A precision cancer drug that’s designed to kill cancer cells that carry a fault in the BRCA genes could hold some advanced pancreatic cancers at bay for a short time after chemo, according to new clinical trial results. 

Olaparib (Lynparza) delayed the progression of the disease by 7.4 months on average, compared with 3.8 months in those treated with a dummy drug (placebo), according to results reported at the American Society of Clinical Oncology (ASCO) Annual Meeting, and published in the New England Journal of Medicine.

Longer term survival analysis is still needed to gauge the potential impact. But with pancreatic cancer among the most difficult to treat cancers, experts at ASCO were cautiously optimistic about the trial results. 

“We’re potentially on the cusp of a new age of treatment for pancreatic cancer, where for the first time we can tailor therapy based on a biomarker and where having a BRCA mutation opens up more treatment options,” said Dr Suzanne Cole in a comment from ASCO.

Progress for PARP inhibitors

Olaparib is among a group of precision drugs called PARP inhibitors. They’re designed to target cells that carry faults in genes that help cells repair damage to their DNA. 

Because of these faults, the cells’ repair systems are hampered, and they become reliant on a molecule called PARP. By switching off PARP, olaparib – and other PARP inhibitors – can kick away this crutch and kill the cancer cells. 

The drugs have already offered benefits to patients with ovarian and breast cancers, some of which are known to carry faulty BRCA genes. 

Now, thanks to technology that can find cancers carrying these faults, trials in other cancers – including pancreatic cancer – have been gathering pace. 

Slowing pancreatic cancer progression

The researchers carried out genetic testing on 3,315 people with pancreatic cancer. Of those, 247 were found to have an inherited fault in either the BRCA 1 or 2 genes. 

On the trial, 154 patients were treated four to eight weeks after they finished standard chemotherapy treatment – 92 received olaparib and 62 the placebo.

The researchers then looked at the time it took before patients’ cancers got worse, called progression-free survival.

Two years after treatment, just over two in 10 people (22.1%) treated with olaparib had no cancer progression, compared with one in 10 (9.6%) who received the placebo. 

Professor Hedy L. Kindler, who led the study from the University of Chicago, said that seeing a fifth of patients with BRCA faults respond to olaparib was “truly remarkable for metastatic pancreatic cancer”. 

Side effects were more common among those treated with olaparib. The most serious side effects occurred in four in 10 patients (40%) taking the targeted drug, compared with two in 10 (23%) taking the placebo. But the researchers said there was no difference in quality of life between the two groups of patients.

Professor Ruth Plummer, director of the Cancer Research UK Newcastle centre, said that based on this trial, olaparib could be viewed as a new treatment option for pancreatic cancer patients with inherited faulty BRCA genes.

But she added that there were still further data needed from the ongoing study to look at how olaparib might impact patient survival.