Cancer Research Lab

The use of growth hormone-releasing hormone (GHRH) antagonists seems to greatly increase the reduction in breast cancer volume achieved with docetaxel, the results of animal study show.

GHRH antagonists block tumor growth through direct and indirect pathways, and a number of the agents are currently being developed as anti-cancer therapies.

In the present study, Dr. Andrew V. Schally, from the VA Medical Center in Miami, and colleagues examined the anti-tumor efficacy of the GHRH antagonist JMR-132 alone or combined with docetaxel in nude mice bearing human breast cancers.

The researchers’ findings appear in the January 29th Early Edition of the Proceedings of the National Academy of Sciences.

After 22 days, daily treatment with 10 micrograms sc JMR-132 alone significantly inhibited tumor volume and weight by 62.9% and 47.8%, respectively. When docetaxel alone was given at 20 micrograms daily, the corresponding figures were 74.1% and 58.6%.

Combination of 10 micrograms of JMR-132 daily for 22 days and 20 mg/kg ip docetaxel at day 1 and 5 arrested the growth of most of the tumors, and reduced tumor volume and weight by 97.7% and 95.6%, respectively (p < 0.001).

“This study demonstrates that GHRH antagonists are effective in the treatment of estrogen-independent breast cancers and can be combined with taxane chemotherapy,” the authors conclude. “It is possible that the development of GHRH antagonists might lead to improved therapy of early and late stage breast cancers.”