Scancell Holdings PLC (AIM:SCLP, OTC:SCNLF) said the results from the initial stage of its phase II SCOPE trial in advanced melanoma surpassed expectations.
The study investigated the efficacy of Scancell's SCIB1 in combination with checkpoint inhibitors (CPIs).
Preliminary data from 11 patients indicate an 82% objective response rate (ORR), surpassing the trial's target of a 70% ORR.
"These results, if confirmed in a larger cohort, will be a significant improvement on what patients can expect from available treatment today. We look forward to continuing the second stage of the study and reporting further data in due course," said professor Poulam Patel, chief investigator.
Researchers aimed to enhance the ORR in patients suffering from unresectable metastatic melanoma through the combined use of SCIB1 and CPIs.
The vaccine is believed to either initiate new immune responses or amplify existing ones, which are then safeguarded within the tumour environment by the CPIs.
In this evaluation, patients were administered SCIB1 through a needle-free device, along with the currently most effective CPIs, nivolumab and ipilimumab.
The first milestone of the trial was to achieve positive responses in over eight out of 15 patients, thereby suggesting that SCIB1, when combined with doublet CPI therapy, could significantly improve patient outcomes.
Out of 16 stage IV metastatic patients who have received this combination, 11 have been evaluated at 13 weeks through radiological imaging. Nine of these have shown an objective response, equating to an 82% ORR without any increase in toxicity levels. The reduction in tumour volume ranged from 31% to 94%.
These results are particularly noteworthy when compared to a 50% ORR in patients receiving only the doublet CPI therapy, with a progression-free survival time of 11.5 months.
"We are excited by these highly impressive results for SCIB1 combined with the doublet CPI therapy," said Scancell's chief executive, professor Lindy Durrant.
"We thought results from the phase I/II trial evaluating SCIB1 as a monotherapy were positive but results from this combination are even more meaningful.
"Previous studies indicated that a response rate of 50% was the best that could be achieved in the real-world setting for patients with unresectable metastatic melanoma, as no other combination had improved on the response rates for doublet CPI alone.
"Confirmation of this data in a larger cohort could make a significant impact on melanoma patient survival, especially as melanoma is now one of the most common cancers in young women."