Eisai’s 2008 Eribulin NDA Plan Foiled; Beaten To The Punch By Ixempra

FDA has dealt a setback to Eisai's burgeoning oncology pipeline by denying the company's efforts to seek accelerated approval for its microtubule growth suppressor E7389 (eribulin mesylate).

By the end of March 2008, Eisai was hoping to file an NDA for E7389 based on promising Phase II results in third-line advanced breast cancer after treatment with an anthracycline, taxane or capecitabine for E7389, the firm said.

But FDA denied Eisai's request because the agency recently approved a product with an identical indication, the company announced Feb. 1 during a third-quarter earnings call for its fiscal year (ending March 31, 2008).

Bristol-Myers Squibb received approval for Ixempra (ixabepilone) for advanced breast cancer for monotherapy (fourth-line) and combination (third-line) in October 2007, but Eisai continued to pursue a subpart H submission because it believed there was still "an unmet medical need for the third-line," Eisai R&D Senior VP Kentaro Yoshimitsu said during the call.

Eisai now expects to file an NDA in the U.S. in fiscal year 2009-2010, based on results from two ongoing Phase III studies. The company started a Phase II study for breast cancer in Japan last month, with a 2009-2010 target for NDA submission in Japan, Yoshimitsu said.

The company still has high hopes for E7389, seeking to accelerate development for other cancer types, including prostate, sarcoma and non-small cell lung. For prostate cancer, the firm is in the final stage of a Phase II proof-of-concept trial. Eisai also is trying eribulin in a U.S. Phase Ib/II study with carboplatin for non-small cell lung cancer.

Eisai CEO Haruo Naito said during the call that the company expects the drug to become a source of large revenue, and the firm will continue to "make an aggressive investment" in the product.

While disappointing for Eisai, FDA's decision is tempered by Eisai's 2007 acquisition of MGI Pharma, which added numerous oncology products to Eisai's pipeline. Eisai said it expects to complete its integration of MGI activities by May 2009, "cutting the overlapping personnel" to reduce cost.

Eisai reported another pipeline setback, withdrawing its Japanese application for a supplemental indication of non-erosive GERD for rabeprazole ( Pariet in Japan) to conduct an additional study, with plans to resubmit in FY2008.

The firm had to push back the filing of its novel AMPA receptor antagonist perampanel for Parkinson's disease, after the drug failed to show an efficacy benefit over placebo in a Phase III study (¹ Pharmaceutical Approvals Monthly November 2007, p. 19).

- Daniel Poppy ([email protected])

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