Early Results With Cirmtuzumab/Ibrutinib Therapy for CLL
Posted: Monday, September 30, 2019
According to a phase I/II trial, presented at the 2019 American Society of Clinical Oncology Annual Meeting (Abstract 7527) and published in the Journal of Clinical Oncology, a combination treatment of cirmtuzumab—a first-in-class anti-ROR1 monoclonal antibody—and ibrutinib appears to be active and safe in patients with chronic lymphocytic leukemia (CLL).
“[Complete responses] were observed in [two] cases, a result that would be highly unusual with [ibrutinib] monotherapy in CLL,” concluded Michael Y. Choi, MD, of the University of California San Diego Moores Cancer Center, and colleagues.
The study included 12 patients with CLL, 2 of whom had undergone previous treatment. Participants underwent a total of 52 weeks of treatment, receiving a dose of 2, 4, 8, or 16 mg/kg of cirmtuzumab every other week for 8 weeks, then once every 28 days. In addition, patients received 420 mg of ibrutinib orally every day beginning on the day 28 of cirmtuzumab treatment.
A single serious adverse event, tonsillitis requiring hospitalization, occurred during cirmtuzumab monotherapy. Except for this event and one case of grade 3 hyperkalemia, all other adverse events were grade 2 or below. No patients discontinued treatment or received limited doses due to toxicity.
After 16 to 48 weeks of treatment, the overall response rate was 67%. Overall, one patient achieved a complete response with no remaining evidence of disease in the bone marrow, one reached a clinical complete response, six achieved a partial response, and four had stable disease. Notably, all cirmtuzumab dose levels included at least one patient who achieved a partial response. None of the participants experienced disease progression.
Moving forward to the randomized phase II portion of the protocol, 600 mg of cirmtuzumab was selected as the recommended dose.
Disclosure: The study authors’ disclosure information may be found a coi.asco.org.
