Small trial shows promise of pancreatic cancer vaccine

Five years ago, a small group of cancer scientists gathered at a restaurant in a nonconsecrated church hospital in Mainz, Germany, with a bold plan. Even patients whose tumors have been removed are notorious for roaring back.

Some scientists thought a vaccine might not stop these relapses. However, the patient was desperate. Also, the rate at which the disease pancreatic cancer often recurs could work in scientists’ favor. For better or worse, we will soon find out if the vaccine worked.

On Wednesday, scientists reported results It defied long odds. The vaccine elicited an immune response in half of the treated patients, and those people did not show cancer recurrence during the course of the study.

The study, published in Nature, was a landmark in a long-running campaign to create cancer vaccines that are tailored to individual patient tumors.

Researchers at Memorial Sloan Kettering Cancer Center in New York, led by Dr. Vinod Balachandran, removed the patient’s tumors and shipped the samples to Germany. There, scientists at his BioNTech, the company that worked with Pfizer to produce his highly successful Covid vaccine, analyzed the genetic make-up of specific proteins on the surface of cancer cells.

Using that genetic data, BioNTech scientists created a personalized vaccine designed to teach each patient’s immune system to attack the tumor. Cancer vaccines, like BioNTech’s Covid vaccine, relied on messenger RNA. In this case, the vaccine would instruct the patient’s cells to make some of the same proteins found in the resected tumor, potentially triggering a helpful immune response against the actual cancer cells.

“This is the first demonstrable success of an mRNA vaccine in pancreatic cancer, and we call it a success despite the preliminary nature of the study,” said an expert on the disease at the University of Texas School of Medicine. Dr. Anirban Maitra said. Anderson Cancer Center not involved in the study. “By that standard, it’s a milestone.”

The study was small and only 16 patients were treated, all of whom were Caucasian. The vaccine was part of a treatment regimen that included chemotherapy and drugs to prevent tumors from evading people’s immune responses. Also, this study could not completely exclude factors other than the vaccine contributing to improved outcomes in some patients.

“It’s relatively early,” said Dr. Patrick Ott of Dana-Farber Cancer Institute.

More than that, “cost is a major barrier to the wider availability of these types of vaccines,” said Dr. Niha Zaidi, a pancreatic cancer specialist at the Johns Hopkins University School of Medicine. This can lead to disparities in access.

But the simple fact that scientists can create, qualify, and deliver personalized cancer vaccines very quickly (patients receive the vaccine intravenously about nine weeks after the tumor is removed) ) is a promising sign, experts said.

BioNTech has shortened the process to less than six weeks since the study began in December 2019, said Dr. Ugur Sahin, the company’s co-founder who worked on the study. Ultimately, the company expects he will be able to produce a cancer vaccine in four weeks.

And since it began testing the vaccine about a decade ago, BioNTech has automated some of the production, cutting cost per run from about $350,000 to less than $100,000, Dr. Sahin said. said.

A personalized mRNA cancer vaccine developed by Moderna and Merck has lowered the risk of recurrence in patients undergoing surgery for melanoma, a type of skin cancer, the companies announced last month. has set the bar higher by targeting pancreatic cancer, which is considered to be less genetically altered and ripe for vaccine treatment.

In patients who did not respond to the vaccine, the cancer tended to recur about 13 months after surgery. However, responding patients showed no signs of recurrence for approximately 18 months of follow-up.

Interestingly, one patient showed evidence of a vaccine-activated immune response after developing abnormal proliferation in the liver. The growth disappeared later on imaging studies.

“This is anecdotal, but it’s great data to support that vaccines can penetrate these other tumor areas,” said Nina Bhardwaj, Ph.D., who studies cancer vaccines at the Icahn School of Medicine in Mount Sinai.

Scientists have struggled to develop cancer vaccines for decades. One reason is that they trained the immune system with proteins found in both tumor and normal cells.

But tailoring vaccines to mutated proteins found only in cancer cells could help elicit stronger immune responses and open new avenues for treating cancer patients of all kinds. said Ira Mellman, vice president of immuno-oncology at Genentech, which developed a pancreatic cancer vaccine with BioNTech.

“It just establishes a proof of concept that a cancer vaccine can actually do something. Thirty years of failure probably isn’t a bad thing. Let’s start with that.”