Immunocore presents three-year overall survival data from the KIMMTRAK Phase 3 trial

Immunocore presents three-year overall survival data from the KIMMTRAK Phase 3 trial

Data published in New England Journal of Medicine and presented as a late breaking abstract in mini oral session at ESMO Congress 2023

KIMMTRAK demonstrated long-term survival benefit in HLA-A*02:01 positive patients with previously untreated metastatic uveal melanoma

(OXFORDSHIRE, England & CONSHOHOCKEN, Penn. & ROCKVILLE, Md, 21 October 2023) Immunocore Holdings plc (Nasdaq: IMCR), a commercial-stage biotechnology company pioneering the development of a novel class of T cell receptor (TCR) bispecific immunotherapies designed to treat a broad range of diseases, including cancer, infectious diseases and autoimmune conditions, today announces that the three-year overall survival (OS) data from the KIMMTRAK (tebentafusp-tebn) Phase 3 trial in previously untreated HLA-A*02:01 positive patients with metastatic uveal melanoma has been published in The New England Journal of Medicine, and presented as a late breaking abstract in a mini oral session at the European Society for Medical Oncology (ESMO) Congress 2023.

“These long-term overall survival results further solidify KIMMTRAK as the first-line standard of care for HLA-A*02:01 positive patients with metastatic uveal melanoma,” said Mohammed Dar, Immunocore Chief Medical Officer. “The survival benefit appears early, within the first six weeks, and the survival curve remains separated from the control arm; this long-term survival benefit is a hallmark of cancer immunotherapy.”

In the Phase 3 trial follow up – the longest of any randomized trial for metastatic uveal melanoma – the three-year OS rate was 27% in the KIMMTRAK arm, versus 18% in the control arm (investigator’s choice, predominantly [82%] single agent pembrolizumab). The median OS was 21.6 months on KIMMTRAK, versus 16.9 months on investigator’s choice. The OS Hazard Ratio (HR) favored KIMMTRAK, HR=0.68 (95% CI: 0.54 to 0.87), over investigator’s choice.

Overall response rate remained in favor of KIMMTRAK when compared with the control arm (11% vs 5%) and the median duration of response for KIMMTRAK patients was 11.1 months.The rate of disease control (complete response, partial response, or stable disease for ≥12 weeks) was also higher in the KIMMTRAK arm (46% vs 27%) versus the control arm. Over half (57%; n=139) of all patients treated with KIMMTRAK were treated beyond initial radiographic progression.

The trial evaluated circulating tumor DNA (ctDNA) clearance as a predictor of overall survival. ctDNA clearance on KIMMTRAK occurred in 37% of evaluable patients (compared with previously reported 13% in second-line patients¹) and was associated with longer OS.

No new adverse events (AEs) related to long-term KIMMTRAK treatment were observed. The rate of discontinuation due to treatment-related AEs continued to be lower (2%) in the KIMMTRAK arm than for the control arm (5%). There were no treatment-related deaths.

In a separate poster at the Congress, an analysis of the role of subsequent therapy from the Phase 3 trial in first-line mUM patients confirmed that the survival benefit mostly comes from KIMMTRAK treatment rather than subsequent therapy.   

A further poster included an analysis from the Phase 1b study in previously treated metastatic cutaneous melanoma patients, demonstrating the safety and activity of KIMMTRAK by BRAF mutation status. A third poster investigated the reprogramming effect of KIMMTRAK on immunosuppressive M2 macrophages from Phase 2 unresectable or metastatic uveal melanoma patients, as well as in vitro.   

Presentation and poster details

Title: Three-year survival with tebentafusp in previously untreated metastatic uveal melanoma in a phase 3 trial

Presenting author: Sophie Piperno-Neumann

Session: Mini oral session – Melanoma and other skin tumours, Saturday 21 October, 2023

Title: Tebentafusp reprograms immunosuppressive tumor-associated M2 macrophages towards anti-tumoral M1 macrophages

Presenting author: Josep M. Piulats

Session: Poster display, Saturday 21 October, 2023

Title: BRAF mutation status does not impact outcomes with tebentafusp in advanced cutaneous melanoma

Presenting author: Alexander N. Shoushtari

Session: Poster display, Sunday 22 October, 2023

Title: Effect of subsequent therapies including checkpoint inhibitors on overall survival in a phase 3 randomized trial of tebentafusp in first line metastatic uveal melanoma: long-term follow up

Presenting author: Marcus Butler

Session: Poster display, Sunday 22 October, 2023