292P Exploring HER3; A potentially targetable biomarker in rare metaplastic breast cancers

Table: 289P Key AECIs in patients treated with pimi in MANEUVER AEs (any grade) a Pimicotinib (N63) n (%) Time tofirst onset Median (IQR), days Duration of AE Median (IQR) number of events, days Asymptomatic laboratory abnormalities Elevation of blood creatinine phosphokinase a 45 (71) 15 (15-29) 63 (30-138) 86 Elevation of aminotransferase a 35 (56) 17 (15-56) 43 (24-113) 74 Clinical Edema a,b 39 (62) 37 (24-74) 103 (48-226) 28 Pruritus 38 (60) 3 (2-50) 14 (4-48) 46 Rash a 34 (54) 81 (43-116) 55 (28-92) 37 Periorbital edema a 28 (44) 28 (16-64) 91 (11-153) 19 Hypertension a 12 (19) 82 (29-133) 90 (15-91) 5 a AE was a grouped term; b Excluded periorbital.IQR, interquartile rangeConclusions: This analysis provides insight into the longer-term safety of pimi, confirming that toxicity was generally manageable, reversible, and consistent with known CSF-1R inhibitor class effect, therefore allowing the potential to maximize treatment benefit in TGCT.Longer-term pimi continued to provide sustained, robust antitumor activity with few AE-related treatment discontinuations. Clinical trial identification:The MANEUVER trial is ongoing (NCT05804045).