Bayer Pharmaceuticals Corporation and Onyx Pharmaceuticals Inc announced results from a phase II clinical trial of BAY 43-9006 administered as a single agent in patients with advanced hepatocellular carcinoma (HCC), or liver cancer (hepatoma).

BAY 43-9006, a novel RAF kinase and VEGFR inhibitor under investigation for the treatment of different types of cancer, combines two anticancer activities: inhibition of tumour cell proliferation and angiogenesis (the growth of new blood vessels).

"In this phase II study of advanced primary liver cancer, 43 per cent of patients treated with BAY 43-9006 experienced stable disease for at least four months and an additional nine percent of patients experienced tumour shrinkage," said Dr. Ghassan K Abou-Alfa, lead investigator and clinical assistant attending at the Memorial Sloan-Kettering Cancer Centre, New York, USA. "As we continue to evaluate BAY 43-9006, this clinical study offers a promising step in the fight against primary liver cancer, a disease that has very limited treatment options," he continued.

Of 137 patients enrolled in the study, investigators reported seven patients with partial responses (tumour shrinkage of 50 per cent or greater), five with minor responses (tumour shrinkage of 25 to 50 per cent) and 59 with stable disease for at least four months as their best response. Median overall survival for all patients was 9.2 months and median time-to-tumour progression (TTP) was 4.2 months.

In the study, safety data generated showed that BAY 43-9006 was well tolerated and side effects were predictable and manageable. The most common grade 3/4 drug-related toxicities were fatigue (9.5 per cent), diarrhoea (8 per cent), and hand-foot skin reaction (5 per cent).

"More than 500,000 people worldwide succumb to hepatocellular carcinoma each year. The disease is increasing in incidence rates and remains one of the most difficult tumour types to treat. We are encouraged by the signs of activity of BAY 43-9006 in HCC patients enrolled in this study," Susan Kelley, vice president, Oncology, Bayer Pharmaceuticals Corporation said adding, "Based on these preliminary data, we will be advancing the BAY 43-9006 clinical development program in HCC and will be initiating a phase III single-agent study as well as a phase II combination study with the chemotherapy agent doxorubicin."

The data of the study were presented at the 16th American Association for Cancer Research-National Cancer Institute-European Organization for Research and Treatment of Cancer (AACR-NCI-EORTC) meeting in Geneva, Switzerland.

BAY 43-9006, a novel investigational drug candidate, has demonstrated anti-proliferative and anti-angiogenic properties - two important anticancer activities. In preclinical models, BAY 43-9006 inhibited tumour cell proliferation by targeting the RAF/MEK/ERK signalling pathway at the level of RAF kinase. BAY 43-9006 also exerted an antiangiogenic effect by targeting the receptor tyrosine kinases VEGFR-2 and PDGFR and their associated signalling cascades.

Hepatocellular carcinoma, also known as primary liver cancer, is the most common form of liver cancer and is responsible for 80 per cent of the primary malignant liver tumours in adults. It is the fifth most common cancer in the world. In 2000, approximately 564,000 HCC cases were reported worldwide.