Scancell Holdings plc announced positive data from the first stage in its Phase 2 SCOPE trial, investigating SCIB1 in combination with checkpoint inhibitors (CPIs) in advanced melanoma. Initial data from 11 patients showed an 82% objective response rate (ORR) to treatment, which is better than 70% ORR that the trial was configured to show. The Phase 2 SCOPE trial was designed to determine if the ORR in patients with unresectable metastatic melanoma could be improved in combination with CPIs.

The concept is that the vaccine induces new, or boosts existing, immune responses which are subsequently protected in the tumour environment by the CPIs. During the first stage of the SCOPE trial patients received SCIB1 via a needle-free device in combination with the most efficacious treatment currently available, namely the CPIs nivolumab and ipilimumab. The first milestone in the SCOPE trial was to achieve responses in more than 8 out of 15 patients which would suggest that SCIB1 in combination with doublet CPI therapy might meaningfully improve current outcomes for these patients.16 stage IV metastatic patients have received this combination.

To date, 11 of these study patients have reached 13 weeks and been evaluated at radiological imaging and nine have already shown an objective response, equating to an ORR of 82% with no increase in toxicity. At this time point the reduction in tumour volume was 31%-94%. Four patients reaching the 25 weeks imaging evaluation and two reaching the 37 weeks evaluation have shown a 69%-94% and a 87%-94% reduction in total tumour burden, respectively.

This compares to an ORR of 50% reported in patients just receiving this doublet CPI therapy in the real world setting with a progression free survival time of 11.5 months. The SCOPE trial has now successfully transitioned into the second stage,which willrecruit a further 27 patients (for a total of 43). The aim is to achieve at least 18 further responses (that is 27 responses in total) which would statistically demonstrate that SCIB1, in combination with doublet therapy, exceeds currently achievable ORRs.

Recruitment is expected to be complete by the end of 2023 with data available in first half of 2024. Based upon the first 11 patients there is a greater than 90% probability that the second phase will also be successful. If validated in the second stage of the SCOPE trial this will provide confidence to initiate a randomised phase 2/3 adapted registration programme in patients with unresectable melanoma which represents a potential $1.5 billion per annum market.

The Phase 2 part of the adapted trial should take 18 months and will likely generate significant partner interest. In addition to SCIB1, Scancell expects significant results from its other programmes in 2024 including top-line Modi-1 CPI combination data and attractive out-licensing opportunities from the GlyMab® and AvidiMab® platforms.