Precision Medicine, Part II

 

From diagnosis to treatment, every aspect of how researchers and clinicians approach cancer is changing for the better. In the second of a two-part series by Laura Putre, discover how researchers are working to help make lifesaving treatments accessible to more patients more quickly.

Access to treatment presents another barrier in cancer care, but one that the current work aims to lessen. The cost of genomic tumor sequencing used to be out of reach for all but the most affluent, but it has dropped dramatically in recent years. Gradually, the procedure is becoming more accessible to a larger number of patients.

However, obtaining results from such sequencing is just the first step. Without targeted therapy for a particular genetic alteration, or an accessible clinical trial, data remains raw information.

That’s why Davendra Sohal, MD, MPH, staff physician in Cleveland Clinic’s Department of Hematology and Oncology, says his work is critical. Rethinking how clinical trials are conducted could help make lifesaving treatments accessible to more patients more quickly.

Currently, many clinical trials are decided by location, rather than being made available to everyone who meets the genetic and disease criteria. “If you sequence tumors from 10 patients, and one patient has alteration A, another B, and another C, trials for those drugs could be in different corners of the country,” Dr. Sohal says.

To highlight the need for widespread availability of targeted therapies, Dr. Sohal led a multidisciplinary study that systematically tracked outcomes of cancer patients who had their tumor specimens sequenced. The results were published in the Journal of the National Cancer Institute, and demonstrated that clinical trial availability is the critical bottleneck limiting treatment options for patients with advanced cancers.

“I think there’s a growing realization, as we learn more from studies like ours, that yes, you can sequence 1,000 genomes, but if only five to 10 patients are receiving a drug, then this is not very helpful,” Dr. Sohal says.

Another hurdle to providing targeted therapies is a scarcity of diagnostic tissue for certain cancers, including biliary (bile duct) and pancreatic cancers. Researchers need viable specimens in the lab to identify key genetic alterations and develop drugs to target them. Patients with these types of cancers, frequently diagnosed in the late stages of the disease, often are too ill to tolerate chemotherapy.

“The options are quite limited, and the outcomes are quite poor,” Dr. Sohal says. “The science is way behind some other cancers.” A targeted therapy, if one is available, may be the best hope.

To improve research prospects in these areas, Dr. Sohal is leading an effort to create a biorepository of pancreatic and biliary cancer specimens. Currently, the tumor samples are solely from Cleveland Clinic patients, but a reciprocal relationship with other institutions is part of the long-term plan.

“There are a couple of exciting, hopeful drugs that might work in these diseases, but we need to do the studies and find out for sure,” he says.

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