Recent Patents on Anti-Cancer Drug Discovery - Volume 7, Issue 3, 2012

CXCL12, also known as SDF-1, is the single natural ligand for chemokine receptors CXCR4 and CXCR7. CXCL12 has angiogenic properties in normal endothelial tissue and is involved in the outgrowth and metastasis of CXCR4 expressing tumors. Recent investigations have indicated that CXCL12 levels increase after chemo- and anti- VEGF therapy, favouring recurrences. The blockade of CXCL12/CXCR4 axis has emerged as a potential additional or alternative target for neo-adjuvant treatments. We have reviewed recent patent applications between 2008 and 2011 in tumor angiogenesis and the most clinical data supporting the potential use of anti-CXCR4 agents in this field. Among these, AMD3100, also known as Plerixaform (Mozobil® by Genzyme), is approved for stem cell mobilisation in patients with leukaemia, while BKT140 (Emory University), POL6326 (Polyphor Ag) and TG-0054 (ChemoCentryx) are currently in clinical trials in combination with chemotherapy for multiple myeloma and leukaemia. The aptamer Nox-A12 (Noxxon) is in trials for chronic lymphatic leukaemia treatment. MSX-122 (Metastatix) is in Phase I trials for solid tumor treatment, while CXCR7-specific inhibitor CCX2066 (ChemoCentryx) is still in preclinical studies. We have also considered other strategies, such RNA interference and miRNA, which could be tested for solid tumor adjuvant therapy.

Carcinoembryonic antigen (CEA), a glycosylated protein of MW 180 kDa, is overexpressed in a wide range of human carcinomas, including colorectal, gastric, pancreatic, non-small cell lung and breast carcinomas. Accordingly, CEA is one of several oncofetal antigens that may serve as a target for active anti-cancer specific immunotherapy. Experimental results obtained by employing animal models have supported the design of clinical trials using a CEA-based vaccine for the treatment of different types of human cancers. This review reports findings from experimental models and clinical evidence on the use of a CEA-based vaccine for the treatment of cancer patients. Among the diverse CEA-based cancer vaccines, DCs- and recombinant viruses-based vaccines seem the most valid. However, although vaccination was shown to induce a strong immune response to CEA, resulting in a delay in tumor progression and prolonged survival in some cancer patients, it failed to eradicate the tumor in most cases, owing partly to the negative effect exerted by the tumor microenvironment on immune response. Thus, in order to develop more efficient and effective cancer vaccines, it is necessary to design new clinical trials combining cancer vaccines with chemotherapy, radiotherapy and drugs which target those factors responsible for immunosuppression of immune cells. This review also discusses relevant patents relating to the use of CEA as a cancer vaccine.

Cancer is the second leading cause of death in the Western world. The limited successes of available treatments for cancer mean that new strategies need to be developed. The possibility of modifying the cancer cell with the introduction of genetic material opens the way to a new approach based on gene therapy. There are still many technical difficulties to be overcome, but recent advances in the molecular and cellular biology of gene transfer have made it likely that gene therapy will soon start to play an increasing role in clinical practice, particularly in the treatment of cancer. Gene therapy will probably be the therapeutic option in cases in which conventional treatments such as surgery, radiotherapy and chemotherapy have failed. The development of modified vectors, and an improved understanding of interactions between the vector and the human host, are generating inventions that are being protected by patents due to the considerable interest of industry for their possible commercialization. We review the latest strategies, patented and/or under clinical trial, in cancer gene therapy. These include patents that cover the use of modified vectors to increase the security and specificity, recombining adenovirus that leads to loss or gain of gene function, activation of the patient's own immune cells to eliminate cancer cells by expression of molecules that enhance immune responses, silencing genes related to the development of drug resistance in patients, inhibition of angiogenesis of solid tumors by targeting the tumor vasculature, and the development of enzymes that destroy viral or cancerous genetic material.

The molecular chaperone heat shock protein 90 (HSP90) is essential for the folding stability, intracellular disposition and proteolytic turnover of many of the key regulators of cell growth, differentiation and survival. These essential functions are used by the cells during the oncogenesis process to allow the tumor transformation and facilitate the rapid somatic evolution. Inhibition of HSP90 would provide combinatorial blockade of a range of oncogenic pathways, antagonizing many of the hallmark traits of cancer. Several HSP90 inhibitors are currently under clinical trial investigation for the treatment of cancer. This review summarizes the current state and progress achieved in the development of HSP90 inhibitors targeting the N-terminal ATP pocket, C-terminal domain, different compartmentalized isoforms, and protein (cochaperones and/or client proteins)/HSP90 interactions. In the context of drug discovery, the most relevant patents which appeared recently in the literature are discussed as well.

North-America and northern European countries exhibit the highest incidence rate of breast cancer, whereas women in southern regions are relatively protected. Immigrants from low cancer incidence regions to high-incidence areas might exhibit similarly higher or excessive cancer risk as compared with the inhabitants of their adoptive country. Additional cancer risk may be conferred by incongruence between their biological characteristics and foreign environment. Many studies established the racial/ethnic disparities in the risk and nature of female breast cancer in United States between African-American and Caucasian women. Mammary tumors in black women are diagnosed at earlier age, and are associated with higher rate of mortality as compared with cancers of white cases. Results of studies on these ethnic/racial differences in breast cancer incidence suggest that excessive pigmentation of dark skinned women results in a relative light-deficiency. Poor light exposure may explain the deleterious metabolic and hormonal alterations; such as insulin resistance, deficiencies of estrogen, thyroxin and vitamin-D conferring excessive cancer risk. The more northern the location of an adoptive country the higher the cancer risk for dark skinned immigrants. Recognition of the deleterious systemic effects of darkness and excessive melatonin synthesis enables cancer protection treatment for people living in lightdeficient environment. Recent patents provide new methods for the prevention of hormonal and metabolic abnormities.

The patents annotated in this section have been selected from various patent databases. These recent patents are relevant to the articles published in this journal issue, categorized by therapeutic areas/targets and therapeutic agents related to anti-cancer drug discovery....