Rare Daily Staff

Jasper Therapeutics has launched out of Stanford University with $35 million in series A financing and a clinical stage antibody-based conditioning agent that it says can expand the use of curative hematopoietic stem cell transplants and gene therapies for rare genetic disorders, autoimmune diseases, and hematologic cancers.

Abingworth and Qiming Venture Partners USA served as lead investors in the financing, with additional investment from Surveyor Capital and Alexandria Venture Investments.

The proceeds will be used to advance the clinical development of the company’s lead product candidate, JSP191, which targets CD117 and is designed to replace or reduce the toxicity of chemotherapy and radiation therapy used to prepare patients for hematopoietic (blood-forming) cell transplant.

JSP191 is a first-in-class humanized monoclonal antibody in clinical development as a conditioning agent that clears hematopoietic stem cells from bone marrow. JSP191 binds to human CD117, a receptor for stem cell factor (SCF) that is expressed on the surface of hematopoietic stem and progenitor cells. The interaction of SCF and CD117 is required for stem cells to survive. JSP191 blocks SCF from binding to CD117 and disrupts critical survival signals, causing the stem cells to undergo cell death and creating an empty space in the bone marrow for donor or gene-corrected transplanted cells to engraft.

Preclinical studies have shown that JSP191 as a single agent safely depletes normal and diseased hematopoietic stem cells, including in an animal model of myelodysplastic syndrome, creating the space needed for transplanted normal donor or gene-corrected hematopoietic stem cells to successfully engraft in the host bone marrow.

JSP191 is currently being evaluated in an ongoing phase 1 clinical trial as a sole conditioning agent to enable stem cell transplantation in patients with severe combined immunodeficiency (SCID) who received a prior stem cell transplant that failed. This severe genetic immune disorder leaves patients without a functioning immune system. Clinical studies to evaluate the safety and efficacy of JSP191 as a conditioning agent in patients undergoing hematopoietic cell therapy for hematologic cancers are planned for 2020.

Jasper’s development of JSP191 is also supported through collaboration with the California Institute for Regenerative Medicine (CIRM), which has been funding the program and is committed to providing a total of $23 million in grant support. As part of the series A financing, Amgen, which discovered JSP191, has licensed worldwide rights to the drug, as well as translational science and materials from Stanford University.

Jasper was co-founded by Judith Shizuru, a hematopoietic stem cell transplant expert at Stanford University, and Susan Prohaska, a Stanford University-trained immunologist, stem cell biologist and early-stage drug development professional. Shizuru’s CIRM-funded lab advanced the understanding of the ability of anti-CD117 to impact hematopoietic stem cells and, together with the Lucile Packard Children’s Hospital Stanford and University of California, San Francisco pediatric transplant teams, was the first to study an anti-CD117 antibody in the clinic as a conditioning agent. That humanized antibody, now called JSP191, was first studied for conditioning for transplant in immune-deficient patients in collaboration with Amgen, UCSF and CIRM.

“Stem cell transplantation is a potential curative therapy for people with hematologic cancers, autoimmune diseases, and debilitating genetic diseases. However, the pre-transplant conditioning required to prepare patients for transplant involves highly toxic chemotherapy, which can be life-threatening and limits the number of people who are able to benefit,” said Shizuru. “JSP191 is the only anti-CD117 antibody to demonstrate safety and efficacy in severely ill patients receiving stem cell transplant in the clinic. We plan to expand clinical development to patients receiving transplants for acute myeloid leukemia/ myelodysplastic syndrome or autoimmune diseases and to patients receiving stem cell-directed gene therapies.”

Photo: Judith Shizuru, co-founder of Jasper Therapeutics

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