8-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of
the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): August 4, 2021

Humanigen, Inc.

(Exact name of registrant as specified in its charter)

Delaware	001-35798	77-0557236
(State or other Jurisdiction of Incorporation)	(Commission File No.)	(IRS Employer Identification No.)

533 Airport Boulevard, Suite 400

Burlingame, CA 94010

(Address of principal executive offices, including zip code)

(650) 243-3100

(Registrant’s telephone number, including area code)

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2):

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock	HGEN	The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

Emerging growth company o

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Item 7.01. Regulation FD Disclosure

On August 4, 2021, Humanigen, Inc. (the “Company”) issued a press release announcing a retrospective data analysis from its pivotal Phase 3 trial of lenzilumab in patients hospitalized with COVID-19 (the “LIVE-AIR” study) suggesting Black and African-American patients having a CRP<150 mg/L may be the highest responders to treatment, with a nearly 9-fold increase in likelihood of survival without ventilation (SWOV) [n=51, p-value=0.0412]. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Also on August 4, 2021, the Company made available a presentation further examining this data analysis on the Company's website, www.humanigen.com. A copy of this presentation is furnished as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated herein by reference.

Cautionary Note Regarding Forward-Looking Statements

This Current Report on Form 8-K, including Exhibit 99.1 and Exhibit 99.2, contains 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 regarding the effectiveness of lenzilumab in Black and African-American patients; the review of the Company’s submission for emergency use authorization by the FDA; and the Company’s other plans to explore the effectiveness of lenzilumab and other candidates in its development portfolio as therapies for other inflammation and immune-oncology indications. These forward-looking statements are subject to a number of risks and uncertainties including, but not limited to, the risks inherent in the Company’s lack of profitability and need for additional capital to grow its business; the Company’s dependence on partners to further the development of its product candidates; the uncertainties inherent in the development, attainment of the requisite regulatory authorization 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 and elsewhere in the Humanigen's periodic and other filings with the Securities and Exchange Commission.

All forward-looking statements are expressly qualified in their entirety by this cautionary notice. You should not place undue reliance on any forward-looking statements, which speak only as of the date of this filing. The Company undertakes no obligation to revise or update any forward-looking statements made in this filing 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.

Certain Information

The information in this Item 7.01, including Exhibit 99.1 and Exhibit 99.2, is being furnished pursuant to Item 7.01 of Form 8-K and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any of the Company’s filings under the Securities Act of 1933, as amended, except to the extent expressly set forth by specific reference in such a filing.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.	Exhibit Description
99.1	Press Release, dated August 4, 2021
99.2	Humanigen Presentation “LIVE-AIR Phase 3 Study Update: Highest Response Rates Observed in Black and African-American Patients” dated August 2021

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Humanigen, Inc.
By:	/s/ Cameron Durrant
	Name: Cameron Durrant Title:   Chairman of the Board and Chief Executive Officer

Dated: August 4, 2021

EX-99.1

Exhibit 99.1

 

Lenzilumab Treatment May Provide Enhanced Likelihood of Survival Without Ventilation in Hospitalized Black and African-American COVID-19 Patients

· Lenzilumab treatment in Black and African-American patients in the positive LIVE-AIR Phase 3 trial, having a CRP<150 mg/L, resulted in a nearly 9-fold increase in survival without ventilation

· CDC data shows Black and African-American persons are at an almost 3-fold greater risk of hospitalization and 2-fold greater risk of death from COVID-19 infection¹

· Black American vaccination rates are lowest nationally, resulting in higher risk of infection, hospitalization, and death²

BURLINGAME, Calif. August 4, 2021--(BUSINESS WIRE)--Humanigen, Inc. (Nasdaq: HGEN) (“Humanigen”), a clinical-stage biopharmaceutical company focused on preventing and treating an immune hyper-response called ‘cytokine storm’, announced analysis of results from its Phase 3 LIVE-AIR study of lenzilumab in hospitalized patients with COVID-19 suggesting Black and African-American patients having a CRP<150 mg/L may be the highest responders to treatment, with a nearly 9-fold increase in likelihood of survival without ventilation (SWOV) [n=51, p-value=0.0412]. In the overall population with CRP<150 mg/L, LIVE-AIR Phase 3 results show patients treated with lenzilumab demonstrated a 2.5-fold increased likelihood of SWOV [mITT, n=351, p-value=0.0009].

“Humanigen believes this analysis is an important finding because Black and African-American patients are hyper-vulnerable to COVID-19,” said Cameron Durrant, MD, Chief Executive Officer, Humanigen. “In light of the rapid ongoing spread of the Delta variant, data suggesting that Black and African-American patients, who are hyper-vulnerable to COVID-19, and may be hyper-responsive to lenzilumab is important in the broader context of the potential benefits that may result if the FDA were to grant emergency use authorization.”

The Centers for Disease Control and Prevention (CDC) has found that race and ethnicity are risk markers for other conditions that affect health, including socioeconomic status, access to health care, and exposure to SARS-CoV-2 related to occupation, such as frontline, essential, and critical infrastructure workers.¹ The American Heart Association’s COVID-19 Cardiovascular Disease Registry found that Black patients had the highest prevalence of obesity, hypertension, and diabetes, all of which are medical conditions the CDC identifies as making adults of any age more likely to get severely ill from COVID-19.^3,4

“In the interest of public health and safety, it is our priority to share data with stakeholders to improve our understanding of the disease and potential treatments,” said Adrian Kilcoyne, MD, Chief Medical Officer, Humanigen. “While there may be some limitations to subset analyses, we believe the ongoing public health crisis caused by SARS-CoV-2 warrants consideration of these important data by regulatory authorities.”

Humanigen intends to submit data from this analysis for publication in a peer-reviewed journal and present the findings at a medical meeting. These new data from the LIVE-AIR study will also be shared with regulatory authorities in the US, UK, European Union, and other geographies.

Black/African-American Patients May Be Hyper-Responders to Lenzilumab Treatment

Population in LIVE - AIR Study Lenzilumab vs Placebo Hazard Ratio (95% CI) P - Value Study Population (mITT, n=479) 1.54 (1.02 – 2.32) 0.0403 Black/African - American Population (mITT, n=71) 2.68 (0.89 - 8.12) 0.0811 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Study Population with CRP<150 mg/L (n=351) 2.54 (1.46 - 4.41) 0.0009 Black/African - American Population with CRP<150 mg/L (n=51) 8.96 (1.09 – 73.55) 0.0412

Source: Humanigen analysis of LIVE-AIR Phase 3 study results.

 

About the LIVE-AIR, Phase 3 Study of Lenzilumab

LIVE-AIR Phase 3 study met its primary endpoint of survival without ventilation demonstrating a 1.54-fold improvement overall and trended to a 2.68-fold improvement in Black and African-American patients. This study was a randomized, double-blind, placebo-controlled, multi-center Phase 3 trial for the treatment and prevention of serious and potentially fatal outcomes in patients hospitalized with COVID-19 pneumonia. The primary objective was to assess whether lenzilumab, in addition to other treatments, which included dexamethasone (or other steroids) and/or remdesivir, could alleviate the immune-mediated ‘cytokine storm’ and improve survival without ventilation, or ‘SWOV’ (sometimes referred to as ‘ventilator-free survival’). SWOV is a composite endpoint of time to death and time to invasive mechanical ventilation (IMV), which is a robust measure that is less prone to favor a treatment with discordant effects on survival or days free of ventilation.⁵

The LIVE-AIR study enrolled 520 patients in 29 sites in the US and Brazil who were at least 18 years of age; experienced blood oxygen saturation (SpO₂) of less than or equal to 94%; or required low-flow supplemental oxygen, or high-flow oxygen support, or non-invasive positive pressure ventilation; and were hospitalized but did not require IMV. Following enrollment, subjects were randomized to receive three infusions of either lenzilumab or placebo, each infusion separated by eight hours over a 24-hour period. The primary endpoint was the difference between lenzilumab treatment and placebo treatment in SWOV through day 28 following treatment. Key secondary endpoints, also measured through day 28, included ventilator-free days, duration of ICU stay, incidence of IMV, extracorporeal membrane oxygenation (ECMO), and/or death, time to death, all-cause mortality, and time to recovery. Results of the trial have been submitted for publication in a peer-reviewed journal.

About Humanigen, Inc.

Humanigen, Inc. (Nasdaq: HGEN) (“Humanigen”), 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 is developing lenzilumab as a treatment for cytokine storm associated with CD19-targeted CAR-T cell therapies and exploring the effectiveness of lenzilumab in other inflammatory conditions such as acute Graft versus Host Disease (aGvHD) in patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT), eosinophilic asthma, and rheumatoid arthritis. Humanigen is also developing a portfolio of clinical and pre-clinical therapies for the treatment of inflammation and immuno-oncology. For more information, visit www.humanigen.com and follow Humanigen on LinkedIn, Twitter, and Facebook.

Humanigen 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 regarding the effectiveness of lenzilumab in Black and African-American patients; the review of our submission for emergency use authorization by the FDA; and our other plans to explore the effectiveness of lenzilumab and other candidates in our development portfolio as therapies for other inflammation and immune-oncology indications.

 

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. The Company undertakes no obligation to revise or update any forward-looking statements made in this filing 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.

Humanigen Media
Grace Catlett
RXMD
gcatlett@rxmedyn.com
516-318-8563

Humanigen Investor Relations 

Ken Trbovich 

Humanigen 

trbo@humanigen.com 

650-410-3206 

Sources:

1. Centers for Disease Control and Prevention. (2021, July 16). Risk for Covid-19 infection, hospitalization, and death by race/ethnicity. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/covid-data/investigations-discovery/hospitalization-death-by-race-ethnicity.html#print.

2. Ndugga, N., Hill, L., Artiga, S., & Parker, N. (2021, July 21). Latest Data On COVID-19 Vaccinations by Race/Ethnicity. Coronavirus (COVID-19). https://www.kff.org/coronavirus-covid-19/issue-brief/latest-data-on-covid-19-vaccinations-race-ethnicity/.

3. Rodriguez, F., Solomon, N., de Lemos, J. A., et al. (2020). Racial and Ethnic Differences in Presentation and Outcomes for Patients Hospitalized with COVID-19: Findings from the American Heart Association’s COVID-19 Cardiovascular Disease Registry. Circulation, 143(24), 2332–2342. https://doi.org/10.1161/circulationaha.120.052278

4. Centers for Disease Control and Prevention. (2021, May 13). Certain medical conditions and risk for severe covid-19 illness. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/people-with-medical-conditions.html.

5. Novack V., Beitler J., Yitshak-Sade M., et al. (2020). Alive and Ventilator-Free: A Hierarchical, Composite Outcome for Clinical Trials in the Acute Respiratory Distress Syndrome. Critical Care Medicine, 48(2), 158–166. https://doi.org/10.1097/ccm.0000000000004104

EX-99.2

Exhibit 99.2

Confidential LIVE - AIR Phase 3 Study Update: Highest Response Rates Observed in Black and African - American Patients August 2021

2 Cautionary Note Regarding Forward - Looking Statements All statements other than statements of historical facts contained in this presentation 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 regarding the effectiveness of lenzilumab in Black and African - American patients ; the potential role of lenzilumab in the treatment of COVID - 19 ; the review of our submission for emergency use authorization by the FDA ; and our other plans to explore the effectiveness of lenzilumab and other candidates in our development portfolio as therapies for other inflammation and immune - oncology indications . 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 . The Company undertakes no obligation to revise or update any forward - looking statements made in this filing 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 .

3 Summary • Hyper - vulnerable to COVID - 19 • Vaccine hesitancy, underlying medical conditions, socioeconomic factors • 13% of the population and 23% of COVID - 19 deaths 1 • Hyper - responders to lenzilumab treatment • In Black/African - American overall, 2.7x increase in survival without ventilation • In Black/African - American with CRP <150, 9x increase in survival without ventilation • In LIVE - AIR, lenzilumab offered significant clinical benefit and is currently under review for Emergency Use Authorization Black / African - American Patients Lenzilumab is being developed as a potential treatment for COVID - 19, it is not currently authorized or approved for use in any c ountry 1. https://usafacts.org/articles/covid - deaths - race - state - age - black - hispanic - white/

4 Reasons Why African - Americans are Disproportionately Affected by COVID - 19 • 36% vaccinated • Lowest among all groups • Vaccine hesitancy • Historical mistrust of healthcare and Government system Vaccination Rates • Higher incidence and prevalence of chronic illnesses e.g., diabetes • Associated with worse outcomes • Challenged access to healthcare Background health conditions 1 • Physical environment • Housing • Occupation • Education • Economic stability • Discrimination Social determinants of health 1 African - Americans represent 13% of the US population, but 23% of COVID - 19 Deaths 1. https://www.cdc.gov/coronavirus/2019 - ncov/community/health - equity/race - ethnicity.html, April 19, 2021 Lenzilumab is being developed as a potential treatment for COVID - 19, it is not currently authorized or approved for use in any c ountry

5 Black American Vaccination Lowest by Race/Ethnicity 1 1. Kaiser Family Foundation, https://www.kff.org/coronavirus - covid - 19/issue - brief/latest - data - on - covid - 19 - vaccinations - race - ethnici ty/, July 21, 2021 Percent of total Population with at Least One COVID - 19 Vaccine Dose by Race/Ethnicity, 3 - 1 - 21 to 7 - 19 - 21

6 LIVE - AIR: Lenzilumab Phase 3 Randomized , Double - blind, Placebo - controlled Study Design Early intervention with lenzilumab, in addition to current standard of care, to prevent and treat CS and prevent progression to IMV and/or death • Randomized , double - blind, placebo - controlled, multi - center pivotal trial NCT 04351152 • All subjects received other treatment, which may have included corticosteroids and/or remdesivir Primary Endpoint: ▪ Ventilator - free survival/Survival without ventilation Key Secondary Endpoints: ▪ Ventilator - free days ▪ Duration of ICU stay ▪ Survival ▪ Time to recovery • Adults ≥ 18 years • Hospitalized • Confirmed SARS - CoV - 2 COVID - 19 pneumonia • SpO 2 ≤ 94% and pre - IMV Follow - up Assessment Day 60 Enrollment Screening Randomization Lenzilumab, 600 mg IV Q8H x3 Day 1 Placebo IV Q8H x3 Treatment Phase Follow - up Phase Daily assessments while hospitalized Endpoint Assessment Through Day 28 Evaluated through Day 28 Lenzilumab is being developed as a potential treatment for COVID - 19, it is not currently authorized or approved for use in any c ountry

7 Black and African - Americans Well Represented in LIVE - AIR Patient Population 1 60.1 18.5 13.4 5.9 1.3 0.8 43.2 38.5 14.8 1.9 0.5 1.1 0 10 20 30 40 50 60 70 White (non- hispanic) Hispanic Black/African American Asian American Indian/Alaskan native other % LIVE - AIR Diversity Compared with US Census US Census LIVE-AIR 1. https://www.census.gov/quickfacts/fact/table/US/PST045219 Lenzilumab is being developed as a potential treatment for COVID - 19, it is not currently authorized or approved for use in any c ountry

8 Primary Endpoint met: Survival without Ventilation (“SWOV”) 8 Patients who died or required ventilation K - M Estimate Population Lenzilumab Placebo Lenzilumab vs placebo hazard ratio (95% CI) P value mITT (n=479) 15.6% (11.5 – 20.9) (n=236) 22.1% (17.4 – 27.9) (n=243) 1.54 (1.02 – 2.32) 0.0403 Treatment with lenzilumab resulted in a 1.54x Increase in the likelihood of surviving and without needing to be on mechanical ventilation Lenzilumab is being developed as a potential treatment for COVID - 19, it is not currently authorized or approved for use in any c ountry

9 SWOV in All Patients with Baseline CRP < 150* 9 Patients who died or required ventilation K - M Estimate Population Lenzilumab (95% CI) Placebo (95% CI) Lenzilumab vs placebo hazard ratio (95% CI) P value (n=351) 9.8% (6.1 - 15.4) (n=168) 21.2% (15.9 - 27.9) (n=183) 2.54 (1.46 – 4.41) 0.0009 *C - Reactive Protein is routine and accepted measure of inflammation. A retrospective analysis of data from LIVE - AIR suggests tha t patients with a CRP < 150 have an even greater response to lenzilumab Baseline CRP was evaluable in 482 patients. For patients with a CRP<150, treatment with lenzilumab resulted in a 2.54x Increase in the likelihood of surviving and without needing to be on mechanical ventilation Lenzilumab is being developed as a potential treatment for COVID - 19, it is not currently authorized or approved for use in any c ountry

10 Black/African - American population with Baseline CRP < 150* 10 For Black/African - American Patients, treatment with lenzilumab resulted in a 9x Increase in the likelihood of surviving and without needing to be on mechanical ventilation Lenzilumab is being developed as a potential treatment for COVID - 19, it is not currently authorized or approved for use in any c ountry Patients who died or required ventilation K - M Estimate Population Lenzilumab Placebo Lenzilumab vs placebo hazard ratio (95% CI) P value (n=51) 4.0% (n=25) 26.9% (n=26) 8.96 (1.09 – 73.6) 0.0412 *C - Reactive Protein is routine and accepted measure of inflammation. A retrospective analysis of data from LIVE - AIR suggests tha t patients with a CRP < 150 have an even greater response to lenzilumab Baseline CRP was evaluable in 482 patients.

11 Black/African - American Patients had a 9 - fold increase in the likelihood of Survival without ventilation 11 Lenzilumab is being developed as a potential treatment for COVID - 19, it is not currently authorized or approved for use in any c ountry

12 Patient Reach Disease Severity Anti - viral Antibodies Outpatient Antiviral Immuno - Modulators COVID - 19 Vaccines Prophylaxis Critical patients in the ICU on mechanical ventilation and progressing rapidly 2,6,7 IMV – 2020: ~294K, 2021: ~349K, 2025: ~192K Bamlanivimab + Etesevimab Casirivimab + Imdevimab VIR - 7831 Lenzilumab; EUA Submitted Actemra (tocilizumab) Critical condition, exhibiting rapid respiratory decompensation Veklury (r emdesivir ) Narrowest Population, But Significant Broadest Population BNT162b2 mRNA - 1273 JNJ - 78436735 Newly Hospitalized Outpatient Treatment Pre/Post Exposure Prophylaxis Corticosteroids (dexamethasone) Hospitalized and hypoxic patients with confirmed diagnosis of COVID - 19 Mild - to - Moderate symptoms in high - risk non - hospitalized patients COVID - 19 negative or 90 - days post confirmed Dx Hospitalized and hypoxic patients; 12 years+, weighing at least 40kg Hospitalizations 2,6,7 – 2020: ~1.33M, 2021: ~1.58M, 2025: ~870,000 Within 3 - days of positive diagnosis; Requires presentation to infusion center; Low utilization of outpatient mAbs to date All patients 12 years+ Hospital mAbs Hospitalized - Critical Inpatient >67% of US Population At Least Partially Vaccinated 4 ~40% of COVID - 19 Patients are High - Risk 3 ~8% of Cases Require Hospitalization 5,6 ~2% of Cases Require IMV 1,5 There Remains A Significant Unmet Need For Hospitalized And Hypoxic Patients Sources: FDA Fact Sheets for Healthcare Providers for Veklury (Accessed June 29, 2021), REGEN - COV. (Accessed June 29, 2021), Bamlanivimab + Etesevimab (Accessed June 29, 2021), Actemra ( Accessed June 29, 2021), Olumiant ( Accessed August 3, 2021), Pfizer - BioNTech COVID - 19 Vaccine (Accessed June 29, 2021), Moderna COVID - 19 Vaccine (Accessed June 29, 2021). Janssen “ J&J” COVID - 19 Vaccine (Accessed June 29, 2021) using https://www.fda.gov/emergency - preparedness - and - response/mcm - legal - regulatory - and - policy - framework/emergency - use - authorization#coviddrugs 1. Based on lenzilumab Ph3 Data. 2. Humanigen Internal Forecast – Based upon 1.8% of Cases. 3. CDC: Estimated County - Level Prevalence of Selected Underlying Medical Conditions Associated with Increased Risk for Severe COVID - 19 Illness — United States, 2018. (Accessed June 29, 2021). https://www.cdc.gov/mmwr/volumes/69/wr/mm6929a1.htm?s_cid=mm6929a1_w. 4. CDC COVID Tracker: Vaccinations (Accessesed August 3 , 2 021). https://covid.cdc.gov/covid - data - tracker/#vaccinations. 5. Our World in Data / University of Oxford. (Accessed August 3, 2021). Number of US Cases YTD. https://covid.ourworldindata.org /da ta/owid - covid - data.csv. 6. CDC – COVID Data Tracker. (Accessed August 3, 2021). New Admissions of Patients with Confirmed COVID - 19, United States. https://covid.cdc.gov/covid - data - tracker/#new - hospital - admissions. 7. The COVID Tracking Pro ject – Hospitalization Increase data for dates before 7/31/21 when HHS new admissions data began (accessed June 29, 2021). https://covidtracking.com/data/download/national - history.csv JAK Inhibitor Olumiant (baricitinib) Lenzilumab is being developed as a potential treatment for COVID - 19, it is not currently authorized or approved for use in any c ountry

13 Conclusion • Higher infection rates • Higher hospitalization rates • Higher death rates Black and African Americans are disproportionately affected by COVID - 19 1 • Systemic disparities • Social determinants of health • Low vaccination rates Multiple potential reasons for this 1, 2 • 9x Increase in survival and without requiring mechanical ventilation Black/African - American patients appeared to demonstrate exceptional response rates to lenzilumab 3 Currently under review for Emergency Use Authorization by FDA 1. https://www.cdc.gov/coronavirus/2019 - ncov/covid - data/investigations - discovery/hospitalization - death - by - race - ethnicity.htm, July 16, 2021 2. Kaiser Family Foundation, https://www.kff.org/coronavirus - covid - 19/issue - brief/latest - data - on - covid - 19 - vaccinations - race - ethnici ty/, July 21, 2021 3. LIVE - AIR Phase 3 data on file at Humanigen, Inc. Lenzilumab is being developed as a potential treatment for COVID - 19, it is not currently authorized or approved for use in any c ountry