Moderna stock (NASDAQ: MRNA) just delivered one of the most dramatic single-day moves in biotech history. Shares skyrocketed roughly 177% on Wednesday, August 19, after Moderna and partner Merck announced that their personalized mRNA cancer vaccine — combined with Merck's blockbuster immunotherapy Keytruda — met its primary goal in a late-stage Phase 3 trial designed to keep melanoma from returning. The news re-rated the stock overnight and left investors racing to determine whether the rally still has room to run.
Inside Moderna's Historic 177% Surge
The announcement was the long-awaited payoff for Moderna's biggest pipeline bet beyond COVID-19. The company said the Phase 3 trial of its individualized neoantigen therapy, known as mRNA-4157 (V940), given together with Keytruda (pembrolizumab), met the trial's primary endpoint of preventing recurrence in patients with high-risk melanoma following surgery. Reuters framed the result as a "breakthrough" that "could usher in a wave of cancer vaccines," opening a new avenue of treatment that doctors hope will work against many types of tumors, not just melanoma.
The market's response was immediate and historic. Moderna shares jumped nearly 177% on Wednesday — the biggest one-day gain in the company's history — while Merck also climbed. Just as quickly, the momentum cooled. On Thursday, August 20, Moderna tumbled more than 10% in pre-market trading as investors locked in profits from the surge. By Friday, August 21, the buyers were back: the stock climbed another 16.57% to roughly $155, pushing Moderna's market capitalization to about $62 billion.
Timeline: From Falling COVID Sales to a Cancer Vaccine Breakthrough
Moderna's path to this moment was anything but smooth. After peaking during the pandemic, the company's COVID-19 vaccine business steadily shrank, dragging trailing-twelve-month revenue down 27.6% to about $2.23 billion and leaving the company with a net loss of roughly $3.15 billion.
The cancer vaccine program emerged as the centerpiece of Moderna's post-COVID strategy. The therapy, co-developed with Merck, repurposes the same mRNA platform that powered Moderna's COVID shot to teach a patient's immune system to recognize and attack the specific mutations found in their own tumor.
The key milestones that led to this week's surge:
- 2023–2025: Moderna and Merck advance mRNA-4157/V940 into late-stage testing for melanoma after earlier-phase data suggested a meaningful reduction in the risk of recurrence when added to Keytruda.
- August 19, 2026: The companies announce the Phase 3 trial met its primary goal of preventing melanoma recurrence. Moderna surges roughly 177%, its largest one-day gain ever.
- August 20, 2026: Shares pull back more than 10% in pre-market trading as traders take profits.
- August 21, 2026: The stock rallies again, rising 16.57% to about $155 as Wall Street's re-ratings sink in.
Why Wall Street Raced to Re-Rate Moderna Stock
The data prompted a rapid-fire repricing of analyst targets, even as the broader consensus rating stayed at "Hold." Among the most notable moves:
- UBS analyst Michael Yee nearly tripled his price target to $150 from $50.
- Bank of America Securities upgraded the stock and raised its target to $170 from $40.
- Goldman Sachs lifted its target to $120 from $67.
- Morgan Stanley raised its target to $89 from $39.
The gap between the stock's price and the average analyst target tells its own story. According to data compiled by S&P Global from 23 analysts, the consensus one-year price target sits near $89 — roughly 42% below where Moderna was trading on Friday. Targets range from a low of $25 to a high of $170, reflecting deep disagreement about how much of the cancer-vaccine opportunity is already priced in.
The stakes are substantial. The melanoma indication alone represents a meaningful market, but Reuters reported that doctors and analysts see the approach extending across many tumor types. If the personalized mRNA platform proves broadly applicable, Moderna's $2.23 billion in trailing revenue and ongoing losses could look very different a few years from now. The stock's roughly 467% jump in market value over the past year shows just how aggressively investors are pricing in that possibility.
Where Moderna Stock Stands Now
Moderna traded near the $155 level on Friday morning, up about 16.6% on the day, with a market value close to $62 billion. The move has lifted the stock far above where it traded before the announcement, but it remains just below the highest Wall Street target of $170.
The company's financial picture still shows a business in transition. Trailing revenue of roughly $2.23 billion is down sharply from the pandemic peak, and the company is not yet profitable, posting a net loss of about $3.15 billion over the trailing twelve months. Analysts currently project revenue of about $2.11 billion for fiscal 2026 and $2.43 billion for 2027 — modest growth that does not yet fully capture a potential cancer-vaccine launch.
What Happens Next for Moderna and Merck
The next steps are likely to center on regulatory filings and the full presentation of the Phase 3 data. Investors will watch for the detailed recurrence-free survival results, the safety profile, and the companies' plans to seek regulatory approval and expand into additional tumor types.
The biggest question hanging over the stock is valuation. After a nearly 177% single-day move followed by a renewed rally, much of the near-term enthusiasm may already be reflected in the price — a dynamic underscored by an average analyst target well below the current level. For investors, the tension is between a transformative pipeline story and a stock that has already repriced dramatically. The wide range of price targets, from $25 to $170, reflects genuine uncertainty about how large the cancer-vaccine market will ultimately be.
The Bottom Line: Key Takeaways for Investors
- Moderna and Merck's personalized mRNA cancer vaccine met its primary Phase 3 goal in melanoma, preventing recurrence when combined with Keytruda.
- Moderna stock surged roughly 177% on August 19, its biggest one-day gain ever, and continued climbing to about $155 by August 21.
- Wall Street rapidly raised price targets — UBS to $150, BofA to $170, Goldman to $120 — but the consensus rating remains a Hold with an average target near $89.
- Moderna is still unprofitable, with revenue down 27.6% and a $3.15 billion trailing net loss, making the cancer vaccine the key swing factor for the stock.
