Medicenna Presented Insights from the Phase 2b Clinical Trial of MDNA55 at the European Society for Medical Oncology 2018 Congress

TORONTO and HOUSTON, TX, Oct. 22, 2018 /PRNewswire/ - Medicenna Therapeutics Corp.  ("Medicenna" or "the Company") (TSX: MDNA andOTCQB: MDNAF) a clinical stage immuno-oncology company, presented a poster discussion entitled "Understanding Biological Activity, Tumor Response and Pseudoprogression in a Phase-2b Study of MDNA55 in Adults with Recurrent or Progressive Glioblastoma" at the European Society for Medical Oncology (ESMO) Congress this past Saturday (October 20, 2018) in Munich, Germany.

Dr. Martin Bexon, Head of Clinical Development at Medicenna, presented results outlining the patterns of responses seen in the MDNA55 Phase 2b clinical trial in patients treated at low doses implemented during the first half of the study. The presentation highlighted the use of advanced imaging modalities to help response evaluation and identify treatment artefacts that can mask underlying tumor response particularly when evaluating treatments with a substantial immune mediated component, such as MDNA55. Localized inflammation occurring from treatment by immunotherapies (called pseudo-progression) is common and difficult to distinguish from true disease progression using routine clinical MRI.

"For MDNA55, we can first see evidence of pseudo-progression in the 30 days post-treatment," states Dr Bexon. "In some cases it resolves relatively rapidly thereafter but it has also been seen to get more extensive for up to 6 months and can take over 10 months to resolve. Once the inflammation resolves, we have seen evidence of underlying tumor shrinkage and sustained disease control, despite substantial increases in initial measurements."

"It is necessary to accurately detect pseudo-progression in order to identify the treatment time course of MDNA55 and fully evaluate treatment benefit" states Dr. John H. Sampson, MD, PhD, Chair of the Department of Neurosurgery at Duke University. "Use of supportive diagnostic modalities such as biopsy or advanced imaging should be integrated in order to optimize evaluation by the current response assessment criteria in neuro-oncology. In the MDNA55 trial, we see clear evidence of treatment benefits. The appearance of treatment artefacts can not only conceal tumor response but can also cause premature withdrawals of patients before fully assessing therapeutic effects."

MDNA55, is the company's lead immunotherapeutic agent targeting the interleukin-4 receptor (IL-4R) which is known to be over-expressed in brain tumors and the tumor micro-environment but not in healthy brain tissue. In the study, MDNA55-05, investigators administer MDNA55 directly into brain tumors using a technique known as Convection Enhanced Delivery (CED).  CED allows precision delivery of MDNA55 directly into the tumor tissue and the surrounding healthy brain containing infiltrative tumor cells, while avoiding exposure to the rest of the body. The Phase 2b clinical trial is currently enrolling adult patients with recurrent glioblastoma (rGBM) at leading brain cancer centers in US and Europe.

About Medicenna

Medicenna is a clinical stage immunotherapy company focused on oncology and the development and commercialization of novel, highly selective versions of IL-2, IL-4 and IL-13 Superkines™ and first in class Empowered Cytokines™ (ECs) for the treatment of a broad range of cancers.  Medicenna's wholly owned subsidiary, Houston-based Medicenna BioPharma, is specifically targeting the Interleukin-4 Receptor (IL4R), which is over-expressed by at least 20 different types of cancer affecting more than one million new cancer patients every year. Supported by a significant non-dilutive grant from CPRIT (Cancer Prevention and Research Institute of Texas), Medicenna's lead IL4-EC, MDNA55 is enrolling patients in a Phase 2b clinical trial for recurrent glioblastoma (rGBM), the most common and uniformly fatal form of brain cancer, at top-ranked brain cancer centres in the US. MDNA55 has completed three clinical trials in 72 patients, including 66 adults with rGBM, demonstrated compelling efficacy and obtained Fast-Track and Orphan Drug status from the FDA and FDA/EMA respectively. For more information, please visit www.medicenna.com.

This news release contains forward-looking statements relating to the future operations of the Company and other statements that are not historical facts. Forward-looking statements are often identified by terms such as "will", "may", "should", "anticipate", "expects" and similar expressions. All statements other than statements of historical fact, included in this release, including, without limitation, statements regarding including, without limitation, statements related to the ongoing Phase 2b clinical trial of MDNA55 for the treatment of rGBM and the future plans and objectives of the Company, are forward-looking statements that involve risks and uncertainties. There can be no assurance that such statements will prove to be accurate and actual results and future events could differ materially from those anticipated in such statements. Important factors that could cause actual results to differ materially from the Company's expectations include the risks detailed in the annual information form of the Company dated June 26, 2018 and in other filings made by the Company with the applicable securities regulators from time to time.

The reader is cautioned that assumptions used in the preparation of any forward-looking information may prove to be incorrect. Events or circumstances may cause actual results to differ materially from those predicted, as a result of numerous known and unknown risks, uncertainties, and other factors, many of which are beyond the control of the Company. The reader is cautioned not to place undue reliance on any forward-looking information. Such information, although considered reasonable by management at the time of preparation, may prove to be incorrect and actual results may differ materially from those anticipated. Forward-looking statements contained in this news release are expressly qualified by this cautionary statement. The forward-looking statements contained in this news release are made as of the date of this news release and the Company will update or revise publicly any of the included forward-looking statements only as expressly required by Canadian securities law.

SOURCE Medicenna Therapeutics Corp.

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