Of 36 patients evaluable for response, 18 (50%) had a response; this included 3 complete responders, 1 patient with a nodular partial response, and 14 with a partial response. The remaining 18 patients had no response (either stable disease or progression on therapy).
All but one of the responses were seen among the patients with CLL or CLL/PLL (response rates of 59% and 50%, respectively); the one patient with PLL had a response. "Although the numbers are relatively small, of patients with the Richter’s transformation or diagnosis of mantle cell leukemia, none responded, and actually all progressed during therapy," Dr. Faderl reported.
About two thirds of patients developed myelosuppression, although it was usually grade 1-2. Episodes of grade 3-4 myelosuppression were rare, usually transient, and could be helped with hematopoietic growth factor support, Dr. Faderl noted. Most nonhematologic toxicities were infusion-related and included rigors, fevers, and skin reactions, mostly grade 1-2. The infection rate was no different than what might be expected with single-antibody therapy.
Six-month follow-up on responders showed a median time to progression of 6 months, with a median survival of 12.5 months, Dr. Faderl said.
In future trials, investigators will probably want to more narrowly define the population of patients that will benefit most from this combination, Dr. Faderl said. In addition, "we want to explore other routes of administration besides IV, especially with alemtuzumab(Drug information on alemtuzumab)," he said.