With the first positive Phase III outcome of the mRNA tumor vaccine obtained, what is Moderna re-evaluating?

On August 19, Moderna and Merck announced that Intismeran Autogene, an individualized neoantigen therapy co-developed by the two parties, has achieved positive top-line results in the Phase III clinical trial for high-risk melanoma.

Following the announcement, Moderna's share price closed up 177%, while Merck's share price rose by 12.6%. For Merck with a larger business scale, this is a rare single-day increase.

This trial named INTerpath-001 shows that adding Intismeran Autogene to pembrolizumab can significantly improve patients' recurrence-free survival and distant metastasis-free survival. According to the two companies, this is the first time that an individualized neoantigen therapy has achieved positive results in a Phase III clinical trial, and it is also the first mRNA-based cancer therapy to cross this threshold.

However, up to now, the two parties have not released core data such as hazard ratio, confidence interval and absolute recurrence rate, and the overall survival results are still immature.

So here comes the question, why can a top-line result without complete published data excite the market so much?

The answer obviously goes far beyond melanoma.

What the market is really trading is that this result may simultaneously answer three long-standing unresolved questions: whether therapeutic cancer vaccines can be validated in large-scale randomized trials; whether mRNA can open up a sufficiently large commercial space beyond COVID-19 vaccines; and whether the "one drug for one patient" individualized therapy can be transformed into a replicable industrial system.

Positive, but the most critical figures have not yet been released

INTerpath-001 is a global randomized, double-blind Phase III trial that enrolled a total of 1137 patients with stage IIB to IV cutaneous melanoma whose tumors have been completely resected but still have a high risk of recurrence.

Patients received Intismeran Autogene combined with pembrolizumab or pembrolizumab monotherapy at a ratio of 2:1, with a maximum treatment course of about one year.

According to the pre-specified interim analysis, the Independent Data Monitoring Committee confirmed that the combination regimen has achieved statistically significant and clinically meaningful improvements in the primary endpoint of recurrence-free survival and the key secondary endpoint of distant metastasis-free survival. The safety profile is basically consistent with previous studies, and no new safety signals have been identified.

However, positive top-line results do not mean that the data is complete.

The Associated Press pointed out that the two companies have not specified how long the recurrence-free survival of patients has been extended, nor have they proved that the combination therapy can prolong overall survival. The relevant detailed data will be released at international medical conferences, and the study will continue to follow up.

The working mechanism of Intismeran Autogene is different from traditional preventive vaccines. Pembrolizumab removes the "brake" that the immune system receives when attacking tumors by inhibiting the PD-1 pathway, while Intismeran Autogene tries to tell the immune system exactly which targets to attack.

Before the start of treatment, the enterprise needs to sequence the tumor tissue and normal tissue of the patient respectively, screen for mutations that only exist in tumor cells, and then select the neoantigens most likely to trigger an immune response through algorithms. The final mRNA drug can encode up to 34 neoantigens and is delivered via lipid nanoparticles.

This means that the drug sequence obtained by each patient may be different. Its goal is not to prevent a healthy person from developing cancer, but to train the immune system to identify residual minimal lesions after the tumor is completely surgically resected, so as to reduce the risk of recurrence and distant metastasis.

The Phase III results did not appear out of thin air.

The previous Phase II study involving 157 patients showed that at a median follow-up of about five years, Intismeran Autogene combined with pembrolizumab reduced the risk of recurrence or death by 49% and the risk of distant metastasis or death by 59% compared with pembrolizumab monotherapy. There was a favorable trend in overall survival, but the confidence interval was wide, and no definite conclusion could be drawn based on this.

The significance of the Phase III trial is to advance this signal from a small-scale study to a registrational trial with more than 1100 participants. It improves the credibility of the results, but does not eliminate the inquiries about effect size, stage differences and overall survival.

Wall Street is buying more than just a melanoma indication

For Moderna, this result is particularly critical.

After the demand for COVID-19 vaccines declined, Moderna has been facing the dual pressure of plummeting revenue and high R&D investment. In the second quarter of 2026, the company's total revenue was only 145 million US dollars, R&D expenses reached 651 million US dollars, and the net loss was 782 million US dollars.

As of the end of the second quarter, Moderna held approximately 6.9 billion US dollars in cash, cash equivalents and investments. The company expects that after considering approximately 950 million US dollars in litigation-related payments, the cash and investment balance at the end of 2026 will be approximately 4.7 billion to 5.2 billion US dollars.

This shows that the positive Phase III result has not immediately solved Moderna's cash consumption problem, but it has changed investors' judgment on what this consumption can bring in return.

Barclays analysts previously estimated that in the melanoma field alone, Intismeran Autogene's sales could reach approximately 3 billion US dollars by 2035. If indications such as lung cancer, bladder cancer and kidney cancer are subsequently validated, the commercial ceiling will continue to rise.

But Moderna does not enjoy all the value exclusively.

In 2016, Moderna and Merck established a partnership for individualized cancer vaccines. In 2022, Merck paid 250 million US dollars to exercise the option of joint development and commercialization. According to the cooperation arrangement, the two parties will jointly bear the relevant development costs and share the profits equally after the product is commercialized. Moderna is mainly responsible for drug design and production, while Merck contributes pembrolizumab and its global oncology commercial system.

At present, the two parties are advancing 9 Phase II or Phase III trials in the fields of melanoma, non-small cell lung cancer, bladder cancer, kidney cancer and other fields.

Therefore, the rise in share price reflects not only the sales expectation of a single indication, but also a re-pricing by the capital market of the success probability of Moderna's oncology mRNA platform.

Previously, investors could only use Phase II data to value this platform. Now, at least in the scenario of post-operative high-risk melanoma, the individualized neoantigen therapy has crossed the key threshold of Phase III clinical trials.

This is why the market reaction far exceeds the magnitude of the announcement of positive Phase III results of an ordinary oncology drug.

Ahead of Keytruda's patent cliff, Merck needs new combination value

This result is equally important for Merck.

In 2025, pembrolizumab's sales reached approximately 31.7 billion US dollars, close to half of Merck's total annual revenue of approximately 65 billion US dollars. Some institutions predict that its sales may peak at approximately 35 billion US dollars around 2028.

But at the same time, the core patent protection of pembrolizumab will expire one after another in major markets around 2028.

Companies such as Sandoz, Samsung Bioepis, Amgen and Celltrion have all advanced the development of pembrolizumab biosimilars. Merck is extending the commercial life cycle of the Keytruda system as much as possible through the subcutaneous injection formulation Keytruda Qlex, perioperative treatment regimens and new combination therapies.

Intismeran Autogene itself cannot extend the patent of pembrolizumab.

What it can do is create new incremental value on the basis of existing PD-1 treatment: if the combination regimen can significantly reduce the risk of recurrence, some patients who originally only used pembrolizumab may switch to higher-value combination therapy in the future.

The other layer is the combination value.

Merck has a huge Keytruda clinical development and commercial network, and Moderna has the capability of individualized mRNA design and production. After the combination of the two, Keytruda is no longer just a single product waiting for biosimilar competition, but may also become the basic partner for individualized cancer vaccines to enter multiple tumor types.

For Merck, this is a defense before the patent cliff; for Moderna, it reduces the market education cost of a brand-new treatment model with the help of the world's most mature oncology immunotherapy commercial platform.

The real moat may lie in the factory

The most easily overlooked difficulty of individualized neoantigen therapy is not whether mRNA can be synthesized, but whether the "one drug for one patient" model can be industrialized.

Traditional drugs are produced in one large batch in the factory and then distributed to thousands of patients. The process of Intismeran Autogene is completely different:

Obtain tumor tissue through surgery, complete sequencing of tumor and normal samples, identify mutations, predict neoantigens, design patient-specific sequences, and then carry out mRNA synthesis, lipid nanoparticle encapsulation, quality testing and transportation.

One patient is one batch.

The Phase II study published in *Journal of Clinical Oncology* shows that among 185 screened patients, 156 successfully completed the individualized drug design, accounting for 84.3%; the manufacturing success rate after entering the subsequent production links exceeded 99%.

This set of data shows that algorithm design and sample quality may become the loss link earlier than pure mRNA production.

Information disclosed as early as 2023 shows that it took about 6 to 8 weeks from tumor sampling to drug delivery at that time. For post-operative adjuvant therapy, this cycle still has a certain operating space; but if it enters advanced tumors with faster progression in the future, the delivery speed may directly affect the number of treatable patients.

To this end, Moderna has built a dedicated production facility for individualized neoantigen therapies in Marlborough, Massachusetts, with relevant investment of at least 322 million US dollars.

The significance of this factory is not only to expand production capacity, but also to try to establish a new production paradigm: simultaneously manage a large number of small-batch products with different sequences, and ensure that each batch of drugs can complete production, release and distribution within the specified time.

Therefore, what investors need to observe next cannot only be clinical endpoints.

How many days does it take from surgery to the first dose? What is the sample failure rate? How high is the one-time production success rate? Can it be released on time? Can the unit production cost decrease as the scale expands?

These indicators will not appear directly on the recurrence-free survival curve, but they may determine how many hospitals, how many countries and how many patients this product can ultimately cover.

If Moderna can stably complete this process, what it has established is not just a drug, but an industrial system that connects sequencing, algorithms, mRNA production and clinical delivery.

Positive Phase III result does not mean the whole track passes the customs

The success of Intismeran Autogene will increase the market's attention to individualized cancer vaccines, but it will not automatically increase the success probability of all neoantigen companies.

On the one hand, the positive result obtained this time is for post-operative high-risk melanoma.

Melanoma usually has a high tumor mutation burden and is more likely to produce neoantigens that can be recognized by the immune system; at the same time, the trial selected patients whose tumors have been completely resected but still have a risk of recurrence, with a relatively low tumor burden.

This may be one of the ideal application scenarios for therapeutic cancer vaccines.

On the other hand, Intismeran Autogene did not succeed as a single agent, but was used in combination with the mature PD-1 drug pembrolizumab. The cancer vaccine is responsible for expanding and training T cells targeting tumors, while the PD-1 inhibitor helps these T cells maintain their attack ability.

This is more like a combination verification of "antigen supply + immune de-suppression", rather than a general endorsement of all mRNA oncology therapies.

The experience of competitors also shows that this track is far from smooth sailing.

autogene cevumeran, an individualized mRNA neoantigen therapy co-developed by BioNTech and Genentech (a subsidiary of Roche), is still advancing clinical research in pancreatic cancer and colorectal cancer, but the two parties stopped its urothelial cancer project in 2026.

IO Biotech developed the off-the-shelf peptide cancer vaccine Cylembio. Its Phase III trial for melanoma showed that after combining with nivolumab, the risk of disease progression or death decreased by 23%, but the result did not reach statistical significance. After that, the company laid off staff and sought strategic alternatives.

GRANITE, an individualized neoantigen vaccine developed by Gritstone bio, once showed some early signals in the study of microsatellite stable colorectal cancer, but the key results have great uncertainty. The company filed for bankruptcy protection in 2024.

These cases point to the same conclusion: the neoantigen platform is reusable, but clinical results cannot be simply replicated across different tumor types, different disease stages, different antigen forms and different combination regimens.

Intismeran Autogene has opened a door for this field, but it has not walked the whole road for all latecomers.

Next, the market is waiting for four sets of figures

For Biotech leaders and investors, what really determines the value of Intismeran Autogene is not the word "positive", but the four sets of figures to be disclosed soon.

The first set is hazard ratio, confidence interval and absolute benefit.

Statistical significance only indicates that the difference between the two groups is unlikely to be caused by random factors, and cannot indicate how large the difference is. Only by combining the recurrence-free survival rates at different time points can we judge how many patients need to be treated to avoid one recurrence or death event.

The second set is the benefits of patients at different stages.

Patients with stage IIB and IIC have different recurrence risks, treatment foundations and acceptable risks from patients with stage III and IV. If the efficacy is mainly driven by the population with the highest recurrence risk, the final approved population and commercial space may be affected.

The third set is safety, discontinuation rate and manufacturing completion rate.

A drug for post-operative adjuvant therapy is targeted at patients who have completed tumor resection and have no visible lesions for the time being. Regulators, doctors and patients usually have lower tolerance for toxicity and treatment burden than advanced tumor treatment.

At the same time, how many patients successfully obtained exclusive drugs after random enrollment and how long the actual waiting time is will also affect the interpretation of real-world efficacy.

The fourth set is overall survival, pricing and unit economics.

If the combination therapy can only prolong recurrence-free survival, whether it can be converted into overall survival benefit will affect its long-term clinical status. Even if approved, the enterprise still needs to answer questions such as how to price individualized drugs, whether payers accept it, and whether manufacturing costs can support large-scale commercialization.

Apart from data, there are regulatory paths to observe.

The US FDA released two draft guidance documents in 2025 respectively: one suggests that new tumor combination regimens need to explain the contribution of each component to the overall efficacy; the other suggests that randomized tumor trials should include overall survival analysis in the design and statistical analysis plan, and take it as a pre-specified safety endpoint.

INTerpath-001 uses pembrolizumab monotherapy as the control, which objectively helps to identify the incremental contribution after adding Intismeran Autogene; the study will also continue to follow up overall survival according to the established protocol.

It should be noted that the above documents are still drafts, and their suggestions are not equivalent to the current regulations with mandatory effect.

The FDA's draft guidance on platform technology recognition provides another imagination space for reusable technology platforms such as mRNA and lipid nanoparticles: if the platform meets the corresponding conditions, subsequent products may leverage existing experience in some production, quality control or non-clinical data.

However, platform recognition is not an automatic accelerated approval, let alone that the success of one tumor type can replace the clinical evidence of another tumor type.

From Merck paying 250 million US dollars to exercise the cooperation option in 2022, to Moderna's share price rising by 177% in a single day in 2026, Intismeran Autogene has demonstrated huge capital leverage.

Next, it also needs to prove its industrial leverage.

The positive Phase III result has only crossed the key clinical verification threshold. That is to say, the truly difficult second half has just begun.

This article is from the WeChat official account "Molecular Steady State", written by Innovative Drug Team · Steady State Jun, published with authorization from 36Kr.