CRISPR-edited CAR-T appears safe, effective for advanced large B-cell lymphoma
More than half of patients who received a single dose of CTX110 for relapsed or refractory large B-cell lymphoma responded to therapy, according to topline data released by the agent’s manufacturer.
Response rates improved in tandem with higher doses of the investigational chimeric antigen receptor T-cell therapy. The therapy also exhibited a favorable safety profile, with no cases of high-grade cytokine release syndrome (CRS) among the first 26 patients treated.
CTX110 (CRISPR Therapeutics) is an allogeneic, CD19-targeted, CRISPR/Cas9 gene-edited CAR T-cell therapy designed to treat CD19-positive B-cell malignancies.
The phase 1, open-label, multicenter CARBON trial is designed to assess the safety and efficacy of the therapy among adults with relapsed or refractory CD19-positive B-cell malignancies who received at least two previous lines of therapy.
Thirty patients have enrolled in the CARBON trial. To date, enrollment has focused on patients with diffuse large B-cell lymphoma, transformed follicular lymphoma, and high-grade double- or triple-hit lymphomas.
Patients completed a 3-day course of lymphodepletion and then received IV infusions of CTX110 at one of five dose levels — 30 × 106 (dose level 1, n = 3), 100 × 106 (dose level 2, n = 3), 300 × 106 (dose level 3, n = 6), 450 × 106 (dose level 3.5, n = 6) or 600 × 106 (dose level 4, n = 8) CAR T cells.
Safety — determined by incidence of dose-limiting toxicities — and overall response rate served as primary endpoints. Duration of response, PFS and OS served as secondary endpoints.
The topline data analysis included 26 patients who had at least 28 days of follow-up by data cutoff on Aug. 26.
Fourteen patients developed CRS after CTX110 infusion; however, researchers reported no cases of grade 3 or higher CRS as determined by American Society for Transplantation and Cellular Therapy criteria.
One case of grade 3 or higher immune effector cell-associated neurotoxicity syndrome (ICANS) occurred in a patient who had concurrent HHV-6 encephalitis. This was the only report of ICANS among patients who received the highest and second-highest dose levels.
Additionally, researchers reported no cases of graft-versus-host disease or infusion reactions after lymphodepletion or CTX110 infusion.
The ORR was 58% for dose levels 2, 3 and 4 on an intent-to-treat basis, with a corresponding 38% complete response rate among these patients. Results showed a dose-dependent relationship for response rates, starting at 33% for dose level 2, 50% for dose level 3, and 75% at dose level 4.
Four of nine patients who achieved complete response by day 28 remained in remission at 6 months after therapy.
“We are excited to share positive data from our CARBON trial, which show that CTX110 could offer patients with large B-cell lymphomas an immediately available ‘off-the-shelf’ therapy with efficacy similar to autologous CAR-T and a differentiated safety profile,” Samarth Kulkarni, PhD, CEO of CRISPR Therapeutics, said in a company-issued press release.
“We have the potential to improve upon already observed efficacy with a consolidation dosing strategy,” Kulkarni added. “Based on these encouraging results, we are planning to expand CARBON into a potentially registrational trial in the first quarter of 2022.”