Dasatinib promising as induction therapy of Ph+ ALL

January 1, 2008

The first interim results from the first study of dasatinib (Sprycel) as induction therapy of Ph+ acute lymphoblastic leukemia (ALL) show complete and early hematologic responses with good overall compliance

ATLANTA-The first interim results from the first study of dasatinib (Sprycel) as induction therapy of Ph+ acute lymphoblastic leukemia (ALL) show complete and early hematologic responses with good overall compliance, Roberto Foa, MD, of the University "La Sapienza," Rome, said at the 49th ASH meeting (abstract 7). So far, investigators have enrolled 28 de novo adult Ph+ ALL patients out of an intended 48 patients. Median age is 56 years, with six patients older than age 60.

A prednisone pre-phase is started 7 days prior to the first dasatinib dose and continued until day 31, allowing identification of the Bcr/Abl transcripts. Patients receive dasatinib, 70 mg twice daily, for 84 days, with intrathecal methotrexate at days +22 and +43. The primary endpoint is complete hematological remission (CHR) rate.

Among 27 evaluable patients, 21 patients (80.8%) had a ≥ 75% response to pre-phase prednisone. With dasatinib, all 27 patients (100%) attained a CHR, Dr. Foa reported. Most patients (77.8%) had achieved CHR by day 22. There were no fatalities.

Debulking of disease was marked and rapid (documented by immunophenotypic and molecular monitoring), and tracked closely with CHR. Monitoring of Bcr-Abl/Abl ratio also showed a consistent decline, with a small proportion of patients appearing to be negative at the end of treatment.

One patient discontinued treatment after 14 days due to intestinal toxicity; 27 reached day 43 of treatment, 25 reached day 57, and 22 reached day 84.

At least one severe adverse event occurred in 10 patients: One was considered life-threatening, 9 others severe, 10 moderate, and 3 mild.

Dr. Foa concluded, "This interim analysis of the GIMEMA LAL1205 protocol shows that use of dasatinib as a treatment for Ph+ ALL patients, including older patients, is feasible with good overall compliance."

He noted that some of the patients, after being treated initially in-house, were able to receive later treatments at their homes.

Dr. Foa commented that adding the 27 patients in this trial to those who had entered the earlier imatinib (Gleevec) protocol among patients older than age 60 (GIMEMA LAL0201) gave a total of more than 60 Ph+ ALL patients treated with a tyrosine kinase inhibitor alone without an induction fatality.