Incyte (INCY) on Sunday said the U.S. Food and Drug Administration has granted Breakthrough Therapy designation to INCA033989, an experimental antibody designed to treat patients with a specific genetic form of essential thrombocythemia, a rare blood cancer that causes dangerously high platelet
The designation applies to patients with essential thrombocythemia (ET) who carry a Type 1 mutation in the CALR gene and who can no longer tolerate, or don’t respond to, standard treatments that suppress blood cell production, according to the pharmaceutical company.
The designation applies to patients with essential thrombocythemia (ET) who carry a Type 1 mutation in the CALR gene and who can no longer tolerate, or don’t respond to, standard treatments that suppress blood cell production, according to the pharmaceutical company.
ET belongs to a group of diseases known as myeloproliferative neoplasms (MPNs), or chronic blood cancers in which the bone marrow produces too many blood cells. In ET, the excess cells are platelets, which help blood clot. When platelet levels are persistently high, patients face increased risks of blood clots, stroke, bleeding complications and, in some cases, progression to more severe diseases such as myelofibrosis, a condition marked by bone marrow scarring, or acute leukemia.
Roughly a quarter of ET patients carry mutations in the calreticulin (CALR) gene, which disrupts normal blood cell regulation. Among those patients, the most common variant is a 52-base-pair deletion known as a Type 1 CALR mutation. It is associated with the greatest risk of progressing to myelofibrosis. INCA033989 is designed to recognize and bind specifically to the mutated form of the calreticulin protein, targeting diseased cells while largely sparing healthy ones.
“This Breakthrough Therapy designation underscores the potential of INCA033989 to significantly transform the treatment of ET patients, who today have limited options,” Dr. Pablo Cagnoni, Incyte’s (INCY) president and head of research and development, said in a statement. He added that the company plans to begin a Phase 3 clinical trial, typically the final and largest stage of testing, in mid-2026 after additional discussions with regulators.
The FDA’s decision was based on early results from a Phase 1 clinical trial, which primarily assesses safety but can also provide initial signs of effectiveness. Data presented earlier this year showed that INCA033989 was generally well tolerated and led to rapid, sustained reductions in platelet counts across multiple dose levels, a key goal of ET treatment. Larger and more sustained responses were observed at higher doses.
Updated Phase 1 results, including additional safety and effectiveness data in ET as well as new findings in patients with myelofibrosis, are scheduled to be presented at the 2025 American Society of Hematology annual meeting
Incyte (INCY) said it plans to expand development of INCA033989 beyond Type 1 CALR mutations to include other CALR mutation types. The company aims to launch a broader, registration-enabling study in ET patients who are resistant or intolerant to at least one existing therapy as early as the first half of next year.
By focusing on mutant-specific targeting, Incyte (INCY) is betting that INCA033989 can offer a more precise approach to ET and related diseases, one that limits side effects while addressing the genetic driver of the cancer itself.
Incyte (INCY) is known for making Jakafi, which is primarily used for treating myeloproliferative neoplasms, polycythemia vera, and graft-versus-host disease (GVHD) in adults and children. counts.
