Pancreatic cancer vaccine shows promise in small trial

By using mRNA tailored to each patient's tumor, the vaccine may have prevented the return of one of the deadliest forms of cancer. murderous in half of those who received it.

Five years ago, a small group of cancer scientists gathered in a restaurant at a disused religious hospital in Mainz, Germany, hatched a bold plan: they would test their novel cancer vaccine against one of the most virulent forms of the disease, a cancer known to recur even in patients whose tumors have been removed.

The vaccine may not stop these relapses, some of the scientists figured. But the patients were desperate. And the speed with which the disease, pancreatic cancer, often returned could work to scientists' advantage: for better or worse, they would soon find out if the vaccine had helped.

On Wednesday, scientists reported results that defied long odds. The vaccine elicited an immune response in half of the patients treated, and those people showed no relapse of their cancer during the study, a finding that outside experts have called extremely promising.

The study, published in Nature, marked a turning point in the years-long movement to make cancer vaccines tailored to the tumors of each patient.

Researchers at Memorial Sloan Kettering The Cancer Center in New York, led by Dr. Vinod Balachandran, extracted tumors from patients and shipped samples to Germany. There, scientists from BioNTech, the company that made a highly successful Covid vaccine with Pfizer, analyzed the genetic makeup of certain proteins on the surface of cancer cells.

Using this genetics, BioNTech scientists then produced personalized vaccines designed to teach each patient's immune system to attack tumors. Like BioNTech's Covid vaccines, cancer vaccines relied on messenger RNA. In this case, the vaccines instructed the patients' cells to make some of the same proteins found on their excised tumors, potentially eliciting an immune response that would be useful against actual cancer cells.

"This is the first demonstrable success - and I will call it a success, despite the preliminary nature of the study - of an mRNA vaccine in pancreatic cancer," said Dr. Anirban Maitra, a disease specialist at the University. from Texas MD Anderson Cancer Center, which was not involved in the study. "By this standard, this is a significant milestone."

The study was small: only 16 patients, all white, received the vaccine, in the part of a treatment regimen that also included chemotherapy and a drug to prevent tumors from escaping people's immune responses. And the study couldn't entirely rule out factors other than the vaccine that contributed to better outcomes in some patients.

"It's relatively early," said said Dr. Patrick Ott of the Dana-Farber Cancer Institute.

Beyond that, "cost is a major barrier to wider use of these types of vaccines," said Dr. Neeha Zaidi, a pancreatic cancer specialist at Johns Hopkins University School of Medicine. This could potentially create disparities in access.

But the simple fact that scientists can create, verify quality and deliver personalized cancer vaccines so quickly — the patients began receiving the vaccines intravenously about nine weeks after their tumors were removed - was a promising sign, experts said.

Since the When the study began in December 2019, BioNTech shortened the process to less than six weeks, said the company's co-founder Dr. Ugur Sahin, who worked on the study. Eventually, the company aims to be able to manufacture cancer vaccines in four weeks.

And since it started testing vaccines ago about a decade, BioNTech reduced the cost from about $350,000 per dose to less than $100,000 by automating parts of production, Dr. Sahin said.

A personalized mRNA cancer vaccine developed by Moderna and Merck has reduced the risk of relapse in patients who have undergone surgery for melanoma, a type of skin cancer, the companies announced last month. But the latest study has raised the bar by targeting...