The Cancer Biomarker Conundrum: Too Many False Discoveries

The boom in cancer [including ovarian] biomarker investments over the past 25 years has not translated into major clinical success. The reasons for biomarker failures include problems with study design and interpretation, as well as statistical deficiencies, according to an article published online August 12 in The Journal of the National Cancer Institute.

The boom in cancer [including ovarian] biomarker investments over the past 25 years has not translated into major clinical success. The reasons for biomarker failures include problems with study design and interpretation, as well as statistical deficiencies, according to an article published online August 12 in The Journal of the National Cancer Institute.

The National Institutes of Health defines a biomarker as “a characteristic that is objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention.” In the past decade, there have been numerous biomarker discoveries, but most initially promising biomarkers have not been validated for clinical use.

Eleftherios P. Diamandis, M.D., Ph.D., Head, Section of Clinical Biochemistry, Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada

To understand why so-called biomarker “breakthroughs” have not made it to the clinic, Eleftherios P. Diamandis, M.D., Ph.D., professor of pathology and laboratory medicine at Mount Sinai Hospital in Toronto and associate scientist at the Samuel Lunenfeld Research Institute of Mount Sinai Hospital, reviewed some biomarkers initially hailed as breakthroughs and their subsequent failings.

Diamandis first describes the requirements for biomarkers to be approved for clinical use: A biomarker must be released into circulation in easily detectable amounts by a small asymptomatic tumor or its micro-environment; and it should preferably be specific for the tissue of origin. Also, if the biomarker is affected by a non-cancer disease, its utility for cancer detection may be compromised. For example, the prostate-specific antigen (PSA) biomarker, which is used to detect prostate cancer, is also elevated in benign prostatic hyperplasia.

Diamandis looks at seven biomarkers that have emerged in the past 25 years, all of which were considered promising when they were first described. These include nuclear magnetic resonance of serum for cancer diagnosis; lysophosphatidic acid for ovarian cancer; four– and six-parameter diagnostic panels for ovarian cancer; osteopontin for ovarian cancer; early prostate cancer antigen-2 (EPCA-2) for prostate cancer detection; proteomic profiling of serum by mass spectrometry for ovarian cancer diagnosis; and peptidomic patterns for cancer diagnosis. Problems ranged from inappropriate statistical analysis to biases in case patient and control subject selection. For example, the problems with EPCA-2 included reporting values that were beyond the detection limit of the assay and using inappropriate reagents to test EPCA-2, such as solid surfaces coated with undiluted serum.

Diamandis concludes that “problems with pre-analytical, analytical, and post-analytical study design could lead to the generation of data that could be highly misleading.”

Sources:

The Cancer Biomarker Conundrum: Too Many False Discoveries, Journal of the National Cancer Institute Advance Access,  published on August 12, 2010, DOI 10.1093/jnci/djq335.

Eleftherios P. Diamandis. Cancer Biomarkers: Can We Turn Recent Failures into Success? Commentary, Journal of the National Cancer Institute Advance Access published on August 12, 2010, DOI 10.1093/jnci/djq306.

Preclinical Results Validate Lpathomab As A Potential Future Treatment for Ovarian Cancer

“Lpath, Inc. … , the category leader in bioactive-lipid-targeted therapeutics, reported compelling new in vivo and in vitro results relating to its preclinical drug candidate, Lpathomab, in various ovarian cancer studies …”

“Lpath Presents Compelling New Preclinical Results of Its Anti-Cancer Drug Candidate, Lpathomab(TM), at the AACR 100th Annual Meeting –

New In Vivo and In Vitro Results Provide Further Validation of Lpathomab as Potential Treatment for Cancer

SAN DIEGO, CA, Apr 20, 2009 (MARKET WIRE via COMTEX)Lpath, Inc. (OTCBB: LPTN), the category leader in bioactivelipid-targeted therapeutics, reported compelling new in vivo and in vitro results relating to its preclinical drug candidate, Lpathomab, in various ovarian cancer studies. The results were presented today by Lpath scientists at the 100th Annual Meeting of the American Association for Cancer Research (AACR) in Denver, Colorado.

Lpathomab is a monoclonal antibody that binds to the bioactive lipid lysophosphatidic acid (LPA) and acts as a molecular sponge to absorb LPA, thereby neutralizing LPA-mediated biological effects on tumor growth, angiogenesis, and metastasis. LPA has been associated with a variety of cancer types, but the correlation with ovarian cancer and breast cancer has been particularly strong.

Using the human ovarian cell line called SKOV3, Lpath’s preclinical studies demonstrated Lpathomab significantly reduced IL-8 and IL-6 cytokine release in SKOV3-conditioned media and blocked tumor-cell migration triggered by LPA (both IL-8 and IL-6 promote tumor angiogenesis and metastasis). More important, Lpathomab inhibited the progression of SKOV3 tumor cells when injected into the peritoneal cavity of mice and reduced levels of pro-metastatic factors in these animals.

Lpathomab also reduced neovascularization (new blood-vessel growth) in two classical angiogenic models and showed preliminary anti-metastatic activity when tested in a classical experimental metastasis model.

According to Roger Sabbadini, Ph.D., Lpath’s founder and chief scientific officer, ‘In view of these promising preclinical results, we believe Lpathomab has the potential to augment the efficacy of current ovarian cancer therapy by blocking the growth-promoting, angiogenic, and metastatic effects of LPA.’

About Lpath

San-Diego-based Lpath, Inc. is the category leader in bioactive-lipid-targeted therapeutics, an emerging field of medical science whereby bioactive signaling lipids are targeted for treating important human diseases. ASONEP(TM), an antibody against Sphingosine-1-Phosphate (S1P), is currently in a Phase 1 clinical trial in cancer patients and also holds promise against multiple sclerosis and various other disorders. ASONEP is being developed with the support of partner Merck-Serono as part of a worldwide exclusive license. A second product candidate, iSONEP(TM) (the ocular formulation of the S1P antibody), has demonstrated superior results in various preclinical models of age-related macular degeneration (AMD) and retinopathy and is in a Phase 1 clinical trial in wet-AMD patients. Lpath’s third product candidate, Lpathomab(TM), is an antibody against lysophosphatidic acid (LPA), a key bioactive lipid that has been long recognized as a valid disease target (cancer, neuropathic pain, fibrosis). The company’s unique ability to generate novel antibodies against bioactive lipids is based on its ImmuneY2(TM) drug-discovery engine, which the company is leveraging as a means to expand its pipeline. For more information, visit www.Lpath.com …”

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