Vitamin D receptor (VDR) is a nuclear receptor that is activated by calcitriol, the active form of vitamin D. It is best known for regulating dietary calcium uptake necessary for bone growth, but it also affects cell proliferation and differentiation. Therefore, it was thought that treatment with calcitriol or its derivatives could be useful to treat the uncontrolled proliferation typical of cancer cells. However, this approach has been unsuccessful to date because it leads to toxic levels of calcium in the blood.

This invention relates to derivatives of calcitriol that can block cell growth without harmfully raising calcium levels. Specifically, these compounds act as antagonists of VDR blocking its ability to stimulate cell proliferation. This technology can be useful in treating breast cancer or other malignancies.