Patients with advanced multiple myeloma who received three or more lines of therapy have shown promising safety and efficacy results in a Phase 1 trial assessing bluebird bio’s new CAR T-cell therapy bb2121.
New data, to be presented at the American Society of Clinical Oncology (ASCO) 2017 Annual Meeting, have shown that the overall response rate for patients included in higher-dose cohorts is 100%, with some responses still ongoing after six months. Treatment-related side effects were mild and manageable.
The poster, titled “First-in-Human Multicenter Study of bb2121 anti-BCMA CAR T Cell Therapy for Relapsed/Refractory Multiple Myeloma: Updated Results,” will be presented on June 5 by Jesus G. Berdeja, MD, from Sarah Cannon Research Institute and Tennessee Oncology, Nashville, Tennessee.
CAR T-cells are genetically engineered T-cells designed to do a better job of detecting and eliminating cancer cells. The cells are removed from a patient and taken to a lab, where they are modified to express a chimeric antigen receptor, or CAR, that is specific to a cancer protein.
Bluebird’s second-generation CAR therapy is designed to target cells expressing the B-cell maturation antigen (BCMA).
The first-in-human Phase 1 trial (NCT02658929) is a two-part, open-label, multicenter trial testing the safety and effectiveness of bb2121 in patients with relapsed or refractory multiple myeloma. Participants had received at least three prior treatment regimens, including a proteasome inhibitor such as Ninlaro (ixazomib), and an immunomodulatory agent such as Revlimid (lenalidomide). Participants were also required to have at least 50% of their myeloma cells expressing the BCMA protein.
The study is divided into two parts. In Part A, patients will be assigned escalating doses of bb2121 at 50 million, 150 million, 450 million, 800 million, and 1.2 billion CAR+ T-cells. Following establishment of the recommended Phase 2 dose, Part B will include a dose-expansion cohort to further assess the safety and efficacy of the selected dose.
“This past November we presented the initial clinical data from the first three dosing cohorts in this ongoing Phase 1 study of bb2121 in patients with relapsed/refractory multiple myeloma. At ASCO in June, we look forward to presenting data on those same patients with longer follow-up, as well as safety and efficacy data on an additional 9 patients treated subsequently,” David Davidson, chief medical officer at bluebird bio, said in a press release. “These data will advance our understanding of the bb2121 risk-benefit profile and inform planning with our partners at Celgene for the dose expansion cohort of this study, and the design of a potential pivotal study.”
The company said that all patients treated with doses of 150 million cells and higher responded to the treatment, including two complete responses and two minimal residual disease-negative responses (patients did not have cancer cells in their bone marrow).
Bluebird also reported that cytokine release syndrome, a common complication caused by systemic activation of T-cells, was mild and manageable, suggesting that bb2121 is a potential therapy for this patient population.