All eyes are on the American Society of Clinical Oncology meeting in Chicago and among the mountains of data being presented, Bayer and Onyx Pharmaceuticals’ Nexavar has made observers really sit up as it appears to represent a major breakthrough in liver cancer.

The companies presented data on Nexavar (sorafenib), which was approved by the US Food and Drug Administration in December 2005 for patients with advanced kidney cancer, from its Phase III SHARP trial which randomised and evaluated 602 patients with hepatocellular carcinoma (HCC) who had no prior systemic therapy. The results show that those who took Nexavar lived a median time of 10.7 months compared with 7.9 months for patients on placebo, which means that the drug is the first agent ever to demonstrate significant survival benefit in liver cancer, by 44%. The data also revealed that patients administered Nexavar had a median time-to-disease progression of 5.5 months, compared with 2.8 months for those on placebo.

Great things were expected from Nexavar given that Bayer and Onyx halted SHARP in February when an independent data monitoring committee said that the overall survival endpoint had been met, but the results presented at ASCO are more spectacular than most observers had expected. Based on the strength of that data, the companies are now in the process of preparing applications to the FDA and European regulators for this new indication.

"Unprecedented achievement

Jordi Bruix, co-principal investigator and senior consultant at the liver unit of Barcelona’s Hospital Clinic, said that although much progress has been made in oncology, the number of lives lost to liver cancer is increasing “and for that reason, these results represent an unprecedented achievement.” He added that Nexavar “could become the first widely-approved new therapy for this difficult to treat cancer.”

HCC is responsible for about 90% of the primary malignant liver tumours and is the fifth most common cancer in the world and the third leading cause of cancer-related deaths globally. Over 600,000 new cases are diagnosed globally each year and in 2002 that number of people died of HCC. The market is certainly there and Nexavar is the first oral multi-kinase inhibitor that targets both the tumour cell and vasculature and does not require patients to interrupt their treatment schedule.

The data seems to confirm Bayer’s confidence that Nexavar had the potential to be huge. The drug brought in 130 million euros for its first year on the market as a treatment for kidney cancer, and the firm had said that if approved for extensions into melanoma and advanced liver cancer, Nexavar sales could easily reach 500 million euros.

However the firms were rocked by clinical data from a late-stage trial last December which revealed that Nexavar was not effective in treating patients with advanced melanoma but in March Arthur Higgins, chairman of Bayer HealthCare, told PharmaTimes World News that the liver cancer trial was looking very promising. That has proved to be the case and if the drug gets the go-ahead for other cancers, including breast and lung cancer, blockbuster status looks on the cards.