Forty Seven, Inc. and Rocket Pharmaceuticals, Inc. announced that they have entered into a research collaboration to pursue clinical proof-of-concept for Forty Seven's novel antibody-based conditioning regimen, FSI-174 (anti-cKIT antibody) plus magrolimab (anti-CD47 antibody), with Rocket's ex vivo lentiviral vector hematopoietic stem cell (LVV HSC) gene therapy, RP-L102. The initial collaboration will evaluate this treatment regimen in Fanconi Anemia (FA), a genetic disease that affects patients' capacity to produce blood cells and is associated with an increased risk of leukemia and other neoplasms. RP-L102, Rocket's gene therapy approach for FA, involves treatment with patients' own gene-corrected blood forming stem cells (hematopoietic stem cells, or HSCs). Gene therapies for monogenic blood disorders have broad potential.

One concern associated with these treatments is the toxicity of pre-therapy conditioning regimens that utilize cytotoxic chemotherapy and/or radiation to destroy existing HSCs and facilitate engraftment of gene-corrected HSCs. Forty Seven's all-antibody based conditioning regimen is designed to address the limitations of current pre-treatment conditioning therapies. These regimens are often associated with serious side effects, including severe infection, cognitive impairment, infertility, endocrine dysfunction, secondary malignancies and organ damage.

These toxicities are especially difficult for pediatric patients and are particularly severe for patients with FA, who are more sensitive to the DNA-damaging effects of traditional conditioning agents. Preliminary data demonstrate that RP-L102 may confer efficacy without pre-treatment conditioning. The combination of RP-L102 with Forty Seven's all-antibody conditioning regimen may provide patients an alternate treatment option in situations where conditioning may be advantageous.

Under the terms of the agreement, Rocket will provide its ex vivo LVV HSC gene therapy platform and Forty Seven will contribute its innovative antibody-based conditioning regimen for the collaboration.