New Cancer Vaccines on the Horizon: Renewed Hope or Hype?

Vaccines for treating and preventing cancer have long been considered a holy grail in oncology.

But aside from a few notable exceptions — including the human papillomavirus (HPV) vaccine, which has dramatically reduced the incidence of HPV-related cancers, and a Bacillus Calmette-Guerin vaccine, which helps prevent early-stage bladder cancer recurrence — most have failed to deliver.

Following a string of disappointments over the past decade, recent advances in the immunotherapy space are bringing renewed hope for progress.

In an American Association for Cancer Research (AACR) series earlier this year, Catherine J. Wu, MD, predicted big strides for cancer vaccines, especially for personalized vaccines that target patient-specific neoantigens — the proteins that form on cancer cells — as well as vaccines that can treat diverse tumor types.

“A focus on neoantigens that arise from driver mutations in different tumor types could allow us to make progress in creating off-the-shelf vaccines,” said Wu, the Lavine Family Chair of Preventative Cancer Therapies at Dana-Farber Cancer Institute and a professor of medicine at Harvard Medical School, both in Boston.

A prime example is a personalized, messenger RNA (mRNA)–based vaccine designed to prevent melanoma recurrence. The mRNA-4157 vaccine encodes up to 34 different patient-specific neoantigens.

“This is one of the most exciting developments in modern cancer therapy,” said Lawrence Young, a virologist and professor of molecular oncology at The University of Warwick, Coventry, England, who commented on the investigational vaccine via the UK-based Science Media Centre.

Other promising options are on the horizon as well. In August, BioNTech announced a phase 1 global trial to study BNT116 — a vaccine to treat non–small cell lung cancer (NSCLC). BNT116, like mRNA-4157, targets specific antigens in the lung cancer cells.

“This technology is the next big phase of cancer treatment,” Siow Ming Lee, MD, a consultant medical oncologist at University College London Hospitals, which is leading the UK trial for the lung cancer and melanoma vaccines, told The Guardian. “We are now entering this very exciting new era of mRNA-based immunotherapy clinical trials to investigate the treatment of lung cancer.”

Still, these predictions have a familiar ring. While the prospects are exciting, delivering on them is another story. There are simply no guarantees these strategies will work as hoped.

Then: Where We Were

Cancer vaccine research began to ramp up in the 2000s, and in 2006, the first-generation HPV vaccine, Gardasil, was approved. Gardasil prevents infection from four strains of HPV that cause about 80% of cervical cancer cases.

In 2010, the US Food and Drug Administration approved sipuleucel-T, the first therapeutic cancer vaccine, which improved overall survival in patients with hormone-refractory prostate cancer.

Researchers predicted this approval would “pave the way for developing innovative, next generation of vaccines with enhanced antitumor potency.”

In a 2015 AACR research forecast report, Drew Pardoll, MD, PhD, co-director of the Cancer Immunology and Hematopoiesis Program at Johns Hopkins University, Baltimore, said that “we can expect to see encouraging results from studies using cancer vaccines.”

Despite the excitement surrounding cancer vaccines alongside a few successes, the next decade brought a longer string of late-phase disappointments.

In 2016, the phase 3 ACT IV trial of a therapeutic vaccine to treat glioblastoma multiforme (CDX-110) was terminated after it failed to demonstrate improved survival.

In 2017, a phase 3 trial of the therapeutic pancreatic cancer vaccine, GVAX, was stopped early for lack of efficacy.

That year, an attenuated Listeria monocytogenes vaccine to treat pancreatic cancer and mesothelioma also failed to come to fruition. In late 2017, concerns over listeria infections prompted Aduro Biotech, Inc. to cancel its listeria-based cancer treatment program.

In 2018, a phase 3 trial of belagenpumatucel-L, a therapeutic NSCLC vaccine, failed to demonstrate a significant improvement in survival and further study was discontinued.

And in 2019, a vaccine targeting MAGE-A3, a cancer-testis antigen present in multiple tumor types, failed to meet endpoints for improved survival in a phase 3 trial, leading to discontinuation of the vaccine program.

But these disappointments and failures are normal parts of medical research and drug development and have allowed for incremental advances that helped fuel renewed interest and hope for cancer vaccines, when the timing was right, explained vaccine pioneer Larry W. Kwak, MD, PhD, deputy director of the Comprehensive Cancer Center at City of Hope, Duarte, California.

When it comes to vaccine progress, timing makes a difference. In 2011, Kwak and his colleagues published promising phase 3 trial results on a personalized vaccine. The vaccine was a patient-specific tumor-derived antigen for patients with follicular lymphoma in their first remission following chemotherapy. Patients who received the vaccine demonstrated significantly longer disease-free survival.

But, at the time, personalized vaccines faced strong headwinds due, largely, to high costs, and commercial interest failed to materialize. “That’s been the major hurdle for a long time,” said Kwak.

Now, however, interest has returned alongside advances in technology and research. The big shift has been the emergence of lower-cost rapid-production mRNA and DNA platforms and a better understanding of how vaccines and potent immune stimulants, like checkpoint inhibitors, can work together to improve outcomes, he explained.

“The timing wasn’t right” back then, Kwak noted. “Now, it’s a different environment and a different time.”

A Turning Point?

Indeed, a decade later, cancer vaccine development appears to be headed in a more promising direction.

Among key cancer vaccines to watch is the mRNA-4157 vaccine, developed by Merck and Moderna, designed to prevent melanoma recurrence. In a recent phase 2 study, patients receiving the mRNA-4157 vaccine alongside pembrolizumab had nearly half the risk for melanoma recurrence or death at 3 years compared with those receiving pembrolizumab alone. Investigators are now evaluating the vaccine in a global phase 3 study in patients with high-risk, stage IIB to IV melanoma following surgery.

Another one to watch is the BNT116 NSCLC vaccine from BioNTech. This vaccine presents the immune system with NSCLC tumor markers to encourage the body to fight cancer cells expressing those markers while ignoring healthy cells. BioNTech also launched a global clinical trial for its vaccine this year.

Other notables include a pancreatic cancer mRNA vaccine, which has shown promising early results in a small trial of 16 patients. Of 16 patients who received the vaccine alongside chemotherapy and after surgery and immunotherapy, eight responded. Of these eight, six remained recurrence free at 3 years. Investigators noted that the vaccine appeared to stimulate a durable T-cell response in patients who responded.

Kwak has also continued his work on lymphoma vaccines. In August, his team published promising first-in-human data on the use of personalized neoantigen vaccines as an early intervention in untreated patients with lymphoplasmacytic lymphoma. Among nine asymptomatic patients who received the vaccine, all achieved stable disease or better, with no dose-limiting toxicities. One patient had a minor response, and the median time to progression was greater than 72 months.

“The current setting is more for advanced disease,” Kwak explained. “It’s a tougher task, but combined with checkpoint blockade, it may be potent enough to work.” 

Still, caution is important. Despite early promise, it’s too soon to tell which, if any, of these investigational vaccines will pan out in the long run. Like investigational drugs, cancer vaccines may show big promising initially but then fail in larger trials.

One key to success, according to Kwak, is to design trials so that even negative results will inform next steps.

But, he noted, failures in large clinical trials will “put a chilling effect on cancer vaccine research again.”

“That’s what keeps me up at night,” he said. “We know the science is fundamentally sound and we have seen glimpses over decades of research that cancer vaccines can work, so it’s really just a matter of tweaking things to optimize trial design.”

Companies tend to design trials to test if a vaccine works or not, without trying to understand why, he said.

“What we need to do is design those so that we can learn from negative results,” he said. That’s what he and his colleagues attempted to do in their recent trial. “We didn’t just look at clinical results; we’re interrogating the actual tumor environment to understand what worked and didn’t and how to tweak that for the next trial.”

Kwak and his colleagues found, for instance, that the vaccine had a greater effect on B-cell–derived tumor cells than on cells of plasma origin, so “the most rational design for the next iteration is to combine the vaccine with agents that work directly against plasma cells,” he explained.

As for what’s next, Kwak said: “We’re just focused on trying to do good science and understand. We’ve seen glimpses of success. That’s where we are.”

Sharon Worcester, MA, is an award-winning medical journalist based in Birmingham, Alabama, writing for Medscape Medical News, MDedge, and other affiliate sites. She currently covers oncology, but she has also written on a variety of other medical specialties and healthcare topics. She can be reached atsworcester@mdedge.com or on X:@SW_MedReporter.