MB-105 Gains FDA RMAT Designation in R/R T-Cell Lymphoma

The autologous CAR-T cell therapy MB-105 has received regenerative medicine advanced therapy (RMAT) designation from the FDA for relapsed or refractory (R/R) CD5-positive T-cell lymphoma, a disease characterized by limited therapeutic options.¹

The FDA’s RMAT program is granted to cell therapies and related products that show preliminary clinical promise in treating serious or life-threatening diseases and conditions.² With this designation, March Biosciences, the sponsor, can avail all associated benefits to facilitate MB-105’s progression through clinical development and the regulatory process, including more frequent communications with the FDA and eligibility for rolling and priority review.

“The FDA’s RMAT designation further validates MB-105’s potential to address a critical unmet medical need for patients with [R/R] T-cell lymphoma, who face a median survival of only [6] months with current therapies,” said Sarah Hein, CEO of March Biosciences, in a news release.¹ “We are encouraged by the responses observed to date and look forward to working closely with the FDA to advance MB-105 as efficiently as possible.”

This designation marks MB-105’s second FDA recognition this year. The first, an orphan drug designation granted in January 2025, was based on promising phase 1 (NCT03081910) efficacy signals, particularly a 44% overall response rate (ORR) among patients with T-cell lymphoma.

The designation is supported by positive preliminary findings from a single-arm, open-label, multicenter phase 2 clinical trial (NCT06534060) of MB-105 in adult patients with R/R peripheral T-cell lymphoma (PTCL) or cutaneous T-cell lymphoma (CTCL).^3,4 This study is assessing the primary end points of safety and ORR, as well as the secondary end points of duration of response, progression-free survival, and overall survival.

According to the sponsor, MB-105 demonstrated further clinical activity with a manageable safety profile at the recommended phase 2 dose in the safety run-in cohort (n = 6). Data from this cohort are forthcoming at the 2025 American Society of Hematology (ASH) Annual Meeting in December.

The study is actively recruiting patients for its second stage. The trial aims to enroll an additional 9 patients to conduct an efficacy evaluation (n = 15), followed by a broader evaluation in an additional 31 patients for a grand total of 46 patients at multiple sites across the US.

Patients are eligible if they have R/R T-cell lymphoma, laboratory-confirmed CD5 positivity, and have failed at least 1 or 2 prior systemic lines of therapy for PTCL and CTCL, respectively. Key exclusion criteria include Sézary syndrome, prior treatment with any CD5-targeted therapy, and active central nervous system lymphoma.

Along with continuing phase 2 follow-up and engaging with the FDA to advance MB-105’s clinical development, the sponsor has also announced plans to pursue development outside of the US. Together, these initiatives position MB-105 to bring potential clinically meaningful benefits to an expanded patient population.

REFERENCES

1. March Biosciences receives FDA regenerative medicine advanced therapy (RMAT) designation for MB-105 in relapsed/refractory CD5-positive T-cell lymphoma. News release. BioSpace. November 12, 2025. Accessed November 12, 2025. https://tinyurl.com/47fmftx6

2. Regenerative medicine advanced therapy designation. US Food & Drug Administration. Updated November 4, 2025. Accessed November 12, 2025. https://tinyurl.com/yx9dbzfa

3. MB-105 in patients with CD5-positive T-cell lymphoma. ClinicalTrials.gov. Updated October 3, 2025. Accessed November 12, 2025. https://clinicaltrials.gov/study/NCT06534060

4. Iyer SP, Horwitz SM, Jain S, et al. A phase 2 study to confirm safety and efficacy of MB-105, an autologous CD5-directed CAR T-cell therapy, in relapsed/refractory T-cell lymphoma (R/R TCL). J Clin Oncol. 2025;43(16_suppl). doi:10.1200/jco.2025.43.16_suppl.tps7086