A Phase III trial of Gilead's idelalisib has been stopped early after data showed that the drug offers a benefit for patients with leukaemia.
Idelalisib is from a new class of drugs that inhibit phosphoinositide 3-kinase (PI3K) delta, a protein which plays a critical role in cell growth and survival and trafficking of B lymphocytes, and is hyperactive in many B-cell malignancies.
Gilead's 220-patient study was assessing the drug in previously-treated patients with chronic lymphocytic leukemia (CLL) who are not fit for chemotherapy.
But the drugmaker called time on the trial after interim analysis by an independent data monitoring committee found "highly statistically significant efficacy" for the primary endpoint of progression-free survival in patients receiving combination of idelalisib plus rituximab compared to those receiving the latter alone.
The safety profile of the drug was also found to be "acceptable and consistent with prior experience" when combing it with rituximab in previously treated CLL.
Norbert Bischofberger, Gilead’s R&D chief, said the firm is pleased that idelalisib has shown a clinically meaningful benefit, particularly as these patients are not able to receive chemotherapy.
He also noted that this is the first Phase III study "to report positive results for a new class of targeted therapies that inhibit B-cell receptor signaling as a major component of their mechanism of action, an important area of focus in the development of chemotherapy-free regimens in CLL and other B-cell malignancies".
Gilead, which has long been a key player in the HIV/AIDS market, said that it will now have discussions with US regulators on filing its drug in CLL. A new drug application for idelalisib was submitted for refractory indolent non-Hodgkin’s lymphoma (iNHL) back in September 11, marking the firm's first step into the oncology arena.
ISI Group analyst Mark Schoenebaum said Wall Street analysts expect idelalisib to have sales of $100 million in 2015, rising to $800 million in 2017, but that the "consensus numbers will likely go up in the near term," reports Reuters.