A Personalised Cancer Vaccine Meets Its Goal in Phase 3, and the ASX Companies Working With the Immune System

On 19 August 2026, Merck and Moderna reported that a cancer vaccine made for each patient had met its goals in a Phase 3 melanoma trial [R1]. The full results followed on 22 October 2026, ahead of the European Society for Medical Oncology (ESMO) Congress [R2].

All prices in this piece are as at the close of ASX trading on 30 October 2026.

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What the Personalised Cancer Vaccine Is

The vaccine is called intismeran autogene. After surgery, the tumour's DNA is read and compared with DNA from the patient's healthy cells to find mutations only the cancer carries. These mutations make abnormal protein pieces, called neoantigens. Each dose carries mRNA instructions for up to 34 of them, according to the companies [R2]. The body makes those proteins and the immune system learns to attack cells that carry them.

TRIAL TERMS

Phase 1, 2 and 3. The stages of testing a medicine in people. Phase 1 checks safety in a small group. Phase 2 looks for a sign that it works. Phase 3 compares it with the standard treatment in hundreds or thousands of patients. It is usually the last stage before a company asks a regulator, such as the US Food and Drug Administration (FDA), to approve it.

Primary endpoint. The main result a trial is designed to measure.

What the Phase 3 Trial Showed

The trial, INTerpath-001, enrolled 1,137 people whose stage IIB to IV melanoma had been fully removed by surgery [R2]. Every patient received Keytruda. It is Merck's immunotherapy and a standard treatment after melanoma surgery. Two in every three also received the vaccine. The rest received a placebo, a dummy injection.

The primary endpoint was recurrence-free survival, the time patients lived without the cancer coming back. After a median follow-up of 24.6 months, the companies reported adding the vaccine cut the risk of recurrence or death by 42% (hazard ratio 0.58). At two years, 82.2% of the vaccine group were free of recurrence, against 70.0% on Keytruda alone [R2].

READING THE RESULT

Stage IIB to IV melanoma. Ranges from thick skin tumours to cancer that has spread to lymph nodes or other organs.

Hazard ratio. Compares the rate at which an event, here the cancer returning or death, happened in one group against the other at any point during the trial. A ratio of 0.58 means the vaccine group's rate was about 58% of the Keytruda-only group's rate, reported as a 42% lower risk.

Median follow-up. Half the patients had been tracked for longer than 24.6 months, half for less.

Grade 3 to 5 side effects. Side effects are graded 1 to 5. Grade 3 is severe, 4 is life-threatening and 5 is death.

The trial was led by Professor Georgina Long of Melanoma Institute Australia, who presented it at the ESMO Congress [R3]. The two groups did about the same in the first six months, and the gap opened after that [R2]. Professor Long put this down to the wait for the first dose, a median of 64 days, and the time the vaccine takes to work [R3]. Grade 3 to 5 treatment-related side effects occurred in 14.2% of the vaccine group and 13.4% of the Keytruda-only group [R2].

What Is Still to Come for Intismeran

Merck and Moderna are engaging with regulators and running three Phase 3 trials in lung cancer [R2]. Overall survival, whether patients live longer, is still being measured. The companies reported a favourable trend [R2]. OncLive's ESMO report gives a hazard ratio of 0.77, which is not yet statistically significant [R3]. Intismeran is not yet approved anywhere.

ASX Companies in Cancer Immunotherapy

Keytruda is a checkpoint inhibitor. It releases a brake cancer cells use to hide from T cells, the immune cells that kill abnormal cells. Many patients still relapse, so the field is testing what to add to it.

Imugene (ASX: IMU) had cancer vaccines in its earlier pipeline. Its 2026 annual report says it is now focused on azer-cel, a CAR T cell therapy for blood cancers, and has stopped developing its PD1-Vaxx vaccine [R7]. Part 4 of this series covers azer-cel.

Immutep (ASX: IMM)

Testing. Immutep develops eftilagimod alfa (efti), which it describes as activating antigen-presenting cells, the immune cells that show T cells what to attack [R5]. Like intismeran, it has been tested with Keytruda.

Latest. Immutep's review of its stopped Phase 3 lung cancer trial, TACTI-004, has found structural differences between the efti in that trial and in earlier trials. TACTI-004 used efti made in 2,000-litre batches. Earlier trials used 200-litre batches. Immutep considers these potentially relevant, and has contracted a new 200-litre run [R4]. The trial was stopped in March 2026 after a planned futility analysis, on the advice of its independent monitoring committee. At that analysis 42.9% of patients on efti had responded, against 55.1% without it [R6].

Next. Immutep is targeting registration-directed trials in head and neck cancer (CPS below 1) and in soft tissue sarcoma before surgery. In a Phase 2 sarcoma trial, efti with radiotherapy and Keytruda met its primary endpoint, according to Immutep [R4]. It aims to start the new trials in the second half of 2027 [R5]. It held A$48.5 million in cash and term deposits at 30 September 2026. It expects this to last well into the first half of 2028 [R4]. A further update on its review is due at its AGM on 27 November 2026 [R4].

IMMUTEP TERMS

Futility analysis. A planned check partway through a trial to see whether it can still meet its goal. If it is unlikely to, an independent committee can recommend stopping it.

Registration-directed trial. A trial designed to support an application for approval. Immutep says the start of these trials depends on trial design, regulators, manufacturing, partnering and resources [R5].

Primary endpoint in the sarcoma trial. How much of the removed tumour had turned to scar-like tissue. The median was 51.5%, against a 35% target, according to Immutep [R4].

CPS below 1. The combined positive score measures how many cells in a tumour sample carry PD-L1, the protein that applies the brake Keytruda releases. Below 1 means very little. These patients have few approved treatment options, according to Immutep [R5].

Noxopharm (ASX: NOX)

Testing. Noxopharm develops short synthetic RNA strands, called oligonucleotides. SOF-VAC aims to reduce the inflammation mRNA vaccines can cause. SOF-CAN aims to help the immune system detect tumours. Both are at laboratory stage. Its most advanced drug, SOF-SKN, is a skin treatment for lupus that has completed its first human trial [R8].

Latest. On 1 September 2026, Noxopharm reported laboratory work by CSL on blood cells from three human donors. Noxopharm says its molecules greatly reduced an inflammatory signal from an experimental mRNA flu vaccine [R9]. Its September 2026 presentation says the INTerpath-001 result strengthens the potential of its approach, and that its programs have no relationship with that trial [R8].

Next. Noxopharm shares have been suspended since 29 October 2026, pending a capital raising announcement [R10].

Where the Share Prices Sit

All three share prices are lower than a year ago (TABLE 01). Immutep's shares last traded at 39.5 cents on 6 March 2026. They closed at 4.5 cents on 13 March, the day Immutep announced the trial would stop [R6]. We can probably safely assume the trial news drove that move. All three are below 10 cents, so a small move in price is a large move in percentage terms.

Samso Concluding Comments

Merck and Moderna describe INTerpath-001 as the first positive Phase 3 result for an mRNA cancer therapy. They say it is also the first for a treatment built from the mutations in one patient's tumour [R1]. Each course is made for one person. More than 99% of patients in the vaccine group had their vaccine made [R3]. We expect manufacturing time and cost to be large questions once regulators rule.

For ASX investors the exposure is indirect. Immutep is further along than Noxopharm, having run a Phase 3 trial. In our view, the next test for efti is whether the new 200-litre run matches the efti used in earlier trials. Immutep lists this as a risk in its latest quarterly [R4].

THE OTHER WAY TO READ THIS

The trial measured recurrence over about two years in one cancer, after surgery, when little cancer is left in the body. Results in advanced disease or other cancers may differ. More patients in the vaccine group stopped a study drug after an adverse event, 16.6% against 9.5% [R3]. An adverse event is any health problem during a trial, whether or not the drug caused it.

VOCABULARY, IN PLAIN ENGLISH

Antigen-presenting cell

An immune cell that picks up pieces of a threat and shows them to T cells so they know what to attack.

CAR T therapy

Immune cells (T cells) engineered in a laboratory to carry a receptor that finds a marker on cancer cells. Usually made from the patient's cells. Off-the-shelf versions use donor cells.

Checkpoint inhibitor

A drug that releases a brake cancer cells put on the immune system. Keytruda is one.

Hazard ratio

How often an event happened in one group compared with another over a trial. Below 1 favours the new treatment.

mRNA

Messenger RNA. A set of instructions that tells cells which protein to make.

Neoantigen

An abnormal protein made only by cancer cells because of mutations in their DNA.

Oligonucleotide

A short, man-made strand of DNA or RNA designed to act on a specific target.

Overall survival

How long patients live from the start of a trial, whatever happens to their cancer.

Placebo

A dummy treatment with no active drug, used so patients and doctors do not know who is getting the real one.

Recurrence-free survival

How long patients live without the cancer coming back.

Response rate

The share of patients whose cancer shrank by a set amount, or disappeared, after treatment.

Statistical significance

A test of whether a difference between two groups is large enough that it is unlikely to be chance.

References and Sources

Each source carries an identifier, [R1] to [R11]. The same identifier appears in the text where the source is used.

[R1] Merck and Moderna, "Merck and Moderna Announce Phase 3 INTerpath-001 Trial of Intismeran Autogene Plus KEYTRUDA Met Endpoints of Recurrence-Free Survival (RFS) and Distant Metastasis-Free Survival (DMFS) in Patients With Completely Resected Stage IIB-IV Melanoma", news release, 19 August 2026. Link

[R2] Merck and Moderna, "Merck and Moderna Will Present Results From Landmark Phase 3 INTerpath-001 Trial for Intismeran Autogene Plus KEYTRUDA (pembrolizumab) at ESMO 2026 Presidential Symposium", news release, 22 October 2026. Link

[R3] OncLive, "Adjuvant Intismeran Autogene Plus Pembrolizumab Improves RFS and DMFS in Melanoma", 24 October 2026, reporting ESMO 2026 abstract LBA1 (G. V. Long). Samso has not read the abstract or the NEJM paper. Link

[R4] Immutep (ASX: IMM), Quarterly Activities Report and Appendix 4C, 29 October 2026. Link

[R5] Immutep (ASX: IMM), "Immutep Outlines Focused Development Strategy for Eftilagimod Alfa (efti)", 11 September 2026. Link

[R6] Immutep, Quarterly Activities Report Q4 FY26, 30 July 2026 (BioSpace copy of the company's media release). Link

[R7] Imugene (ASX: IMU), Appendix 4E and Annual Report 2026, Directors' Report dated 28 August 2026. Link

[R8] Noxopharm (ASX: NOX), Investor Presentation September 2026, 4 September 2026. Link

[R9] Noxopharm (ASX: NOX), "Noxopharm novel oligonucleotides data presented at Options XIII Conference", 1 September 2026. Link

[R10] ASX, "Noxopharm Limited (ASX: NOX), Suspension from Quotation", with Noxopharm's Request for Voluntary Suspension attached, 29 October 2026. Link

[R11] Yahoo Finance, daily closing prices for IMM.AX, IMU.AX and NOX.AX, read 31 October 2026. Link

Cover photo: mRNA strand illustration, from the Noxopharm Limited (ASX: NOX) Investor Presentation, September 2026, page 8.

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