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, 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 jurisdictio ...

| --- | --- | --- | --- | --- | --- | |----------------------------------------------------------|-------|-------|-------|-------|-------| | | | | | | | | Pioneering the Development of Engineered IgM Antibodies | | | | | | | May 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 C ...

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 March 31, 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 jurisdicti ...

Financial Data and Key Metrics Changes - In 2019, the company raised gross proceeds of $201 million from its initial public offering and $102 million from a Series C private placement, resulting in cash and investments totaling $236.6 million as of December 31, 2019 [31] - The net loss for Q4 2019 was $14.8 million, or a loss of $0.49 per share, while the full year net loss was $43.1 million, or a loss of $4.80 per share [32] Business Line Data and Key Metrics Changes - Research and development expenses for Q4 2019 were $12.8 million, and for the full year, they totaled $35.3 million [32] - General and administrative expenses for Q4 2019 were $3.2 million, with a total of $9.2 million for the full year [32] Market Data and Key Metrics Changes - The company is optimistic about the potential of its pipeline, particularly IGM-2323, which is in a Phase 1 clinical trial targeting non-Hodgkin's lymphoma [7][8] - IGM-8444 and IGM-7354 are also in development, with IND filings expected in 2020 and 2021, respectively [9][26] Company Strategy and Development Direction - The company aims to establish itself as a leader in engineered IGM antibodies, with a focus on advancing its clinical trials and expanding its manufacturing capabilities [36][28] - Plans to build a GMP manufacturing facility in Mountain View, California, are underway, with construction expected to begin once COVID-19 restrictions are lifted [28] Management's Comments on Operating Environment and Future Outlook - Management acknowledges the uncertainty brought by the COVID-19 pandemic but remains hopeful that its impact on timelines will be modest [6] - The company has adequate cash reserves to last into 2022 and plans to extend its cash runway if necessary [7][34] Other Important Information - The company has completed its fourth GMP manufacturing run of IGM-2323, with yields improving on each run [27] - The IGM antibody platform is believed to offer safety and efficacy advantages over traditional IGG antibodies [11][22] Q&A Session Summary Question: Will the company commit to a year-end dose escalation presentation regardless of potential delays? - The company intends to update the market by the end of the year on the clinical trial status, although uncertainties may affect this plan [40] Question: What dose from a molar equivalency perspective does the 30 mg fixed dose cohort represent? - At the 30 mg dose, approximately 50% of peripheral B cells were depleted in nonhuman primates [42] Question: What is the timeline for IND filings for other tumor antigens? - The company is pushing forward with preclinical programs for CD123 and CD38 as quickly as possible, with IND filings likely in the year following IGM-8444 [44][45] Question: What are the expectations for data from the IGM-2323 program later this year? - The company aims to have dosed IGM-2323 at the 1,000 mg level by the time of the ASH 2020 conference, although this is subject to enrollment pace [51] Question: What types of patients will be enrolled in the Phase 1 study for IGM-8444? - The initial Phase 1 study will include all solid tumors, with plans to expand into hematologic malignancies after dose escalation [75]

Table of Contents For the fiscal year ended December 31, 2019 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. 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 (Exact name of Registrant as specified in its Charter) De ...

| --- | --- | --- | --- | --- | --- | |----------------------------------------------------------|-------|-------|-------|-------|-------| | | | | | | | | Pioneering the Development of Engineered IgM Antibodies | | | | | | | | | | | | | | March 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 ...

| --- | --- | --- | --- | --- | --- | |--------------------------------------------------------|-------|-------|-------|-------|-------| | | | | | | | | Pioneering the Development of | | | | | | | Engineered IgM Antibodies for the Treatment of Cancer | | | | | | | February 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 "C ...

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, 2019 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 ...