Sona Nanotech Inc (CSE:SONA, OTCQB:SNANF) said tissue analysis from its first human trial of its heat-based cancer therapy showed immune system activation in late-stage melanoma patients, raising hopes it could be combined with existing immunotherapy drugs to improve their effectiveness.
The Canadian biotech firm said analysis conducted at Dalhousie University found natural killer cell infiltration in tumor tissue after treatment with its Targeted Hyperthermia Therapy (THT), a marker associated with innate immune response.
In the study, 10 advanced-stage melanoma patients who had stopped responding to standard immunotherapy received THT on days one and eight of the trial.
By day 15, eight of ten showed a clinical response, with six of those showing no detectable residual melanoma in biopsied tumors.
Tissue analysis also found that partial responders exhibited elevated T-regulatory cells and strong PD-L1 expression, suggesting those tumors could be vulnerable to PD-1 checkpoint inhibitor drugs.
"Our analysis confirms that patients responding to Sona's THT treatment experienced a strong immunogenic response characterized by extensive innate immune activation with abundant macrophage infiltration and a robust natural killer cell infiltration," said Dr Carman Giacomantonio, Sona's Chief Medical Officer.
Giacomantonio added that partial responders would likely benefit from PD-1 and CTLA-4 immunotherapy, especially when given alongside THT.
The company said the findings could extend to colorectal cancer, where immunotherapy response rates run below 20%.
Giacomantonio said the results, combined with pre-clinical modelling data, support the strategy of priming tumors with THT before administering immunotherapy, which he said could help the roughly 80% of colorectal cancer patients who fail to respond to existing treatments.
The findings are being prepared for peer-reviewed publication.