Although Gilead made a name for itself with its HIV and liver drugs, its most recent drug, Zydelig, was an attempt to get into the oncology market. However, despite initial success, it’s attempts to expand use of the drug were halted when patient deaths occurred in clinical trials.
Zydelig was approved on 2014 by the FDA, and soon after by the European Medicines Agency, for the treatment of:
•Relapsed chronic lymphocytic leukemia, in combination with rituximab, in patients for whom rituximab alone would be considered appropriate therapy due to other co-morbidities.
•Relapsed follicular B-cell non-Hodgkin lymphoma in patients who have received at least two prior systemic therapies.
•Relapsed small lymphocytic lymphoma in patients who have received at least two prior systemic therapies.
Gilead was in the midst of clinical trials working on expanding its indication to increase sales. The studies were testing Zydelig in newly diagnosed leukemia and lymphoma patients using the drug in combination with a variety of other therapies. Sales in 2015 were $132 million, not what they were hoping, hence the efforts to expand the approval and use of the drug.
Gilead halting oncology clinical trials
But that all came to a halt when the company announced last week that it was ending 6 Zydelig trials after reports of serious side effects, including multiple deaths, mostly due to infections, among participants in several of the studies. Gilead said it would also stop other programs using Zydelig as a first-line therapy.
Regulators in the US, Europe and Canada announced investigations into the trials after sending out alerts. In its alert, the FDA urged health care professionals and patients to report any adverse events involving Zydelig to the FDA MedWatch program.
In the short term, the halted trials won’t have much effect on Zydelig’s prospects, because its current approvals for use as a third line drug remain intact. Zydelig is a first-in-class PI3k inhibitor, and it was armed with some impressive data for its July 2014 launch in CLL, indolent B-cell non-Hodgkin’s lymphoma and small lymphocytic lymphoma (SLL). For instance, adding the drug to Roche’s Rituxan, a standard CLL treatment, held off cancer growth twice as long as Rituxan alone: 10.7 months compared with 5.5 months.
But the red flags on Zydelig combinations are likely to halt any plans for long-term growth, because combining drugs is standard practice in these diseases. Zydelig also has formidable competition in the market which will only benefit from the announcement. Johnson & Johnson and AbbVie’s Imbruvica has done will in the leukemia and lymphoma area. AbbVie also has ABT-199 in the pipeline, an add-on for Rituxan and Imbruvica itself.
Another bad sign for Gilead’s attempts to expand its offerings into oncology is that, according to The Street, one of their top cancer researchers, Phillipe Bishop, left the company in February 2016 after being hired a little over a year ago to spearhead Gilead’s oncology development. Gilead Chief Scientific Officer Norbert Bischofberger told The Street that the decision for Bishop to leave was unrelated to the challenges with Zydelig. But beyond that, he did not provide additional details.