Post by Allen on Aug 4, 2014 17:38:45 GMT -8
IMMUNOTHERAPIES
The immune system is diverse, and still largely a mystery. We don't know why some immunotherapies that work for other cancers, don't work for prostate cancer, and vice versa. Provenge is the only immunotherapy that is FDA-approved for asymptomatic and minimally symptomatic mCRPC. It's best use may prove to be earlier use, possibly before castrate resistance, mets, or even surgical or radiation therapy. Clinical trials are examining earlier use. Meanwhile, it can be prescribed for earlier use, but it is very costly, and insurance isn't likely to cover those off-label uses.
Prostvac-VF, GVAX & DVAC, to name a few, are still in active clinical trials, while TroVax has been abandoned. Yervoy (ipilimumab) is FDA-approved for melanoma, but not yet for prostate cancer. It's expense is prohibitive for the 99%. There are various clinical trials for all kinds of combinations (e.g., Provenge + Yervoy).
Other than Yervoy and early use of Provenge, there are several immunotherapies that could be prescribed off label.
Cyclophosphamide
Low doses have been used effectively in other cancers. High dose cyclophosphamide has a paradoxical effect in that it suppresses the immune system and has been used with autoimmune diseases. Metronomic dosing - frequent very low doses, seems to maximize safety and efficacy. There have been several published studies about its use with PC that have demonstrated efficacy and safety. I don't know why it isn't used more often.
• Clinical outcome of patients with docetaxel-resistant hormone-refractory prostate cancer treated with second-line cyclophosphamide-based metronomic chemotherapy
• Metronomic Oral Cyclophosphamide Chemotherapy Possibly Contributes to Stabilization of Disease in Patients With Metastatic Castration-Resistant Prostate Cancer: A Prospective Analysis of Consecutive Cases
• Docetaxel plus oral metronomic cyclophosphamide: A phase II study with pharmacodynamic and pharmacogenetic analyses in castration-resistant prostate cancer patients.
• Oral cyclophosphamide for the management of hormone-refractory prostate cancer.
• Oral low-dose cyclophosphamide in metastatic hormone refractory prostate cancer (MHRPC)
• Oral/metronomic cyclophosphamide-based chemotherapy as option for patients with castration-refractory prostate cancer – Review of the literature
• Major Response to Cyclophosphamide and Prednisone in Recurrent Castration-Resistant Prostate Cancer - a single case study
IL-2
Interleukine-2 is a cytokine produced by T-cells in response to foreign bodies. It signals killer T cells and other antigen-specific lymphocytes to attack, creating the immune system's memory. It is also responsible for distinguishing self from non-self. It is highly toxic, and has been used to attack melanoma and renal cell carcinoma. It is approved for that use and sold under the brand name Proleukin. However, with metronomic dosing, it seems to be much safer, and has shown an anti-PSA response when a PSA-honing virus and radiation were used with it (see below for radioimmunotherapy):
• Safety and Immunologic Response of a Viral Vaccine to PSA in Combination with Radiation Therapy when Metronomic-Dose IL-2 Is Used as an Adjuvant
GM-CSF
Granulocyte Macrophage - Colony Stimulating Factor (GM-CSF) is an immune stimulant sold as Leukine (sargramostim). It is part of Provenge treatment, which is a mixture of immunological agents. It is also part of the experimental immunological agent GVAX, and may find use with several other immunological combos, including IL-2. It may reduce the incidence of febrile neutropenia, a potentially fatal side effect of chemotherapy. It seems to have significant PSA-reducing effects when used as a single agent; however, it does not always generate an immune response on its own, and the adaptive immune system may eventually overcome an initial response. A trial combining GM-CSF and Yervoy (Yervoy mitigates the adaptive immune response) demonstrated a 35% increase in overall survival vs men taking Yervoy alone in men with melanoma.
• Therapy of Advanced Prostate Cancer with Granulocyte Macrophage Colony-stimulating Factor1
• Prostate-Specific Antigen Kinetics as a Measure of the Biologic Effect of Granulocyte-Macrophage Colony-Stimulating Factor in Patients With Serologic Progression of Prostate Cancer
• Clinical and Immunological Characteristics of Patients With Serologic Progression of Prostate Cancer Achieving Long-Term Disease Control With Granulocyte-Macrophage Colony-Stimulating Factor
Radioimmunotherapy
There have been case studies that have noted that cancers may disappear in parts of the body far afield of the radiation treatment area. This is called the abscopal effect, and is thought to be mediated by the immune system. All kinds of radiation therapy and ADT have been found to stimulate an immune response.
Here are some references:
• Combining radiation and immunotherapy for synergistic antitumor therapy (Review)
• Clinical opportunities in combining immunotherapy with radiation therapy
• Combining radiotherapy and immunotherapy: a revived partnership.
• Enhancement of T Cell Responses as a Result of Synergy between Lower Doses of Radiation and T Cell Stimulation
• Tumor Vaccination Combined With Radiation Therapy Mitigates Development and Progression of Metastatic Prostate Cancer
• Combined Treatment Effects of Radiation and Immunotherapy: Studies in an Autochthonous Prostate Cancer Model
• Radiation Therapy Alters Tumor Cell Phenotypes and Enhances the Immune Response
• Radiation-induced immunogenic modulation of tumor enhances antigen processing and calreticulin exposure, resulting in enhanced T-cell killing
• Radiation-induced modulation of costimulatory and coinhibitory T-cell signaling molecules on human prostate carcinoma cells promotes productive antitumor immune interactions.
• Regulatory T cells in radiotherapeutic responses
Hypofractionation enhances radioimmunological Effect
The radioimmunological effect is maximized by hypofractionated radiation (SBRT or HDR brachy). This creates a unique opportunity when mets are irradiated, either singly or with oligometastatic disease. Taking an immune stimulant and ADT (see below) before SBRT to the mets will maximize the abscopal effect. The same can be said about initial SBRT or HDR brachy to the prostate during initial treatment for high risk PC.
• Radiation as an immunological adjuvant: current evidence on dose and fractionation
• Maximizing Tumor Immunity with Fractionated Radiation.
• Fractionated but not single dose radiotherapy induces an immune-mediated abscopal effect when combined with anti-CTLA-4 antibody
Androgen Ablation with Immunotherapy
In most cases, ADT will be used before, during and after immunotherapy. It is worth noting that ADT seems to enhance the immunological effects.
• Combining immunological and androgen-directed approaches: an emerging concept in prostate cancer immunotherapy
The immune system is diverse, and still largely a mystery. We don't know why some immunotherapies that work for other cancers, don't work for prostate cancer, and vice versa. Provenge is the only immunotherapy that is FDA-approved for asymptomatic and minimally symptomatic mCRPC. It's best use may prove to be earlier use, possibly before castrate resistance, mets, or even surgical or radiation therapy. Clinical trials are examining earlier use. Meanwhile, it can be prescribed for earlier use, but it is very costly, and insurance isn't likely to cover those off-label uses.
Prostvac-VF, GVAX & DVAC, to name a few, are still in active clinical trials, while TroVax has been abandoned. Yervoy (ipilimumab) is FDA-approved for melanoma, but not yet for prostate cancer. It's expense is prohibitive for the 99%. There are various clinical trials for all kinds of combinations (e.g., Provenge + Yervoy).
Other than Yervoy and early use of Provenge, there are several immunotherapies that could be prescribed off label.
Cyclophosphamide
Low doses have been used effectively in other cancers. High dose cyclophosphamide has a paradoxical effect in that it suppresses the immune system and has been used with autoimmune diseases. Metronomic dosing - frequent very low doses, seems to maximize safety and efficacy. There have been several published studies about its use with PC that have demonstrated efficacy and safety. I don't know why it isn't used more often.
• Clinical outcome of patients with docetaxel-resistant hormone-refractory prostate cancer treated with second-line cyclophosphamide-based metronomic chemotherapy
• Metronomic Oral Cyclophosphamide Chemotherapy Possibly Contributes to Stabilization of Disease in Patients With Metastatic Castration-Resistant Prostate Cancer: A Prospective Analysis of Consecutive Cases
• Docetaxel plus oral metronomic cyclophosphamide: A phase II study with pharmacodynamic and pharmacogenetic analyses in castration-resistant prostate cancer patients.
• Oral cyclophosphamide for the management of hormone-refractory prostate cancer.
• Oral low-dose cyclophosphamide in metastatic hormone refractory prostate cancer (MHRPC)
• Oral/metronomic cyclophosphamide-based chemotherapy as option for patients with castration-refractory prostate cancer – Review of the literature
• Major Response to Cyclophosphamide and Prednisone in Recurrent Castration-Resistant Prostate Cancer - a single case study
IL-2
Interleukine-2 is a cytokine produced by T-cells in response to foreign bodies. It signals killer T cells and other antigen-specific lymphocytes to attack, creating the immune system's memory. It is also responsible for distinguishing self from non-self. It is highly toxic, and has been used to attack melanoma and renal cell carcinoma. It is approved for that use and sold under the brand name Proleukin. However, with metronomic dosing, it seems to be much safer, and has shown an anti-PSA response when a PSA-honing virus and radiation were used with it (see below for radioimmunotherapy):
• Safety and Immunologic Response of a Viral Vaccine to PSA in Combination with Radiation Therapy when Metronomic-Dose IL-2 Is Used as an Adjuvant
GM-CSF
Granulocyte Macrophage - Colony Stimulating Factor (GM-CSF) is an immune stimulant sold as Leukine (sargramostim). It is part of Provenge treatment, which is a mixture of immunological agents. It is also part of the experimental immunological agent GVAX, and may find use with several other immunological combos, including IL-2. It may reduce the incidence of febrile neutropenia, a potentially fatal side effect of chemotherapy. It seems to have significant PSA-reducing effects when used as a single agent; however, it does not always generate an immune response on its own, and the adaptive immune system may eventually overcome an initial response. A trial combining GM-CSF and Yervoy (Yervoy mitigates the adaptive immune response) demonstrated a 35% increase in overall survival vs men taking Yervoy alone in men with melanoma.
• Therapy of Advanced Prostate Cancer with Granulocyte Macrophage Colony-stimulating Factor1
• Prostate-Specific Antigen Kinetics as a Measure of the Biologic Effect of Granulocyte-Macrophage Colony-Stimulating Factor in Patients With Serologic Progression of Prostate Cancer
• Clinical and Immunological Characteristics of Patients With Serologic Progression of Prostate Cancer Achieving Long-Term Disease Control With Granulocyte-Macrophage Colony-Stimulating Factor
Radioimmunotherapy
There have been case studies that have noted that cancers may disappear in parts of the body far afield of the radiation treatment area. This is called the abscopal effect, and is thought to be mediated by the immune system. All kinds of radiation therapy and ADT have been found to stimulate an immune response.
Here are some references:
• Combining radiation and immunotherapy for synergistic antitumor therapy (Review)
• Clinical opportunities in combining immunotherapy with radiation therapy
• Combining radiotherapy and immunotherapy: a revived partnership.
• Enhancement of T Cell Responses as a Result of Synergy between Lower Doses of Radiation and T Cell Stimulation
• Tumor Vaccination Combined With Radiation Therapy Mitigates Development and Progression of Metastatic Prostate Cancer
• Combined Treatment Effects of Radiation and Immunotherapy: Studies in an Autochthonous Prostate Cancer Model
• Radiation Therapy Alters Tumor Cell Phenotypes and Enhances the Immune Response
• Radiation-induced immunogenic modulation of tumor enhances antigen processing and calreticulin exposure, resulting in enhanced T-cell killing
• Radiation-induced modulation of costimulatory and coinhibitory T-cell signaling molecules on human prostate carcinoma cells promotes productive antitumor immune interactions.
• Regulatory T cells in radiotherapeutic responses
Hypofractionation enhances radioimmunological Effect
The radioimmunological effect is maximized by hypofractionated radiation (SBRT or HDR brachy). This creates a unique opportunity when mets are irradiated, either singly or with oligometastatic disease. Taking an immune stimulant and ADT (see below) before SBRT to the mets will maximize the abscopal effect. The same can be said about initial SBRT or HDR brachy to the prostate during initial treatment for high risk PC.
• Radiation as an immunological adjuvant: current evidence on dose and fractionation
• Maximizing Tumor Immunity with Fractionated Radiation.
• Fractionated but not single dose radiotherapy induces an immune-mediated abscopal effect when combined with anti-CTLA-4 antibody
Androgen Ablation with Immunotherapy
In most cases, ADT will be used before, during and after immunotherapy. It is worth noting that ADT seems to enhance the immunological effects.
• Combining immunological and androgen-directed approaches: an emerging concept in prostate cancer immunotherapy