Prostate cancer is a malignant disease that affects the male reproductive system. The prostate, which is located below men’s bladder, near the rectum and around the urethra, is a walnut-like shaped and sized gland, and its main function is to produce a fluid that protects and nourishes sperm cells in semen, making the semen more liquid. Prostate cancer occurs when the cells in the prostate start to grow out of control, affecting both the urinary and reproductive systems.

Treatment options for prostate cancer include watchful waiting, surgery, radiation therapy, cryotherapy, hormone therapy, chemotherapy, vaccine treatment, and bone-directed treatment. Hormone therapy consists of reducing the levels of the male hormones androgens in order to stop cancer growth. It may be achieved through surgical castration or drugs like luteinizing hormone-releasing hormone (LHRH) analogs, and anti-androgens.

How Sipuleucel-T Works

Sipuleucel-T is one of the compounds used in hormone therapy for the treatment of patients with prostate cancer. “A cell-based vaccine composed of autologous antigen-presenting peripheral blood mononuclear cells (enriched for a dendritic cell fraction) that have been exposed to a recombinant protein consisting of granulocyte-macrophage colony-stimulating factor (GM-CSF) fused to prostatic-acid phosphatase (PAP), a protein expressed by prostate cancer cells. Upon administration, the vaccine may stimulate an antitumor T-cell response against tumor cells expressing PAP,” note the National Cancer Institute (NCI) Drug Dictionary.

The compound is considered a personalized treatment since the patient’s own immune cells are used and reprogramed to attack the cancer. The treatment takes six appointments and is designed for each patient. During a primary session, blood is collected from the patient in a process called leukapheresis or aphaeresis that takes three to four hours and takes place at a blood center. The immune cells found in the blood are then sent to an FDA-approved manufacturing facility to be made into a dose of sipuleucel-T. Each dose is delivered three days after the cell collection in a process that takes about two hours. The two phases of the treatment are repeated three times, which means that after six appointments the treatment is completed. The main purpose is not to lower patients’ PSA levels, but to help them live longer.

Sipuleucel-T to Treat Prostate Cancer

“On April 29, 2010, the Food and Drug Administration (FDA) approved sipuleucel-T (PROVENGE®, made by the Dendreon Corporation), an autologous cellular immunotherapy for the treatment of asymptomatic or minimally symptomatic metastatic castrate-resistant (hormone refractory) prostate cancer,” explain the NCI. The approval of the vaccine was based on a randomized double-blind placebo-controlled multicenter trial that included 512 patients and investigated the use of sipuleucel-T having overall survival as primary efficacy endpoint. The therapeutic option, which is delivered by the company Dendreon under the brand name Provenge, is particularly indicated for patients with metastatic castrate resistant prostate cancer.

Patients who were treated with sipuleucel-T had a median survival of 25.8 months compared to 21.7 months for patients who received the control treatment, which demonstrated the efficacy of sipuleucel-T in increasing patients’ life span. During the same study, investigators also reported the side effects associated with the treatment. Common adverse reactions reported included chills, fatigue, fever, back pain, nausea, joint ache, and headache, which were in the majority of the cases mild or moderate. Severe adverse events like acute infusion reactions or stroke occurred in 23.6% of patients, while life-threatening adverse events were observed in 4.0% of the patients and fatal adverse events in 3.3%.

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