Patent Application
20160022810
The present invention relates to the field of combination therapeutics in the treatment of cancers, particularly for inducing long-term remissions or cures of advanced metastatic cancers. Specific realizations of this invention are combinations between innate immunotherapeutics, preferably Cysteine-rich Adjuvant Therapeutics (CATS), with an oncolytic chemotherapeutic or biologic. This strategy directs the oncoimmunologic to prepare the immune system for activity, immediately upon which fresh cancer targets are exposed to immune surveillance by the directed action of the oncolytic, as Bidirected oncolYtic Eradicators (BYES). A further preference in advanced and metastatic cancers is targeting the oncolytic drug against cancer stem cells to destroy the microenvironment nurturing cancer growth. Targeting of cancer stem cells can ideally and selectively be done through interruption of the WNT signaling pathway specific to each tumor phenotype, but also more generally by targeting against cancer (stem) cell surface proteins or receptors. The cancer oncolytic agent could also have activity against T Regulatory cells, but no claim is made here regarding the use of biologic T cell “checkpoint” inhibitors such as Yervoy®, either alone, in combination with PM checkpoint inhibitors, such as Opdivo® or Keytruda®, or in combination with the proprietary agents described in this invention.
In the year 2000, an estimated 22 million people were suffering from cancers worldwide and 6.2 million deaths were attributed to these diseases. Every year, there are over 10 million new cases and this estimate is expected to grow by 50% over the next 15 years (WHO, World Cancer Report. Bernard W. Stewart and Paul Kleihues, eds. IARC Press, Lyon, 2003), Current cancer treatments are dominated by invasive surgery, radiation therapy and chemotherapy protocols, which are frequently ineffective and can have potentially severe side-effects, non-specific toxicity and/or cause traumatizing changes to an individual's body image and/or quality of life. One of the causes for the inadequacy of current cancer treatments is their lack of selectivity for affected tissues and cells. More selective cancer treatments would leave normal cells unharmed thus improving outcome, side-effect profile and quality of life.
Newly FDA-approved immunotherapeutics for metastatic melanoma, such as Yervoy®, Opdivo® or Keytruda®, are harbingers for treating a broad spectrum of human cancers by harnessing the natural protective power of the immune response. To date these approved “checkpoint inhibitors” are large biologic molecules that work by inhibiting T regulatory cells (TReg). Because of their size and complexity, they are frequently targets of immune autoreactivity with resultant toxicities, and more rarely life-threatening “cytokine storm.” Because TReg inhibitors are downstream regulators of immune response, they do not trigger fresh immune surveillance against tumors. In contrast agents capable of stimulating innate immunity deriving from dendritic cells, NK cells, or myelocytes, or countering innate suppression deriving from Tumor Associated Macrophage (TAMs) or Myeloid-derived Suppressor Cells (MDSCs), do support de novo anti-tumor immune responses. As an example of this class of oncoimmunologic, the anti-prostate cancer biologic Provenge® gained FDA-approval for the treatment of recurrent, refractory prostate cancer. As a cell-based therapy, however, Provenge® is expensive to manufacture, associated with small-batch variabilities, and has significant toxcities. New oncoimmunologic therapeutics in this class could deliver major advances in major cancer markets.
Breast and prostate cancers are among the most frequently diagnosed malignancies in the United States other than skin cancers. Generally these cancers can only be curatively resected, when detected early, and resection has little if any role in metastatic cancer. Non-surgical approaches, such as radiotherapy or chemotherapy, affect normal cells and result in side effects that limit treatment. Importantly, all current treatments for recurrent or metastatic cancer are only palliative. Consequently, development of novel systemic approaches to treat advanced, recurrent and metastatic cancers are urgently needed, particularly insofar as these approaches offer an extended quality of life to the diseased individual.
Immunotherapy has potential as a promising treatment for cancer patients because of its specificity and freedom from many of the toxic effects of chemotherapies. Cancer is one of many common human diseases that respond to immune-based treatments even at advanced stages. Clinical trials in humans have established that an immune response could regress some metastatic human melanomas, prostate cancers, lung cancers, and renal cancers. No oncoimmunologics are currently FDA-approved for the treatment of breast cancers. These observations were broadened by the discovery the dendritic cells, a specific class of antigen-presenting cells (APC), are particularly effective at initiating cytotoxic T lymphocyte (CTL) activity against cancers and other diseases. Technologies that target and activate dendritic cells have yielded some early successes against human prostate cancers and cervical premalignancies, caused by infection with Human Papilloma Virus (HPV).
Many current cancer immunotherapy strategies focus priming CTLs to lyse tumor cells. These antigen-specific cancer “vaccines” identify epitopes expressed by cancer cells that can be used as targets. However, the resident CTL epitopes of cancers are not always optimal because the CTL repertoire against highly expressed epitopes is often tolerized (Gross et al., J. Clin. Invest. 113(3):425-433, 2004).
The development of immunotherapeutic drugs to treat cancer has been hampered by technical difficulties in activating dendritic cells to deliver signals that overcome tolerance of CTL and other anti-cancer immune responses, Antigen targeting for the induction of a CTL response is a challenge insofar as natural processing requires that the antigen enter the cytoplasm of the cell in order to bind to the immune system's major histocompatibility complex (MHC) class I antigen, a prerequisite to CTL activation because the ligand for activating the T cell receptor on CTL is a complex of antigen and MHC class I. In almost all cases, protein antigens, even when they are coupled with a dendritic cells co-activator, enter exclusively into the alternative MHC Class II antigen presentation pathway that excludes CTL stimulation. This can be overcome, in part, by peptide-based technologies, because peptides bind to MHC Class I that is already on the surface of the dendritic cells. However, this technology is non-specific and most peptides are poor dendritic cells activators, which limits their efficacy as “vaccines” for human cancer.
While significant advancements have been made, treatment of cancers by chemotherapy frequently results in severe side effects because the therapy used is not specific to the cancer, killing non-cancerous cells including hematopoietic cells critical to immune surveillance. One important advantage as described here of preceding chemotherapy by immunotherapy is that immune stimulation is achieved before chemotherapeutic immunosuppression sets in, meaning that both agents work in an optimal sequence. When the cancer mutates to chemotherapy resistance, dosages must be increased, and the side effects become more pronounced. By restricting cancer replication via an oncoimmunologic, the potential for mutation to resistance decreases and the sensitivity of cancer cells to chemotherapy increases. The result is superior responses at tower dosages.
In addition to standard chemotherapy and hormone replacement therapy, new classes of therapies have emerged with directed oncolytic mechanisms. One approach targets either toxins or radioactive isotopes directly into the cancers by coupling the oncolytic agent to monoclonal antibodies (MAb) directed against cancer antigen. Genentech's Kadcyla® is an example of this kind of “smart-bomb” approved for the treatment of breast cancer. However, Kadcyla® is not an oncoimmunologic agent. Another class are drugs like Gleevac®(Novartis) that antagonize growth pathways specific to cancer cells, such as the ber-abl oncogene of chronic myelogenous leukemia targeted by Gleevac®. Other approaches are being designed directed against growth pathways specific to cancer stem cells, which are the seeds for cancer metastasis to distant sites. This stem cell strategy is a preferred realization of this invention.
At the present time, patients with recurrent cancer have few options of treatment that offer extended quality of life. The regimented approach to cancer therapy has produced overall improvements in global survival and morbidity rates. However, to the particular individual, these improved statistics do not necessarily correlate with an improvement in their personal situation. When cancer recurs after these consolidation therapies, it is almost always rapidly fatal even when treated by any of the newer targeted agents.
A superior approach to treatment would be a customized combination of stimulating the innate immune system from outside the cancer, and then inhibiting cancer-specific growth signaling mechanisms from inside the cancer cell. This one-two punch would first engage dendritic cells for cancer immunosurveillance, and then oncolysis by a chemotherapy or targeted agent would generate fresh cancer antigens to charge the dendritic cell almost like a customized cancer vaccine. According to the mechanism it is critical that the immunotherapy be administered first, because only this sequence primes the immune system before suppression by the oncolytic agent.
The present invention describes methods in the treatment of cancer that incorporates the administration of Cysteine-rich Adjuvant Therapeutics (CATS™) to activate the immune system and provide an immunotherapeutic means to treat cancer. One embodiment of the present invention provides for an alternating combination of CATS™ with a cytotoxic agent. Cyclophosphamide is a preferred realization of this combination strategy because cyclophosphamide, in addition to its chemotherapeutic efficacy against breast cancers, also antagonizes TReg immune suppression. Still another approach of the present invention alternates CATS™ with other targeting agents such as a targeted growth factor pathway inhibition using Directed Antagonists to Growth (DAGR™s) such as, but not limited to, RNAi, MAb coupled to a toxin or radioisotope, a directed antagonist to a cancer-specific growth pathway such as Gleevac®, or an anti-growth activity intrinsically linked into CATS™ so that CATS™ and DAGR™s are delivered sequentially as the biologic first binds to the cell surface and then enters the cell (cytoplasm and nucleus). Such Bidirected oncolYtic Eradicators (BYES) achieve superior remissions of advanced metastatic breast and other cancers, as demonstrated in the figures. Another embodiment incorporates targeted chemotherapeutic agents linked to a monoclonal antibody in combination with CATS™. In all these realizations, CATS™ is preferentially delivered prior to the DAGRs so that the tumor antigens shed by the lysed cancer cells can be rapidly attracted into the activated dendritic cell microenvironment.
Oncolmmunologics are targeted drugs aimed to controlling tumor growth and preventing or resolving metastases, while avoiding many of the side effects associated with standard chemotherapy. This is particularly relevant in breast cancer where disease strikes young women where loss of reproductive function and physical deformity are particularly disabling. Although many standard chemotherapies have efficacy against early breast cancer, only a few agents (eg. Paclitaxel are active in recurrent disease. Accept in unusual circumstances, such endstage breast cancer therapeutics give transient palliation. None of the currently approved oncoimmunologics are active in breast cancers
One embodiment of present invention incorporates the administration of Cysteine-rich Adjuvant Therapeutics (CATS™) in the treatment of tumors and reducing tumor growth. Using an orthotopic murine model for established breast cancer, significant reduction in the size of primary tumors was obtained in mice receiving CATS™.
Another embodiment of the present invention is sustained treatment of breast cancer by CATS™ CATS™ differ from Tat-based immunotherapeutics (TIRX or “PINS”) described earlier by my laboratory, insofar as CATS™ are fully human biologics devoid of immunosuppressive toxicities associated with TIRX or “PINS”. Mice (ten per cohort) were implanted s.c. in the mammary fat pad on Day 0 with 1×105 4T1 breast cancer cells (ten times our standard 4T1 implantation), and then treated biweekly starting on Day 4 with 10 ng IV inactive protein (Control, Blue), TIRX (Magenta) or CATS (Green) until further dosing was no longer tolerated. Over the course of this protocol mice received 8 injections of CATS over tour weeks, white 8/10 mice receiving TIRX in a parallel trial succumbed acutely to their fifth TIRX injection, presumably by cytokine storm, so that in the therapeutic trial shown 4 doses of TIRX (weeks one and two) were administered. 10 tumor volume is recorded as ((length (mm)×width (mm)2)×0.52). The difference in 10 growth suppression by CATS over TIRX is highly statistically significant (P<0.01) even at the end of two weeks when TIRX therapy was forced to cease. At day 28 when all animals were sacrificed, 4/10 CATs-treated animals were in complete remission, as determined by scarified or absent primary tumor, and no visible lung metastases.
CATS™ provided survival benefit in endstage murine breast cancer (see
This reflects into a much stronger anti-metastatic activity (
CATS™ improved survival as a single regimen significantly over cytotoxic drug (CD, Cyclophosphamide,
The ultimate strategy and invention proposed here is to alternate CATS™ immunotherapeutic with an oncolytic drug in a protocol that first primes and countersuppresses the immune system, and then releases fresh cancer antigens to trigger an oncoimmunologic response. The realization demonstrated in
A therapeutic active in depleting stem cells could be particularly efficacious at reducing and treating metastatic disease. The 4T1 murine breast cancer cell line grows in vitro as a mixed cell population of adherent and non-adherent cells. Adherency is a well-recognized property of cancer stem cells.
Non-Adherent cells (Right bars) were harvested by decanting the flasks, in which case remaining 4T1 cells are clearly visible adhering to the flasks. Such Adherent 4T1 cells (middle bars), typically constituting 1-2% of the 4T1 population, are covered with 10 ml fresh RPMI 1640 and scraped into the RPMI. After centrifugation, 4T1 cells were resuspended at 1×106 cells/ml and treated (10 ng/ml protein) for eighteen hours @37° C. with either Sham protein, which is monomer Tat deleted at its amino terminus, Monomer Tat, or Trimeric Tat all synthesized in E. Coli. Viable cells were enumerated through trypan blue exclusion, and % viable cells scored as the ratio of viable treated cells/viable sham-treated cells to normalize for non-specific cell death (about 5% of cells) due to overnight culture.
An embodiment of the strategy of depleting stern (adherent) cells to reduce metastatic cancer spread is illustrated in
Other embodiments of the present invention incorporate the combination of CATS™ with other known treatment regimens such as, but not limited to, radiation therapy, targeted growth factor pathway inhibition (DAGR™s=Directed Antagonists to Growth) using, for example, RNAi, or targeted chemotherapy such as with a chemotherapeutic linked to a monoclonal antibody. A preferred realization is a DAGR™ that targets and kills stem cells, as illustrated in
This application claims the benefit of U.S. Provisional Patent Application No 62/028,924, filed Jul. 25, 2014, the disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62028924 | Jul 2014 | US |
