Merck drug shows promise in pelvic cancer patients

LONDON (Reuters) - An anti-cancer pill from Merck & Co can fight tumors and is safe in combination with palliative radiotherapy for patients with advanced pelvic cancer, data from early stage trials showed on Wednesday.

The drug, called vorinostat and sold in the United States under the name Zolinza, is a new type of therapy called a histone deacetylase (HDAC) inhibitor.

It is thought to work by stopping tumor growth by altering the levels of several genes needed for cancer cells to grow.

In a study published in The Lancet Oncology journal, Norwegian researchers said they found vorinostat could enhance the effect of palliative radiotherapy and may in future become an important part of long-term curative pelvic radiotherapy, including in rectal cancer patients.

Palliative radiotherapy treatment is designed to shrink tumors, reduce pain and possibly prolong the life of patients who are unlikely to have their cancer cured. Curative radiotherapy is aimed at destroying cancer cells and shrinking tumors before or after surgery.

The Phase I trial was designed to examine the safety and effects of four different doses of vorinostat in 16 patients receiving palliative radiotherapy for advanced pelvic cancer.

The researchers said the drug was generally well tolerated and most side effects were not too serious, with symptoms such as nausea and fatigue. Seven out of 16 patients taking the highest doses of 300mg and 400mg of vorinostat had more serious side effects but there was no toxicity, the study found.

Most patients' tumors had shrunk six weeks after completion of treatment and the researchers concluded that 300mg of vorinostat daily in combination with palliative radiotherapy for two weeks was the maximum tolerated dose.

"This study adds to mounting evidence supporting the use of HDAC inhibition in cancer therapy. These data encourage further examination of this class of molecularly targeted agents in clinical radiotherapy," Anne Hansen Ree of the Norwegian Radium Hospital in Oslo, wrote in the study.

The once-a-day oral drug Zolinza is licensed in the U.S. for use in treating a rare and slow-growing skin cancer called advanced cutaneous T-cell lymphoma (CTCL).

Merck acquired Zolinza when it bought Aton Pharma in 2004. Analysts see the drug reaching annual sales of $137 million by 2013, according to Thomson Reuters consensus forecasts.

(Reporting by Kate Kelland, editing by Sharon Lindores)