Glossary
Immunotherapy
In 2010, Prostate Oncology Specialists published an abstract form the results of 24 men on intermittent TIP who received the combination of Leukine, Celebrex and low-dose Cytoxan during their holiday period after an initial course of TIP. Fourteen of the 24 men on this combination had more than a 100% slowing in their PSA doubling time. In the 14 responders the median doubling time before treatment was five months. The median doubling time while on immune therapy was 24 months.
Celebrex, a potent Cox-2 inhibitor, is FDA-approved for arthritis treatment. Several small studies have evaluated Celebrex administered to men with cancer recurring after surgery or radiation. These studies show a significant slowing in the rate of disease progression. Low-dose Cyclophosphamide, otherwise known as Cytoxan, functions by inhibiting the regulatory cells of the immune system - the T-Regulatory cells. When the regulatory cells are inhibited the net effect is increased immune activity. Cytoxan is usually free of side effects at very low usage doses. Leukine stimulates the proliferation of macrophages, a type of white blood cell that fights cancer.
More recently, we have added Revlimid 5 mg on a 21 out of 28 day protocol to the other medications cited in the previous paragraph and though we have yet to perform a formal analysis, results seem improved. Revlimid's immune effects appear to be mediated by the inhibition of proinflamitory cytokines.
Provenge
Provenge is the first FDA approved treatment for prostate cancer as two randomized prospective trials show longer survival. It consists of three visits every two weeks to a specialized center to undergo plasmapharesis, an experience sort of like undergoing kidney dialysis. Plasmapharesis removes immune cells from the blood which are specially enhanced in the laboratory. These enhanced cells are then reinfused a couple days after the plasmapharesis. Side effects are modest consisting of mild chills and fevers in some patients. Insurance coverage is limited to patients with documented metastasis who are castration resistant and who have rising PSA levels.
Ipilimumab
Ipilimumab is an immunotherapeutic agent being studied for its potential to "turn on" the immune system enabling the immune system to attack and kill cancer cells. Ipilimumab is an antibody that potentiates natural antitumor responses by blocking inhibitory T cells. This drug showed antitumor effects in prostate cancer and is FDA approved for the treatment of malignant melanoma. Studies indicate that radiation in combination with Ipilimumab may increase tumor immunogenicity and enhance the anticancer effect. Some experts speculate that Ipilimumab may also enhance the anticancer effects of other immune treatments such as Provenge. Preliminary studies at the Mayo Clinic have shown surprisingly good results by combining Ipilimumab with TIP in men who were recently diagnosed with fairly advanced prostate cancer.
