Moderna and Merck report melanoma vaccine trial success in phase three
Personalised mRNA shot combined with Keytruda extended time without cancer returning in over 1,100 patients
AI-assisted coverage comparison, editor-supervised · How this was made
Moderna and Merck report melanoma vaccine trial success in phase three
Photograph: CNBC (embedded from source)
What this story says
- The phase three trial tested a personalised mRNA cancer vaccine combined with Merck’s Keytruda in over 1,100 melanoma patients after surgical removal of their cancer.
- The treatment met its primary goal, extending the time patients lived without melanoma returning compared with Keytruda alone, and reduced the risk of distant spread.
- Moderna’s stock rose over 10% and Merck’s by more than 1% following the announcement, reflecting investor expectations for the therapy’s potential.
- The companies plan to present full data at an upcoming medical meeting but have not yet disclosed when they will seek regulatory approval.
Who covered it
Percentages are shares of the 12 outlets carrying a published leaning rating. 3 of the 15 outlets we know ran this story carry no rating and are not counted in them. Coverage measured .
Trust
85/100
Craft
85/100
Hype
15/100
15 sources · methodology
Merck and Moderna announced on 19 August 2026 that their personalised mRNA cancer vaccine, combined with Merck’s immunotherapy drug Keytruda, met the primary goal of a phase three trial in patients with high-risk or advanced melanoma. The trial involved more than 1,100 participants whose cancer had been surgically removed. The combination treatment extended the time patients lived without melanoma returning compared with Keytruda alone, and reduced the risk of the cancer spreading to distant parts of the body.
The companies reported the results in a joint statement. Merck’s shares rose more than 1% in premarket trading, while Moderna’s stock jumped over 10%. The trial’s secondary outcomes, including overall survival, are still being assessed. The drugmakers plan to present the full data at an upcoming international medical meeting but have not specified when they will submit applications for regulatory approval in the United States.
The vaccine is designed to target the unique mutations in each patient’s tumour, training the immune system to recognise and attack those markers. Keytruda, already a standard treatment for melanoma, is used to enhance the immune response. Side effects were reported to be similar to those of other vaccines. The trial’s success marks the first positive late-stage results for an mRNA cancer vaccine.
What the coverage left out
None of the digests from the centre-rated or right-rated outlets mentioned the planned presentation of full data at an upcoming medical meeting. The CNBC report, the only full article in the material, was the only one to include details about the vaccine’s personalised mechanism, the side effects, or the broader implications for other cancer types.
Still developing. We have re-checked which outlets are covering this 4 times, most recently on 19 Aug 2026, 12:15, and will add the sides that appear.
How each side covered it
Our own reading of the reporting listed below, written from the outlets’ articles rather than quoted from them. The reasoning is set out on our methodology page.
Left
3 rated outlets
- CNBC led its report with the trial meeting its primary goal of extending the time patients lived without melanoma returning. It quoted Dr. Jane Healy, Merck’s head of oncology early development, who called the results "very exciting" and noted the treatment’s "clinically meaningful improvement" over Keytruda alone. The report also highlighted the personalised approach of the vaccine, describing how it targets unique tumour mutations, and included analyst expectations that the results could validate Moderna’s broader cancer vaccine strategy.
Centre
5 rated outlets
- The three centre-rated digests, from the Wall Street Journal, STAT, and Reuters, all led on the trial’s success in preventing melanoma from returning or spreading. The Wall Street Journal’s digest framed the results as paving the way for a "potentially new life-extending treatment" for melanoma patients. STAT’s digest noted the vaccine’s effect in slowing both recurrence and distant spread. Reuters’ digest described the trial as the first positive late-stage results for an mRNA cancer vaccine, emphasising the reduction in recurrence and spread compared with Keytruda alone.
Right
4 rated outlets
- All four right-rated digests report that Moderna and Merck’s mRNA-based melanoma vaccine succeeded in a phase-three trial. They agree the trial met its primary goal of reducing the risk of melanoma returning or death in patients who had high-risk tumours removed.
- Three digests lead on the share-price reaction. Seeking Alpha and Zero Hedge both note Moderna’s premarket surge, with Zero Hedge quoting an 83 % gain. The News and ussanews.com instead lead on the trial’s status as the first late-stage success for a personalised cancer vaccine.
- None of the digests mention the absolute risk reduction, the number of patients enrolled, or the median follow-up period. Zero Hedge is the only digest to name the vaccine (mRNA-4157/V940) and to specify that the trial combined the vaccine with Merck’s Keytruda.
Read it at the source
15 outlets, grouped by the leaning a published rating gives them. Every headline links to the original; an underlined outlet name opens our profile of that publisher.
Left
3- Moderna, Merck mRNA melanoma vaccine succeeds in first late-stage cancer trial (opens Ynet News in a new tab)
- Cancer treatment could face landmark moment with promising vaccine ... (opens The Washington Post in a new tab)
The Washington Post — is The Washington Post biased? Our profile of this outlet
- Personalized cancer vaccine from Moderna, Merck shows promise in first late-stage melanoma trial (opens CNBC in a new tab)
Centre
5- Moderna-Merck MRNA Shot Helped Cut Melanoma Recurrence in Big Trial (opens Bloomberg in a new tab)
- Novel Cancer Vaccine Prevents Melanoma From Returning in First for mRNA (opens Wall Street Journal in a new tab)
Wall Street Journal — is Wall Street Journal biased? Our profile of this outlet
- Merck, Moderna say melanoma vaccine meets goals in large trial (opens WTVB in a new tab)
- Moderna and Merck say mRNA cancer vaccine succeeded in late-stage melanoma trial (opens STAT in a new tab)
- Merck, Moderna say melanoma vaccine meets goals in large trial (opens Reuters in a new tab)
Right
4- Moderna, Merck ‘personalized’ cancer vaccine succeeds in late-stage melanoma trial (opens The News in a new tab)
- Moderna, Merck post trial win for mRNA cancer drug (update) (opens Seeking Alpha in a new tab)
Seeking Alpha — is Seeking Alpha biased? Our profile of this outlet
- Merck and Moderna’s personalized cancer vaccine shows promise in first late-stage melanoma trial (opens ussanews.com in a new tab)
ussanews.com — is ussanews.com biased? Our profile of this outlet
- Holy Grail In Cancer Treatment? Moderna Erupts After Melanoma Vaccine Late-Stage Trial Success (opens Zero Hedge in a new tab)
Zero Hedge — is Zero Hedge biased? Our profile of this outlet
Not rated
3- Moderna Shares Rally: Melanoma Study Shows Initial Success in Cancer Therapy, BioNTech Also Benefits (opens manager magazin in a new tab)
manager magazin — is manager magazin biased? Our profile of this outlet
- Bombed-Out Vaccine Company Surges 60 Percent in the US (opens Dagens industri in a new tab)
Dagens industri — is Dagens industri biased? Our profile of this outlet
- New Pancreatic Cancer Vaccine Shows Promise in Prevention (opens European Medical Journal in a new tab)
European Medical Journal — is European Medical Journal biased? Our profile of this outlet
Questions about this coverage
- How did the left and right cover Moderna and Merck report melanoma vaccine trial success in phase three?
- Of the 12 outlets on this story carrying a published leaning rating, 25% are rated left, 42% are rated centre, 33% are rated right. Those percentages are shares of the rated outlets, not of every outlet that ran it, which was 15. The sections above set out what each side emphasised, in its own terms.
- Is Moderna and Merck report melanoma vaccine trial success in phase three left or right?
- Neither side dominates it. Of the 12 rated outlets on this story, 25% are rated left, 42% are rated centre, 33% are rated right, and no side holds the 70% this site would want before calling a field one-sided. A story is not left or right in any case; the outlets that carried it are what carry ratings.
- Is the coverage of Moderna and Merck report melanoma vaccine trial success in phase three biased?
- Moderna and Merck report melanoma vaccine trial success in phase three is one event reported by 15 outlets, and this page does not rate the story as biased or unbiased. What it publishes is the spread: which outlets ran it, where named rating organisations place each of them on the spectrum, and what each side chose to lead with. A leaning rating describes an outlet's record over time, not this article, and the two should not be run together.
- Which outlets covered Moderna and Merck report melanoma vaccine trial success in phase three?
- 15 that we know of, every one of them listed further up this page with a link to its own report and to what we hold on the publisher. Nothing here is a summary of somebody else's summary: the outlets are named so the original reporting can be read.
- What did the melanoma vaccine trial achieve?
- The phase three trial found that a personalised mRNA cancer vaccine combined with Keytruda extended the time patients lived without melanoma returning and reduced the risk of the cancer spreading. The results mark the first successful late-stage trial for an mRNA cancer vaccine, with further data to be presented at a medical meeting.
- How many patients were in the melanoma vaccine trial?
- The trial included more than 1,100 patients with higher-risk or advanced melanoma whose cancer had been surgically removed. The combination treatment was compared with Keytruda alone to assess its effectiveness in preventing recurrence and spread.
- When will the melanoma vaccine be available?
- Merck and Moderna have not disclosed when they will submit applications for regulatory approval in the U.S. The companies plan to present full data at an upcoming international medical meeting, but the timeline for approval remains unclear.
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