Unlocking the potential of vaccines built on messenger RNA
Brad Kremer had waited months to receive an experimental cancer vaccine called BNT122, during which time the melanoma on his skin had spread to his liver and spine. His back pain was getting worse, he was rapidly losing weight and new cancerous lesions kept appearing on his left thigh. “It was very scary,” says Kremer, a 52-year-old sales representative from Acton, Massachusetts.
But within weeks of his first injection in March, Kremer could see that the vaccine was working. The coin-sized melanoma spots that popped up from his skin were now flat discolourations measuring millimetres across. “I was actually witnessing the cancer cells shrinking before my eyes,” he says. Several doses later, his appetite has returned, his back pain has subsided and scans show that his cancer is continuing to retreat.
Kremer’s dramatic response exemplifies the medical potential of vaccines built on messenger RNA. In this method, strings of lab-synthesized nucleotides train the immune system to recognize and destroy disease-causing agents — be they cancer cells or infectious viruses.