The U.S. Food and Drug Administration has granted regenerative medicine advanced therapy (RMAT) and fast track designations to prizloncabtagene autoleucel, an investigational bispecific CAR-T therapy for relapsed or refractory large B-cell lymphoma, according to an announcement from developer AbelZeta Inc. The decision, disclosed on November 10, 2026, highlights the clinical evidence thresholds the agency uses when awarding its two most prominent expedited pathways simultaneously.
Legal Framework Under the 21st Century Cures Act
Congress created the RMAT designation through Section 3033 of the 21st Century Cures Act, which added Section 506(g) to the Federal Food, Drug, and Cosmetic Act. The statute tasks the FDA with identifying regenerative medicine therapies that target serious conditions and show preliminary clinical evidence of addressing unmet needs. The program is administered by the Center for Biologics Evaluation and Research (CBER), primarily through its Office of Therapeutic Products (OTP), which was elevated to a Super Office within CBER in 2023.
The law defines qualifying products broadly. Regenerative medicine therapies include cell therapies, therapeutic tissue engineering products, human cell and tissue products, and certain combination products. Under the FDA’s interpretation, gene therapies and genetically modified cells with a lasting effect — such as chimeric antigen receptor (CAR) T-cell therapies — also meet the definition. Products regulated solely under Section 361 of the Public Health Service Act, which covers minimally manipulated tissues for homologous use, are explicitly excluded.
Three Statutory Criteria for RMAT
To secure RMAT designation, a sponsor must satisfy three requirements set out in Section 506(g)(1) and detailed in FDA guidance from February 2019. First, the product must fall within the statutory definition of a regenerative medicine therapy. Second, it must intend to treat, modify, reverse, or cure a serious or life-threatening condition. Third, it must be supported by preliminary clinical evidence indicating the potential to address the unmet medical need.
That third criterion is the evidentiary gate. The FDA does not prescribe a fixed numerical threshold — such as a specific response rate or patient count — but looks for early human data suggesting a meaningful effect. In the case of prizlon-cel, the designation relied on a Phase 1 study conducted in China and published in Blood in April 2025. Among 44 patients with large B-cell lymphoma, the overall response rate was 90.7% and the complete response rate was 86.0%, with two-year Kaplan-Meier estimates showing a duration of response of 66.0%, progression-free survival of 62.6%, and overall survival of 76.5%.
Other recent RMAT decisions illustrate the range of evidence the agency considers. Kamau Therapeutics received RMAT for nula-cel, a gene-corrected stem cell therapy for sickle cell disease, based on three patients treated with an optimized manufacturing process who achieved transfusion independence and sickle hemoglobin below 20%. Vittoria Biotherapeutics earned RMAT for Senza5 CART5 in T-cell lymphoma based on Phase 1 data slated for presentation at the American Society of Hematology meeting in December 2026. In 2020, the FDA granted 12 of 34 RMAT requests, a 35.3% success rate.
How Fast Track Complements RMAT
Fast track designation operates under a separate statutory provision but shares the requirement that a therapy target a serious condition and fill an unmet medical need. Its evidentiary standard is similarly flexible, accepting preclinical or early clinical data. When granted together, the two designations layer benefits: RMAT confers all fast track and breakthrough therapy advantages, including intensive FDA guidance, early multidisciplinary meetings on trial design and surrogate endpoints, and statutory flexibilities for accelerated approval. Fast track adds the practical ability to hold more frequent agency meetings and to submit sections of a biologics license application on a rolling basis.
Surrogate Endpoints and Accelerated Approval
A distinctive feature of RMAT is the explicit statutory pathway to accelerated approval based on surrogate or intermediate endpoints. A surrogate endpoint is a biomarker — such as a laboratory value or imaging measure — that substitutes for a direct clinical benefit like survival or symptom improvement. For cell therapies, this can include minimal residual disease negativity, cytokine levels, or persistence of engineered cells. The FDA works with sponsors to agree on these endpoints early, often during the multidisciplinary meetings that RMAT designation unlocks.
The agency also permits accelerated approval based on data from a limited but meaningful number of study sites, and it encourages the use of real-world evidence — including patient registries, clinical records, and case studies — particularly for orphan diseases where large pre-market trials are impractical. These flexibilities do not lower the standard for safety or manufacturing quality; they alter the type and timing of efficacy evidence required for initial approval, with confirmatory trials required post-marketing.
What This Means for Patients and Developers
For patients with relapsed or refractory cancers, dual designations signal that the FDA sees early promise worth accelerating. The encouraging part is that these pathways can shorten the wait for new options without compromising the review of safety or manufacturing. For developers, the designations provide a structured forum to align with regulators on the evidence needed for approval, reducing the risk of late-stage surprises.
Early findings suggest that bispecific CAR architectures like prizlon-cel’s CD19/CD20 targeting may mitigate antigen escape, a common resistance mechanism. Patients should understand that RMAT and fast track are developmental designations, not approvals. The encouraging part is the FDA’s willingness to engage early on trial endpoints and real-world evidence strategies. Talk to your doctor or oncologist about what clinical trials or approved therapies may be appropriate for your situation.
Sources
- FDA Grants RMAT and Fast Track Status to Prizlon-Cel in R/R LBCL | Targeted Onc – Immunotherapy, Biomarkers, and Cancer Pathways
- Regenerative medicine advanced therapy
- FDA grants RMAT and fast track designations to prizloncabtagene autoleucel for R/R LBCL
- RMAT Designation: FDA Expedited Program Guide — CASRAI
- Kamau Therapeutics Receives FDA Regenerative Medicine Advanced Therapy (RMAT) Designation for Nula-cel, a Gene-Corrected Stem Cell Therapy for Sickle Cell Disease
- Vittoria Biotherapeutics Announces FDA RMAT and Orphan Drug Designations for Senza5 CART5 (VIPER-101) in T-Cell Lymphoma
Photo: Shixart1985 (CC BY 2.0)
