Rarity PBC Closes $4.6 Million Seed Round to Commercialize Gene Therapy for ADA-SCID

LOS ANGELES, CA — October 29, 2025 — Rarity PBC, a Public Benefit Corporation focused on expanding access to rare disease gene therapies, today announced the closing of a $4.6 million seed financing round. The funding was led by biotech investor Steve Oliveira, Head of Nemean Asset Management. Proceeds from the financing will accelerate the development of Rarity’s lead program: a one-time autologous hematopoietic stem cell (HSC) gene therapy designed to treat adenosine deaminase severe combined immunodeficiency (ADA-SCID).

Clinically Validated, Curative Potential

The financing follows Rarity’s exclusive licensing of the ADA-SCID gene therapy, originally invented and developed by Dr. Donald B. Kohn at UCLA in collaboration with researchers at University College London.

In long-term studies, this ex vivo gene therapy approach has demonstrated robust and durable immune reconstitution in 59 of 62 children treated, with over 70 children having benefited to date. ADA-SCID is a life-threatening condition where children are extremely vulnerable to infections, and most do not survive beyond early childhood without effective treatment.

“This investment is about turning proven science into sustainable patient reach,” said Paul Ayoub, PhD, MBA, Co-Founder and CEO of Rarity PBC. “We’re moving faster to establish commercial-grade manufacturing, complete the work needed for FDA approval, and ensure that every child with ADA-SCID can benefit from this therapy.”

Strategic Use of Proceeds and Public Benefit Mandate

The newly secured capital will support Rarity’s push toward commercial readiness, specifically by strengthening manufacturing capabilities, advancing regulatory preparations for FDA approval, and building the foundation for sustainable patient delivery.

Steve Oliveira of Nemean Asset Management praised Rarity’s model, noting the potential to “redefine how rare disease treatments reach patients” by combining a clinically validated, curative therapy with a public benefit mandate. As a Public Benefit Corporation, Rarity legally prioritizes the long-term availability and sustainability of its rare disease therapies.

The company acknowledged that this funding builds upon critical support previously received from the California Institute for Regenerative Medicine (CIRM).

About the ADA-SCID Gene Therapy

The therapy corrects the genetic mutation causing ADA-SCID by harvesting a child’s own blood-forming stem cells, inserting a functional ADA gene using a viral vector, and reinfusing the corrected cells so they can produce all blood and immune cell types necessary to fight infections. Children with ADA-SCID are extremely vulnerable to life-threatening infections; without effective treatment, most do not survive beyond early childhood.