--- title: "Moderna and Merck report melanoma vaccine trial success in phase three" publication: "MediaBias News" url: "https://mediabias.news/health/moderna-and-merck-report-melanoma-vaccine-trial-success-in-phase-three" api: "https://mediabias.news/api/v1/stories/moderna-and-merck-report-melanoma-vaccine-trial-success-in-phase-three" markdown: "https://mediabias.news/health/moderna-and-merck-report-melanoma-vaccine-trial-success-in-phase-three.md" audio: "https://mediabias.news/api/audio/moderna-and-merck-report-melanoma-vaccine-trial-success-in-phase-three" category: "Health" published: "2026-08-19T11:25:56.535Z" source_reported: "2026-08-19T10:57:00.000Z" updated: "2026-08-19T12:15:11.562Z" trust_score: 85 critic_score: 85 hype_score: 15 assessment_type: "coverage-and-source-reporting-analysis" fact_check_status: "not-performed" coverage_measured: "2026-08-19T12:58:41.717Z" --- # 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* **Scores for the source reporting** (0-100, assessing the original journalism this article was written from, not this write-up): - Trust 85 of 100, higher is better. Five outlets corroborate the trial outcome; CNBC's full report adds named sources and figures. - Craft 85 of 100, higher is better. All outlets quote affected parties or experts; CNBC names analysts and doctors. - Hype 15 of 100, lower is better. Headlines are measured; no outlet overstates beyond the body text. Scored by MediaBias News; method at https://mediabias.news/methodology. **The short version** - 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. 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. ## Who covered it Shares of the 19 covering outlets with a published leaning rating: - Left: 26% (5) - Centre: 42% (8) - Right: 32% (6) 6 of 25 covering outlets carried no usable leaning rating and were excluded from those percentages. Coverage measured 2026-08-19T12:58:41.717Z. **Coverage watch:** developing. Checked 6 times; 1 check found a material change. Most recently checked 2026-08-19T12:45:09.864Z. ## How the sides framed it ### Left - 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 - 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 - 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. ## Factuality profile of the covering outlets These are published factuality ratings of the outlets, not a verdict on whether this story or its claims are true. - low: 2 - mixed: 2 - high: 7 - unknown: 6 - veryHigh: 8 ## Verification scope This page compares coverage and scores the source reporting. It is not a ClaimReview verdict on whether the underlying event or claim is true. ## Original reporting this was written from - [Crypto Briefing](https://cryptobriefing.com/moderna-stock-soars-over-90-premarket-on-first-phase-3-success-for-mrna-cancer-vaccine) — Moderna stock soars over 90% premarket on first Phase 3 success for mRNA cancer vaccine - [Anadolu Ajansı](https://aa.com.tr/en/world/experimental-cancer-vaccine-shows-promise-in-late-stage-trial/4031729) — Experimental cancer vaccine shows promise in late-stage trial - [France24](https://france24.com/fr/info-en-continu/20260819-moderna-et-merck-annoncent-des-r%C3%A9sultats-encourageants-pour-un-vaccin-th%C3%A9rapeutique-contre-le-cancer-de-la-peau) — Moderna and Merck Announce Encouraging Results for a Therapeutic Skin Cancer Vaccine - [Sud Ouest](https://sudouest.fr/sante/cancer-de-la-peau-moderna-et-merck-annoncent-les-resultats-positifs-d-un-vaccin-experimental-30304119.php) — Skin Cancer: Moderna and Merck Announce Positive Results of an Experimental Vaccine - [CNN](https://cnn.com/2026/08/19/health/moderna-merck-mrna-melanoma-vaccine) — Moderna shares surge as melanoma vaccine with Merck succeeds in large trial - [Forbes](https://forbes.com/sites/tylerroush/2026/08/19/moderna-shares-skyrocket-85-toward-best-day-ever-on-success-of-cancer-drug-trial) — Moderna Shares Skyrocket 85% Toward Best Day Ever—On Success Of Cancer Drug Trial - [Handelsblatt](https://handelsblatt.com/unternehmen/industrie/pharma-moderna-papiere-steigen-vorboerslich-um-fast-60-prozent/100248330.html) — Pharma: Moderna Papers Increase Pre-Trade by Almost 60 Percent - [The News](https://thenews.com.pk/latest/1412794-moderna-merck-personalized-cancer-vaccine-succeeds-in-late-stage-melanoma-trial) — Moderna, Merck ‘personalized’ cancer vaccine succeeds in late-stage melanoma trial - [Bloomberg](https://bloomberg.com/news/articles/2026-08-19/moderna-merck-mrna-shot-helped-cut-melanoma-recurrence-in-big-trial) — Moderna-Merck MRNA Shot Helped Cut Melanoma Recurrence in Big Trial - [manager magazin](https://manager-magazin.de/unternehmen/moderna-aktien-mit-kursrallye-melanom-studie-zeigt-erste-erfolge-bei-krebstherapie-auch-biontech-profitiert-a-d206673a-4bb5-4aa6-9ce3-6a926ffb5f00) — Moderna Shares Rally: Melanoma Study Shows Initial Success in Cancer Therapy, BioNTech Also Benefits - [Seeking Alpha](https://seekingalpha.com/news/4634814-moderna-merck-post-trial-win-mrna-cancer-drug) — Moderna, Merck post trial win for mRNA cancer drug (update) - [BITRSS](https://bitrss.com/moderna-%E7%9B%98%E5%89%8D%E6%B6%A8%E5%B9%85%E6%89%A9%E5%A4%A7%E8%87%B3-30-242777) — Moderna's Pre-Market Gains Widened to 30%. - [Portfolio](https://portfolio.hu/befektetes/20260819/oriasi-attores-tortent-a-rakkutatasban-100-szazalekot-ugrott-a-moderna-arfolyama-857262) — A Huge Breakthrough Has Occurred in Cancer Research - Moderna's Share Price Has Jumped 100 Percent! - [Ynet News](https://ynetnews.com/health_science/article/hk31gm7dfx) — Moderna, Merck mRNA melanoma vaccine succeeds in first late-stage cancer trial - [Dagens industri](https://di.se/live/utbombade-vaccinbolaget-rusar-60-procent-i-usa) — Bombed-Out Vaccine Company Surges 60 Percent in the US - [The Washington Post](https://washingtonpost.com/health/2026/08/19/cancer-treatment-could-face-landmark-moment-with-promising-vaccine) — Cancer treatment could face landmark moment with promising vaccine ... - [Wall Street Journal](https://wsj.com/health/pharma/moderna-merck-vaccine-succeeds-in-preventing-melanoma-from-returning-540e9e18) — Novel Cancer Vaccine Prevents Melanoma From Returning in First for mRNA - [WTVB](https://wtvbam.com/2026/08/19/merck-moderna-say-melanoma-skin-cancer-vaccine-meets-goals-in-large-trial) — Merck, Moderna say melanoma vaccine meets goals in large trial - [CNBC](https://cnbc.com/2026/08/19/moderna-merck-cancer-vaccine-shows-initial-late-stage-melanoma-data.html) — Personalized cancer vaccine from Moderna, Merck shows promise in first late-stage melanoma trial - [STAT](https://statnews.com/2026/08/19/mrna-cancer-vaccine-trial-melanoma-merck-moderna) — Moderna and Merck say mRNA cancer vaccine succeeded in late-stage melanoma trial - [ussanews.com](https://ussanews.com/2026/08/19/merck-and-modernas-personalized-cancer-vaccine-shows-promise-in-first-late-stage-melanoma-trial) — Merck and Moderna’s personalized cancer vaccine shows promise in first late-stage melanoma trial - [UOL](https://www1.folha.uol.com.br/equilibrioesaude/2026/08/moderna-e-merck-anunciam-resultados-promissores-de-vacina-contra-o-cancer-de-pele.shtml) — MSD and Moderna Announce Progress with mRNA Against Melanoma - 19/08/2026 - Balance and Health - [European Medical Journal](https://emjreviews.com/oncology/news/new-pancreatic-cancer-vaccine-shows-promise-in-prevention) — New Pancreatic Cancer Vaccine Shows Promise in Prevention - [Zero Hedge](https://zerohedge.com/markets/holy-grail-cancer-treatment-moderna-erupts-after-melanoma-vaccine-late-stage-trial-success) — Holy Grail In Cancer Treatment? Moderna Erupts After Melanoma Vaccine Late-Stage Trial Success - [Reuters](https://reuters.com/legal/litigation/merck-moderna-say-melanoma-skin-cancer-vaccine-meets-goals-large-trial-2026-08-19) — Merck, Moderna say melanoma vaccine meets goals in large trial ## Questions **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. --- MediaBias News — https://mediabias.news. Reproduced from https://mediabias.news/health/moderna-and-merck-report-melanoma-vaccine-trial-success-in-phase-three. Please cite as: MediaBias News, "Moderna and Merck report melanoma vaccine trial success in phase three", https://mediabias.news/health/moderna-and-merck-report-melanoma-vaccine-trial-success-in-phase-three