Abstract PO2-11-06: Anti-Müllerian hormone in Young women with breast CAncer to predict permanent loss of ovarian function after chemotherapy and anti-HER2 therapy (AMYCA): a biomarker analysis of the BETH and KAITLIN trials

Abstract Background: The ability to predict and identify ovarian function loss accurately after anticancer treatment is important for appropriate oncofertility counseling and to aid in therapy decision making for young women with early breast cancer (eBC). Anti-Müllerian hormone (AMH) has been proposed as both a pre- and post-treatment predictor of subsequent permanent loss of ovarian function. The present biomarker analysis conducted within two randomized controlled trials (RCTs) in a large and well-characterized patient population with HER2+ eBC receiving homogeneous treatment aimed to assess AMH use, alone and in combination with other hormonal biomarkers, for predicting loss of ovarian function at 36 months from randomization, i.e. approximately 2 years after end of therapy. Methods: BETH (NCT00625898) and KAITLIN (NCT01966471) were RCTs investigating adjuvant chemotherapy (CT) plus anti-HER2 therapy in high-risk HER2+ eBC patients. For the purpose of the present analysis, only samples of patients receiving currently adopted treatments were used, i.e. cohort 1A (6 cycles of docetaxel/carboplatin+trastuzumab (T)) and cohort 2A (3 cycles of docetaxel plus T followed by 3 cycles of anthracycline- and cyclophosphamide-based CT) of BETH trial, and arm 1 (3-4 cycles of anthracycline- and cyclophosphamide-based CT followed by 3-4 cycles of taxane plus T plus pertuzumab (P)) of KAITLIN trial. Women selected for this analysis were ≤45 years with known premenopausal status, available serum samples at baseline (pre-treatment) and/or end of therapy and 36 months (± 6 months) from randomization (i.e. min of 2 samples in all cases). Selected samples were centrally tested measuring AMH, follicle stimulating hormone (FSH) and estradiol (E2) using Roche Elecsys assays. Permanent ovarian loss was defined as FSH 25 IU/L and E2 110 pmol/L at 36 months. Results: Of 194 included patients, 62 were from BETH and 132 from KAITLIN. 139 (71.6%) received both taxane and anthracycline- and cyclophosphamide-based CT and 55 (28.4%) taxane only. Pertuzumab was used in addition to trastuzumab in 132 (68.0%) patients. AMH values declined from baseline median 8.44 pmol/L to undetectable levels in many women at end of therapy (median 0.08 pmol/L), with partial recovery at 36 months (median 0.14 pmol/L). Ovarian loss at 3 years was observed in 56 women with AMH available at baseline (29.5%) and in 52 women with AMH available at end of therapy (29.7%). For prediction of ovarian loss, in ROC analysis, AMH measured at baseline showed AUC 0.784 (internally validated using bootstrap: 0.783). While age influenced risk of ovarian loss, addition to AMH only slightly improved AUC to 0.800 (internal validation: 0.795) while addition of baseline FSH and E2 did not improve prediction. AMH measured at the end of therapy showed AUC 0.741 (internal validation: 0.742), which increased slightly to 0.785(internal validation: 0.781) with addition of age but without improved prediction with the addition of FSH and E2. The combination of AMH at baseline and end of therapy increased prediction slightly to 0.808 (internal validation 0.806) and with addition of age added to 0.820 (internal validation: 0.806). Conclusions: These results support the use of pretreatment measurement of AMH in predicting loss of ovarian function in women withHER2+ eBC aged ≤45 receiving CT and anti-HER2 therapy. Measurement of AMH at end of treatment was comparably valuable to pretreatment and added slightly to the value of pretreatment sampling. Inclusion of ovarian function assessment by measuring AMH before commencing treatment can inform subsequent risk of ovarian function loss with value for fertility preservation counselling and treatment decisions. Further validation is required in larger cohorts. Citation Format: Matteo Lambertini, Deirdre Allegranza, Ruediger Laubender, Nadia Harbeck, Sandra Swain, Charles Geyer, Dennis Slamon, Gabriella Bobba, Chiara Lambertini, Sanne Lysbet De Haas, Eleonora Restuccia, Ines Vaz Luis, David Cameron, Ian Krop, Eric Winer, Richard Anderson. Anti-Müllerian hormone in Young women with breast CAncer to predict permanent loss of ovarian function after chemotherapy and anti-HER2 therapy (AMYCA): a biomarker analysis of the BETH and KAITLIN trials abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-11-06.