Favorable Safety Profile, Robust Response Rates Reinforce Potential of Novel Immunotherapy
SAN DIEGO – December 16, 2013 — 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.”
Melanoma is the most serious form of skin cancer. If it is recognized and treated early, it is almost always curable. If it is not, the cancer can advance and spread to other parts of the body, where it becomes hard to treat and can be fatal. While it is not the most common of the skin cancers, it causes the most deaths. The American Cancer Society estimates that at present, about 123,000 new cases of melanoma in the U.S. are diagnosed in a year, resulting in approximately 10,000 deaths. Melanoma originates in melanocytes, the cells that produce the pigment melanin that colors our skin, hair, and eyes. The majority of melanomas are black or brown, but often they can also be skin-colored, pink, red, purple, blue or white. Currently, few treatment options remain for patients with late-stage metastatic disease that can extend survival for the broad population.
Data Presented at 27th Annual Meeting of the Society for Immunotherapy of Cancer
SAN DIEGO – October 23, 2012 – OncoSec Medical Inc. (OTCBB: ONCS), a company developing its advanced-stage ImmunoPulse DNA-based immunotherapy and NeoPulse therapies to treat solid tumor cancers, announced positive preliminary results from a Phase II multicenter trial investigating the use of ImmunoPulse in Merkel cell carcinoma (MCC) patients at the 27th Annual Meeting of the Society for Immunotherapy of Cancer (SITC 2012). The data suggest that ImmunoPulse, which locally delivers a DNA-based cytokine coded for the immune stimulating agent interleukin-12 (DNA IL-12) via electroporation, may elicit increased levels of IL-12 in the tumor microenvironment, which has the potential to result in a systemic immune response in treating aggressive cancers like MCC without serious adverse safety events.
The preliminary results were published in the Journal of Immunotherapy (35(9):721-791, November-December 2012) and will be presented in a poster titled “Intratumoral delivery of Interleukin-12 DNA with in vivo electroporation can lead to regression of injected and non-injected tumors in Merkel cell carcinoma: Results of a phase II study.” Dr. Shailender Bhatia, principal investigator and assistant professor at the University of Washington School of Medicine, is lead author and will be presenting the data.
This open-label study is evaluating the ability of ImmunoPulse to increase levels of IL-12 in the tumor microenvironment, in addition to the efficacy and safety of this treatment for patients with MCC. Preliminary results of this study have demonstrated that 100 percent (3/3) of subjects treated with at least one cycle of ImmunoPulse showed an increased level of IL-12 expression in tumor biopsy done three weeks post-treatment as compared to pre-treatment biopsy. Correlative analysis of limited samples demonstrated that at least one subject had increased CD8+ T-cells (also referred to as killer T-cells) in the tumors. Correlative studies of patient samples are ongoing.
Of the first five subjects enrolled, the overall response rate is 20% (1/5). One patient with baseline progressive MCC, despite multiple prior therapies (systemic chemotherapy, surgery, RT, IT interferon) has had a confirmed partial response (greater than 70 percent regression) that persisted for approximately eight months. The regression of injected as well as non-injected tumors, along with no new tumors over six months, suggest successful induction of systemic immune response from local intratumoral immunotherapy in this patient. This subject remains in the study and will receive a third treatment cycle.
Dr. Bhatia commented, “These preliminary results are encouraging, and we are looking forward to continuing our study of ImmunoPulse. We are pleased to see that a patient with progressive MCC, despite failing multiple other therapies, had a confirmed partial response with regression of even distant non-injected tumors. This creative immunotherapy approach to deliver DNA IL-12 directly into the tumors appears to be tolerated well and so far without any systemic side-effects.”
All five subjects treated at the time of this preliminary analysis had distant metastatic disease, and were eligible to receive up to two treatment cycles. Two subjects have withdrawn from the study with progressive disease, and only received one cycle of treatment. Three subjects completed the study and received both treatment cycles. To date, the treatment has been safe and well-tolerated, with treatment-related adverse events including transient grade 1 pain (n=5) and grade 1 injection site reaction (n=1) without any systemic or residual toxicity.
Punit Dhillon, President and CEO of OncoSec Medical, added, “These subset data are positive and validate the results seen in our previous clinical trial. Thus far studies have shown that the administration of IL-12 using electroporation safely results in efficient transfection of the agent and a marked increase in production of the IL-12 protein inside the tumor. These results represent the first human data for a gene therapy using in vivo electroporation in MCC patients, and is a positive step towards advancement of this program.”
About Merkel Cell Carcinoma
Merkel cell carcinoma is a rare and highly aggressive cancer, with approximately 1,500 new cases each year in the United States, in which malignant cancer cells develop on or just beneath the skin and in hair follicles. The majority of Merkel cell carcinomas appear to be caused in part by a virus, Merkel cell polyomavirus. If this cancer metastasizes to the lymph nodes, the five-year survival rate is about 50 percent. A patient with a small tumor (less than 2 cm) that has not metastasized to the lymph nodes may have a five-year survival rate of more than 80 percent. Current treatment options for these patients is surgery, radiation and chemotherapy; however, up to half of patients suffer a recurrence.