FDA Granted RMAT Designation to CTX110 for B-Cell Malignancies

A regenerative medicine advanced therapy (RMAT) designation has been granted by the FDA to CTX₁₁₀, an allogeneic chimeric antigen receptor T-cell therapy that targets CD19-positive B-cell malignancies, according to a press release issued by CRISPR Therapeutics.¹

With a RMAT designation, clinical trial development and application reviews for CTX₁₁₀ will be expedited by the FDA based on the drug’s potential to treat, modify, reverse, or cure a serious or life-threating disease or condition. To have been granted this designation, preclinical evidence must have indicated that CTX₁₁₀ can fill an unmet medical need.

“This RMAT designation is based on the encouraging clinical data we have presented thus far, and it is an important milestone that recognizes the transformative potential of CTX₁₁₀ for the treatment of hematological malignancies,” said Samarth Kulkarni, PhD, chief executive officer of CRISPR Therapeutics, in a press release. “We look forward to working closely with the FDA as we continue our efforts to bring this important new therapeutic modality to patients.”

Positive results have been reported with CTX₁₁₀ from the large B-cell lymphoma (LBCL) cohort in the phase 1 CARBON study (NCT04035434). In 26 patients with LBCL followed for at least 28 days, the objective response rate (ORR) was 58% with complete responses (CRs) in 38% of patients.

The 6-month CR rate in the LBCL cohort was 21% with the longest response having exceeded 18 months. Investigators noted, in a press release, that these responses were similar to what has been achieved in this population with CAR T-cell therapy.

In terms of safety, there were no cases of grade 3 or higher cytokine release syndrome and rate of infection and immune effector cell-associated neurotoxicity syndrome were low.

The study is ongoing and aiming to enroll 143 patients with relapsed or refractory nonHodgkin lymphoma. The coprimary end points of the study include the incidence of adverse events and dose-limiting toxicities and ORR. Secondary end points explored in the study include duration of response, duration of clinical benefit, progression-free survival, overall survival, and ORR in the B-cell acute lymphoblastic leukemia population.

To be eligible for inclusion in the study, patients are required to be 18 years of age with NHL, or between the ages of 18 and 70 years with B-cell ALL. All patients must have an ECOG performance status of 0 or 1, adequate renal, liver, cardiac, and pulmonary organ function, and be using acceptable method of contraception throughout the study.

Patients who have been previously treated with gene therapy or genetically modified cell therapy are excluded from the study. The study also excludes individuals who recently underwent allogeneic hematopoetic stem cell transplant, have history of central nervous system involvement, or seizure disorder, have bacterial or viral infection, a previous or concurrent malignancy, received anti-cancer therapy within 15 days, have an immunodeficiency disorder, or are pregnant or breastfeeding.

Patients who meet the study criteria are being actively recruited at treatment centers in 15 states.

_Reference:

_{1. CRISPR Therapeutics announces fda regenerative medicine advanced therapy (RMAT) designation granted to CTX110™ for the treatment of relapsed or refractory cd19+ b-cell malignancies. News release. CRISPR Therapeutics. November 22, 2021. Accessed November 23, 2021. https://bit.ly/3cID04i}

_{2. CRISPR Therapeutics reports positive results from its phase 1 CARBON trial of CTX110™ in relapsed or refractory cd19+ b-cell malignancies. News release. CRISPR Therapeutics. October 12, 2021. Accessed November 23, 2021. https://bit.ly/3CJzami}