Oral Minoxidil for the Treatment of Recurrent Platinum Resistant Epithelial Ovarian Cancer

Minoxidil is approved by the Food and Drug Administration (FDA) for treatment of hypertension. In previous studies, the sulfonylurea receptor (SUR) subunit controls the selectivity of the pharmacological response to drugs that either inhibit or stimulate the Kir6/SUR channel. Oral minoxidil acts as an activator of the Kir6/SUR2 channel upon selective binding to sulfonylurea receptor 2 (SUR2). Activation of the Kir6.2 potassium channel by minoxidil leads to potassium outflow and calcium entry which produces a cytoplasmic electrical charge that is more negative. This in turn creates an attractive force for calcium to enter the cell. Increased intracellular calcium disrupts mechanisms of cell division by arresting the cell cycle in G2/M phase and this is associated with alteration of the oxidative state, disruption of the mitochondria and activation of the caspase-3-independent cell death pathway.

Evaluation of arrest of tumor growth was evaluated in a previous study. This was done in vitro as well as in vivo by establishing a xenograft model from a Kir6.2/SUR2 positive high grade serous ovarian cancer cell line. In the mice treated with minoxidil, five of the 6 mice had no evidence of measurable disease at necropsy. In contrast, the untreated mice were found to have carcinomatosis and ascites in all 6 mice, demonstrating tumor reduction with minoxidil treatment.

While recurrent ovarian cancer can be treated with a multitude of drugs, the response rates are limited. Treatment options can also be limited secondary to myelosuppression as a result of patients being heavily pretreated. Minoxidil appears to have the advantage of not causing severe myelosuppression which can limit treatment options for patients. Laboratory results provide promising evidence that minoxidil could be used for the treatment of recurrent ovarian cancer.

This study plans to conduct a single center phase II study to evaluate the efficacy and safety of oral minoxidil in the treatment of platinum resistant ovarian cancer. The primary goal is to assess whether treatment with minoxidil will reduce tumor burden in patients with recurrent ovarian cancer and have a minimal toxicity profile.