Buffalo, NY — Men with metastatic prostate cancer who received the new biologic agent tasquinimod (TASQ) saw their progression-free survival time double compared to men who received a placebo, according to initial findings of a phase II clinical study to be presented by Roberto Pili, MD, Professor of Oncology and Co-leader of the Genitourinary Program at Roswell Park Comprehensive Cancer Center, at the 46th annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago on Sunday, June 6.
The multicenter, international trial involving researchers and patients in the United States and Sweden was sponsored by the Swedish pharmaceutical company Active Biotech, which manufactures TASQ. “The mechanism of action is still unclear, but it appears to be twofold,” explains Dr. Pili, the study’s principal investigator. “The compound may work as an angiogenesis inhibitor, disrupting the formation of new blood vessels to the tumor, which the tumor needs to grow. In addition, it may act as an immuno-modulator, enhancing the body’s immune response to the cancer.”
For the study, 200 men with a median age of 72.5 years were randomly assigned, at a ratio of two to one, respectively, to receive either TASQ or placebo. The patients all had metastatic castrate-resistant prostate cancer. They had received hormonal therapy to shut down the body’s production of testosterone but their disease continued to progress. The patients had not yet received chemotherapy, and were considered asymptomatic when enrolled.
In the treatment group, 133 men took a daily oral dose of TASQ, beginning with an initial dose level of 0.25 milligrams (mg) per day and escalating to 1.0 mg per day over four weeks. In the control group, 67 men took a placebo. After six months, 57 percent of the patients receiving TASQ showed no disease progression compared to 33 percent of patients receiving the placebo.
The duration of time that the patients treated with TASQ remained progression-free was nearly double — 24.7 weeks, compared to 12.9 weeks for the control group. Disease progression was determined with the use of bone scans, CT scans and whether the patient had any symptoms such as pain or fatigue, but excluded PSA levels.
Although PSA screening remains a vital tool for early prostate cancer detection, this study “confirms that PSA does not seem to be an optimal marker or predictor of response to treatment,” says Dr. Pili. “PSA may go up or remain stable, but the patient still benefits from the agent.”
Another promising finding: TASQ’s beneficial effect was the same no matter where the cancer had spread. “Patients had disease in their bones, lymph nodes or other organs,” says Dr. Pili, “but we saw the same response to treatment regardless of where the cancer had metastasized.”
Side effects were slightly more prevalent in the treatment group and included serious vascular events such as myocardial infarction, heart failure, or stroke (3 percent compared to 0 percent) and deep vein thrombosis (4 percent compared to 0 percent). More common side effects included gastrointestinal disorders, fatigue, musculoskeletal pains and asymptomatic elevation of pancreatic enzymes and proinflammatory markers.
“Tasquinimod may be considered a bridge between hormonal therapy and chemotherapy,” says Dr. Pili, “and overall it seems to be less toxic than chemotherapy. While our results are encouraging, TASQ’s early promise will need to be borne out in future clinical studies.”
The mission of Roswell Park Comprehensive Cancer Center is to understand, prevent and cure cancer. Roswell Park, founded in 1898, was one of the first cancer centers in the country to be named a National Cancer Institute-designated comprehensive cancer center and remains the only facility with this designation in Upstate New York. The Institute is a member of the prestigious National Comprehensive Cancer Network, an alliance of the nation’s leading cancer centers; maintains affiliate sites; and is a partner in national and international collaborative programs. For more information, visit Roswell Park’s website at www.roswellpark.org, call 1-800-ROSWELL (1-800-767-9355) or email AskRoswell@Roswellpark.org.
Editor's note: Dr. Pili's presentation, "A randomized multicenter international phase II study of tasquinimod in chemotherapy-naïve patients with metastatic castrate-resistant prostate cancer (CRPC)," part of the Genitourinary Prostate Oral Abstract Session, is set to begin at 11:45 am in E Hall, Room D2, of McCormick Place.
Annie Deck-Miller, Senior Media Relations Manager