Biopharmaceutical company OncoSec Medical has reported positive interim immune response data from Phase II study of ImmunoPulse in metastatic melanoma patients.

According to the data, ImmunoPulse demonstrated a change in tumour immunity subsequent to treatment with DNA IL-12 and electroporation.

The University of California San Francisco principal investigator Dr Adil Daud said that the statistical significance of the data confirms an understanding of the mechanism of action of IL-12.

"We look forward to understanding further if these changes in immune responses also correlate with positive clinical outcomes," Daud said. "These data will be shared later on this year."

At baseline Day 1 and Day 90, blood samples from subjects treated with ImmunoPulse were analysed for quantification of changes in activated T-cells and regulatory T-cells.

Following treatment, a significant decrease in circulating exhausted CD8/PD-1+ (p=0.0017) and CD8/CD69+ (p=0.008) T-cells was observed at Day 90.

"We are encouraged by these immune data, since they highlight a potential mechanism of action for ImmunoPulse."

Blocking PD-1, which is expressed in activated exhausted T cells, is a new treatment modality for multiple cancers and plasmid delivery of interleukin-12 leads to decrease in exhausted T-cells thereby leading to improvement in clinical outcomes for ImmunoPulse-treated patients.

In addition, NK cell frequency and activation boost from baseline, increase in antigen-specific T-cell responses to melanoma with DNA IL-12 were also observed.

OncoSec president and CEO Punit Dhillon said: "We are encouraged by these immune data, since they highlight a potential mechanism of action for ImmunoPulse, and demonstrate the biologic activity of this therapy after only a single cycle of treatment."

ImmunoPulse already demonstrated clinical benefit in both locally treated and untreated distant melanoma lesions with considerable safety and tolerability profile, after analysing the first 13 patients.

Image: Lymph node with almost complete replacement by metastatic melanoma. The brown pigment is focal deposition of melanin. Photo: courtesy of Gabriel Caponetti.