New solution to cancer treatment

Although Evan Johnson struggled with a weeks-long cold, nosebleeds and extreme fatigue, it was the strange bruises and chest pain that determined the then 23-year-old senior at the University of North Dakota to go to the Mayo Clinic. A genetic test conducted revealed a particularly aggressive form of acute myeloid leukemia.

Even though that was a couple of years ago, the agonizing path that Johnson and his family had to take highlights new directions oncologists are taking with genetic testing to find and attack cancer. Tumors can evolve to resist treatments, and doctors are beginning to turn such setbacks into possible advantages by identifying new targets to attack as the tumors change.

The medical team behind Johnson was desperate to find effective treatments to fight the genetic mutations driving his disease. Such treatments included a failed stem cell transplant, half-dozen different drug regimens, where he suffered four relapses and life-threatening side effects related to his treatment.

Nine months later, his leukemia started evolving to develop a surprising new mutation. Although that meant that the cancer managed to escape a treatment, the new anomaly gave doctors a way out, being susceptible to drugs for other cancers.  Doctors adjusted Johnson’s treatment accordingly, knocked out the disease and paved the way for a second, more successful stem cell transplant. He’s since been leukemia-free for a year.

“You could see the cancer evolution happen,” through regular genetic testing, enabling his treatment to be “personalized in real time,” says Dr Pashtoon Kasi, an oncology fellow at the Rochester, Minn.-based Mayo Clinic and a member of the team that cared for Johnson. “This is where oncology is headed down the line.”

Just a decade ago, “we were shooting in the dark,” says Jose Baselga, physician-in-chief at Memorial Sloan Kettering Cancer Center in New York. If first- or second-line treatments failed, “we either had nothing to do next, or what we did was totally disconnected with the biology of the disease.”

It is now possible for patients with advanced cancer who are treated at major centers to have their tumors sequenced, to hopefully find a suitable match in a growing medicine chest of drugs that precisely target mutations that drive cancer’s growth. When they work, such matches can have a dramatic effect on tumors. But these “precision medicines” aren’t cures. They are often foiled when tumors evolve, pushing doctors to take the next step to identify new mutations in hopes of attacking them with an effective treatment.

The approach is, nevertheless, demanding. There aren’t drugs to treat many cancer-causing mutations. Yet when the drugs exist, there still isn’t a guarantee that they will be effective.

Moreover, DNA tests of tumors may lead to a recommendation for a drug that isn’t approved for the type of cancer being treated, jeopardizing reimbursement for drugs that typically cost $10,000 or more a month.

Dr Kasi warns that this approach is not for every patient or cancer. But as more drugs are developed and more treatment pathways are opened, it will become a reasonable option for a lot of patients.

Dr Kasi and his Mayo colleagues—Naseema Gangat, a hematologist, and Shahrukh Hashmi, a transplant specialist—are among the authors of an account of Mr. Johnson’s case published in January in the journal Leukemia Research Reports.

After spending 17 months at the Mayo Clinic, Johnson was finally well enough to return home. He is now finishing his senior year in college.