HIV Drug, Nelfinavir, Inhibits The Growth Of HER2+ Breast Cancer

By Dr. Kathleen T. Ruddy

Protease inhibitors are used to prevent progression to AIDS in patients infected with HIV.  A recent study conducted at the Johns Hopkins School of Medicine revealed that one of these protease inhibitors, nelfinavir, effectively inhibits the growth of HER2+ breast cancer cells, and also inhibits the growth HER2+ human breast tumors transplanted in mice.  Clinical trials using nelfinavir can now begin to see if it is similarly effective in treating women with HER2+ breast cancer.

What is HER2?

HER2 is a human epidermal growth factor receptor that increases the growth of breast cancer cells.

What percentage of women are diagnosed with HER2+ breast tumors?

Approximately 15-20% of women are diagnosed with HER2+ breast cancer.

How is HER2+ breast cancer different from other forms of breast cancer?

HER2+ tumors are highly aggressive and are associated with a higher risk of recurrence and death than tumors that express hormone receptors such as estrogen or progesterone.

What forms of treatment are effective for use in women with HER2+ breast tumors?

In addition to traditional forms of chemotherapy, targeted therapies with drugs like Herceptin can delay recurrence and increase survival for women with HER2+ breast cancer.

How did scientists at Johns Hopkins identify HER2+ tumors as potential targets for treatment with the HIV protease inhibitor drug, nelfinavir?

Dr. Joong Sup Shim discovered that nelfinavir inhibited the growth of HER2+ breast cancer cells and HER2+ human breast tumors transplanted in mice.  The results of his experiments were strongly positive, indicating a likely benefit of nelfinavir for use in women with HER2+ breast cancer.  Dr. Shim also discovered that nelfinavir was effective against HER2+ tumors that were resistant to Herceptin.

Will it be necessary to alter the dose of nelfinavir in human trials of women with HER2+ breast cancer compared to the dose used to treat patients with HIV?

No.  The same dose regimen used to treat patients with HIV can be used to test the efficacy of nelfinavir in women with HER2+ breast cancer.  Of note, nelfinavir has been extensively tested in humans and is associated with a low risk for dangerous side effects.

What can we conclude from Dr. Shim’s study of nelfinavir in HER2+ tumors?

Nelfinavir used in doses equivalent to those used to treat HIV in humans is effective in inhibiting the growth of HER2+ breast cancer cells and human breast cancer tumors transplanted in mice, and is ready for testing to see if it is similarly effective for use in treating women with HER2+ breast cancer.

REFERENCE

Joong Sup Shim, et al. “Selective Inhibition of HER2-Positive Breast Cancer Cells by the HIV Protease Inhibitor Nelfinavir”, J National Cancer Institute, October 5, 2012