Bringing targeted therapy of metastatic melanoma into the clinic–the crucial role of translational researchers

During the week of February 22, 2010, the New York Times (NYT) ran a three-part series on a Phase I trial in 2008/2009 of a targeted therapy for metastatic melanoma, a disease that is almost always fatal within a year. The trial was led by Keith T. Flaherty, M.D. (then at the University of Pennsylvania in Philadelphia, and now at the Dana-Farber Cancer Center in Boston). The drug was PLX4032, developed by Plexxikon, which is co-developing the compound with Roche. PLX4032 is a kinase inhibitor, which specifically targets the V600E mutant of the B-Raf oncoprotein. This is the most common somatic mutation found in human melanomas. Researchers believe that B-Raf(V600E) is a “driver mutation” that is particularly critical for the malignant phenotype of human metastatic melanomas that carry the mutation. PLX4032 entered Phase III clinical trials in 2009.

The NYT series, authored by Amy Harmon, focused on the stories of several patients, and on the dogged efforts of Dr. Flaherty to help his patients and to prove the value of targeted therapy. Although the targeted kinase inhibitor imatinib (Novartis’ Gleevec/Glivec) produces complete responses in the majority of treated patients in the chronic phase of CML (chronic myelogenous leukemia) and long-lasting remissions in many of these patients, many researchers believe that this is a special case, and they cite evidence that targeted therapy, especially in solid tumors, almost never produces durable responses. But Dr. Flaherty pressed on with his quest to prove the value of targeted therapy, despite this skepticism.

A key point in the story was when the original formulation of PLX4032, at the highest dose that patients could absorb, produced neither adverse effects nor clinical responses. Because of his belief in targeted therapy, and in this particular drug, Dr. Flaherty convinced Roche to reformulate the drug to enable patients to absorb a higher dose. With the higher doses of the drug made possible by the new formulation, the researchers saw dramatic clinical responses in the great majority of patients whose tumors contained B-Raf(V600E). Responses lasted an average of nearly 9 months, a dramatic breakthrough in treatment of metastatic melanoma.

As the series ended, Dr. Flaherty was working with his colleagues and the pharmaceutical industry to find ways to enable the testing of combination therapies of targeted drugs (including PLX4032) that might result in long-lasting remissions in patients with metastatic melanoma. Meanwhile, Plexxikon and Roche have taken PLX4032 into Phase II clinical trials and now into Phase III.

The NYT series is essentially a human-interest story. I commend it to all researchers, executives, and consultants in the industry whose work does not involve contact with patients, since creating products that can help patients is what our work is all about.

Dr. Flaherty reminds me, and others who have commented on this story, of Brian J. Druker, M.D. at the Oregon Health Sciences University in Portland. It was Dr. Druker’s efforts, centered on helping patients and proving the value of targeted therapy, that was the driving force behind the development of imatinib (Novartis’ Gleevec/Glivec). Without this effort (conducted in collaboration with biochemist Nicholas B. Lydon, then at Novartis), the whole field of kinase inhibitors for targeted therapy of cancer would not have emerged. Dr. Flaherty, as well as several other oncologists, is continuing this worthy tradition.

As pointed out to me by a leading Boston-area academic researcher in a cancer-related area, the NYT series did not give credit to the academic researchers who identified the role of B-Raf in cancer, and especially the role of B-Raf(V600E) in human melanoma. (For that matter, it did not credit the Plexxicon researchers who discovered PLX4032.) She said that the series sounded as if only one person, Dr. Flaherty, was responsible for the development of PLX4032. Moreover, the development of imatinib was made possible by decades of academic research on the target of the drug, Bcr-Abl, a fusion protein formed as the result of a chromosomal translocation. Drs. Druker and Lydon thus were not solely responsible for the development of imatinib either.

The academic researcher has a point. However, some industry commentators take a contrary point of view, downplaying the role of academic researchers in the drug discovery/development process and giving most of the credit to industry.

For years, we have taken the point of view that biology-driven drug discovery and development (arguably the most successful drug discovery/development strategy in the post-genomic era) requires the contributions of both academia and industry, and that more effective collaboration between academia and industry would result in more effective drug discovery and development. (See also my 2005 letter to the editor of BusinessWeek.)

It is basic research, usually in academic laboratories, that has resulted in the very best validated targets. Basic research on a particular target typically takes years or even decades (as in the case of Bcr-Abl). Many of the breakthrough drugs that have emerged in the past 10-15 years (as well as numerous promising pipeline drugs now in clinical testing) were made possible by this research. In contrast, large-scale “target validation” testing in industry more often than not results in targets whose role in normal physiology and in disease is poorly understood. This is an important cause of clinical attrition in drug development.

Nevertheless, it is industry, not academia, which uses this basic research to create drugs. In particular, it is industry that bears the enormous economic risk of drug development, especially of late-stage clinical trials.

Translational researchers, who are involved in taking the results of academic research and/or of discovery research in industry, and translating them into therapies that benefit patients, are—or should be—a key component of the drug discovery-development process. Drs. Druker and Flaherty are two outstanding examples.

However, at least some sectors of academia (and of governmental policy-makers and the media) are suspicious of the type of closer industry-academic collaboration that is needed to produce more effective translation of basic and drug-discovery research into the clinic. An editorial in the 25 February issue of Nature notes that there has been criticism of the recent hiring of William Chin, Lilly’s senior VP for discovery and clinical research, to be the executive dean for research at Harvard Medical School. The critics charge that strong research collaborations between academia and industry will inevitably result in conflicts of interest. The Nature editorial supports institutional policies that require disclosure of links between academic researchers and industry, but deplores the views of influential critics who believe that any collaboration between academic researchers and industry “corrupts” the academic research enterprise.

In addition to Nature, some leading academic researchers say that it is time for industry and the academic medical community to fight back against the critics, rather than appeasing them with ever more restrictive conflict-of-interest policies. These researchers note that the main purpose of medical research is not to publish scientific papers, but to translate this knowledge into therapies that benefit patients. This requires effective collaboration between academia and industry. We agree.

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