Merck and Moderna weigh which tumors to test next for their melanoma vaccine
Merck and Moderna are preparing to file their personalized mRNA melanoma vaccine after a Phase 3 trial showed it delayed recurrence. At the STAT Summit, executives said the next task is showing it works in other tumors, and that they must pick where to look first.
The Scientist · Science desk
Vaccine tumor settings. Adjuvant melanoma: focus to date. Adjuvant lung, kidney, bladder: trials running. Adjuvant pancreatic, gastric: small tests underway. May explore: tumors where Keytruda failed, standalone use in very early stage tumors. Li: others chose cold or metastatic tumors.
- What it sets up precedent Adjuvant melanoma Where the companies have largely focused to date, a setting where Keytruda has worked best, claim 6
- Who has to decide decision Adjuvant lung, kidney, bladder The companies are already running trials, claim 7
- Who has to decide decision Adjuvant pancreatic, gastric Small tests are underway, claim 8
- Who's exposed exposure Tumors where Keytruda failed A setting Li and Hoge may explore, where another kind of immunotherapy worked, claim 9
- Who's exposed exposure Very early stage tumors Li and Hoge suggested possible use as a standalone therapy, claim 9
- Who has to decide decision Cold or metastatic tumors Li contrasted the companies with "other people" who have chosen to go after these tumors, claim 20
| Who | How | Kind | Claim |
|---|---|---|---|
| Adjuvant melanoma | Where the companies have largely focused to date, a setting where Keytruda has worked best | precedent | 6 |
| Adjuvant lung, kidney, bladder | The companies are already running trials | decision | 7 |
| Adjuvant pancreatic, gastric | Small tests are underway | decision | 8 |
| Tumors where Keytruda failed | A setting Li and Hoge may explore, where another kind of immunotherapy worked | exposure | 9 |
| Very early stage tumors | Li and Hoge suggested possible use as a standalone therapy | exposure | 9 |
| Cold or metastatic tumors | Li contrasted the companies with "other people" who have chosen to go after these tumors | decision | 20 |
What happened
- Keytruda works better in so-called hot tumors, which often have lots of mutations, than in cold ones.
- Trials of the vaccine are already running in adjuvant lung, kidney and bladder cancer.
- Small tests in adjuvant pancreatic and gastric cancer are also underway.
- Executives also named tumors where Keytruda failed but another immunotherapy worked, and standalone use in very early-stage tumors, as settings they may explore.
- Each vaccine is built from an individual tumor, with an algorithm selecting up to 34 mutant proteins to show the immune system.
Why it matters
- What it costs cost Each tumor type is its own trial or test, and STAT calls the work careful and costly, so the order in which the companies enroll tumors decides where the money goes first.
- What's now possible capability Immune-system data from trial patients gives Moderna and Merck a way to improve the selection software, though STAT notes the algorithm is imperfect and the gain is so far theoretical.
- What it sets up precedent STAT calls the melanoma result a landmark for a field that has long struggled to live up to its hype, so the next tumor results will be read as a test of whether cancer vaccines reach beyond one disease.
Adjuvant therapy for melanoma is among the settings where Keytruda has worked best, and the companies have largely stayed in such settings so far [6]. The vaccine, intismeran autogene, works in combination with Keytruda [3], a drug tested in thousands of trials over 15 years [4]. Merck R&D chief Dean Li said the companies know "where a checkpoint inhibitor works, where it doesn't, where it almost worked and didn't make it" [10].
That record guides the first trials and also bounds them. Li contrasted the approach with "other people" who "may not have the advantage" of Merck and Moderna's expertise and have chosen to go after cold or metastatic tumors. STAT read this as an apparent nod at BioNTech [20], whose early data are promising in places and include notable failures [22]. "We have chosen not to do this," Li said [21].
The thing this doesn't tell you is how large the melanoma effect is. Merck and Moderna said in August only that the vaccine significantly delayed both recurrence and metastatic disease in a large Phase 3 trial [2]. The statements STAT reported do not include a hazard ratio, event counts, the trial's enrollment or a filing date. Hoge's "several thousand people" is a figure for the Phase 3 program as a whole [14].
Five tumor types beyond melanoma are now in testing: three in adjuvant trials [7] and two in small tests [8], five in all [19]. We think those trials can show whether the vaccine adds to Keytruda in cancers where Keytruda already has a record. They cannot show that it works where Keytruda does not, and that holds only while the trials stay in that territory; STAT's account does not describe their endpoints. Speaking at the STAT Summit on Thursday [17], Moderna President Stephen Hoge said: "We have a lot of exploring to do and need to prioritize where we explore" [11].
Hoge described the longer aim as moving earlier in the disease. "There's an incredible opportunity to think about how we bring immunotherapy into earlier interventions and really intercept cancer so that we don't present with stage three, stage four disease later," he said [18].
What to watch
- The melanoma filing itself, and any hazard ratio, event counts or enrollment figures released with it.
- First readouts from the adjuvant lung, kidney and bladder trials, the nearest test outside melanoma.
- Positive data from a rival such as BioNTech in cold or metastatic tumors, the path Merck and Moderna said they chose not to take.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence40
- Adoption
- Insufficient
- Hype gap+15
- Incentives60
- Confidence55
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
Merck and Moderna are preparing to file their personalized mRNA cancer vaccine for approval.
- [2]
In August, Merck and Moderna announced that the vaccine significantly delayed both cancer recurrence and the development of metastatic disease in melanoma patients in a large Phase 3 trial.
- [3]
The vaccine, known chemically as intismeran autogene, works in combination with Merck's immunotherapy Keytruda.
- [4]
Keytruda has been tested in thousands of trials over the last 15 years.
- [5]
Keytruda works better in so-called hot tumors, which often have lots of mutations, than in so-called cold tumors.
- [6]
The companies have largely focused to date on settings where Keytruda has worked best, such as adjuvant therapy for melanoma patients whose visible tumors have already been removed by a surgeon.
- [7]
The companies are already running trials in adjuvant lung, kidney and bladder cancer.
- [8]
Small tests in adjuvant pancreatic and gastric cancer are underway.
- [9]
Li and Hoge suggested other settings they may explore, including tumors where Keytruda failed but another kind of immunotherapy worked, or use as a standalone therapy in very early stage tumors.
- [10]
"We know exactly where I-O [immuno-oncology] works, where a checkpoint inhibitor works, where it doesn't, where it almost worked and didn't make it," said Dean Li, Merck's R&D chief.
- [11]
"We have a lot of exploring to do and need to prioritize where we explore," Moderna President Stephen Hoge said on stage at the summit.
- [12]
The vaccine is made by looking at individual tumors and using an algorithm to select up to 34 mutant proteins, to flash as a "wanted sign" to the immune system.
- [13]
The selection algorithm is imperfect, but by closely analyzing the immune systems of patients in their trials, Moderna and Merck could in theory build even better software.
- [14]
"It's a real privilege to have all that information across the now several thousand people in our phase three program," Hoge said.
- [15]
STAT described the work of proving the vaccine across other tumors as careful and costly.
- [16]
STAT called the melanoma result a landmark moment for a cancer vaccine field that has long struggled to live up to its hype.
- [17]
Hoge and Li spoke at the STAT Summit on Thursday.
- [18]
"There's an incredible opportunity to think about how we bring immunotherapy into earlier interventions and really intercept cancer so that we don't present with stage three, stage four disease later," said Hoge.
- [19]
Five tumor types beyond melanoma (lung, kidney, bladder, pancreatic, gastric) are in trials or small tests.
- [20]
Li contrasted Merck and Moderna's approach with "other people" who "may not have the advantage" of their expertise and have chosen to go after cold or metastatic tumors; STAT called this an apparent nod at Moderna's mRNA rival BioNTech.
- [21]
"We have chosen not to do this," Li said.
- [22]
BioNTech has some early promising data but also notable failures.
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Sources
1 independent publisher whose own reporting we read for this story.
- statnews.comMerck and Moderna have ‘lot of exploring to do’ after initial cancer vaccine success
1 article · October 15, 2026
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