Madison Vaccines Announces Patient Dosing Underway in Clinical Trial Pairing Its Lead Prostate Cancer Vaccine, MVI-816, with PD1 Inhibitor Pembrolizumab

--Trial Will Test Potential Synergy of the Two Immunomodulatory Approaches on Men with Metastatic, Castrate-Resistant Prostate Cancer--

--Trial Underway at the University of Wisconsin-Madison--

August 19, 2015 08:03 AM Eastern Daylight Time
MADISON, Wis.--(BUSINESS WIRE)--Madison Vaccines Incorporated (MVI) today announced dosing has begun in a combination trial for MVI-816 (pTVG-HP), its lead prostate cancer vaccine, paired with pembrolizumab (Keytruda®), a PD-1 inhibitor, also called a checkpoint inhibitor. A PD-1 inhibitor works by exposing cancer cells to attack by the immune system by preventing the cancer cells from blocking an effective immune response. MVI-816, already in a Phase 2 clinical trial as monotherapy, has been shown to induce persistent T-cell responses in prostate cancer patients. The combination trial will test the hypothesis that both treatments work together synergistically. The first-of-its kind combination to reach this stage will be tested in men with metastatic, castrate-resistant prostate cancer, and will be conducted at the University of Wisconsin – Madison, Carbone Cancer Center under the direction of Douglas McNeel, MD, PhD, a leading prostate cancer researcher at the university.

Richard Lesniewski, PhD, President of MVI noted, "Immunomodulatory drugs such as PD-1 inhibitors made headlines again at this year's global ASCO cancer conference. However, in prostate cancer, they have failed to produce a clinical response. We believe this trial may show that combining a PD-1 inhibitor with our MVI-816 vaccine will unleash the potential of immunomodulators in patients in the late stages of this disease."

MVI-816 is a plasmid DNA vaccine that can be delivered to patients by simple intradermal injection. It targets prostatic acid phosphatase (PAP), a well-defined prostate antigen and is now in a Phase 2 clinical trial in patients with early biochemically recurrent prostate cancer to delay the onset of metastatic disease after primary therapy. Currently, the standard of care for these men is active surveillance (watch and wait), a potentially risky decision for men with rapidly increasing PSA, or to move ahead with surgical or chemical castration (Androgen Deprivation Therapy).

The new combination trial, testing a two-pronged immune activation in late stage prostate cancer, could increase the utility of the vaccine and may advance the timetable for demonstrating its clinical efficacy. Support for the trial is provided by MVI and an award from the Prostate Cancer Foundation.

MVI also plans to initiate a trial for its second prostate cancer vaccine, MVI-118, a vaccine targeting the androgen receptor intended to address treatment resistance and disease progression in metastatic prostate cancer.

About MVI

Wisconsin-based MVI is developing two plasmid DNA vaccines to treat men with prostate cancer. MVI has licensed patented technologies that were developed in the laboratory of Dr. Douglas McNeel at the University of Wisconsin-Madison. More information is available at

Madison Vaccines Incorporated
Richard Lesniewski, PhD, 610-850-4697
Initiate PR
Andrew Viegas, 424-371-9600