Nature of Operations	3 Months Ended
Mar. 31, 2023
Nature of Operations [Abstract]
Nature of Operations	1. Nature of Operations Description of the Business The Company is a clinical stage biopharmaceutical company, developing its portfolio of proprietary Humaneered^® anti-inflammatory immunology and immuno-oncology monoclonal antibodies. The Company’s proprietary, patented Humaneered technology platform is a method for converting existing antibodies (typically murine) into engineered, high-affinity human antibodies designed for therapeutic use, particularly with acute and chronic conditions. Humanigen has developed or in-licensed targets or research antibodies, typically from academic institutions, and then applied its Humaneered technology to optimize them. The Company’s lead product candidate, lenzilumab, or LENZ^®, and its other product candidate, ifabotuzumab (“iFab”), are Humaneered monoclonal antibodies. The Company’s Humaneered antibodies are closer to human antibodies than chimeric or conventionally humanized antibodies and have a high affinity for their target. In addition, the Company believes its Humaneered antibodies offer further important advantages, such as high potency, a slow off-rate and a lower likelihood to induce an inappropriate immune response or infusion related reactions. The Company is developing lenzilumab in chronic myelomonocytic leukemia (“CMML”), a rare blood cancer, for which the Precision Approach to Chronic Myelomonocytic Leukemia (“PREACH-M”) study is underway, and is continuing its plans for the Risk Adapted Therapy in Acute GvHD (“RATinG”) study in acute graft versus host disease (“aGvHD”) that occurs in patients undergoing bone marrow transplant, as these studies are majority funded by its partners. In April 2023, the Company announced that as of December 31, 2022, eleven subjects had been dosed with lenzilumab and with current standard of care, azacytidine, in the PREACH-M study. Six subjects were evaluable based on at least three months of follow-up, including those with high risk CMML, and all demonstrated clinical benefit. In addition, LENZ appeared to be well-tolerated. The Company anticipates the first patient dosing in the RATinG study to occur in the second quarter of 2023. A leading network of centers, The Mayo Clinics, is currently progressing with an investigator-initiated trial (“IIT”) of lenzilumab in combination with CAR-T therapies. With the exception of the one lenzilumab batch in process, the Company has discontinued the manufacturing of lenzilumab and is consolidating the remaining inventory of lenzilumab bulk drug substance and drug product in a central location for potential future use. The Company is also developing iFab, an EpAh-3 targeted monoclonal antibody, currently in Phase 1 development, as part of an antibody drug conjugate (“ADC”), for certain solid tumors. See Management’s Discussion and Analysis of Financial Condition and Results of Operations included in Item 7 of the Company’s 2022 Annual Report on Form 10-K for additional information regarding the business. Liquidity and Going Concern The Condensed Consolidated Financial Statements for the three months ended March 31, 2023 were prepared on the basis of a going concern, which contemplates that the Company will be able to realize assets and discharge liabilities in the normal course of business. However, the Company has incurred net losses since its inception, and has negative operating cash flows and its total liabilities exceed total assets. These conditions raise substantial doubt about the Company’s ability to continue as a going concern. As of March 31, 2023, the Company had cash and cash equivalents of $3.1 million. Considering the Company’s current cash resources and its current and expected levels of operating expenses for the next twelve months, which includes combined accounts payable and accrued expenses recorded in the Company’s consolidated balance sheets as of March 31, 2023 of $52.4 million, certain of which are in dispute, and manufacturing commitments of $1.8 million for the remaining nine months of 2023, with no significant commitments thereafter (see Note 6 below), the Company requires additional capital to fund the Company’s planned operations. The Company intends to seek to defer payments, negotiate lower amounts or pursue other courses of action for certain amounts owed to manufacturing and other partners at March 31, 2023. In order to remain a going concern, the Company must successfully renegotiate these amounts owed, and settle disputes, including current and potential future arbitration and litigation. During 2022, the Company engaged SC&H Capital, an affiliate of SC&H Group, Inc.(“SC&H”), to advise the Company on exploration of strategic options to maximize value around its development pipeline. The Company has not set a timetable for the conclusion of its review of strategic alternatives, and there can be no assurance that this process will result in any transaction. As previously reported, the Company has executed a non-binding letter of intent and is engaged in exclusive negotiations relating to a proposed business combination with a privately held biopharmaceutical company, which contemplates a tax-free stock-for-stock merger. The Company is seeking external financing in connection with the potential business combination. There can be no assurance that the potential business combination or financing will be consummated on favorable terms or at all. The Company also may seek to raise additional capital through public or private equity offerings, including under the Controlled Equity Offering^SM Sales Agreement (the “Sales Agreement”) with Cantor Fitzgerald & Co. (“Cantor”), grant financing, convertible and other debt financings, collaborations, strategic alliances, or licensing arrangements involving LENZ and iFab. Additional funds may not be available when the Company needs them on terms that are acceptable to the Company, or at all. If adequate funds are not available, the Company may be required to delay or reduce the scope of or eliminate one or more of its research or development programs and may not be able to continue as a going concern. In addition, if the Company raises additional funds through collaborations, strategic alliances, or licensing arrangements with third parties, the Company may have to relinquish rights to its technologies, future revenue streams or product candidates or to grant licenses on terms that may not be favorable to the Company. While management believes its realignment plans and its plans to raise additional funds will alleviate the conditions that raise substantial doubt about the Company’s ability to continue as a going concern, these plans are not entirely within the Company’s control and cannot be assessed as being probable of occurring. Basis of Presentation The accompanying interim unaudited Condensed Consolidated Financial Statements have been prepared in accordance with US generally accepted accounting principles (“US GAAP”) for interim financial information and on a basis consistent with the annual consolidated financial statements and include all adjustments necessary for the presentation of the Company’s condensed consolidated financial position, results of operations and cash flows for the periods presented. The Condensed Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries. These financial statements have been prepared on a basis that assumes that the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. The December 31, 2022 Condensed Consolidated Balance Sheet was derived from the audited financial statements but does not include all disclosures required by US GAAP. These interim financial results are not necessarily indicative of the results to be expected for the year ending December 31, 2023, or for any other future annual or interim period. The accompanying unaudited Condensed Consolidated Financial Statements should be read in conjunction with the audited consolidated financial statements and the related notes thereto included in the Company’s 2022 Annual Report on Form 10-K. The preparation of financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the amounts and disclosures reported in the Condensed Consolidated Financial Statements and accompanying notes. Actual results could differ materially from those estimates. The Company believes judgment is involved in accounting for the determination of revenue recognition, fair value-based measurement of stock-based compensation and accruals. The Company evaluates its estimates and assumptions as facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ from these estimates and assumptions, and those differences could be material to the Condensed Consolidated Financial Statements.

Nature of Operations

3 Months Ended

Mar. 31, 2023

1. Nature of Operations

Description of the Business

The Company is a clinical stage biopharmaceutical company, developing its portfolio of proprietary Humaneered^® anti-inflammatory immunology and immuno-oncology monoclonal antibodies. The Company’s proprietary, patented Humaneered technology platform is a method for converting existing antibodies (typically murine) into engineered, high-affinity human antibodies designed for therapeutic use, particularly with acute and chronic conditions. Humanigen has developed or in-licensed targets or research antibodies, typically from academic institutions, and then applied its Humaneered technology to optimize them. The Company’s lead product candidate, lenzilumab, or LENZ^®, and its other product candidate, ifabotuzumab (“iFab”), are Humaneered monoclonal antibodies. The Company’s Humaneered antibodies are closer to human antibodies than chimeric or conventionally humanized antibodies and have a high affinity for their target. In addition, the Company believes its Humaneered antibodies offer further important advantages, such as high potency, a slow off-rate and a lower likelihood to induce an inappropriate immune response or infusion related reactions.

The Company is developing lenzilumab in chronic myelomonocytic leukemia (“CMML”), a rare blood cancer, for which the Precision Approach to Chronic Myelomonocytic Leukemia (“PREACH-M”) study is underway, and is continuing its plans for the Risk Adapted Therapy in Acute GvHD (“RATinG”) study in acute graft versus host disease (“aGvHD”) that occurs in patients undergoing bone marrow transplant, as these studies are majority funded by its partners. In April 2023, the Company announced that as of December 31, 2022, eleven subjects had been dosed with lenzilumab and with current standard of care, azacytidine, in the PREACH-M study. Six subjects were evaluable based on at least three months of follow-up, including those with high risk CMML, and all demonstrated clinical benefit. In addition, LENZ appeared to be well-tolerated. The Company anticipates the first patient dosing in the RATinG study to occur in the second quarter of 2023. A leading network of centers, The Mayo Clinics, is currently progressing with an investigator-initiated trial (“IIT”) of lenzilumab in combination with CAR-T therapies. With the exception of the one lenzilumab batch in process, the Company has discontinued the manufacturing of lenzilumab and is consolidating the remaining inventory of lenzilumab bulk drug substance and drug product in a central location for potential future use. The Company is also developing iFab, an EpAh-3 targeted monoclonal antibody, currently in Phase 1 development, as part of an antibody drug conjugate (“ADC”), for certain solid tumors.

See Management’s Discussion and Analysis of Financial Condition and Results of Operations included in Item 7 of the Company’s 2022 Annual Report on Form 10-K for additional information regarding the business.

Liquidity and Going Concern

The Condensed Consolidated Financial Statements for the three months ended March 31, 2023 were prepared on the basis of a going concern, which contemplates that the Company will be able to realize assets and discharge liabilities in the normal course of business. However, the Company has incurred net losses since its inception, and has negative operating cash flows and its total liabilities exceed total assets. These conditions raise substantial doubt about the Company’s ability to continue as a going concern.

As of March 31, 2023, the Company had cash and cash equivalents of $3.1 million. Considering the Company’s current cash resources and its current and expected levels of operating expenses for the next twelve months, which includes combined accounts payable and accrued expenses recorded in the Company’s consolidated balance sheets as of March 31, 2023 of $52.4 million, certain of which are in dispute, and manufacturing commitments of $1.8 million for the remaining nine months of 2023, with no significant commitments thereafter (see Note 6 below), the Company requires additional capital to fund the Company’s planned operations. The Company intends to seek to defer payments, negotiate lower amounts or pursue other courses of action for certain amounts owed to manufacturing and other partners at March 31, 2023. In order to remain a going concern, the Company must successfully renegotiate these amounts owed, and settle disputes, including current and potential future arbitration and litigation. During 2022, the Company engaged SC&H Capital, an affiliate of SC&H Group, Inc.(“SC&H”), to advise the Company on exploration of strategic options to maximize value around its development pipeline. The Company has not set a timetable for the conclusion of its review of strategic alternatives, and there can be no assurance that this process will result in any transaction.

As previously reported, the Company has executed a non-binding letter of intent and is engaged in exclusive negotiations relating to a proposed business combination with a privately held biopharmaceutical company, which contemplates a tax-free stock-for-stock merger. The Company is seeking external financing in connection with the potential business combination. There can be no assurance that the potential business combination or financing will be consummated on favorable terms or at all.

The Company also may seek to raise additional capital through public or private equity offerings, including under the Controlled Equity Offering^SM Sales Agreement (the “Sales Agreement”) with Cantor Fitzgerald & Co. (“Cantor”), grant financing, convertible and other debt financings, collaborations, strategic alliances, or licensing arrangements involving LENZ and iFab. Additional funds may not be available when the Company needs them on terms that are acceptable to the Company, or at all. If adequate funds are not available, the Company may be required to delay or reduce the scope of or eliminate one or more of its research or development programs and may not be able to continue as a going concern. In addition, if the Company raises additional funds through collaborations, strategic alliances, or licensing arrangements with third parties, the Company may have to relinquish rights to its technologies, future revenue streams or product candidates or to grant licenses on terms that may not be favorable to the Company. While management believes its realignment plans and its plans to raise additional funds will alleviate the conditions that raise substantial doubt about the Company’s ability to continue as a going concern, these plans are not entirely within the Company’s control and cannot be assessed as being probable of occurring.

Basis of Presentation

The accompanying interim unaudited Condensed Consolidated Financial Statements have been prepared in accordance with US generally accepted accounting principles (“US GAAP”) for interim financial information and on a basis consistent with the annual consolidated financial statements and include all adjustments necessary for the presentation of the Company’s condensed consolidated financial position, results of operations and cash flows for the periods presented.

The Condensed Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries. These financial statements have been prepared on a basis that assumes that the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. The December 31, 2022 Condensed Consolidated Balance Sheet was derived from the audited financial statements but does not include all disclosures required by US GAAP. These interim financial results are not necessarily indicative of the results to be expected for the year ending December 31, 2023, or for any other future annual or interim period. The accompanying unaudited Condensed Consolidated Financial Statements should be read in conjunction with the audited consolidated financial statements and the related notes thereto included in the Company’s 2022 Annual Report on Form 10-K.

The preparation of financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the amounts and disclosures reported in the Condensed Consolidated Financial Statements and accompanying notes. Actual results could differ materially from those estimates. The Company believes judgment is involved in accounting for the determination of revenue recognition, fair value-based measurement of stock-based compensation and accruals. The Company evaluates its estimates and assumptions as facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ from these estimates and assumptions, and those differences could be material to the Condensed Consolidated Financial Statements.