MATEON’S UPDATE ON C001 - GLOBAL STUDY FOR OT-101 AGAINST COVID-19

PART 1 AND 2 SENTINEL PATIENTS COMPLETED TREATMENT

THE FIRST COHORT OF 18 PART 1 PATIENTS COMPLETED TREATMENT.

AGOURA HILLS, Calif., March 08, 2021 (GLOBE NEWSWIRE) -- Mateon Therapeutics, Inc. (“Mateon”) (OTCQB:MATN) announced today that it has completed the enrollment of its sentinel Part 1 and Part 2 COVID-19 patients which allows for the continuing expansion to the targeted 18 patients in part 1 and 18 patients in part 2. Additionally, the targeted enrollment of the 18 patients of Part 1 has also been reached. The study was conducted through Oncotelic, Inc. (“Oncotelic”) - a wholly own subsidiary of Mateon.

As explained in a prior press release, the trial is a multi-center, double blind, randomized, placebo-control study to evaluate safety and efficacy of OT-101 in combination with standard of care on two (2) patient cohorts – 1) Part 1 which constitutes mild or moderate disease patients, and 2) Part 2 which constitutes severe disease patients requiring mechanical ventilation or intubation. The primary efficacy endpoint is the proportion of subjects with clinical improvement score (measured by an 8‑point World Health Organization [WHO] COVID‑19 Clinical Improvement Ordinal Scale) as assessed by the Odds Ratio (OR) at Day 14.

These 6 sentinel patients (three per cohort) were treated every 24 hours sequentially, as a precaution to detect any acute adverse events associated with the delivery of OT-101. No acute adverse events related to OT-101 were observed.

Oncotelic also completed the enrollment of the first cohort of 18 Part 1 patients. Once a complete data assessment of these 18 patients is competed by Oncotelic and its Data Safety Monitoring Board (DSMB), Oncotelic may continue to screen and enroll an additional cohort of 18 Part 1 patients. In total, the study can enroll up to 72 patients.

“The completion of the sentinel cohorts indicates there were no overt safety signals with the administration of OT-101 into COVID-19 patients of all severity - mild, moderate or severe. With that we were able to complete the treatment of the first cohort of 18 part 1 patients. We are now awaiting the outcome of a complete and thorough data assessment by Oncotelic and the DSMB to expand the part 1 cohort to 36 pts.” said Dr. Anthony Maida, Chief Clinical Officer – Translational Medicine, Mateon Therapeutics.

“It is reassuring that the initial safety data from these sentinel cohorts are as we predicted previously by Chen et al., 2020/ Uckun et al. 2020. As it stands OT-101 with its inhibition of TGF-beta has the potential of treating COVID-19 through inhibition of myriads of pathological responses to the TGF-beta surge due to COVID-19.” Said Dr. Wanjun Chen, NIH and advisor to the study.

“The rise of B.1.1.7 and P.1 variants in Latin America is concerning as they are able to reinfect patients who recovered from COVID-19 and are probably responsible for the recent surge in Manaus, Brazil where herd immunity has already been declared. Therefore, it is important to look to the future and for us to assess COVID-19 therapeutics in Latin America.” said Dr. Vuong Trieu, CEO and Chairman, Mateon Therapeutics.

About OT-101

OT-101 is an antisense against the host TGF-β protein required for viral replication and its overexpression likely to cause the wide range of clinical symptoms associated with COVID-19 including Kawasaki syndrome (Fatih M. Uckun, Vuong Trieu. Targeting Transforming Growth Factor-beta for Treatment of COVID-19-associated Kawasaki Disease in Children. Clin Res Pediatr 2020; 3(1): 1-3) and acute respiratory distress syndrome (ARDS) (Fatih M. Uckun, Larn Hwang, Vuong Trieu. Selectively targeting TGF-β with Trabedersen/OT-101 in treatment of evolving and mild ARDS in COVID-19. Clin. Invest. (Lond.) 2020; 10(2), 167-176. DOI: 10.4172/ Clinical-Investigation.1000166.).

TGF-β is elevated in COVID-19 (Xiong Y. et al. Transcriptomic characteristics of bronchoalveolar lavage fluid and peripheral blood mononuclear cells in COVID-19 patients. Emerging Microbes & infections 2020; 9:1, 761-770, DOI: 10.1080/22221751.2020.1747363. Agrati C. et al. Expansion of myeloid-derived suppressor cells in patients with severe coronavirus disease (COVID-19). Cell Death & Differentiation 2020; https://doi.org/10.1038/s41418-020-0572-6.).

About Mateon Therapeutics

Mateon was created by the 2019 merger with Oncotelic, which became a wholly owned subsidiary of Mateon, thereby creating an immuno-oncology company dedicated to the development of first in class RNA therapeutics as well as small molecule drugs against cancer and infectious diseases. OT-101, the lead immuno-oncology drug candidate of Mateon/Oncotelic, is a first-in-class anti-TGF-βRNA therapeutic that exhibited single agent activity in some relapsed/refractory cancer patients in clinical trial settings. OT-101 also has activity against SARS-CoV-2. Mateon/Oncotelic is seeking to leverage its deep expertise in oncology drug development to improve treatment outcomes and survival of cancer patients with a special emphasis on rare paediatric cancers. Mateon has rare paediatric designation for DIPG (OT-101), melanoma (CA4P), and AML (OXi4503). For more information, please visit www.oncotelic.com and www.mateon.com.

Mateon's Cautionary Note on Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical facts, included in this communication regarding strategy, future operations, future financial position, prospects, plans and objectives of management are forward-looking statements. Words such as “may”, “expect”, “anticipate” “hope”, “vision”, “optimism”, “design”, “exciting”, “promising”, “will”, “conviction”, "estimate," "intend," "believe", “quest for a cure of cancer”, “innovation-driven”, “paradigm-shift”, “high scientific merit”, “impact potential” and similar expressions are intended to identify forward-looking statements. Forward-looking statements contained in this press release include, but are not limited to, statements about future plans, the progress, timing, clinical development, scope and success of future clinical trials, the reporting of clinical data for the company’s product candidates and the potential use of the company’s product candidates to treat various cancer indications. Each of these forward-looking statements involves risks and uncertainties and actual results may differ materially from these forward-looking statements. Many factors may cause differences between current expectations and actual results, including unexpected safety or efficacy data observed during preclinical or clinical studies, clinical trial site activation or enrollment rates that are lower than expected, changes in expected or existing competition, changes in the regulatory environment, failure of collaborators to support or advance collaborations or product candidates and unexpected litigation or other disputes. These risks are not exhaustive, the company faces known and unknown risks, including the risk factors described in the company’s annual report on Form 10-K filed with the SEC on April 10, 2019 and in the company’s other periodic filings. Forward-looking statements are based on expectations and assumptions as of the date of this press release. Except as required by law, the company does not assume any obligation to update forward-looking statements contained herein to reflect any change in expectations, whether as a result of new information future events, or otherwise.

Contact Information:
For Mateon Therapeutics, Inc.:
Amit Shah
ashah@oncotelic.com