Emerging Potential of mRNA Cancer Vaccines
Gary Keblish, a teacher diagnosed with melanoma in 2019, faced a challenging battle against cancer that began with the surgical removal of his tumor. When standard treatments posed ongoing risks of recurrence, he enrolled in a clinical trial for the personalized mRNA cancer vaccine developed by Merck and Moderna.
Reflecting on his journey during a video session at the recent STAT Summit, Keblish compared the experience to a ride on Ms. Frizzle’s Magic School Bus, humorously quipping, “Seatbelts, everyone!” His participation in the trial offered him renewed hope, and he’s now living cancer-free, as these companies prepare to seek regulatory approval for their vaccine after reporting significant findings in their Phase 3 study.
A Promising Landmark Moment
This development represents a pivotal point for the cancer vaccine sector, which has historically struggled to deliver on expectations. However, the work of Merck and Moderna is far from complete; their immediate goal is to validate that this mRNA vaccine is effective not only for melanoma but can also adapt to treat various other forms of cancer as immunotherapies began to do in the past.
"We have a lot of exploring to do and need to prioritize where we explore," commented Moderna President Stephen Hoge during discussions at the summit.
Strategizing for Broader Applications
Alongside Hoge, Merck's R&D chief Dean Li outlined an expansive strategy. The vaccine, known chemically as intismeran autogene, operates in conjunction with Merck’s established immunotherapy, Keytruda. Keytruda has shown variable effectiveness, excelling in tumors characterized by a high mutation burden, often referred to as hot tumors, while displaying limited success in cold tumors.
“We know exactly where immuno-oncology works, where a checkpoint inhibitor works or doesn't, and where near misses occur,” explained Li.
Identifying New Targets for Trials
Currently, the focus is on the most favorable applications of Keytruda, particularly as an adjuvant therapy for melanoma patients whose tumors have been surgically excised. Trials are already taking place for adjuvant treatments in lung, kidney, and bladder cancers.
Li and Hoge are eyeing additional avenues for exploration. This might include targeting tumors where Keytruda has faltered but other immunotherapies have shown promise, or employing the vaccine as a standalone treatment for early-stage cancers. “There’s an incredible opportunity to think about how we intervene earlier with immunotherapy to prevent the progression to advanced stages,” noted Hoge.
Comparison with Competitors
Whereas some companies, hinting at competitors like BioNTech, are tackling cold or metastatic tumors—often with mixed outcomes—Li emphasized that Merck and Moderna have strategically chosen to avoid those terrains. “But I can assure you, if anyone presents positive data, you'll see us pivot faster than anyone else,” he said confidently.
Expanding Research Horizons
In addition to ongoing trials, small-scale studies are underway in pancreatic and gastric cancers, a step towards assessing the vaccine's effectiveness in more complex scenarios. Furthermore, Li suggested that they may also evaluate using the vaccine on patients with already reduced metastatic tumors from previous treatments.
Advancing Technology Through Data
The development of the vaccine incorporates sophisticated technology. By analyzing individual tumors, the teams utilize algorithms to identify up to 34 mutant proteins, aiming to signal these to the immune system. While this method is not foolproof, continuous data analysis from trials could eventually lead to refinements in the algorithm.
“It's a privilege to have access to extensive data from several thousand individuals enrolled in our Phase 3 program,” Hoge reflected, expressing enthusiasm for the potential insights to be gleaned from this comprehensive data.
As Merck and Moderna advance their mission in the realm of cancer treatments, the road ahead is laden with opportunities and challenges, promising a future that could reshape the landscape of cancer care.