(Reuters) - OncoMed Pharmaceuticals Inc said the U.S. Food and Drug Administration lifted a partial hold on patient enrolments for three trials testing its experimental cancer drug, vantictumab.
The drugmaker's stock rose as much 9 percent in early trade.
Enrolment of new patients is expected to resume in the next few weeks after the revised trial protocol are approved, the company said.
OncoMed had voluntarily halted enrollments on June 13 as a "precautionary measure", after reports that two of its drugs, vantictumab and ipafricept, were causing mild-to-moderate bone-related side effects.
On the same day, the FDA formally placed a partial hold on vantictumab, which is being tested in combination with standard-of-care chemotherapy in three studies in patients with forms of advanced lung, breast and pancreatic cancer.
Vantictumab and ipafricept are being developed in collaboration with Germany's Bayer AG and are in early-stage tests.
OncoMed on Thursday said the amendments to the trials include modified dosing regimens, risk mitigation measures, and modified enrollment criteria.
The company has various anti-cancer drugs in its pipeline and is developing antibodies and other agents that target biological pathways critical to tumor-initiating cells, also known as "cancer stem cells".
The Redwood City, California-based company's shares were up 4.4 percent at $20.50 in early trading on the Nasdaq. Up to Wednesday's close, stock had fallen 21 percent since the trails were halted.
(Reporting by Natalie Grover in Bangalore; Editing by Saumyadeb Chakrabarty and Savio D'Souza)