Investor Presentaiton

IDE161 is Active and Well-Tolerated in HRD ER+ Her2- Breast Cancer Models Observed PARG inhibitor Activity is Distinct from PARP Inhibition Durable Disease Control in BRCA-altered Breast Cancer CDX Durable regressions (vs stasis with niraparib) Robust dose- and time- dependent PAR accumulation Well tolerated; no body weight loss >10% Mean Tumor Volume (mm³) S.E.M. 2500- ER+ / Her2- Breast Cancer CDX Vehicle 2000- IDE161 100 mg/kg QD Niraparib 45 mg/kg QD 1500- 1000- 500- Niraparib IDE161 0+ 0 10 20 30 40 50 60 Days on Treatment Regression in BRCA-altered Breast Cancer PDX Models Mean Tumor Volume (mm³) +/- S.E.M. 1000- + Vehicle IDE161 100 mg/kg QD 800- 600- 400- 200 ER+/Her2- Breast Cancer PDX1 1000- HHHH IDE161 Mean Tumor Volume (mm³) +/- S.E.M. + Vehicle Niraparib 45 mg/kg QD 750- 500- 250- Niraparib Tumor: pg PAR/mg protein ± S.E.M. Ovarian Cancer CDX 201 600000 Vehicle 400000- 200000- IDE161 100 mg/kg QD 3 8 24 Time post Dose (h) 33 IDEAYA Data: 2023 AACR, D. Munoz et al. % Body Weight Change 10-1 - Vehicle IDE161 100 mg/kg QD Niraparib 45 mg/kg QD -20+ 0 10 20 30 IDE161 Niraparib 40 50 60 Days on Treatment Mean Tumor Volume (mm³) +/- S.E.M. 0+ T 10 20 30 40 50 0 7 14 21 28 35 Days on Treatment Days on Treatment ER+ / Her2- Breast Cancer PDX2 2000-1 1000- ■ Vehicle QD IDE161 100 mg/kg QD 1500- 1000- 500- Mean Tumor Volume (mm³) S.E.M. Vehicle Niraparib 45 mg/kg QD 750- 500- Niraparib 250- IDE161 0- 0- 0 10 20 30 40 0 7 14 21 28 35 Days on Treatment Days on Treatment IDEAVA BIOSCIENCES

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