Precision Bio Announces pCAR-19B Achieves 90.63% Overall Response Rate in Pivotal Phase 2 Trial for Pediatric and Young Adult R/R B-ALL

▎WuXi AppTec Content Team Report

The 2024 American Society of Hematology (ASH) Annual Meeting is set to take place in San Diego, USA, from December 7 to 10 local time.Among them, Precision BiotechPhase 2 Clinical Study Data of the CD19-Targeted CAR-T Cell Therapy Drug pCAR-19B (Pujilun Sai Injection)Selected for Oral Presentation.The abstract details have now been published on the ASH official website.

Data shows that Pukilun injection targetsChinese Children and Adolescents Aged 3-21 with CD19-Positive Relapsed or Refractory B-Cell Acute Lymphoblastic Leukemia (R/R B-ALL), Best Objective Response Rate (ORR) Reaches 90.63%.According to the announcement on the ASH official website, this study representsThe First Pivotal Clinical Trial of Pediatric B-ALL in Asian Populations, which is expected to provide a new treatment option for Chinese children and adolescents with R/R B-ALL.

Leukemia is one of the most common malignant tumors globally, with both the total number of cases and the number of new cases each year showing an increasing trend. Among them, Acute Lymphoblastic Leukemia (ALL) is a common malignant tumor in children and one of the leading causes of death in children and adolescents, with B-ALL accounting for approximately 80% of ALL cases.

Puricel Injection, independently developed by Chongqing Precision Biotech Co., Ltd., is a CAR-T cell immunotherapy product designed for the treatment of malignant hematologic diseases originating from CD19-positive B cells.. This product has optimized the CAR structure and adopted a safer gene transduction vector system, thereby potentially offering better efficacy and safety. The new drug application for this product has been accepted by China's NMPA and included inPriority Review, used for treatmentCD19-positive children and adolescents aged 3 to 21R/R B-ALLPatientAccording to a previous press release by Precision Biotech, this product is expected to become the first CAR-T product in China targeting childhood leukemia.

Purilun Injection for the treatment of B-ALL in children and adolescents was approved to conduct registration clinical trials in China in 2019. Previously released Phase I registration clinical trial data shows,All 9 patients enrolled achieved complete remission (CR), with an overall response rate of 100%., and minimal residual disease (MRD) was negative for the first time in patients achieving complete remission (CR), with overall safety and tolerability being good.

At this year's ASH annual meeting, researchers announcedPucilencer Injection forChina3~21 years oldChildren and Young Adults CD19 Positive R/RB-ALLPatientEfficacy and safety results of the pivotal clinical trial. The primary endpoint was ORR, defined as complete response (CR) plus CR with incomplete blood count recovery (CRi) within 3 months post-infusion.

As of April 18, 2024, 89 patients were enrolled and underwent leukapheresis, of which 64 patients received pCAR-19B infusion. Among the infused patients, 6.25% were refractory, 93.75% relapsed from prior multi-line treatments or allogeneic stem cell transplantation, and 75% carried at least one high-risk gene. The median bone marrow (BM) blast burden at baseline was 58.3%, with 56.25% of patients presenting with severe bone marrow blast burden.

The research results showed that the median follow-up was 211 days,The optimal ORR was 90.63%.，78.13% of patients (50/64) achieved CR, and 12.5% of patients achieved CRi.98.27% of ORR patients achievedMinimal Residual Disease (MRD)Negative Remission。The total effective rate at 3 months was 76.56%. The median duration of response (DOR) was 10.61 months. The median overall survival (OS) was 23.92 months.The incidence rates of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were 98.44% and 50%, respectively.

Researchers believe that despite the heavy burden of bone marrow blasts and high genetic variation risks in patients, pCAR-19B demonstrated a high remission rate, high MRD-negative remission rate, durable responses, and tolerable safety.

References:

[1] 4205 A Phase 2 Clinical Trial of Anti-CD19 CAR-T (pCAR-19B) in Chinese Pediatric and Young Adult with Relapsed/Refractory (R/R) CD19+ B-ALL: The First Pivotal Study in an Asian Population.  from https://ash.confex.com/ash/2024/webprogram/Paper206408.html

[2] First in China! Chongqing Precision Biotech's CAR-T Product for Pediatric Leukemia Treatment Accepted for Marketing Application by NMPA. Retrieved Jul 22, 2024, from https://mp.weixin.qq.com/s/4nvMu4OQBcUpNySNS3EQpg