DNA sequencing could allow patients with rare cancers for which no standard treatment is available to receive therapies that work in other cancers that feature the same genetic mutations, according to a multi-drug and multi-tumor clinical trial to be presented at the European Society for Clinical Oncology meeting in Madrid this weekend.

A network of more than 40 hospitals in the Netherlands has been collecting biopsies from patients whose cancers have spread since 2016 and these results have been analyzed by Whole Genome Sequencing to create a database of 2,000 individuals treated for all types of cancer. Of the 250 cases submitted for review, some 70 patients with solid tumors, including glioblastoma or cancer of the brain, and blood cancers, were found eligible and have started treatment.

"We have preclinical evidence and case reports suggesting that certain drugs, which patients with a given a genetic aberration and a certain type of cancer are sensitive to, could equally be active in patients with the same mutation in other tumor groups," said principal study investigator Emile Voest, a professor from the Netherlands Cancer Institute in Amsterdam, who led the trial. "However, we also know that the tissue background is extremely important. That's why we create study cohorts not just according to genetic mutation, but also according to the specific tumor type."

So far, a clinical benefit has been observed in 37% of trial participants and six out of the 20 study cohorts have graduated to stage two — where clinical benefit is defined as either a complete remission or a partial response or disease stability for at least 16 weeks.

Voest said the investigators had seen real success with several anticancer drugs, including immunotherapy, a PARP inhibitor and an antibody combination. He added that the researchers are talking to regulatory agencies to see how these results can be translated into imminent use for this rare subset of patients. "Using drugs that are already available based on DNA sequencing is a truly novel approach to personalizing medicine," he said.

"What makes this trial so exciting is that it could change the way we stratify patients for treatment, that is to say, match their genetic profile with a treatment option," commented Richard Marais, a doctor from the Cancer Research UK Manchester Institute. "The team looks for mutations, some of which will have drugs to target them. If they find them, the patients are treated based on their genetics rather than their indication: This is incredibly powerful."

Some 23,000 cancer specialists and researchers are expected to attend the ESMO 2017 Congress, which kicked off in Madrid on Sept. 8.