Emerging immunotherapies for prostate cancer

This review summarized evidence on emerging immunotherapies for prostate cancer. Authors concluded that immunotherapeutic agents show promising early results in patients with advanced prostate cancer and few symptoms.

Immunotherapies are currently under investigation as possible cancer treatments. Immunotherapies often come in the form of personalized vaccines. These boost the patient’s own immune system to recognize and destroy cancer cells. Immunotherapies are generally associated with fewer side effects than other cancer treatments, such as chemotherapy. A number of immunotherapeutic agents have been developed for prostate cancer with promising early results. Many are used to treat prostate cancer that continues to spread despite standard hormone therapy (also known as metastatic castration-resistant prostate cancer or mCRPC).

The aim of this review was to examine evidence on emerging immunotherapies for prostate cancer.

Sipuleucel-T (Provenge) is a therapeutic vaccine manufactured from the patient’s white blood cells. It is usually used to treat men with mCRPC with few cancer-related symptoms. One study involving 512 patients reported a significant survival advantage with sipuleucel-T (average survival 25.8 months) compared to placebo (average 21.7 months). A placebo is a control drug with no active effect. No differences in time to disease progression were noted between placebo and sipuleucel-T. Overall, sipuleucel-T was well-tolerated. Common side effects included chills, fever, and headache.

DCVAC/PCa is another therapeutic vaccine manufactured from the patient’s white blood cells. One early study involving 25 men with mCRPC found DCVAC/PCa to be well-tolerated when combined with chemotherapy. Common side effects included fatigue, back pain, and pins and needles. DCVAC/PCa plus chemotherapy was also associated with improved survival. Further studies comparing this combination therapy to placebo are ongoing.

BDCA-1 BDC-01 is a type of personalized peptide vaccination. One early study involving 12 men with mCRPC found it to be safe even when administered at higher doses. The most common side effects were fever and mild pain. The average survival in the 12 men treated with BDCA-1 BDC-01 was 18 months.

PROSTVAC is a type of immunotherapy drug that targets the prostate specific antigen (PSA), a protein that is over-produced in patients with prostate cancer. PROSTVAC stimulates the immune system to respond in a specific way. One study involving 125 mCRPC patients reported an 8.5-month survival advantage with PROSTVAC compared to placebo. Another study involving 104 patients found that 57% showed a significant increase in immune response (based on blood tests). Larger trials are currently ongoing.

Future and ongoing trials are examining the combination of immunotherapy with androgen deprivation therapy (blocking the male hormones, such as testosterone, often responsible for cancer growth) and chemotherapy.

Authors concluded that immunotherapeutic agents show promising early results in patients with advanced prostate cancer and few symptoms. Further studies are needed to evaluate the benefit of immunotherapy for prostate cancer.

Sipuleucel-T is the only immunotherapy drug currently approved by the FDA.