Session: 704. Cellular Immunotherapies: Early Phase Clinical Trials and Toxicities: Poster III
Hematology Disease Topics & Pathways:
Research, Clinical trials, Clinical Research
Methods: NCT05643742 is a phase 1/2, open-label, multicenter study evaluating the safety and efficacy of CTX112 in subjects with relapsed or refractory (r/r) B-cell malignancies. Eligible disease subtypes include LBCL, follicular lymphoma (FL) grade 1-3a, marginal zone lymphoma (MZL), mantle cell lymphoma (MCL), and chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). Patients received standard lymphodepleting chemotherapy (LDC) with fludarabine 30 mg/m2 and cyclophosphamide 500 mg/m2 for 3 days followed by CTX112 infusion. The Phase 1 primary endpoint was the incidence of dose limiting toxicities (DLTs), with secondary endpoints including overall and complete response rates (ORR/CRR) and pharmacokinetics (PK). Data are presented from 9 subjects (3 FL, 2 MZL, 4 LBCL) treated with CTX112 at doses ranging from 30 x 106 (Dose Level [DL] 1) to 300 x 106 (DL3) CAR+ T cells who were followed for >3 months.
Results: The study population was enriched for patients with high-risk characteristics, including: 1) primary refractory disease or early relapse to first-line therapy (78%); 2) high tumor burden (SPD > 4000 mm2, 56%); and 3) high disease prognostic index score (IPI, FLIPI, MZL-IPI ≥3) or elevated lactate dehydrogenase (67%). No DLTs or adverse events (AEs) of GvHD, hemophagocytic lymphohistiocytosis, or grade (Gr) ≥3 infections were observed. All Gr ≥3 cytopenias resolved within 30 days following CTX112 infusion. Cytokine release syndrome (CRS) Gr 1/2 was reported in 4/9 (44%) pts with no CRS Gr ≥3. Immune effector cell-associated neurotoxicity syndrome (ICANS) Gr 1 was reported in 2/9 pts (22%) with no Gr ≥2. When comparing CTX112 vs. CTX110 at DL3, the mean Cmax with CTX112 was 7-fold higher (26,235 vs. 3,773 copies/μg) with significantly higher levels detected at D14, leading to a 10-fold increase in mean AUC (133,701 vs.13,830 copies/μg*days). The ORR and CRR (Lugano 2014 criteria) were 6/9 (67%) and 4/9 (44%) respectively. 4 patients have achieved responses lasting for more than 6 months, including 1 patient treated at DL1 who remains in complete remission over a year after CTX112 infusion.
Conclusions: These data provide the first clinical evidence that disruptions in the genes encoding Regnase-1 and transforming growth factor beta receptor 2 can lead to increased expansion and functional persistence of CAR T cells. Compared with first-generation allogeneic CAR T therapies like CTX110, CTX112 results in better efficacy at lower doses, higher response rates, and improved PK. Across multiple Non-Hodgkin lymphoma subtypes, treatment with CTX112 resulted in clinically meaningful responses without requiring the increased intensity LDC used with other allogeneic CAR T cells. Dose optimization within disease-specific cohorts is ongoing. These data demonstrate that CTX112 has the potential to be a highly effective allogeneic CAR T cell therapy for B-cell malignancies.
Disclosures: Ghobadi: Genentech: Research Funding; Wugen Inc: Consultancy; CRISPR Therapeutics: Consultancy; Bristol Myers Squibb: Consultancy; ATARABio: Consultancy; Amgen: Consultancy, Research Funding; Kite (Gilead company): Consultancy, Honoraria, Research Funding. McGuirk: Envision: Consultancy; Novartis: Consultancy; Allo Vir: Consultancy; Autolus: Consultancy; BMS: Consultancy; Kite: Consultancy; NEKTAR therapeutics: Consultancy; CRISPR therapeutics: Consultancy; Caribou bio: Consultancy; Sana technologies: Consultancy; Legend biotech: Consultancy. Shaughnessy: Autolus, Sanofi: Consultancy; BMS: Speakers Bureau; Sanofi: Speakers Bureau. Tam: AbbVie, BeiGene, Janssen: Research Funding; AbbVie, BeiGene, Janssen, LOXO: Honoraria. Allen: CRISPR Therapeutics: Current Employment, Current equity holder in publicly-traded company. Pan: CRISPR Therapeutics: Current Employment, Current equity holder in publicly-traded company. Li: CRISPR Therapeutics: Current Employment, Current equity holder in publicly-traded company. Stevens: CRISPR Therapeutics: Current Employment, Current equity holder in publicly-traded company. Weaver: CRISPR Therapeutics: Current Employment, Current equity holder in publicly-traded company. Cheah: Dizal: Consultancy, Honoraria; Lilly: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MSD: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Speakers Bureau; Sobi: Consultancy, Honoraria; Regeneron: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BeiGene: Consultancy, Honoraria, Other: travel expenses, Speakers Bureau; Menarini: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Research Funding, Speakers Bureau; Genmab: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Research Funding.