#2 - Immunotherapy Using Modified Self Tumor Cells
Title: Cancer Immunotherapy Using Oligonucleotides Conjugated to Apoptotic Tumor Cells
NIH Reference No.: E-266-2009
Executive Summary:
General Description
The goal of cancer immunotherapy is to use a patient’s own immune system to recognize and reject tumor cells. Much of the current strategies for cancer immunotherapy target well-defined tumor-associated antigens (TAAs) presented in tumors. Unfortunately, the results of this type of immunotherapy are limited and inconsistent. Many tumors lack these TAAs and those that do contain the targeted TAAs may differ in the levels of expression. There remains a need for a more widely useful strategy for cancer immunotherapy. In theory, a vaccine that contains a patient’s own tumor cells should elicit an immune response against those TAAs that are best processed, presented, and recognized by that individual’s immune system. Using this method would eliminate the need to pre-identify and target specific TAAs that are present in individual tumors. However, in practice, whole killed tumor cell vaccines are poorly immunogenic, they fail to induce a protective immunity and, in some cases, even induce tolerance. A variety of immune modifiers and co-stimulatory agents have been added to whole tumor vaccines in an attempt to enhance the immune recognition and response. This strategy does improve the immunogenicity of tumor vaccines but unfortunately has not been effective in treating tumors of clinically relevant size or metastatic disease. Synthetic oligodeoxynucleotides (ODN) containing unmethylated Cytosine-Guanine (CpG) motifs stimulate the immune system via toll-like receptor 9 in a way that mimics the activity of bacterial DNA. As a result, CpG ODN are finding use as vaccine adjuvants, where they increase the speed, magnitude and duration of vaccine-specific immune responses. However, simply adding CpG ODN to whole tumor vaccines does not have an effect on tumor growth
Scientific Progress
NCI investigators have discovered that by cross-linking ODN with the target antigen, they can increase the observed immunity up to 100-fold compared to simply mixing ODN with the immunogen. CpG ODN was chemically conjugated to apoptotic tumor cells and then administered to mice either pre- or post-challenge with viable tumor cells. The data generated was from 5-10 mice per experiment, repeated 2-3 times. Initial studies measured the effect of the CpG-conjugated apoptotic tumor cell vaccines on the in vivo growth of prostate cancer cells (TRAMP C-1) in mice. The animals that were pre-treated with TRAMP C-1 cells were immunized with CpG-conjugated to TRAMP C-1 apoptotic cells once the tumors had reached clinically detectable size. Immunization generated strong cellular responses against the established tumor (P < 0.01) and significantly slowed the growth of established TRAMP C-1 tumors in vivo (P < 0.01 vs. unvaccinated animals). The inventors also studied the effect of CpG-conjugated tumor cell vaccines on 4T1 mammary carcinoma in mice. After allowing the tumor to grow to greater than 1 cm in diameter, the tumor was surgically removed and the mice were vaccinated. Mice vaccinated post-surgery with CpG-conjugated 4T1 cells were completely protected against metastasis (P < 0.05)
Future Direction
Strengths
Weaknesses
Patent Status
US Patent Application 13/581,999 filed 1 Mar 2011 Google Patent
Relevant Publications
Shirota H, Klinman DM; Cancer Immunol Immunother. 2011, 60: 659-669. (PMID: 21318638)
Inventor Bios
Dennis Klinman, M.D., Ph.D.
Dr. Klinman received his MD/PhD from the University of Pennsylvania, and completed his fellowship training in Rheumatology at the National Institute of Arthritis, NIH. He headed the Section of Viral Immunology at the Center for Biologics Evaluation and Research of the FDA before joining the Laboratory of Experimental Immunology of the National Cancer Institute as chief of the Immunoregulation Group. He has authored over 250 peer reviewed articles, received of the FDA's 'Outstanding Scientist of the Year' Award, the 'Outstanding Achievement Award In Biology' from the Washington Academy of Science, and 'Meritorious', 'Outstanding' and 'Distinguished' Service Medals from the Public Health Service, among other honors
Hidekazu Shirota, M.D., Ph.D.
Biography
Dr. Hidekazu Shirota obtained his M.D. from Fukushima Medical University, Japan in 1996 and his Ph.D. from Tohoku University, Japan in 2002. His research at Tohoku University focused on regulating allergic inflammation with immunomodulatory CpG oligonucleotides (ODN) with Drs. Sano and Tamura. In 2002, he pursued postdoctoral studies at the Center for Biologics Evaluation and Research of the FDA with Dr. Klinman and then was a staff scientist in the Laboratory of Experimental Immunology of the NCI until 2012. He is currently associate professor in department of clinical oncology at Tohoku University, Japan
Research Focus
He has been studying the mechanisms of action and therapeutic potential of the immuno-stimulatory CpG and suppressive ODN, especially vaccine development using CpG ODN for allergy, infectious pathogen and tumors. His recent findings shows that conjugating CpG ODN to killed tumor cells significantly improves the immunogenicity of the tumor cell vaccine and induces an immune response that prevents tumor growth. Two benefits derived from this unique strategy: 1) it overcomes the limited activity of free CpG ODN to improve vaccine activity by insuring that the ODN remains associated with the tumor antigen so that both are internalized by professional antigen presenting cells and 2) it eliminates the need to define specific tumor-associated antigens, substituting instead the entire tumor cell (which in the absence of CpG ODN is poorly immunogenic). Thus, this tumor vaccine design uses the strategy of conjugating CpG ODN to apoptotic/killed tumor cells to achieve the goal of accelerating and boosting the induction of tumor-specific immunity
This vaccine idea is based on our recent finding: `CpG-conjugated allergen ameliorate allergic inflammation`. This technology was translated to human clinical trials and has a proven similar effects in allergic patients. CpG ODN coupled to ragweed allergen reduced the responsiveness of immune cells in the nasal cavity to allergen stimulation and reduced disease severity for two seasons
NIH Reference No.: E-266-2009
Executive Summary:
- Category: Therapeutic
- Disease Focus: Cancer treatment, broadly, by slowing the growth of tumors and preventing metastasis following surgery
- Basis of Invention: Tumor Cells
- How it works: Uses an immunotherapeutic linked to patient tumor cells to enhance a patient’s immune reaction to cancer
- Patent Status: U.S. Patent Pending
- Lead Inventor: Dennis Klinman, M.D., Ph.D.
- Development Stage: Preclinical in mice, tested both pre- and post-immunization with viable tumor cells from four different cancer cell lines
- Novelty: Personalized medicine with immune system stimulators conjugated to apoptotic tumor cells specific to the individual undergoing treatment. Therapy can be generated from a biopsy sample as it only requires a small amount of cells to create therapy
- Clinical Application: Could be administered to tumor-presenting patients to reduce tumor size, to prevent recurrence and metastasis following surgical resection of tumors, or to prevent tumor development in patients at risk of developing certain types of cancer
General Description
The goal of cancer immunotherapy is to use a patient’s own immune system to recognize and reject tumor cells. Much of the current strategies for cancer immunotherapy target well-defined tumor-associated antigens (TAAs) presented in tumors. Unfortunately, the results of this type of immunotherapy are limited and inconsistent. Many tumors lack these TAAs and those that do contain the targeted TAAs may differ in the levels of expression. There remains a need for a more widely useful strategy for cancer immunotherapy. In theory, a vaccine that contains a patient’s own tumor cells should elicit an immune response against those TAAs that are best processed, presented, and recognized by that individual’s immune system. Using this method would eliminate the need to pre-identify and target specific TAAs that are present in individual tumors. However, in practice, whole killed tumor cell vaccines are poorly immunogenic, they fail to induce a protective immunity and, in some cases, even induce tolerance. A variety of immune modifiers and co-stimulatory agents have been added to whole tumor vaccines in an attempt to enhance the immune recognition and response. This strategy does improve the immunogenicity of tumor vaccines but unfortunately has not been effective in treating tumors of clinically relevant size or metastatic disease. Synthetic oligodeoxynucleotides (ODN) containing unmethylated Cytosine-Guanine (CpG) motifs stimulate the immune system via toll-like receptor 9 in a way that mimics the activity of bacterial DNA. As a result, CpG ODN are finding use as vaccine adjuvants, where they increase the speed, magnitude and duration of vaccine-specific immune responses. However, simply adding CpG ODN to whole tumor vaccines does not have an effect on tumor growth
Scientific Progress
NCI investigators have discovered that by cross-linking ODN with the target antigen, they can increase the observed immunity up to 100-fold compared to simply mixing ODN with the immunogen. CpG ODN was chemically conjugated to apoptotic tumor cells and then administered to mice either pre- or post-challenge with viable tumor cells. The data generated was from 5-10 mice per experiment, repeated 2-3 times. Initial studies measured the effect of the CpG-conjugated apoptotic tumor cell vaccines on the in vivo growth of prostate cancer cells (TRAMP C-1) in mice. The animals that were pre-treated with TRAMP C-1 cells were immunized with CpG-conjugated to TRAMP C-1 apoptotic cells once the tumors had reached clinically detectable size. Immunization generated strong cellular responses against the established tumor (P < 0.01) and significantly slowed the growth of established TRAMP C-1 tumors in vivo (P < 0.01 vs. unvaccinated animals). The inventors also studied the effect of CpG-conjugated tumor cell vaccines on 4T1 mammary carcinoma in mice. After allowing the tumor to grow to greater than 1 cm in diameter, the tumor was surgically removed and the mice were vaccinated. Mice vaccinated post-surgery with CpG-conjugated 4T1 cells were completely protected against metastasis (P < 0.05)
Future Direction
- NCI investigators are extending their studies to examine the utility of CpG-conjugated apoptotic cancer cell vaccines when used in combination with other immunotherapeutic strategies. These include efforts to reverse the immunosuppression present in the tumor microenvironment that would otherwise subvert tumor specific immunity through the use of various TLR agonists
Strengths
- Only requires a small number of cells; a biopsy would provide enough cells to produce the immunotherapy
- Using patient’s own tumor cells reduces the chance of eliciting an undesirable immune response
- Not limited to specific antigens giving the potential to branch out into multiple tumor types
Weaknesses
- Tumor cell isolation needs to be fine-tuned. There is a potential for normal cells to be present in the preparations and cause an auto-immune reaction once administered to patients
Patent Status
US Patent Application 13/581,999 filed 1 Mar 2011 Google Patent
Relevant Publications
Shirota H, Klinman DM; Cancer Immunol Immunother. 2011, 60: 659-669. (PMID: 21318638)
Inventor Bios
Dennis Klinman, M.D., Ph.D.
Dr. Klinman received his MD/PhD from the University of Pennsylvania, and completed his fellowship training in Rheumatology at the National Institute of Arthritis, NIH. He headed the Section of Viral Immunology at the Center for Biologics Evaluation and Research of the FDA before joining the Laboratory of Experimental Immunology of the National Cancer Institute as chief of the Immunoregulation Group. He has authored over 250 peer reviewed articles, received of the FDA's 'Outstanding Scientist of the Year' Award, the 'Outstanding Achievement Award In Biology' from the Washington Academy of Science, and 'Meritorious', 'Outstanding' and 'Distinguished' Service Medals from the Public Health Service, among other honors
Hidekazu Shirota, M.D., Ph.D.
Biography
Dr. Hidekazu Shirota obtained his M.D. from Fukushima Medical University, Japan in 1996 and his Ph.D. from Tohoku University, Japan in 2002. His research at Tohoku University focused on regulating allergic inflammation with immunomodulatory CpG oligonucleotides (ODN) with Drs. Sano and Tamura. In 2002, he pursued postdoctoral studies at the Center for Biologics Evaluation and Research of the FDA with Dr. Klinman and then was a staff scientist in the Laboratory of Experimental Immunology of the NCI until 2012. He is currently associate professor in department of clinical oncology at Tohoku University, Japan
Research Focus
He has been studying the mechanisms of action and therapeutic potential of the immuno-stimulatory CpG and suppressive ODN, especially vaccine development using CpG ODN for allergy, infectious pathogen and tumors. His recent findings shows that conjugating CpG ODN to killed tumor cells significantly improves the immunogenicity of the tumor cell vaccine and induces an immune response that prevents tumor growth. Two benefits derived from this unique strategy: 1) it overcomes the limited activity of free CpG ODN to improve vaccine activity by insuring that the ODN remains associated with the tumor antigen so that both are internalized by professional antigen presenting cells and 2) it eliminates the need to define specific tumor-associated antigens, substituting instead the entire tumor cell (which in the absence of CpG ODN is poorly immunogenic). Thus, this tumor vaccine design uses the strategy of conjugating CpG ODN to apoptotic/killed tumor cells to achieve the goal of accelerating and boosting the induction of tumor-specific immunity
This vaccine idea is based on our recent finding: `CpG-conjugated allergen ameliorate allergic inflammation`. This technology was translated to human clinical trials and has a proven similar effects in allergic patients. CpG ODN coupled to ragweed allergen reduced the responsiveness of immune cells in the nasal cavity to allergen stimulation and reduced disease severity for two seasons