‘A STARTING POINT’
Long before COVID, companies had been eyeing messenger RNA (mRNA) technology, which carries instructions for cells to make specific proteins, as a vehicle for delivering a cancer vaccine.
Merck and Moderna have been collaborating since 2016. Researchers at Memorial Sloan Kettering Cancer Center (MSK) in New York began working with Germany’s BioNTech in 2017.
At that time, there was already proof that immunotherapy could work in so-called “hot” tumors, or highly mutated cancers, such as melanoma. There was little hope it would work in “cold” cancers with few mutations, such as pancreatic cancer, said MSK’s Dr. Vinod Balachandran.
With standard treatment, 90% of pancreatic cancer patients die within five years of diagnosis.
Balachandran’s team studied the rare long-term survivors and found an immune system component called T cells in these individuals were able to recognize mutations derived from the cancer, raising the possibility of a targeted vaccine.
In a small ongoing trial testing a made-to-order BioNTech vaccine plus Roche’s Tecentriq, half of the 16 pancreatic cancer patients mounted an immune response, and none showed signs of relapse after 18 months, according to data published last month in Nature.
Gritstone Bio is taking a different tack, combining two types of customized vaccines in hopes of treating patients with metastatic colon cancer, another cancer that has been largely unresponsive to immunotherapy.
The approach first primes the immune system with an older technology called a chimpanzee adenovirus vaccine that targets patients’ tumors. That is followed by a personalized self-amplifying mRNA vaccine, which includes an enzyme that makes extra copies of the antigens, reducing the required dose.
Gritstone is expecting data from a later-stage trial testing its dual vaccine therapy in the first quarter of 2024.
“Based on everything we’ve shown and we’ve published, we’re really excited,” said Gritstone CEO Andrew Allen.
Merck and Moderna are planning a larger Phase 3 trial in melanoma and are also testing its combination in lung cancer.
“We see this as a starting point,” Healy said.
(Reporting by Julie Steenhuysen and Patrick Wingrove; Editing by Caroline Humer, Bill Berkrot and Sonali Paul)