Onyx Pharmaceuticals and Nexavar partner Bayer will seek approval of the oncologic as a top-line treatment for hepatocellular carcinoma "as soon as possible," after a pivotal Phase III trial met its overall survival endpoint early, Onyx Chief Executive Officer Hollings Renton announced during a Feb. 12 conference call.

"Assuming a favorable review by the regulatory agencies, we could expand our label ... and commercially launch Nexavar next year for advanced liver cancer," Renton said.

Nexavar (sorafenib), an oral multi-kinase inhibitor, was approved as a treatment for advanced kidney cancer in December 2005 (¹ Also see "Bayer/Onyx’ Nexavar Approved For Kidney Cancer" - Pink Sheet, 20 December, 2005.).

An independent data monitoring committee recommended halting the trial after an interim review of safety and efficacy data showed it had "met its primary endpoint of improving overall survival in patients treated with Nexavar alone versus patients treated with placebo," Renton said.

The committee also noted that there was no demonstrated difference in serious adverse event rates between the two treatment arms, Onyx said.

Under a special protocol agreement with FDA, "the endpoint would be achieved if sufficient improvement was shown in either overall survival or time to symptom progression," Onyx Chief Medical Officer Hank Fuchs said. "The trial exceeded the prespecified statistical and clinical hurdle for overall survival agreed in the SPA."

The pivotal SHARP (sorafenib HCC assessment randomized protocol) trial was an international double-blind, randomized, placebo-controlled trial in treatment-naive patients with advanced HCC. The trial enrolled 602 patients, Fuchs said. Data from the trial will be presented at the American Society of Clinical Oncology meeting in June.

A Phase II study of Nexavar in combination with standard chemotherapy as a first-line treatment for metastatic melanoma was completed recently, and preliminary data show positive results, Renton said. An earlier study of the oncologic in refractory metastatic melanoma failed to produce positive results (² Also see "Bayer/Onyx Nexavar Fails Phase III Melanoma Trial" - Pink Sheet, 4 December, 2006.). Data from that study also are to be presented at the ASCO meeting.

Onyx also is studying Nexavar in other kidney and liver cancer indications, as well as in non-small cell lung cancer and breast cancer (³ Also see "Next For Nexavar: Bayer/Onyx Initiate Phase III Lung Cancer Trial" - Pink Sheet, 16 February, 2006.). Among the ongoing studies are trials in Asia/Pacific and a trial in Japan that Onyx hopes will "facilitate entry into the Asian market," Fuchs said.

Elsewhere, Nexavar competitor Sutent (sunitinib) updated its labeling to reflect the conversion of its accelerated kidney cancer approval to regular status, Pfizer announced Feb. 9. (⁴ Also see "Sutent Labeling Updated To Reflect First-Line Renal Cell Carcinoma Data" - Pink Sheet, 9 February, 2007.). Sutent was approved Jan. 26 for treatment of advanced renal cell carcinoma.

- Shirley Haley (s.haley@elsevier.com)

Onyx/Bayer Expect 2008 Launch For Nexavar In Liver Cancer

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