Arcellx, Gilead announce new data from iMMagine-1 study of anitocabtagene autole

Arcellx (ACLX) announced new data from its Phase 2 pivotal iMMagine-1 study of anitocabtagene autoleucel, in patients with relapsed or refractory multiple myeloma, or RRMM. These data will be presented during an oral presentation at the 66th American Society of Hematology, or ASH, annual meeting and exposition on Monday, December 9 at 5:30 p.m. PT. Anito-cel is partnered with Kite, a Gilead (GILD) company. Additional presentations during ASH are also noted below. The Phase 2 iMMagine-1 data are from an October 31 data cutoff date, with a median follow-up of 9.5 months for the efficacy evaluable population. At the time of the data cut, 86 patients were evaluable for efficacy based on a follow-up of at least two months after treatment with anito-cel, and 98 patients were evaluable for safety based on a follow-up of at least one month after treatment with anito-cel. All patients received a single infusion of anito-cel. In the safety evaluable population, 85 of 98 patients were triple refractory, and 41 of 98 patients were penta refractory. Patients received a median of four prior lines of therapy, with 45 of 98 patients having received three prior lines. Overall response rate, or ORR, was 97% with a complete response/stringent complete response, or CR/sCR, rate of 62% and a very good partial response or higher rate of 81%, per International Myeloma Working Group criteria as investigator-assessed. Of those evaluable for minimal residual disease testing, 93.1% achieved MRD negativity at a minimum of 10-5 sensitivity. Median progression-free survival and overall survival were not reached; six-month PFS and OS rates were 93.3% and 96.5%, respectively, and 12-month PFS and OS rates were 78.5% and 96.5%, respectively. No delayed or non-ICANS neurotoxicities, including no Parkinsonism, no cranial nerve palsies, and no Guillain-Barre syndrome, have been observed to date in more than 150 patients dosed with anito-cel. Of the safety evaluable population, 86% had Grade 1 cytokine release syndrome, or CRS, including 17% of patients with no CRS. Among patients experiencing CRS, the median onset was four days. Eight percent of patients were treated as outpatient. Ninety-one percent of patients had no ICANS. Any Grade ICANS was observed in 9 patients, with all cases resolved without sequelae. Three deaths occurred due to treatment-emergent adverse events, or TEAEs. No additional treatment or therapy-related deaths or Grade 3 CRS or ICANs events have occurred to date. Cytopenias were the most common Grade 3 TEAEs; 53 patients had Grade 3 neutropenia, 20 had Grade 3 thrombocytopenia, and 22 had Grade 3 anemia. Preliminary results from the Phase 2 iMMagine-1 study demonstrate deep and durable responses with a predictable and manageable safety profile in a high-risk fourth-line or higher RRMM population, including triple- and penta-class refractory disease. Notably, no delayed or non-ICANS neurotoxicities, including no Parkinsonism, no cranial nerve palsies, and no Guillain-Barre syndrome, have been observed with anito-cel to date.