Attendees at next week's European Society of Medical Oncology (ESMO) meeting in Milan will be presented with top-line Phase III Clinical Trials data on Abiraterone in the treatment of castration-resistant prostate cancer. This new drug is the latest breakthrough for the treatment of advanced cases and is the first-in-class intracrine androgen antagonist for patients whose cancer has stopped responding to androgen deprivation therapy (ADT).
“We are grateful to every researcher in the PCF family whose expertise touched the development of Abiraterone”
The development of Abiraterone is the result of a multinational effort supported by nearly $8.2 million in funding from the Prostate Cancer Foundation (PCF).
Scientists have long known that prostate cancer growth, survival and invasion are fueled by the male hormone testosterone. In cases of advanced, metastatic prostate cancer, physicians routinely prescribe ADT to stop production of testosterone and cut off the "fuel" for this cancer that affects more than 16 million men worldwide. However, during the course of treatment, many men become resistant to current androgen deprivation treatments and their disease recurs. Abiraterone has been shown to be effective in treating hormone-resistant or hormone-refractory cases. It blocks the formation of testosterone by inhibiting CYP17A1, an enzyme involved in the formation of testosterone that can occur at the site of metastatic tumor lesions.
"The data on Abiraterone is exciting and we hope to see final FDA approval soon," said Jonathan W. Simons, MD, president and CEO of PCF. "Clinicians will have a powerful new tool to stem the progression of prostate cancer and extend patients' lives. We are also encouraged that Phase I/II clinical trials evaluating Abiraterone acetate in advanced breast cancer patients are also underway, emphasizing how discoveries in one area of cancer research can provide benefits in others."
Results of two Phase II trials indicate that Abiraterone may reduce prostate specific antigen (PSA) levels, as well as shrink tumors. Phase II trials reported significant improvements in patients' quality of life and some were able to stop taking morphine, used to control the pain caused after the cancer spread into their bones. On average, progression-free survival was prolonged by 161 days in patients which had also been treated with chemotherapy, and by 236 days in chemotherapy naive patients.
In September 2010, an independent panel found that the interim results of the Phase III clinical trial were so successful that all patients who were receiving the placebo in the trial began receiving the drug. Additionally, Johnson & Johnson, the manufacturer of Abiraterone, will be allowed to make the drug available to some prostate cancer patients prior to final FDA approval through the FDA Compassionate Use Program.
PCF's nearly $8.2 million in support for the development of this new drug was provided via competitively-selected, non-corporate academic grants for research related to Abiraterone starting in 2006. Peter Nelson, MD, a PCF-funded research at the University of Washington and the Fred Hutchinson Cancer in Seattle first discovered the mechanism of action of Abiraterone in 2007. Dr. Nelson's findings sparked additional PCF funding in the form of two Challenge Awards and two Young Investigator Awards granted to researchers in his department.
In addition, the Prostate Cancer Clinical Trials Consortium, funded jointly by PCF and the U.S. Department of Defense at M. D. Anderson Cancer Center, Memorial Sloan-Kettering Cancer Center and Dana-Farber Cancer Institute, performed early clinical investigations of Abiraterone that accelerated the development of this promising medication.
"We are grateful to every researcher in the PCF family whose expertise touched the development of Abiraterone," said Howard R. Soule, chief scientist and executive vice president for PCF. "Moreover, we are thankful for the global clinical development efforts of Howard Scher, MD (Memorial Sloan-Kettering, New York), and Johann De Bono, MD (The Royal Marsden Hospital, London), who led the phase III investigation for Abiraterone."
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