Imara M&A

HER2 Mutant NSCLC May Provide More Rapid Market Entrance Opportunity with Expansion into Other HER2-Driven Cancers to Follow Initial Focus: HER2 Mutant NSCLC ● • ~70% of all HER2 mutations in lung cancer are HER2 YVMA High unmet need in this indication may provide a fast to market opportunity ● ● ● Approximately 3% of NSCLC patients harbor HER2 mutations, for which there are no approved TKIs Secondary Focus: Other HER2 Mutant Cancers Represents a larger market with limited treatment options ● Indication Expansion: HER2 Amplified Cancers Largest potential market opportunity, with nearly 30K metastatic patients across breast, colorectal, and gastric cancers Despite the advances in therapeutic options for HER2+ breast cancer, ~25% of patients experience primary or acquired resistance, and up to 50% of patients develop brain metastasis Despite limitations, Tukysa (tucatinib) is on a ~$335mm revenue run rate with only a 2L+ HER2+ MBC label *Other cancers include prostate, endometrial, gastric, stomach, hepatobiliary, etc. BRC = Breast cancer. GI = Gastrointestinal. NSCLC = Non-small cell lung cancer. MBC = Metastatic breast cancer Reference: Robichaux et al. Cancer Cell. 2019;36(4):444-457.e7; SGEN 2Q22 Investor Presentation (28July2022) HER2 Mutant NSCLC Any HER2 Mutation HER2 Overexpressing 0 US Market Size Estimates BRC ~3K ~5K Other Solid Tumors* ~5K Metastatic Breast Cancer ~22K 10 5 US Incidence (1,000's) || GI Cancers ~7K 30 33

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