CDK4/6 inhibitors play important roles in ovarian physiology, but preclinical and clinical data on their gonadotoxicity are limited and conflicting, with some evidence suggesting potential ovarian toxicity, while other studies indicate possible protective effects.69, –71 Anti-HER2 therapies like trastuzumab and pertuzumab generally do not increase the risk of treatment-related amenorrhea (TRA).72, –74 However, there is less data on the effect of HER2-targeted ADCs like T-DM1 on ovarian function. Here, ERBB2 is linked to amenorrhea.