1. The ponatinib dose was reduced to 15mg when patients achieved CMR and was continued for a maintenance phase of at least 5 years. The primary endpoint was CMR for the newly diagnosed cohort and overall response rate (ORR) for the relapsed/refractory cohort.

At baseline, the median age was 59, 99.8% of patients had disease that expressed CD19 and 66% of patients were receiving the ponatinib plus blinatumomab regimen as frontline therapy.

Blinatumomab plus ponatinib resulted in high response rates at 100% in the newly diagnosed cohort, with 85% of patients achieving CMR. The response rate was 89% in the relapsed/refractory cohort and, among responding patients, CMR was achieved by 88%. Among patients with CML-LBC, the response and CMR rates were 100% and 40%, respectively.

There were 4 patients who went on to allogeneic HSCT in the relapsed/refractory cohort; none of the patients who were newly diagnosed or with CML-LBP underwent HSCT.

The 1-year overall survival (OS) rate was 93% and 88% in the newly diagnosed, 80% in the relapsed/refractory, and 100% in the CML-LBC cohorts. The event-free survival was 93%, 61%, and 60%, respectively.

There was 1 blinatumomab discontinuation due to a grade 2 toxicity; most adverse events were grade 1 or 2.  There were no grade 4 or higher events recorded during the study.

“The combination of ponatinib plus blinatumomab is a promising chemotherapy-free, HSCT-sparing regimen for Ph+ ALL,” Dr Short concluded.

Disclosure: This research was supported by Takeda and Amgen. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

Read more of MPR’s coverage of the 2021 ASCO Annual Meeting by visiting the conference page.

Reference

  1. Short NK, Kantarjian HM, Konopleva M, et al. Combination of ponatinib and blinatumomab in Philadelphia chromosome-positive acute lymphoblastic leukemia: Early results from a phase II study. J Clin Oncol. 2021;39;(suppl 15; abstr 7001). doi: 10.1200/JCO.2021.39.15_suppl.7001

This article originally appeared on Cancer Therapy Advisor