NEW YORKAdding the monoclonal antibody HuM195 to chemotherapy for
advanced acute myeloid leukemia (AML) produced a trend toward better patient
response rates than chemotherapy alone in a phase III trial (ASCO abstract
Eric J. Feldman, MD, of the Weill Medical College of Cornell University
in New York City said that the findings also suggest that the combination
therapy might be more effective in certain subgroups of patients. "Our
conclusion is that the drug has activity," Dr. Feldman told ONI. The
results also support further testing at higher doses of HuM195, he added.
"In almost every category there is an improvement in response rate
in patients receiving HuM195 over the control group," he said. This
suggests, he noted, that these numbers might not have reached statistical
significance because the study only randomized 191 patients and a low dose
All Patients Received Standard Induction Therapy
HuM195 targets CD33, an antigen found on the majority of myeloid blasts.
Previous trials had shown that it has modest anti-leukemic activity as a
single agent, with responses primarily in AML patients with low-burden
disease who had already been heavily treated.
The phase III study focused on hard-to-treat adult AML patients who did
not respond initially to chemotherapy or who had their first remission
within 1 year of treatment. Nearly two-thirds (64%) had had a complete
response that lasted less than 6 months, and 26% had an antecedent blood
disorder such as myelodysplastic syndrome.
All patients received standard induction therapy (mitoxantrone
[Novantrone] at 8 mg/m² on days 1-6, etoposide at 80 mg/m² on days 1-6, and
cytarabine 1 g/m² days on days 1-6). HuM195 was also administered to 94
patients as a 4-hour infusion on days 7 to 10 and days 19 to 22 at a dose of
12 mg/m². The remaining 97 patients did not receive any additional therapy.