Johnson & Johnson said it remains committed to developing Zarnestra (tipifarnib) after FDA deemed the oral leukemia agent "not approvable" based on Phase II clinical trials.

The company announced June 30 it had received a not approvable letter from FDA for Zarnestra, requesting additional information about the trial's patient population.

J&J had been pursuing an indication for the treatment of acute myeloid leukemia in elderly patients who are not candidates for standard chemotherapy.

"Recognizing the unmet medical need in this area, the company is reviewing the FDA's letter and will determine appropriate next steps," J&J said.

FDA's Oncologic Drugs Advisory Committee voted 7-4 against accelerated approval for Zarnestra in May based on data from the single-arm Phase II trial, which demonstrated a 15% complete remission rate with the drug. FDA reported an 11% CR rate (¹ Also see "Zarnestra Phase III Data Needed Pre-Approval, Oncology Committee Says" - Pink Sheet, 5 May, 2005.).

The advisory committee expressed concern over the survival rates in patients treated with Zarnestra compared to best supportive care.

AstraZeneca's Iressa also appeared to factor into the committee's decision: the epidermal growth factor receptor inhibitor received accelerated approval based on the surrogate endpoint of tumor response rate but then failed to show a survival benefit in confirmatory trials.

J&J has initiated a Phase III trial that will compare Zarnestra to best supportive care in patients ages 70 and older with AML. Results from that trial are at least two years out.

At the May meeting, however, some advisory committee members questioned whether the Phase III trial will have sufficient power to demonstrate a survival benefit. J&J plans to enroll 300 patients in the study.

The NDA submission for Zarnestra was completed in December under the Continuous Marketing Application Pilot-1 Program, which allows sponsors of fast-track agents to submit NDAs in reviewable units (² Also see "J&J Completes Tipifarnib Submission For Leukemia Under Pilot 1 Program" - Pink Sheet, 24 January, 2005.).

- Jessica Merrill

J&amp;J Zarnestra Receives “Not Approvable” Letter From FDA

More from Archive

More from Pink Sheet

J&J Zarnestra Receives “Not Approvable” Letter From FDA