ASCO 2023: Moderna and MSD’s personalised vaccine reduces chances of melanoma spreading

Moderna and MSD revealed an update on results demonstrating an improved distant metastasis-free survival (DMFS) when their mRNA vaccine was used in combination with Keytruda (pembrolizumab), at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting.

In the KEYNOTE-942 study, the jointly developed mRNA-4157 vaccine (V940), an individualised therapy based on the patient’s tumour DNA, reduced the risk of distant metastasis or death in patients with high-risk stage III/IV melanoma by 65% (HR=0.347 [95% CI, 0.145-0.828]) when used in combination with Keytruda, compared to Keytruda alone. Reported adverse events and safety profile were consistent with previous findings.

Results from the ongoing randomised, open-label Phase IIb trial (NCT03897881), first announced in December 2022, have been promising enough for the US Food and Drug Administration (FDA) to grant breakthrough therapy designation and the European Medicines Agency (EMA) to award a priority medicines (PRIME) designation for the combination therapy. The two companies plan to initiate a Phase III study investigating the combination as an adjuvant therapy for patients with high-risk melanoma in 2023.

The ASCO Annual Meeting is being held 2 –6 June in Chicago.

A total of 157 patients enrolled in KEYNOTE-942 – half received 1 mg of the mRNA vaccine every three weeks for a total of nine doses and 200 mg of Keytruda every three weeks for approximately a year, whilst the rest received Keytruda alone until disease recurred or the toxicity became too high. DMFS is a secondary endpoint of the study.  In another April update, the companies released data on the primary endpoint of relapse-free survival (RFS) – revealing the combination therapy group had a 44% reduction in risk of recurrence or death.

“These results add to the emerging picture of how individualised neoantigen therapy may transform melanoma treatment and the promise it may hold for other types of cancer,” said Dr. Kyle Holen, Moderna’s senior vice president, in a 5 June statement.

The results follow an earlier unveiling at ASCO by MSD that demonstrated patients with early-stage non-small cell lung cancer who took Keytruda alongside chemotherapy had higher event-free survival compared to those who only received chemotherapy. Keytruda, a PD-1 inhibitor is approved to treat more than 15 tumour types in addition to tumors that carry certain genomic alterations. In March 2023, MSD also announced that the PD-1 inhibitor received FDA approval for adults and paediatric patients with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) solid tumours.