# March Biosciences

> March Biosciences is a Houston biotechnology company developing investigational CAR-T therapies for difficult blood cancers. Its lead candidate, MB-105, uses patients’ own T cells and a CD5-targeting CAR design that reduces self-targeting without additional gene editing. A multicenter Phase 2 study is evaluating it in relapsed or refractory CD5-positive T-cell lymphoma.

- **Founded:** 2021
- **Headquarters:** Houston, United States
- **Founders:** Sarah Hein (CEO and Co-Founder), Maksim Mamonkin (Co-Founder; Chair, Scientific Advisory Board (current team page)), Malcolm Brenner (Co-Founder; Scientific Advisory Board member)
- **Products:** MB-105, Additional cell-therapy pipeline
- **Notable:** Company reported five complete responses in five evaluable primary-cohort patients from a six-patient Phase 2 safety run-in at ASH 2025. Preliminary, uncontrolled data; not evidence of cure or a population-level 100% response rate., FDA orphan drug designation for MB-105 in T-cell lymphoma, publicly announced January 2025., FDA RMAT designation for MB-105 in relapsed/refractory CD5-positive TCL announced November 2025.

## Products & services

- **MB-105** — Investigational autologous CD5-targeted CAR-T therapy. A company-supported multicenter Phase 2 study evaluates relapsed/refractory CD5-positive T-cell lymphoma; a separate Baylor Phase 1 study continues for T-ALL/T-LBL. Its CAR design downregulates CD5 on therapeutic cells without additional target-removal gene editing. It is not an approved commercial product.
- **Additional cell-therapy pipeline** — The company reports development of additional pipeline products; identities and commercial availability are not disclosed in its public financing announcement.

## Achievements

- Company reported five complete responses in five evaluable primary-cohort patients from a six-patient Phase 2 safety run-in at ASH 2025. Preliminary, uncontrolled data; not evidence of cure or a population-level 100% response rate.
- FDA orphan drug designation for MB-105 in T-cell lymphoma, publicly announced January 2025.
- FDA RMAT designation for MB-105 in relapsed/refractory CD5-positive TCL announced November 2025.
- First patient dosing in the Phase 2 MB-105 study announced April 2025.
- Closed a $28.4 million Series A in October 2024.

## Latest updates

- **2026-05** — CPRIT approved a $1,993,978 product development award for advancing MB-105 under grant DP240073; do not assume it is a separate wholly new project or add it to cumulative funding without award-accounting verification.
- **2026-05** — Sarah Hein discussed CD5 internalization, patient-cell variability, immune recovery and centralized/regional manufacturing in a May 4 interview.
- **2025-12** — ASH interim Phase 2 data: five of five evaluable primary-cohort patients achieved complete response; independent monitoring committee allowed progression to Simon Stage 2.
- **2025-12** — Appointed Gurpreet Ratra Chief Business Officer.
- **2025-11** — Announced FDA RMAT designation for MB-105.

## Links

- Website: https://march.bio/
- LinkedIn: https://www.linkedin.com/company/march-biosciences/

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Last updated: 2026-10-04