Bluebird bio (NASDAQ:BLUE) is up 22% after hours on increased volume in response to its announcement of positive interim results from a Phase 1 study assessing CAR-T candidate bb2121 in patients with treatment-resistant multiple myeloma (MM). The data will be presented tomorrow at the EORTC-NCI-AACR Molecular Targets and Cancer Therapeutics Symposium in Munich, Germany.
The objectives of the open-label study are safety and preliminary efficacy of ascending doses with the aim of identifying the recommended dose for subsequent trials. As of the November 18th data cutoff, 11 heavily pretreated patients had been enrolled and dosed in four cohorts: 5.0 x 10(7), 15.0 x 10(7), 45.0 x 10(7) and 80 x 10(7) CAR+ T cells.
The first nine patients (first three cohorts) were evaluable for safety and underwent their first MM restaging so they were evaluable for efficacy. All received a conditioning regimen of cyclophosphamide and fludarabine before receiving bb2121.
The overall response rate in the nine patients was 78% and 100% in the second and third cohorts. Two patients achieved stringent complete responses with six and four months follow-up, respectively. All patients in the cohorts 2 and 3 with bone marrow involvement at baseline had no detectable MM cells in their bone marrow on day 14 or beyond.
No dose-limiting toxicities were observed. No Grade 3 (serious) or Grade 4 (life-threatening) cytokine release syndrome or Grade 3 or 4 neurotoxicity was observed. No patients received steroids or tocilizumab (Roche's Actemra).
The company intends to initiate the expansion cohort after the dose escalation phase is completed. According to ClinicalTrials.gov, the estimated study completion date is December 2018.
Management will host a conference call and webcast tomorrow, December 1, at 8:00 am ET to discuss the data.