Leading the Next Evolution of Immunotherapies March 2023 Forward Looking Statements This presentation contains forward-looking statements within the meaning of Section27A of the Securities Act of 1933, Section21E of the Securities Exchange Act of 1934 and the Private Securities Litigation Reform Act of 1995. These forward-looking statements are not based onhistorical fact and include statements regarding Alpine’s platform technology, potential therapies, potential milestone and royalty payments, futuredevel ...

Financial Data and Key Metrics Changes - As of September 30, 2022, the company's cash, cash equivalents, and investments totaled $277.1 million, with a pro forma cash balance of $290.2 million after a public offering [10][11] - Collaboration revenue for Q3 2022 was $8.4 million, slightly down from $8.5 million in Q3 2021, primarily due to revenue from AbbVie and Horizon collaborations [11] - Research and development expenses decreased to $17.6 million in Q3 2022 from $18.3 million in Q3 2021, attributed to reduced clinical development activities [11] - General and administrative expenses increased to $4.6 million in Q3 2022 from $3.5 million in Q3 2021, mainly due to higher personnel costs [11] - The net loss for Q3 2022 was $13.3 million, compared to a net loss of $13.5 million in Q3 2021 [11] Business Line Data and Key Metrics Changes - The company is focusing on ALPN-303, a dual inhibitor of BAFF and APRIL, with plans for multiple clinical studies including RUBY-2 and RUBY-3 [4][8][9] - ALPN-303 is positioned as a best-in-class treatment for autoimmune diseases, with initial data expected by the end of 2023 [12] Market Data and Key Metrics Changes - The company has completed a successful $113 million follow-on offering, extending its cash runway through the end of 2025 [4] - The focus on immunology and inflammation activities is expected to drive value, particularly through collaborations with AbbVie and Horizon [4] Company Strategy and Development Direction - The company aims to operationalize a broad development plan for ALPN-303 across multiple indications, including renal and hematology baskets [3][4] - The strategic focus is on leveraging the unique properties of ALPN-303 to address significant medical needs in autoimmune diseases [12] Management's Comments on Operating Environment and Future Outlook - Management expressed optimism about the potential of ALPN-303 to improve patient outcomes in severe autoimmune and inflammatory diseases [12] - The company anticipates initiating pivotal or accelerated approval studies based on initial data from basket studies by the end of 2023 [12] Other Important Information - The company has reported positive initial data from the RUBY-1 study, indicating that ALPN-303 is well tolerated and shows promising pharmacodynamic effects [8][9] Q&A Session Summary Question: What is the expected adherence of data in the current basket study? - Management indicated that enrollment will reflect the frequency or immunology of indications, with expectations for more subjects in the renal basket and immune basket [16][17] Question: What kind of new healthy volunteer data will be included in the upcoming ASH presentation on RUBY-1? - Management noted that updates will include biomarkers and pre-clinical data supporting hematology target indications [19]

Strategic Partnership - Alpine entered a strategic partnership with Horizon Therapeutics, receiving a \$25 million upfront payment and a \$15 million equity investment at a 25% premium, with potential milestones totaling \$1.52 billion[6,8] - Alpine also has a strategic partnership with AbbVie for Acazicolcept, including a \$60 million upfront payment and up to \$805 million in potential option exercise and milestone payments[87] Davoceticept (ALPN-202) - Davoceticept is being evaluated in a Phase 1/1b study as monotherapy and in combination with KEYTRUDA® for advanced malignancies[5] - In preclinical studies, Davoceticept demonstrated superior efficacy to PD-L1 inhibition as a monotherapy[25,27] - In a Phase 1 study with 32 subjects, 66% experienced any related adverse event, and 3% experienced a Grade ≥ 3 related adverse event[32,33] - Early clinical data for Davoceticept monotherapy showed a partial response in 4.3% and stable disease in 57% of evaluable patients[38] ALPN-303 - ALPN-303 is a dual B cell cytokine antagonist targeting BAFF and APRIL, with a Phase 1 study in healthy volunteers anticipated in mid-2022[5] - Preclinical data suggests ALPN-303 exhibits superior BAFF/APRIL inhibition compared to existing inhibitors[55] - In non-human primates, ALPN-303 demonstrated increased exposure and enhanced immunoglobulin suppression compared to WT TACI-Fc[62] Acazicolcept (ALPN-101) - Acazicolcept is a dual CD28/ICOS antagonist being developed for autoimmune/inflammatory diseases and is currently in Phase 2 for Systemic Lupus Erythematosus[5,85] - Phase 1 data showed dose-proportional PK/PD and was well-tolerated in humans[83,84]