Sumitomo Dainippon Pharma Oncology Announces First Patient Dosed in Phase 2 Dose-Expansion Portion of Study Evaluating Investigational WT1 Immunotherapeutic Cancer Vaccine DSP-7888 (ombipepimut-S*) in Patients with Ovarian Cancer

CAMBRIDGE, Mass., Oct. 27, 2020 /PRNewswire/ -- Sumitomo Dainippon Pharma Oncology, Inc., a developer of novel cancer therapeutics, today announced the first patient has been dosed in the Phase 2 expansion portion of the study evaluating DSP-7888, an investigational immunotherapeutic cancer vaccine that targets Wilms Tumor 1 (WT1), in combination with checkpoint inhibitor pembrolizumab, in patients with platinum-resistant ovarian cancer (PROC).

The Phase 1b/2 open-label, multicenter study consists of two parts. The Phase 1b portion evaluated the safety and tolerability of the combination of DSP-7888 with a PD-1 checkpoint inhibitor in adult patients with solid tumors. Based on the known high prevalence of WT1 in ovarian cancer and the findings from the Phase 1b portion of this study, the Phase 2 part will evaluate the antitumor activity of DSP-7888 in combination with pembrolizumab in patients with PROC.

"Patients with platinum-resistant ovarian cancer have a high unmet need with limited treatment options; therefore, we are excited to advance the study of DSP-7888 plus pembrolizumab and evaluate its role and potential benefits," said Patricia S. Andrews, Chief Executive Officer and Global Head of Oncology, Sumitomo Dainippon Pharma Oncology (SDP Oncology). "Furthermore, we look forward to better understanding how these combined mechanisms may be able to sensitize this patient population to immunomodulators and improve clinical benefits."

The primary objective for the Phase 2 portion of the study is to evaluate the preliminary antitumor activity of DSP-7888 in combination with pembrolizumab in terms of the objective response rate (ORR) in patients with PROC. Secondary objectives of the Phase 2 portion of the study are to evaluate the preliminary clinical activity of DSP-7888 in combination with pembrolizumab in terms of duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), 6-month PFS rate and overall survival (OS) in this patient population. Additional secondary objectives of the Phase 2 portion of the study include evaluating ORR, DCR and PFS per iRECIST of DSP-7888 administered in combination with pembrolizumab in patients with PROC. Exploratory objectives of the Phase 2 portion of the study include determining the progression-free survival ratio (PFSr) as an evaluation of treatment benefit of DSP-7888 administered with pembrolizumab.

Ovarian cancer is the fifth leading cause of cancer-related deaths among women in the United States.1 Patients with ovarian cancer who relapse within six months of completing first-line therapy are classified as being "platinum resistant" and typically have low response rates to subsequent chemotherapy, with a median survival under a year.2 Therefore, more efficient treatment methods are warranted to improve the survival of patients with ovarian cancer. In addition, the majority of ovarian cancer patients with serous histology are positive with WT1 in their tumors.3

The trial is being conducted at sites in the United States. Additional information on this trial, including comprehensive inclusion and exclusion criteria, can be accessed at www.ClinicalTrials.gov (NCT03311334).

About DSP-7888 (ombipepimut-S*)

DSP-7888 is an investigational immunotherapeutic cancer vaccine containing two peptides that induce WT1-specific cytotoxic T lymphocytes (WT1-CTL) and helper T cells to attack WT1-expressing cancerous cells found in various types of hematologic and solid tumors. Researchers have identified that by adding helper T cell inducing peptides, improved outcomes may be achieved compared to a killer peptide treatment regimen alone.4

DSP-7888 is currently being investigated in combination with bevacizumab in a Phase 2 trial in patients with recurrent or progressive glioblastoma (NCT03149003) and in a Phase 1/2 trial in combination with nivolumab or pembrolizumab in patients with advanced solid tumors (NCT03311334). In 2017, the U.S. Food and Drug Administration granted Orphan Drug Designations for DSP-7888 in MDS and brain cancer.

*Adegramotide/nelatimotide is also assigned as the international nonproprietary name (INN).

About Sumitomo Dainippon Pharma Oncology

Sumitomo Dainippon Pharma Oncology, Inc., is a wholly owned subsidiary of Sumitomo Dainippon Pharma Co., Ltd. As a global oncology organization with teams in the U.S. and Japan, SDP Oncology is relentlessly committed to advancing purposeful science by transforming new discoveries into meaningful treatments for patients with cancer. The company's robust and diverse pipeline of preclinical and advanced-stage assets spans multiple areas, including oncogenic pathways, survival mechanisms and novel protein interactions, which aim to address unmet clinical needs in oncology.

For more information, visit www.sdponcology.com.

About Sumitomo Dainippon Pharma

Sumitomo Dainippon Pharma is among the top-10 listed pharmaceutical companies in Japan, operating globally in major pharmaceutical markets, including Japan, the U.S., China and the European Union. Sumitomo Dainippon Pharma aims to create innovative pharmaceutical products in the Psychiatry & Neurology area, the Oncology area and Regenerative medicine/Cell therapy field, which have been designated as the focus therapeutic areas. Sumitomo Dainippon Pharma is based on the merger in 2005 between Dainippon Pharmaceutical Co., Ltd., and Sumitomo Pharmaceuticals Co., Ltd. Today, Sumitomo Dainippon Pharma has more than 6,000 employees worldwide. Additional information about Sumitomo Dainippon Pharma is available through its corporate website at www.ds-pharma.com.

Disclaimer Regarding Forward-Looking Statements

This press release contains "forward-looking statements," as that term is defined in the Private Securities Litigation Reform Act of 1995 regarding the research, development and commercialization of pharmaceutical products. The forward-looking statements in this press release are based on management's assumptions and beliefs in light of information presently available and involve both known and unknown risks and uncertainties. Any forward-looking statements set forth in this press release speak only as of the date of this press release. We do not undertake to update any of these forward-looking statements to reflect events or circumstances that occur after the date hereof. Information concerning pharmaceuticals (including compounds under development) contained within this material is not intended as advertising or medical advice.

References

1. Key Statistics for Ovarian Cancer. American Cancer Society. https://www.cancer.org/cancer/ovarian-cancer/about/key-statistics.html#references. Updated January 2020. Accessed June 26, 2020.

2. Davis, A., Tinker, A., and Friedlander, M. "Platinum resistant" ovarian cancer: What is it, who to treat and how to measure benefit? Gynecologic Oncology. 2014;133(3): 624–631.

3. McCluggage WG, Judge MJ, Clarke BA et al. Data set for reporting of ovary, fallopian tube and primary peritoneal carcinoma: recommendations from the International Collaboration on Cancer Reporting (ICCR). Mod Pathol. 2015;28:1101-1122.

4. Goto M, Nakamura M, Suginobe N, et al. DSP-7888, a novel cocktail design of WT1 peptide vaccine, and its combinational immunotherapy with immune checkpoint-blocking antibody against PD-1. Blood. 2016;128(22):4715.

For media inquiries:

Christine Spasoff
Spectrum™
312-635-6278
cspasoff@spectrumscience.com