Imatinib Increases Complete Response Rate, Decreases HSCT Allocation in Pediatric ALL

The following article features coverage from the American Society of Hematology (ASH) 2017 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Adding continuous imatinib to induction therapy greatly increases the complete response (CR) rate in pediatric patients with Philadelphia chromosome (Ph+) acute lymphocytic leukemia (ALL) and reduces the need for hematopoietic stem cell transplant (HSCT), according to findings presented at the American Society of Hematology (ASH) 59^th Annual Meeting & Exposition in Georgia.¹

Patients with Ph+ ALL typically exhibit poor prognoses with a long-term event-free-survival (EFS) rate of approximately 30%; most patients in first complete remission (CR1) are allocated to HSCT. Based on findings from previous studies (COG AALL0031 and EsPhALL 2004-2009), researchers are assessing the association between continuous imatinib plus chemotherapy with the reduced need for HSCT.

For the single-arm EsPhALL 2010-2014 study, researchers assigned 155 pediatric patients to receive continuous imatinib 300 mg/m² starting day 15 of induction therapy. Patients received HSCT based on early response and minimal residual disease (MRD) levels of at least 5 x 10^-4. Continuous imatinib was recommended throughout the first year after transplant.

Approximately 97% (151) of patients reached CR1 by the end of induction; 100% of patients reached CR1 by the end of consolidation phase 1B. Thirty-eight percent (59) of patients underwent HSCT in CR1. Only 2 patients discontinued imatinib post-HSCT because of an increase in MRD or gastrointestinal (GI) toxicity.

The median overall follow-up was 57 months. The 5-year EFS was 57.0% (standard error [SE], 4.1) and 5-year overall survival (OS) was 71.8% (SE, 3.8). These findings were comparable to rates previously observed in the EsPhALL 2004-2009 study; the 5-year EFS and 5-year OS rates were 60.3% and 71.6%, respectively.

The 5-year cumulative incidence of relapse was 26.9; 46 events occurred among patients who received chemotherapy only, and 19 among patients who received HSCT in CR1.

Overall, 55% of patients had serious adverse events (SAEs); the most frequently reported SAEs included infection, osteonecrosis, and gastrointestinal disorders.

Read more of Cancer Therapy Advisor‘s coverage of the American Society of Hematology (ASH) 2017 meeting by visiting the conference page.

Reference

1. Biondi A, Gandemer V, Campbell M, et al. A treatment protocol with imatinib and intensive chemotherapy for pediatric Philadelphia positive acute lymphoblastic leukemia patients: a single-arm, intergroup study (EsPhALL 2010-2014). Oral presentation at: American Society of Hematology 59th Annual Meeting & Exposition; December 9-12, 2017; Atlanta, GA.