Mateon Therapeutics Announces Initial Pre-clinical

• In one study most animals receiving the combination of CA4P and anti-CTLA4 antibody were tumor free at completion
• Three additional studies provide evidence that CA4P may enhance anti-CTLA4, anti-PD1, and anti-PD-L1 antibody activity

SOUTH SAN FRANCISCO, Calif., Feb. 13, 2017 (GLOBE NEWSWIRE) -- Mateon Therapeutics, Inc. (OTCQX:MATN), a biopharmaceutical company developing vascular disrupting agents (VDAs) for the treatment of orphan oncology indications, today announced encouraging preliminary data from four different syngeneic mouse models evaluating Mateon’s lead investigational drug CA4P in combination with checkpoint inhibitors.

The most compelling results were found combining Mateon’s CA4P with an anti-CTLA4 antibody in an EMT-6 mammary model. In this study, 7 of 8 mice receiving the combination were tumor free at the study’s completion, compared to 1 of 8 in the CA4P monotherapy arm and 2 of 8 in the anti-CTLA4 antibody monotherapy arm.

Three of four follow-up studies also demonstrated that CA4P combined with immune oncology agents delayed tumor growth. These studies were conducted in a larger tumor EMT-6 mammary model, a C3H mammary model and a CT26 colon model. The results provide additional supportive evidence that CA4P enhances anti-CTLA4 antibody activity, as well as initial evidence that CA4P enhances anti-PD-1 and PD-L1 activity.

“We have seen in numerous earlier studies that CA4P, via vascular disruption, induces rapid and extensive necrotic tumor cell death,” stated William D. Schwieterman, M.D., President and Chief Executive Officer. “By causing this tumor cell necrosis, we believe that CA4P may enhance antigen presentation and T-cell activity within the tumors, increasing the effect of checkpoint inhibitors in tumors which do not respond to the immune oncology agents alone. Based upon the results of our initial pre-clinical studies, we are continuing with additional pre-clinical work in this field. Concurrently, our phase 2/3 FOCUS Study, evaluating CA4P in platinum-resistant ovarian cancer, continues to enroll patients and data from the first interim analysis is expected in April. We are also nearing completion of the 3 ^rd dose cohort in our study of OXi4503 in acute myeloid leukemia.”

Mateon reminds investors that a webcast of today’s presentation at the 19th Annual BIO CEO & Investor Conference at 5:30 pm eastern time will be available on the company’s website at www.mateon.com in “Events & Presentations” under the “Investors & News” tab. A replay of the webcast will also be available following the completion of the live event.

About Mateon Mateon Therapeutics, Inc. is a biopharmaceutical company seeking to realize the full potential of vascular targeted therapy (VTT) in oncology. VTT includes vascular disrupting agents (VDAs) such as the investigational drugs that Mateon is developing, and anti-angiogenic agents (AAs), a number of which are FDA-approved and widely used in cancer treatment. These two approaches have distinct yet complementary mechanisms of action.

At Mateon, we believe that we can significantly improve cancer therapy by employing these two complementary approaches simultaneously. When utilized this way, VDAs obstruct existing blood vessels in the tumor leading to significant central tumor cell death while AAs prevent the formation of new tumor blood vessels.

Mateon is committed to leveraging our intellectual property and the product development expertise of our highly skilled management team to enable VTT to realize its true potential and to bring much-needed new therapies to cancer patients worldwide. 

Safe Harbor Statement Certain statements in this news release, including, but not limited to, those concerning the pre-clinical data on the combination of CA4P with checkpoint inhibitors, the potential significance of this data and its relation to other clinical and pre-clinical studies are considered "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. They can be affected by inaccurate assumptions Mateon might make or by known or unknown risks and uncertainties, including, but not limited to: the uncertainties as to the future success of ongoing and planned clinical trials; the unproven safety and efficacy of products under development or that may be developed in the future; and the sufficiency of the Company’s cash resources to conduct and complete future clinical and pre-clinical trials. Consequently, no forward-looking statement can be guaranteed, and actual results may vary materially. Additional information concerning factors that could cause actual results to materially differ from those in the forward-looking statements is contained in Mateon’s reports to the Securities and Exchange Commission, including Mateon’s reports on Forms 10-Q, 8-K and 10-K. However, Mateon undertakes no obligation to publicly update forward-looking statements, whether because of new information, future events or otherwise.

CONTACTS Investors: ir@mateon.com 650-635-7000 Media: JPA Health Communications Nic DiBella nic@jpa.com 617-945-5183