• Humanigen plans to submit an MAA under the centralized procedure seeking Conditional Marketing Authorization (CMA) throughout the European Union (EU) for the use of lenzilumab to treat patients hospitalized with COVID-19 pneumonia
• Humanigen expects to request accelerated assessment, which if granted can reduce review time by 60 days, as part of the MAA pre-submission process

Humanigen, Inc. (Nasdaq: HGEN) (“Humanigen”), a clinical-stage biopharmaceutical company focused on preventing and treating an immune hyper-response called ‘cytokine storm,’ announced today the European Medicines Agency (EMA) has appointed a rapporteur and a co-rapporteur as part of the pre-submission process related to Humanigen’s plan to submit an MAA for the use of lenzilumab to treat patients hospitalized with COVID-19. These appointments by the Committee for Medicinal Products for Human Use (CHMP) are an important step in the pre-submission process leading up to the submission of the MAA. Humanigen plans to request accelerated assessment of the MAA as part of the pre-submission process.

“Highlighting the ongoing need globally for therapeutics to treat patients hospitalized with COVID-19, in the EU in the most recent week for which data is available, there were 7,664 new hospitalizations and 4,429 deaths reported for COVID-19,” said Cameron, Durrant, MD, Chief Executive Officer, Humanigen.¹ “We remain committed to bringing lenzilumab to hospitalized patients with COVID-19 and as part of this effort, we plan to submit our MAA to the EMA as soon as possible.”

EU legislation allows for accelerated assessment of an MAA, reducing review time from 210 days to 150 days not counting clock stops for applicants to provide additional information, if CHMP determines a product is a major public health interest; however, this decision has no impact on the eventual CHMP opinion on whether a marketing authorization should be granted.

About Humanigen

Humanigen, Inc. (Nasdaq: HGEN) (“Humanigen”), is a clinical-stage biopharmaceutical company focused on preventing and treating an immune hyper-response called ‘cytokine storm’. Lenzilumab is a first-in class antibody that binds to and neutralizes granulocyte-macrophage colony-stimulating factor (GM-CSF). Results from preclinical models indicate GM-CSF is an upstream regulator of many inflammatory cytokines and chemokines involved in the cytokine storm. Early in the COVID-19 pandemic, investigation showed high levels of GM-CSF secreting T cells were associated with disease severity and intensive care unit admission. Humanigen’s Phase 3 LIVE-AIR study suggests early intervention with lenzilumab may prevent consequences of a full-blown cytokine storm in hospitalized patients with COVID-19. Humanigen has submitted lenzilumab to Medicines and Health Regulatory Agency in the United Kingdom for a rolling review towards potential Marketing Authorization. Humanigen is developing lenzilumab as a treatment for cytokine storm associated with COVID-19 and CD19-targeted CAR-T cell therapies and is also exploring the effectiveness of lenzilumab in other inflammatory conditions such as acute Graft versus Host Disease in patients undergoing allogeneic hematopoietic stem cell transplantation, eosinophilic asthma, and rheumatoid arthritis. For more information, visit www.humanigen.com and follow Humanigen on LinkedIn, Twitter, and Facebook.

Forward-Looking Statements

All statements other than statements of historical facts contained in this press release are forward-looking statements. Forward-looking statements reflect management's current knowledge, assumptions, judgment, and expectations regarding future performance or events. Although management believes that the expectations reflected in such statements are reasonable, they give no assurance that such expectations will prove to be correct, and you should be aware that actual events or results may differ materially from those contained in the forward-looking statements. Words such as "will," "expect," "intend," "plan," "potential," "possible," "goals," "accelerate," "continue," and similar expressions identify forward-looking statements, including, without limitation, statements about our plans to submit and seek accelerated assessment of an MAA for lenzilumab in COVID-19 with the EMA in the EU; statements regarding our efforts to seek Marketing Authorization for lenzilumab in COVID-19 in the U.K.; and our other plans relating to development of lenzilumab.

Forward-looking statements are subject to a number of risks and uncertainties including, but not limited to, the risks inherent in our lack of profitability and need for additional capital to grow our business; our dependence on partners to further the development of our product candidates; the uncertainties inherent in the development, attainment of the requisite regulatory authorizations and approvals and launch of any new pharmaceutical product; the outcome of pending or future litigation; and the various risks and uncertainties described in the "Risk Factors" sections of our latest annual and quarterly reports and other filings with the SEC.

All forward-looking statements are expressly qualified in their entirety by this cautionary notice. You should not rely upon any forward-looking statements as predictions of future events. We undertake no obligation to revise or update any forward-looking statements made in this presentation to reflect events or circumstances after the date hereof or to reflect new information or the occurrence of unanticipated events, except as required by law.

Reference

1. Hannah Ritchie, Edouard Mathieu, et. Al. (2020) - "Coronavirus Pandemic (COVID-19)". Published online at OurWorldInData.org. Vaccination data for week ending Sep. 25, 2021. Hospitalizations for week ending Sep. 19, 2021. Deaths for week ending Sep. 27, 2021. Retrieved from: https://ourworldindata.org/coronavirus on Sep. 28, 2021.

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