Rare Daily Staff

Jasper Therapeutics, a company focused on hematopoietic cell transplant therapies, and Aruvant Sciences, a company developing gene therapies for rare diseases, have entered a non-exclusive research collaboration to evaluate the use of JSP191, Jasper’s anti-CD117 monoclonal antibody, as a targeted, non-toxic conditioning agent with ARU-1801, Aruvant’s experimental lentiviral gene therapy for sickle cell disease.

Sickle cell disease (SCD) is the most common deadly genetic disorder, affecting more than 300,000 newborns worldwide each year, and a rare disease in the United States. It leads to chronic pain, organ failure, and early death in patients. The root of SCD is two mutated copies of the hemoglobin gene, HBB, which cause red blood cells to transform from a circular disc into a sickle shape — setting off a chain of events leading to organ damage, recurrent pain, and early mortality.

The companies’ is evaluating the use of JSP191 as an effective and more tolerable conditioning agent that can expand the number of patients who can receive ARU-1801, a potentially curative treatment for SCD.

“This research collaboration with Aruvant is the first to use a clinical-stage antibody-based conditioning agent and a novel clinical-stage gene therapy, giving this combination a clear advantage by moving beyond the harsh conditioning agents currently used for gene therapy and establishing this next-generation potentially curative treatment as a leader in sickle cell disease,” said Kevin Heller, executive vice president, research and development of Jasper. “Our goal is to establish JSP191 as a potential new standard of care conditioning agent, broadly in autologous gene therapy and allogeneic hematopoietic stem cell transplantation.”

Gene therapies and gene editing technologies generally require that a patient’s own hematopoietic stem cells first be depleted from the bone marrow to facilitate the engraftment of the new, gene-modified stem cells through a process called conditioning. Other investigational gene therapies and gene editing approaches in SCD use a high-dose chemotherapy such as busulfan for the conditioning regimen, which can place patients at prolonged risk for infection and bleeding, secondary malignancy and infertility. ARU-1801 is currently the only gene therapy that has demonstrated durable efficacy using both a lower dose of chemotherapy and a different agent than busulfan with a more limited side effect profile.

The Aruvant-Jasper partnership is focused on evaluating the potential of using JSP191, a highly targeted anti-CD117 (stem cell factor receptor) monoclonal antibody agent, as the foundation of a novel conditioning regimen for use in combination with ARU-1801 to further reduce the negative side effects while maintaining efficacy.

“The unique attributes of ARU-1801 enable us to bring a potentially curative one-time therapy to individuals with sickle cell disease that can be delivered in the safest way possible,” said Will Chou, CEO of Aruvant. “By partnering with Jasper to evaluate the use of JSP191 with ARU-1801, we are one step closer to developing a next-generation definitive therapy with an even more patient-friendly conditioning regimen. We believe that this combination may be able to further expand the number of patients who can benefit from ARU-1801 in the future, including potentially those with more moderate disease.”

JSP191 is a humanized monoclonal antibody in clinical development as a conditioning agent that blocks stem cell factor receptor signaling leading to clearance of hematopoietic stem cells from bone marrow, creating an empty space for donor or gene-corrected transplanted stem cells to engraft. To date, JSP191 has been evaluated in more than 90 healthy volunteers and patients. It is currently enrolling in two clinical trials for myelodysplastic syndromes /acute myeloid leukemia and severe combined immunodeficiency (SCID) and expects to begin enrollment in four additional studies in 2021 for severe autoimmune disease, sickle cell disease, chronic granulomatous disease and Fanconi anemia patients undergoing hematopoietic cell transplantation.

ARU-1801 is designed to address the limitations of current curative treatment options, such as low donor availability and the risk of graft-versus-host disease seen with allogeneic stem cell transplants. Unlike other experimental gene therapies and gene editing approaches that require fully myeloablative conditioning, ARU-1801 can be given with reduced intensity conditioning (RIC). Compared to myeloablative approaches, the lower dose chemotherapy regimen underlying RIC has the potential to reduce not only hospital length of stay, but also the risk of short- and long-term adverse events such as infection and infertility. Preliminary clinical data from the MOMENTUM study, an ongoing phase 1/2 trial of ARU-1801 in patients with severe sickle cell disease, demonstrate continuing durable reductions in disease burden.

Photo: Will Chou, CEO of Aruvant

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