UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-39045 IGM Biosciences, Inc. (Exact Name of Registrant as Specified in its Charter) Delaware 77-0349194 (State or other jurisdictio ...

Pioneering the Development of Engineered IgM Antibodies IGM Corporate Presentation RBC Capital Markets Global Healthcare Conference May 19, 2021 Forward-Looking Statements This presentation contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 that reflect the current views of IGM Biosciences, Inc. (the "Company," "we" or "our") with respect to the Company's future financial condition, results of operations, business strategy, expectations, mileston ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-39045 IGM Biosciences, Inc. (Exact Name of Registrant as Specified in its Charter) Delaware 77-0349194 (State or other jurisdiction of incorporation or organization) 325 E. Middlefield Road Mountain View, CA 94043 (Address of principal executive offices) (Zip Code) (I. ...

Financial Data and Key Metrics Changes - As of December 31, 2020, the company reported cash and investments totaling $366.3 million following a $230 million public equity offering in December [37] - Research and development expenses for Q4 2020 were $19.6 million, with full-year R&D expenses at $65 million [38] - The net loss for Q4 2020 was $24.6 million, translating to a loss of $0.79 per share, while the full-year net loss was $81.4 million or a loss of $2.65 per share [38] - The company expects full-year 2021 GAAP operating expenses to be between $175 million and $185 million, including approximately $25 million in non-cash stock-based compensation [39] Business Line Data and Key Metrics Changes - The ongoing Phase I trial of IGM-2323 has shown promising safety and efficacy signals, with no dose-limiting toxicities reported to date [16][20] - IGM-8444 is progressing well in its Phase I study, with the first two dose levels completed without dose-limiting toxicity [25][26] Market Data and Key Metrics Changes - The company is focusing on expanding its clinical development efforts in both hematologic and solid tumors, with plans to file INDs for multiple candidates in the near future [24][34] Company Strategy and Development Direction - The company aims to establish a recommended Phase II dose for IGM-2323 and is exploring combination therapies with standard care and novel therapies in non-Hodgkin's lymphoma [23] - IGM is also advancing its T-cell engager pipeline, with plans to begin clinical testing of CD38 and CD123 T-cell engagers for multiple myeloma and acute myeloid leukemia [24][34] - The company is excited about the potential of IGM-7354, a targeted IL-15 immune cell stimulating antibody, and plans to file an IND for it towards the end of 2021 [34] Management's Comments on Operating Environment and Future Outlook - Management expressed confidence in the safety profile of IGM-2323, noting that the majority of patients treated have not experienced significant cytokine release syndrome [16][20] - The management team is optimistic about the ongoing clinical trials and the potential for IGM-2323 to demonstrate best-in-class safety and efficacy [22][84] Other Important Information - The company has completed construction of its GMP manufacturing facility in Mountain View, California, which will enhance its ability to manage clinical supply requirements [35] Q&A Session Summary Question: Can you provide more details on the CRS observed in the 50-mg dose cohort? - The patient experienced a Grade 3 CRS event, but the majority of patients treated at this dose did not show CRS beyond Grade 1 [47][48] Question: How soon post-ASH did the previous PR flip to a CR? - Responses have varied, with some patients taking longer to achieve CR, while others have shown rapid responses [51][52] Question: What is the current number of patients treated in the Phase I trial? - A total of 25 patients have been treated in the IGM-2323 Phase I trial [61] Question: What are the plans for the recommended Phase II dose? - The company plans to determine the recommended Phase II dose based on efficacy and safety data from the ongoing trials [66] Question: Are there any predictive biomarkers for DR5 agonism? - The company is exploring the potential for broader applications of DR5 agonism beyond specific subsets of patients [75][77] Question: What is the status of the IGM-8444 program? - The program is progressing well, with plans to present initial data from the single-agent dose escalation in the second half of the year [90]

Table of Contents Index to Financial Statements UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 | Title of each class | Trading Symbol(s) | Name of each exchange on which registered | | --- | --- | --- | | Common Stock, par value $0.01 per share | IGMS | The Nasdaq Global Select Market | For the fiscal year ended December 31, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 O ...

Pioneering the Development of Engineered IgM Antibodies ASH 2020 Investor Conference Call December 5, 2020 Forward-Looking Statements This presentation contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 that reflect the current views of IGM Biosciences, Inc. (the "Company," "we" or "our") with respect to the Company's future financial condition, results of operations, business strategy, expectations, milestones and plans. All statements other tha ...

| --- | --- | --- | --- | --- | --- | |----------------------------------------------------------|-------|-------|-------|-------|-------| | | | | | | | | Pioneering the Development of Engineered IgM Antibodies | | | | | | | | | | | | | | November 2020 | | | | | | Forward-looking Statements This presentation contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 that reflect the current views of IGM Biosciences, Inc. (the "Company," "we" or "our") wi ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-39045 IGM Biosciences, Inc. (Exact Name of Registrant as Specified in its Charter) Delaware 77-0349194 (State or other jurisd ...

| --- | --- | --- | --- | --- | --- | |----------------------------------------------------------|-------|-------|-------|-------|-------| | | | | | | | | Pioneering the Development of Engineered IgM Antibodies | | | | | | | | | | | | | | September 2020 | | | | | | Forward-looking Statements This presentation contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 that reflect the current views of IGM Biosciences, Inc. (the "Company," "we" or "our") w ...

| --- | --- | --- | --- | --- | --- | |----------------------------------------------------------|-------|-------|-------|-------|-------| | | | | | | | | Pioneering the Development of Engineered IgM Antibodies | | | | | | | | | | | | | | Wedbush PacGrow Healthcare Conference | | | | | | | August 2020 | | | | | | | | | | | | | Forward-looking Statements This presentation contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 that reflect the current ...