(RxWiki News) Male hormones, called androgens, drive prostate cancer. When used to treat prostate cancer, hormone therapy is designed to lower androgen levels. Once prostate cancer no longer responds to this treatment, it’s called castration- or castrate-resistant prostate cancer.
A number of medications have been approved recently to treat castration-resistant prostate cancer, but most extend life only a few months.
A phase ll trial has shown promising results for an investigational oral medication to treat castration-resistant prostate cancer that has metastasized (spread) to the bone.
Tasquinimod stalled disease progression in advanced prostate cancers with bone metastasis by nearly nine months, according to the results of this trial.
These findings, if upheld in phase lll trials, could bring castration-resistant prostate cancer one step closer to becoming a chronic — rather than fatal — disease.
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Andrew J. Armstrong, MD, ScM, associate professor of medicine at the Duke Cancer Institute, directed this trial which looked at the safety and efficacy of tasquinimod, a new candidate for treating advanced and recurrent (returned) prostate cancer.
“In the past three years, there have been seven new agents approved for use in advanced prostate cancer," prostate cancer expert, E. David Crawford, MD, told dailyRx News.
"All of these agents have different modes of action and many of us are optimistic that there is a light at the end of the tunnel with this disease. Hope exists that combining these agents may convert castration resistant prostate cancer into a chronic disease," said Dr. Crawford, who is a professor of surgery, urology and radiation oncology and head of the Section of Urologic Oncology at the University of Colorado Health Sciences Center (UCHSC) in Denver.
The following are the seven recently approved medications Dr. Crawford mentioned:
- sipuleucel-T (brand name Provenge), an immunotherapy medication designed to boost the immune system’s power to fight off the cancer
- docetaxel (brand names Docefrez and Taxotere) and cabazitaxel (brand name Jevtana), which are chemotherapy agents
- abiraterone acetate (brand name Zytiga) and enzalutamide (brand name Xtandi), hormonal medications that block androgens (male hormone including testosterone) that feed prostate cancer
- denosumab (brand name Xgeva) and radium Ra 223 dichloride (brand name Xofigo), which are targeted therapies.
Tasquinimod falls into the class of immunologics, which activate the body’s immune system to fight the cancer.
The mechanism by which tasquinimod works is not fully understood, but it is known to block tumor blood vessel growth, which stimulates tumor growth — a process known as angiogenesis.
For this trial, 201 men with metastatic castration-resistant prostate cancer were randomly assigned to receive tasquinimod (134) or a placebo (67). The participants were followed for three years.
Men who received tasquinimod had progression-free survival (PFS) of 7.6 months, compared to 3.3 months for men who took the placebo.
PFS is a measure of the time during which the disease does not get worse.
Men in the treatment group, whose cancer had metastasized to the bone, had PFS of 8.8 months, compared to 3.4 months among those in the placebo group.
Men were able to switch to the treatment group once signs of progression appeared.
In terms of overall survival, those taking tasquinimod lived an average of 33.4 months, and those taking a placebo lived about 30.4 months.
Participants with bone metastasis who received tasquinimod lived an average of 34.7 months, compared to an overall survival of 27.1 months for men who received placebo.
Tasquinimod was considered safe, with side effects including low or moderate gastrointestinal issues, joint and muscle pain and fatigue.
Dr. Crawford said these early trial findings are encouraging.
“And now there is more reason for optimism from a large randomized phase II trial with an agent that may work in an immunological and antiagiogenic pathway. However, there have been at least 10 promising agents from randomized phase II trials that did not make it. Let's hope the follow-up phase III pivotal trial on this one is a positive one,” Dr. Crawford said.
Trial findings were published November 19 in the journal Clinical Cancer Research.
The research was funded by Active Biotech, which is developing tasquinimod in partnership with Ipsen.
A number of the authors have financial ties with Active Biotech, and two of the authors are employees of the company.