--- title: "Moderna Stock Cools Off After-Hours, Following Massive 177% Cancer Vaccine Rally — Merck, Pfizer and BioNTech Among mRNA Names Trending Tonight" type: "News" locale: "en" url: "https://longbridge.com/en/news/296438657.md" description: "Moderna and Merck shares cooled in after-hours trading following massive intraday rallies driven by positive Phase 3 results for their joint mRNA cancer therapy, intismeran autogene. The trial showed improved survival rates when combined with Merck's KEYTRUDA. Other healthcare stocks like BioNTech, Tempus AI, and Crispr Therapeutics also saw after-hours dips after significant regular-session gains, reflecting broader sector momentum in mRNA and precision oncology." datetime: "2026-08-20T03:29:25.000Z" locales: - [zh-CN](https://longbridge.com/zh-CN/news/296438657.md) - [en](https://longbridge.com/en/news/296438657.md) - [zh-HK](https://longbridge.com/zh-HK/news/296438657.md) generator: "portal-rs" --- # Moderna Stock Cools Off After-Hours, Following Massive 177% Cancer Vaccine Rally — Merck, Pfizer and BioNTech Among mRNA Names Trending Tonight Several healthcare stocks are trending on Wednesday night after popping earlier in the regular session. ## mRNA Names Cool Off After Explosive Session **Moderna Inc.** (NASDAQ:MRNA) shares fell 4.65% to $166.26 after the bell. The biotech stock cooled off an intraday gain of 176.97% to $174.38, according to Benzinga Pro data. **Merck & Co. Inc.** (NYSE:MRK) also dropped 0.46% to $151.50 in after-hours trading. The drop follows an intraday surge of 12.60% to $152.20. ## **Merck, Moderna Report Landmark Phase 3 Cancer Therapy Results** The moves came as Merck and Moderna announced positive Phase 3 results from the INTerpath-001 trial before the market opened Wednesday. The two companies have jointly developed intismeran autogene, an individualized mRNA-based cancer therapy, since 2016. The therapy is custom-built using a patient’s own tumor sample to generate a targeted immune response. The trial evaluated intismeran in combination with KEYTRUDA, Merck’s anti-PD-1 immunotherapy already approved for adjuvant treatment of resected Stage IIB, IIC, or III melanoma. The combination significantly improved recurrence-free survival and distant metastasis-free survival compared to KEYTRUDA alone. This is the first positive Phase 3 result reported for an individualized neoantigen therapy and for an mRNA-based cancer therapy. The trial enrolled 1,137 patients with completely resected stage IIB-IV melanoma. The study will continue to evaluate additional endpoints, including overall survival. ## Trending Peers Also See After-Hours Action **BioNTech SE** (NASDAQ:BNTX) shares dipped 0.55% to $112.50 after hours, following a regular session jump of 21.96%. BioNTech is also developing mRNA-based individualized cancer therapies, placing it in the same treatment category as Merck and Moderna’s intismeran autogene. **Tempus AI Inc.** (NASDAQ:TEM) slipped 0.41% to $61.00 after hours, cooling off from a 24.09% intraday gain. Tempus AI provides genomic sequencing and precision-oncology data used to match cancer patients to targeted therapies, a category that includes individualized neoantigen treatments like intismeran. **Crispr Therapeutics AG** (NASDAQ:CRSP) fell 0.15% to $59.72 after hours, following a 12.91% intraday rise. Crispr Therapeutics develops gene-editing therapies, including cancer treatments, placing it in the broader biotechnology and cell/gene therapy sector alongside Moderna. **Pfizer Inc.** (NYSE:PFE) also eased 0.50% to $28.10 after hours. Pfizer’s muted move reflects its more indirect exposure to Wednesday’s news. The company co-developed the Comirnaty mRNA COVID-19 vaccine with BioNTech and continues to partner with it on updated formulations, but unlike Moderna and BioNTech, Pfizer does not have its own late-stage mRNA-based cancer vaccine program. ## Stock Perfromance | Stock | Market Cap | 52-Week Range | YTD Gain | | ------- | --------------- | ---------------- | -------- | | Moderna | $69.62 Billion | $22.28 – $176.66 | +465.07% | | Merck | $375.50 Billion | $77.58 – $153.50 | +42.98% | With strong Momentum in the 95th percentile, **Benzinga’s Edge Stock Rankings** indicate that MRNA has a positive price trend across all time frames. ***Disclaimer:*** *This content was partially produced with the help of AI tools and was reviewed and published by Benzinga editors.* **Read Also:Big Pharma's Future Growth Rests on Chinese Science? 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