Lower-Cost Vaccine Kills Tumors in Mice

Harvard researchers have successfully tested a new cancer vaccine in mice that could make previously expensive treatments accessible outside state-of-the-art medical centers.

The therapy—which destroyed tumors in 90 percent of mice tested—uses small implants to avoid costly cell reprogramming outside the body. The latter technique requires practitioners to have extensive training and specialized facilities that are only available at elite hospitals.

The findings, published in the journal Nature Materials last month, seek to combat those tumors that fool the immune system’s normal process of identifying dangerous substances.

Normally, a particular type of immune cell—called a dendritic cell—will search the body for foreign matter, targeting it for destruction by T cells, another component of the immune system.

But some tumors manage to escape detection, enabling them to grow uncontrollably, said Nathaniel D. Huebsch, one of the study’s authors.

“The idea with a cancer vaccine is to wake up the immune system and let it know there’s a tumor in the body and it should try to destroy it,” Huebsch said.

Current therapies involve reprogramming immune cells in a petri dish to recognize the patient’s particular tumor, said Omar A. Ali, one of the authors.

But these cells have a low survival rate, requiring physicians to use large numbers of them to effectively treat tumors, said the School of Engineering and Applied Sciences associate.

“These therapies have worked pretty well in many patients and are very promising, but you need a highly trained technician and a very expensive facility,” Huebsch said. “Patients at the Brigham [and Women’s Hospital in Boston] can probably access these therapies but not patients in more rural areas.”

Ali decided to develop an implantable system that would recruit the dendritic cells by mimicking infection and inducing an immune response.

With the new implants, 90 percent of mice with tumors survived, when otherwise they would have been expected to die within 23 days.

The mice’s immune systems also recruited similar numbers of naturally present dendritic cells as are typically injected in reprogramming therapies, Huebsch said, suggesting that the implants are as effective as pricier therapies, potentially opening the possibility of treatment for many who now cannot afford it.

“Firstly, it promises to be more effective than vaccines currently under investigation today,” said SEAS Bioengineering Professor David J. Mooney, an author on the study. “Secondly, it would be a tremendous benefit to patients because it would be more widely available, and less expensive.”

But before the therapy can reach that stage, it must undergo human clinical trials that require approval from the Food and Drug Administration, which Ali said he hopes to obtain soon.

“We’re developing more of the preclinical data that we need to support a clinical trial,” Ali said. “All the components we use in the system are FDA improved for clinical trials and our goal is to get this system into clinical trials as soon as possible.”

—Staff writer Alissa M. D’Gama can be reached adgama@fas.harvard.edu.