OncoSec Medical Inc. (OTCQB:ONCS), a company developing its advanced-stage ImmunoPulse DNA-based immunotherapy to treat solid tumors, today announced positive interim data from its ongoing Phase 2 trial of OMS-I100 in the treatment of metastatic melanoma. The results were presented by principal investigator Adil Daud, MD, at the Advances in Cancer Immunotherapy meeting at the University of California San Francisco.
Data from the multicenter, open-label, single-arm study confirm the safety of OncoSec's lead product candidate, ImmunoPulse, which leverages the company's OMS electroporation technology to deliver the anti-tumor agent pIL-12 directly into the tumor. In Phase 1 and Phase 2 studies, a total of 47 melanoma patients have been treated to date without a single drug-related, serious adverse event.
Patients treated in OMS-I100 also demonstrated positive response rates based on RECIST criteria, the gold standard measure of solid-tumor response to treatment. Interim efficacy analysis of 21 evaluable patients on Day 180 indicated that 38.1% (8/21) achieved an objective overall response, defined as ≥30% reduction in summed size of lesions. At the time of this interim analysis, six patients (28.6%) had demonstrated a partial response, and two patients (9.5%) had achieved a complete response, lasting at least 6 months. An additional 9.5% (2/21) of patients exhibited clinically beneficial disease stabilization for at least 3 months.
These data strengthen and expand upon previously reported Phase 1 results, which indicated a complete response in 16% of patients (3/19) and disease stabilization in 38% (7/19). These data were published in Journal of Clinical Oncology in 2008.
Importantly, 61.1% of patients (11/18) with evaluable lesions exhibited systemic antitumor immune responses, as evidenced by objective regression (≥30% reduction in size) in at least one untreated lesion.
"The response rate of untreated tumors suggests an induction of systemic antitumor response, without systemic toxicity," commented Dr. Daud. "We will continue to assess the responses of our remaining patients and look forward to sharing our findings."
Robert H. Pierce, MD, OncoSec's chief medical officer, added, "Systemic response is significant for two main reasons. First, it suggests that unlike most locally administered melanoma treatments, ImmunoPulse may induce antitumor response throughout the entire body, which would have clear benefits in the treatment of metastatic disease. Secondly, the favorable safety profile of ImmunoPulse indicates its potential to deliver systemic benefit, without the toxicities associated with many other systemic treatments. We are therefore highly encouraged by this finding, combined with the safety and primary efficacy data, and look forward to continuing our investigation of OMS-I100 in the treatment of metastatic melanoma."
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