Sylvester Comprehensive Cancer Center

DCC Funds at Work: Sylvester Scientists Repurpose FDA-Approved Drug to Treat Head and Neck Cancer


Dr. Donald Weed

Sylvester’s Dr. Donald Weed is
leading research into head and
neck cancers.

Tadalafil is a medicine that has been FDA-approved and on the market for the treatment of various diseases since 2003. It’s been prescribed for patients with erectile dysfunction, pulmonary hypertension, and for the treatment of certain prostate conditions. Now, scientists at Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine successfully used tadalafil in the treatment of patients with a type of head and neck cancer called “squamous cell carcinoma” (HNSCC).

Supported by funding from the DCC, Sylvester’s Donald T. Weed, M.D., a head and neck surgeon, and Paolo Serafini, Ph.D., an immunologist, have discovered that myeloid-derived suppressor cells and regulatory T cells – both are cells of the immune system – play a key role in the progression of HNSCC. They also found that an enzyme called “PDE5” modulates these immune system cells and can be inhibited using tadalafil.

In a single-center study conducted at Sylvester, Weed and his colleagues gave tadalafil to patients with HNSCC prior to surgery to remove their cancers and reported that the treatment was well tolerated and significantly reduced both myeloid-derived suppressor cell and regulatory T cell concentrations in the blood. This, in turn, made the HNSCC tumors more susceptible to destruction by the patients’ own immune systems.

Weed and Serafini have recently received FDA approval to move forward with a second trial in which they will treat patients who are undergoing surgery for cancers of the head and neck that have recurred after previous radiation therapy. These patients will receive tadalafil in combination with a tumor vaccine before and after surgery to enhance the immune system’s ability to destroy any microscopic cancer cells that might remain after surgery and, therefore, improve their chances of being cancer free.

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