Moderna to Present Phase 1/2 Data on Its Investigational Cancer Antigen Therapy mRNA-4359 as First-Line Therapy in Combination with Pembrolizumab in Locally Advanced or Metastatic Melanoma at the 2026 AACR Annual Meeting

Rhea-AI Summary

Moderna (NASDAQ:MRNA) will present Phase 1/2 data for investigational cancer antigen therapy mRNA-4359 plus pembrolizumab at AACR, April 17-22, 2026, with a session on April 20.

In a 12-patient cohort, the combo produced an ORR 83% (2 CR, 8 PR), DCR 92%, median time to response six weeks, and received FDA Fast Track for CPI-refractory PD-L1+ melanoma (TPS>1%).

Positive

• ORR 83% among 12 patients
• DCR 92% in dose-expansion cohort
• Two complete responses observed
• Median time to response: six weeks
• FDA Fast Track designation granted

Negative

• Very small cohort: only 12 patients
• Wide confidence intervals around response rates
• Prior CPI-refractory cohort showed ORR 24% (n=29)

News Market Reaction – MRNA

-1.76%

-1.76% Session close to close

In the Apr 17 session, MRNA declined 1.76%, reflecting a mild negative market reaction.

Data tracked by StockTitan Argus on the day of publication.

Market Context

This announcement highlights early but striking first-line melanoma data for mRNA‑4359 plus pembroli...

Analysis

This announcement highlights early but striking first-line melanoma data for mRNA‑4359 plus pembrolizumab, with an ORR of 83% and DCR of 92% in 12 patients and supportive prior CPI‑refractory results. It adds to a pattern of oncology and vaccine trial updates that have driven mixed single‑day moves, averaging -0.94%. Investors may watch for larger, confirmatory studies, durability of responses, regulatory interactions following Fast Track, and how this program fits alongside Moderna’s broader oncology pipeline.

Key Figures

Overall response rate: 83% ORR (95% CI: 52%-98%) Disease control rate: 92% DCR (95% CI: 62%-100%) Patient count: 12 participants +5 more

8 metrics

Overall response rate 83% ORR (95% CI: 52%-98%) Phase 2 dose-expansion, 12 first-line melanoma patients

Disease control rate 92% DCR (95% CI: 62%-100%) Phase 2 dose-expansion, 12 first-line melanoma patients

Patient count 12 participants Phase 2 dose-expansion cohort, first-line melanoma

Complete responses 2 complete responses mRNA-4359 + pembrolizumab Phase 2 cohort

Partial responses 8 partial responses mRNA-4359 + pembrolizumab Phase 2 cohort

Median time to response 6 weeks (range 5.6–24.0) Phase 2 dose-expansion, first-line melanoma

Prior ORR in CPI-R/R 24% ORR 29 evaluable CPI-resistant/refractory melanoma patients at 2025 ESMO

Prior DCR in CPI-R/R 60% DCR 29 evaluable CPI-resistant/refractory melanoma patients at 2025 ESMO

Previous Clinical trial Reports

5 past events · Latest: Jan 20 (Positive)

Same Type Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
Jan 20	Melanoma survival data	Positive	+2.8%	Five-year data showed 49% lower recurrence/death vs KEYTRUDA alone.
Dec 18	Flu vaccine funding	Positive	+1.4%	CEPI committed up to $54.3M for Phase 3 H5 influenza study.
Nov 03	Myeloma TCE first dose	Positive	-8.3%	First patient dosed in Phase 1/2 mRNA‑2808 multiple myeloma trial.
Oct 22	CMV trial failure	Negative	-2.2%	Phase 3 CMV vaccine mRNA‑1647 missed primary endpoint; program discontinued.
Jun 30	Flu Phase 3 success	Positive	+1.6%	Seasonal flu vaccine mRNA‑1010 showed 26.6% superior relative efficacy.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

Clinical trial headlines have mostly led to modest positive reactions, with one notable negative divergence on early-stage oncology data.

Recent Company History

Recent clinical news for Moderna has spanned melanoma, pandemic influenza, multiple myeloma, CMV and seasonal flu vaccines. On Jan 20, 2026, five‑year melanoma data for intismeran autogene plus KEYTRUDA showed a 49% risk reduction, and the stock rose. Earlier, CEPI funding of up to $54.3M for an H5 influenza Phase 3 trial and positive Phase 3 flu vaccine efficacy data also coincided with gains. In contrast, a failed CMV Phase 3 on Oct 22, 2025 and an early multiple myeloma T‑cell engager update on Nov 3, 2025 saw negative moves.

Key Terms

fast track designation, overall response rate, disease control rate, complete response, +4 more

8 terms

fast track designation regulatory

"The U.S. FDA has granted Fast Track designation for mRNA-4359 in combination..."

Fast track designation is a status the U.S. Food and Drug Administration grants to drugs intended to treat serious conditions and address an unmet medical need. It gives the developer more frequent communication with the FDA and can allow parts of the application to be reviewed on a rolling basis, and it may pave the way to priority review or accelerated approval. It can shorten development timelines, though it does not guarantee approval.

overall response rate medical

"mRNA-4359 + pembrolizumab resulted in an overall response rate (ORR) of 83%..."

Overall response rate is the percentage of patients in a clinical study whose measurable disease shrinks or disappears after receiving a treatment. Investors watch it like a product’s “hit rate” because higher response rates can signal a drug’s effectiveness, boost chances of regulatory approval and market demand, and affect a company’s future revenue prospects, similar to how a higher batting average suggests a more reliable player.

disease control rate medical

"...as well as a disease control rate (DCR) of 92% (95% CI: 62%-100%)."

The disease control rate is the share of patients in a clinical trial whose cancer or condition either shrinks or stops getting worse for a specified period after treatment. Think of it like the percentage of people for whom a treatment hits pause or nudges back the problem rather than letting it progress; higher rates suggest the therapy can meaningfully limit disease, which matters to investors assessing a drug’s potential efficacy and commercial value.

complete response medical

"...with two patients achieving a complete response and eight achieving a partial response..."

A complete response is a positive outcome in which a company’s efforts to address issues or questions fully resolve the problem, often meaning that no further action or investigation is needed. For investors, it signals that concerns have been thoroughly addressed, which can boost confidence in the company's stability or decision-making. Think of it like a doctor fully treating an illness, leaving no remaining symptoms.

partial response medical

"...two patients achieving a complete response and eight achieving a partial response..."

A partial response is a clinical outcome where a treatment produces a clear, measurable improvement in a disease — for example a substantial shrinkage of a tumor or reduction in symptom measures — but does not eliminate the disease entirely. For investors it signals meaningful efficacy that can support regulatory progress, further trials, or commercial potential, like seeing a product gain market traction even though it hasn’t achieved a complete cure.

pd-l1 medical

"Responses occurred across baseline tumor PD-L1 expression categories..."

PD-L1 is a protein found on the surface of some cells that acts like a stop sign for the immune system, telling certain immune cells to back off. It matters to investors because many cancer drugs and diagnostic tests target or measure PD-L1 to unlock immune responses or predict which patients will benefit, affecting clinical success, regulatory approval, and potential sales in the oncology market.

checkpoint inhibitor medical

"...checkpoint inhibitor refractory unresectable or metastatic melanoma with PD-L1+..."

A checkpoint inhibitor is a type of medicine that helps the immune system spot and attack cancer by blocking proteins that act like brakes on immune cells. For investors, these drugs matter because clinical trial results, regulatory approvals, safety profiles and market demand can quickly change a developer’s revenue and valuation; think of them as releasing the brakes on the immune system—potentially high reward but with safety and trial-risk consequences.

phase 1/2 medical

"...data from a Phase 1/2 study of mRNA-4359, an investigational cancer antigen therapy..."

Phase 1/2 is a combined early-stage clinical trial that first tests a new drug or treatment for safety and the right dose, then quickly expands to check if it shows any signs of working in patients. For investors, results from a Phase 1/2 study offer an early read on both risk and potential reward—like a prototype test that both confirms a product won’t harm users and suggests whether it could sell—helping guide valuation and development decisions.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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The U.S. FDA has granted Fast Track designation for mRNA-4359 in combination with pembrolizumab for the treatment of checkpoint inhibitor refractory unresectable or metastatic melanoma with PD-L1+ (TPS>1%)

CAMBRIDGE, MA / ACCESS Newswire / April 17, 2026 / Moderna, Inc. (NASDAQ:MRNA) today announced that the Company will present data from a Phase 1/2 study of mRNA-4359, an investigational cancer antigen therapy, at the American Association for Cancer Research (AACR) Annual Meeting in San Diego, CA, on April 17-22, 2026. The presentation reports safety, efficacy and translational data from a Phase 2 dose-expansion cohort of the Phase 1/2 study (NCT05533697), which evaluated mRNA-4359 + pembrolizumab as a first-line therapy in patients with locally advanced or metastatic melanoma.

Among 12 participants, mRNA-4359 + pembrolizumab resulted in an overall response rate (ORR) of 83% (95% CI: 52%-98%), with two patients achieving a complete response and eight achieving a partial response, as well as a disease control rate (DCR) of 92% (95% CI: 62%-100%). The median time to response was six weeks (range, 5.6-24.0). Responses occurred across baseline tumor PD-L1 expression categories, with an ORR of 88% (95%CI: 47%-100%) among patients with PD-L1+ (TPS≥1%) tumors, and 67% (95%CI: 9%-99%) among patients with PD-L1- (TPS<1%) tumors. Consistent with mRNA-4359's mechanistic rationale, antigen-specific T-cell responses and novel expanded T-cell receptor (TCR) clonality was observed in all patients (n=7) with evaluable samples. mRNA-4359 + pembrolizumab demonstrated a manageable safety profile, with no new immune-related adverse events (AEs).

"This study evaluating mRNA-4359 + pembrolizumab as a first-line treatment option reflects our ambition to demonstrate the potential of mRNA technology throughout a cancer patient's journey. While conducted among a small patient population, we are encouraged by the high response rates and mechanistic translational results," said David Berman, M.D., Ph.D., Chief Development Officer of Moderna. "We look forward to further evaluating the potential of mRNA-4359 in patients with melanoma."

"This early data supports the potential activity of the mRNA-4359 + pembrolizumab combination, with promising anti-tumor activity," Dr. Pavlina Spiliopoulou, School of Cancer Sciences, University of Glasgow, the abstract's lead author and presenter. "The consistent activation of antigen-specific T-cell responses provides important early evidence that mRNA technology could be used to help direct the immune system against melanoma in a multi-targeted manner."

This presentation builds on promising early data presented at the 2025 European Society for Medical Oncology Congress, in which mRNA-4359 + pembrolizumab achieved an ORR of 24% and DCR of 60% among 29 evaluable patients with checkpoint inhibitor-resistant/refractory (CPI-R/R) melanoma. Among those with response-evaluable disease and PD-L1+ (TPS≥1%) tumors, the ORR was 67%.

The U.S. FDA has granted Fast Track designation for mRNA-4359 in combination with pembrolizumab for the treatment of CPI refractory unresectable or metastatic melanoma with PD-L1+ (TPS>1%). Fast Track is designed to facilitate the development and expedite the review of therapies and vaccines for serious conditions and that fill an unmet medical need. Programs with Fast Track designation may benefit from early and frequent communication with the FDA, in addition to a rolling submission of the marketing application.

The details of the presentation are as follows:

• Abstract Presentation #CT106: First-Line mRNA-4359 Plus Pembrolizumab (Pembro) in Locally Advanced or Metastatic Melanoma: Results from the Phase 1/2 mRNA-4359-P101 Study

• Session Title: Clinical Trials Plenary 3: Cellular Therapies and Complex Immunotherapies

• Session Date/Time: Monday, April 20, 10:15AM - 12:15PM PT

• Presenter: Dr. Pavlina Spiliopoulou, School of Cancer Sciences, University of Glasgow, UK

About mRNA-4359

mRNA-4359 is an investigational, immune-evasion targeted cancer antigen therapy that encodes broad epitopes of PD-L1 and IDO1. With its dual mechanism of action, it is designed to elicit antigen-specific T-cell responses to simultaneously: (1) kill tumor cells expressing PD-L1 and IDO1, and (2) deplete immunosuppressive cells that shield the tumor from attack. This is hypothesized to rebalance the tumor microenvironment into an immune-permissive state, supporting sustained and durable anti-tumor activity with a manageable safety profile.

About Moderna

Moderna is a pioneer and leader in the field of mRNA medicine. Through the advancement of its technology platform, Moderna is reimagining how medicines are made to transform how we treat and prevent diseases. Since its founding, Moderna's mRNA platform has enabled the development of vaccines and therapeutics across infectious diseases, cancer, rare diseases and more.

With a global team and a unique culture, driven by the company's values and mindsets, Moderna's mission is to deliver the greatest possible impact to people through mRNA medicines. For more information about Moderna, please visit modernatx.com and connect with us on X, Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including statements regarding: the safety and efficacy of mRNA-4359; the potential of mRNA-4359 in oncology; encouraging high response rates and mechanistic translational results; and the potential to benefit from the Fast Track designation for mRNA-4359 in combination with pembrolizumab. In some cases, forward-looking statements can be identified by terminology such as "will," "may," "should," "could," "expects," "intends," "plans," "aims," "anticipates," "believes," "estimates," "predicts," "potential," "continue," or the negative of these terms or other comparable terminology, although not all forward-looking statements contain these words. The forward-looking statements in this press release are neither promises nor guarantees, and you should not place undue reliance on these forward-looking statements because they involve known and unknown risks, uncertainties, and other factors, many of which are beyond Moderna's control and which could cause actual results to differ materially from those expressed or implied by these forward-looking statements. These risks, uncertainties, and other factors include, among others, those risks and uncertainties described under the heading "Risk Factors" in Moderna's Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the U.S. Securities and Exchange Commission (SEC), and in subsequent filings made by Moderna with the SEC, which are available on the SEC's website at www.sec.gov. Except as required by law, Moderna disclaims any intention or responsibility for updating or revising any forward-looking statements contained in this press release in the event of new information, future developments or otherwise. These forward-looking statements are based on Moderna's current expectations and speak only as of the date of this press release.

Moderna Contacts

Media:

Chris Ridley
Vice President, Global Head of Communications
+1 617-800-3651
Chris.Ridley@modernatx.com

Investors:

Lavina Talukdar
Senior Vice President & Head of Investor Relations
+1 617-209-5834
Lavina.Talukdar@modernatx.com

SOURCE: Moderna, Inc.

View the original press release on ACCESS Newswire

FAQ

What were the Phase 1/2 mRNA-4359 plus pembrolizumab results presented by Moderna (MRNA) at AACR 2026?

The combination produced an overall response rate of 83% in a 12-patient first-line cohort, with two complete responses and eight partial responses. According to the company, the study showed a disease control rate of 92% and a median time to response of six weeks.

What does the FDA Fast Track designation for mRNA-4359 mean for Moderna (MRNA)?

Fast Track may expedite development and review for mRNA-4359 in CPI-refractory PD-L1+ melanoma, offering more communication with FDA and potential rolling submissions. According to the company, Fast Track aims to facilitate development for therapies addressing serious unmet medical needs.

When and where did Moderna (MRNA) present the mRNA-4359 data at AACR 2026?

Moderna presented the Phase 1/2 data at the AACR Annual Meeting in San Diego, April 17-22, 2026, with the session on April 20 at 10:15 AM PT. According to the company, the abstract number is CT106 and the presenter is Dr. Pavlina Spiliopoulou.

How should investors interpret the mRNA-4359 efficacy data for Moderna (MRNA)?

The reported 83% ORR and 92% DCR suggest promising early activity, but the cohort included only 12 patients and confidence intervals are wide. According to the company, results are encouraging yet preliminary and require larger studies for confirmation.

What are the next development steps for mRNA-4359 after the AACR 2026 presentation by Moderna (MRNA)?

Moderna indicated plans to further evaluate mRNA-4359 in melanoma, building on these early results and prior 2025 data in CPI-refractory patients. According to the company, additional studies will assess activity across PD-L1 subgroups and continued translational endpoints.