According to a story from Endpoints News, the drug developer Incyte has opted to put an end to its phase III clinical trial evaluating parsaclisib, an orally available PI3K inhibitor, for myelofibrosis, a rare disease. This trial was testing the drug in combination with ruxolitinib in adult patients that hadn’t had a strong response to ruxolitinib on its own. This news follows the withdrawal of Accelerated Approval submission for the inhibitor in another indication a year earlier. 

About Myelofibrosis

Myelofibrosis is considered a rare type of bone marrow cancer. The disease is characterized by the excessive accumulation of abnormal stem cells in the bone marrow which trigger a process called fibrosis, or scarring. Over time, the bone marrow is replaced with scar tissue. While the exact cause of myelofibrosis is not known, genetic mutations affecting the MPL, JAK2, and CALR genes are known risk factors. Symptoms of myelofibrosis include enlarged spleen, anemia, shortness of breath, easy bruising and bleeding, greater risk of infection, bone pain, gout, fatigue, weight and appetite loss, and increased blood cell volume. As a cancer that affects stem cells, stem cell transplant can cure the disease. However, this process carries many significant risks. Other forms of treatment are symptomatic and supportive and do not alter the course of myelofibrosis. There is a dire need for safer and more effective therapies for the disease. To learn more about myelofibrosis, click here.

Unconvincing Interim Data

The company stated that after an interim analysis of the trial data, the chance of the study achieving its primary endpoint of reducing spleen volume was low. The study’s secondary endpoints included time to the onset of reduced spleen volume, number of adverse effects, and overall survival rate.

Why the news is certainly a blow for Incyte and parsaclisib, the company is still evaluating the treatment in another indication: warm autoimmune hemolytic anemia.

A couple of therapies in the PI3K inhibitor class have seen approval from the US Food and Drug Administration (FDA), such as Piqray, developed by Novartis and cleared for a certain form of breast cancer, and alpelisib (marketed as Vijoice), also from Novartis and approved for PI3KCA-related overgrowth spectrum.