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Jasper Therapeutics spent the past 11 months working to kick off a phase 3 blood cancer trial. Now, with the first-quarter start date in sight, the biotech has pulled a volte-face, dropping plans to start the pivotal study and switching its focus to other indications.

The now-canned phase 3 clinical trial has loomed on the horizon since Jasper posted phase 1b data on its anti-CD117 monoclonal antibody briquilimab in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) in February. Jasper outlined plans to talk to the FDA about a pivotal study at the time of the data drop and quickly nailed down the first quarter of 2023 as its target start date.

California-based Jasper reaffirmed its plans in November after discussing the trial with the FDA but has now had a change of heart. Jasper CEO Ronald Martell explained the U-turn in a statement to disclose the new clinical development strategy.

“We believe focusing on the most well-characterized opportunities with the clearest and potentially fastest pathway to market is in the best interest of patients and our shareholders. As such, our near-term development program will consist of moving rapidly into a clinical trial in chronic severe urticaria and initiating our chronic lower-risk MDS study, while continuing recruitment in the [severe combined immunodeficiency] (SCID), Fanconi anemia and sickle cell disease transplant studies,” Martell said.

The active clinical trials of briquilimab, which are sponsored by Jasper and its collaborators, are all phase 1 or phase 1/2. While Jasper plans to work with “potential partners to explore development pathways and ensure briquilimab remains ready for a pivotal phase 3 study,” abandoning near-term plans to start the trial deprives it of an advanced application of its asset. Jasper is targeting a 2024 BLA filing in SCID.

Dropping plans for a pivotal AML/MDS clinical trial also removes the question of where funding for the study would come from. Jasper ended September with $51 million, down from $84.7 million at the start of 2022. The biotech forecast the money would keep it going “through early 2023.”

Jasper’s remaining funds will now go into a set of indications that it thinks are a good fit for briquilimab, an antibody that is designed to block c-Kit signaling and thereby deplete mast cells and diseased stem cells. The identification of chronic urticaria as an attractive indication moves Jasper onto turf targeted by Celldex’s barzolvolimab.