Evaxion reports three-year EVX-01 melanoma responses and sustained T-cell activity in six patients, but the findings remain preliminary.
Written By: Malavatu Satvika, PharmD
Reviewed By: Pharmacally Editorial Team
Evaxion A/S has reported three-year clinical and immune findings for EVX-01, its investigational personalized cancer vaccine for advanced melanoma. Six patients who continued into a one-year extension maintained their previously observed clinical responses while receiving EVX-01 alone, following two years of combination treatment with pembrolizumab. The company also reported that 89% of vaccine neoantigens generated specific T-cell responses. The findings extend previously reported Phase 2 results, but the small extension cohort limits the conclusions that can be drawn about long-term treatment benefit.
Clinical Outcomes: Responses Persist in Six Patients
The Phase 2 trial enrolled 16 patients with advanced melanoma. During the first two years, participants received EVX-01 alongside pembrolizumab, an anti-PD-1 immunotherapy.
Previously reported two-year results showed an objective response rate (ORR) of 75%, with 12 of 16 patients achieving an objective response, including four complete responses. Evaxion also reported that 11 of the 12 responders, or 92%, remained in response at 24 months, with no relapses observed. Tumor reduction in target lesions was reported in 15 of the 16 enrolled patients, while 54% experienced a deepened response, improving from stable disease or partial response to partial or complete response.
Six of the 12 responders continued into the one-year extension and received EVX-01 as monotherapy. According to the October 23 update, all six maintained their clinical responses through the third year, with no tumor progression reported.
The persistence of responses after pembrolizumab was discontinued is a relevant observation. However, it does not establish that EVX-01 alone maintained disease control. The extension included only six patients selected from those who had already responded to combination treatment. Without a comparator group, the independent contribution of continued vaccination cannot be determined.
Immune Findings: T-Cell Activity Is Not Proof of Clinical Benefit
Evaxion reported that EVX-01 induced an immune response in all patients. At the two-year assessment, 86% of vaccine neoantigens generated potent, specific T-cell responses. Analysis of additional samples collected during the extension increased this proportion to 89%. The company also reported that the magnitude and breadth of these responses were preserved during the third year.
These findings are consistent with the vaccine’s intended approach of targeting tumor-specific neoantigens to stimulate individualized immune responses. Sustained T-cell activity provides evidence of continued biological activity, but it does not independently demonstrate tumor control or improved survival.
The 89% figure refers to vaccine neoantigens generating specific T-cell responses, not the percentage of patients who responded clinically. The available findings do not establish whether this immune measure predicts long-term clinical outcomes.
Clinical Interpretation
The three-year update provides preliminary evidence of durable clinical responses and sustained vaccine-induced T-cell activity in a small group of patients receiving EVX-01 alone after two years of combination treatment with pembrolizumab.
The principal limitation is the extension cohort: only six of the original 16 participants continued into the third year. Their previous responses also mean that the findings cannot be generalized to all enrolled patients or the broader advanced melanoma population. The results do not establish a survival benefit, superiority over existing treatment, or an independent effect of EVX-01 monotherapy.
The findings are scheduled for presentation at the European Society for Medical Oncology (ESMO) Congress 2026 on October 24, under poster number 2006P. Further trial details may help clarify the analyses and follow-up. Larger studies with appropriate comparators and longer follow-up will be needed to determine whether the observed response durability translates into a reproducible clinical benefit.
Reference
Evaxion A/S. Evaxion announces 89% vaccine target precision and sustained T-cell and clinical responses at three-year follow-up in Phase 2 trial with personalized cancer vaccine EVX-01. October 23, 2026.
A Single Arm Trial Evaluating the Efficacy and Safety of EVX-01 in Combination with Pembrolizumab in Adults with Unresectable or Metastatic Melanoma, ClinicalTrials.gov ID NCT05309421
About the Writer
Malavatu Satvika (Linkedin) is a Pharm.D professional and aspiring healthcare medical writer with clinical exposure and research experience. Her interests include medical writing, drug safety, pharmaceutical research, and evidence-based healthcare communication. She has contributed to two research publications in pharmaceutical journals and has gained practical experience in prescription review, patient counselling, medication review, adverse drug reaction monitoring, drug information services, literature review, and clinical documentation through regular hospital training.
She has completed certifications in clinical research, ICH-GCP E6(R3), data management for clinical research, and congenital hypothyroidism. With a strong foundation in pharmacy, clinical practice, and scientific research, she aims to translate complex medical and pharmaceutical information into accurate, clear, and evidence-based healthcare content. She is also preparing to pursue a PhD and further develop her expertise in medical writing and pharmaceutical research.