Biscayne Pharmaceuticals, Inc., has announced that data supporting the anti-cancer potential of its growth hormone-releasing hormone (GHRH) technology was discussed in a poster presentation at the 2015 ASCO Annual Meeting. The data show that the family of receptors for GHRH, the target for Biscayne's anti-cancer GHRH blockers, is present on many primary breast cancer cells regardless of hormone receptor status. These findings suggest that GHRH antagonists could have broad anti-cancer potential in breast cancer.1
GHRH is primarily made in the brain and acts on the pituitary to produce the growth hormone needed for tissue growth and repair. Dr. Andrew V. Schally, a renowned drug researcher and Nobel laureate, discovered that cancer cells also make GHRH and have receptors for GHRH, thereby fueling their own growth. Biscayne Pharmaceuticals has licensed rights to Dr. Schally's GHRH discoveries and is developing GHRH antagonists that inhibit tumor growth by blocking the activity of the GHRH-family of receptors on cancer cells.
The study objective was to assess whether expression of the GHRH-type receptors differed across the major subtypes of breast cancer - estrogen or progesterone hormone receptor-positive (HR+), HER2-neu receptor-positive (HER2) and triple negative (TNBC) breast cancer, where the tumor lacks either estrogen, progesterone or HER2-neu receptors. Tumor specimens from 96 primary breast cancer patients that included the three subtypes were analyzed. The results showed that the GHRH-type receptors were highly expressed on the tumor cells of patients in all three subtypes, although the prevalence differed among the three--it was highly expressed in 92% of HER2, in 68% of HR+ and in 44% of TNBC cancers.
The authors conclude that the findings confirm that the majority of primary breast tumors express the GHRH receptor regardless of hormone receptor status, and they support continued development of therapeutic approaches using GHRH-type receptor antagonists, which have already shown significant efficacy with very good safety profiles in experimental cancer models.
Study co-author and Biscayne Medical Director, Norman Block, MD, who is also Clinical Director of the Endocrine, Polypeptide and Cancer Institute at the Veterans Affairs Medical Center in Miami and the L. Austin Weeks Family Professor of Urologic Research at the University of Miami Miller School of Medicine, commented, "This work expands on data we presented last year confirmining the presence of GHRH receptors in both primary and metastatic breast cancers. The new data shows that GHRH-type receptors are highly expressed across breast cancer subtypes regardless of hormonal status, further reinforcing the potentially broad application of GHRH blockers as novel treatments for breast cancer. Extensive preclinical studies make us confident that GHRH is an important driver of tumor growth, and these new data reinforce our commitment to advancing a GHRH antagonist into clinical trials next year."
Biscayne's GHRH antagonists are in preclinical development for the treatment of cancer. In xenograft studies, these antagonists have shown promising anti-tumor activity in a range of cancer types, and the company believes that its GHRH antagonists may therefore have therapeutic potential in many types of tumors, including breast cancer.