Medicenna Announces Completion of Enrolment in MDNA55 Phase 2b Recurrent Glioblastoma Clinical Study

Interim Top-Line Results to be Announced in June, 2019

TORONTO and HOUSTON, April 30, 2019 /PRNewswire/ - Medicenna Therapeutics Corp. ("Medicenna" or the "Company") (TSX: MDNA; OTCQB: MDNAF), a clinical stage immuno-oncology company, is pleased to announce that it has completed enrolment in the Phase 2b clinical study of MDNA55 for the treatment of recurrent glioblastoma (rGBM), the most common and uniformly fatal form of brain cancer.

"The completion of patient enrolment with our flagship clinical asset is a significant milestone for Medicenna and we look forward to reporting interim top-line data from this trial in June 2019." said Dr. Fahar Merchant, Chairman, President and CEO, "Glioblastoma is a devastating disease and it is particularly aggressive in patients overexpressing the IL4 receptor (IL4R), a biomarker that is specifically targeted by MDNA55. The interim results we presented in February 2019 demonstrated that a single low dose treatment with MDNA55 was able to extend survival by 2-fold to 15.2 months in rGBM patients expressing the IL4R when compared to expected survival of 6 to 8 months. We would like to thank our shareholders for their patience, the Cancer Prevention and Research Institute of Texas (CPRIT) for a generous grant, investigators, clinical sites, patients and their families for their continued support to bring MDNA55 to patients who need it the most."

The Company is now evaluating data from 25 patients with rGBM treated at the high dose and assessing the impact of IL4R expression on survival outcomes as well as tumor response. Interim top-line results for all patients will be announced this quarter. To date MDNA55 has been used to treat more than 130 patients in multiple clinical trials, including more than 110 patients with rGBM, building a significant safety profile, evidence of anti-tumor effect and mechanistic dataset. Medicenna expects multiple presentations of clinical results at relevant conferences this year and provide updates following meetings with regulatory agencies regarding future path to commercialization of MDNA55.

MDNA55, an IL4R directed toxin, has been the subject of a Phase 2b open-label study in up to 52 patients with glioblastoma (GBM) at first or second relapse. In the study, investigators administered MDNA55 only once directly into the brain tumor 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. Retrospective analysis of GBM tissue obtained at first diagnosis is performed by immunohistochemistry for IL-4Ra expression. Biopsy samples are categorized based on IL4Rα expression levels and compared against survival outcomes.

About Medicenna

Medicenna is a clinical stage immunotherapy company developing novel highly selective versions of IL-2, IL-4 and IL-13 Superkines and first in class Empowered Cytokines™ (ECs). Our mission is to become the leader in the development and commercialization of ECs and Superkines for the treatment of a broad range of cancers and immune-mediated diseases. MDNA55 is Medicenna's lead EC that has completed enrolling in a multi-centre Phase 2b clinical trial for the treatment of recurrent glioblastoma (rGBM), the most common and uniformly fatal form of brain cancer. MDNA55 has secured Orphan Drug Status from the United States Food and Drug Administration (FDA) and the European Medicines Agency as well as Fast Track Designation from the FDA for the treatment of rGBM. 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 related to the Phase 2b clinical trial of MDNA55 for the treatment of rGBM including, without limitation, top line data reporting timelines, 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 (including, without limitation, the ability of the Company to fully replicate these interim data results) 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.

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SOURCE Medicenna Therapeutics Corp.

Company Codes: OTC-QX:MDNAF, Toronto:MDNA, OTC-QB:MDNAF