ESMO Congress 2026

Cemiplimab is an anti-PD-1 antibody, listed among the ten approved anti-PD-1 antibodies worldwide ^[1] and also identified as one of the FDA-approved PD-1 inhibitors ^[3]. In cutaneous squamous cell carcinoma (CSCC), its evidence base rests on studies in advanced disease: in the phase 1 expansion cohorts, 13 of 26 patients (50%) had a response ^[2]; an open-label, single-arm phase 2 trial in locally advanced CSCC used objective response rate by independent central review as the primary endpoint, with cemiplimab 3 mg/kg every 2 weeks for up to 96 weeks ^[6]. Beyond CSCC, the drug has a published phase 3 randomised controlled trial, EMPOWER-Lung 1, in first-line advanced NSCLC with PD-L1 of at least 50% ^[5]. In other words, its existing CSCC evidence is concentrated in locally advanced or metastatic settings with response rate as the primary endpoint, while the neoadjuvant (pre-surgical) population was not covered in the background literature.

At this ESMO26 meeting, Neil Gross presented the final analysis of a phase 2 study of neoadjuvant cemiplimab for stage II–IV CSCC, published simultaneously (with a full-text link in the @JCO_ASCO post). No specific figures were disclosed in the conference posts—pathological complete response rate, objective response rate, sample size, and safety data are all absent from the posts and must be confirmed in the simultaneously published full paper.

Relative to existing knowledge, this readout moves cemiplimab's CSCC evidence from locally advanced or metastatic disease ^[2][6] forward into neoadjuvant treatment of stage II–IV surgical patients, presented as a final analysis with more mature follow-up data. Gross also discussed a further question at the meeting: what a trial would need to show before complete responders could skip surgery. This points toward a response-guided, surgery-omission pathway, going beyond the earlier framework in which objective response rate was the primary endpoint ^[6].

As for limitations: this is a phase 2 study (whether a control arm was used is undisclosed in the posts), and the conference posts contain no efficacy or safety figures, so effect size cannot be judged from them; skipping surgery for complete responders remains a topic under discussion, and per Gross's remarks, the trial evidence threshold he outlined would need to be met before it could approach clinical practice.