Abstract PS3-10-07: Addressing unmet clinical need in HR-positive/HER2-negative early breast cancer: baseline profile of Italian patients included in a compassionate use program ribociclib plus NSAI

Abstract Background: Hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative early breast cancer (EBC) patients at high risk of recurrence have limited treatment options. The phase 3 NATALEE trial1 showed that adjuvant ribociclib plus non-steroidal aromatase inhibitors significantly improved invasive disease-free survival in stage II-III HR-positive/HER2-negative EBC, supporting ribociclib for a broader population. On these data, the corresponding ribociclib label extension was approved by the Food and Drug Administration and the European Medicines Agency in September and November 2024, respectively. A Managed Access Program (MAP) was opened to allow access to ribociclib for eligible patients with HR-positive/HER2-negative EBC (stages II and III, based on NATALEE inclusion/exclusion criteria and no alternative authorized option). We assessed the baseline profile of patients included in the MAP of ribociclib in Italy. Methods: This retrospective analysis uses real-world data from Italian patients with HR-positive HER2-negative EBC stages II and III, approved for ribociclib access. The requesting physician submitted an unsolicited request, which was evaluated against eligibility criteria. The descriptive analysis reports their baseline profiles -demographics, clinical characteristics, and (neo-)adjuvant treatment patterns. Results: From December 2024 to April 2025, 634 requests for ribociclib were approved, and 87 patients started ribociclib adjuvant therapy. Local ethical committee approval was pending for 253 requests. The mean age of patients requiring treatment access was 54.6 years (SD 10.9; range 28-87). Most were female (629; 99.2%), and 162 (25.6%) had at least one comorbidity. Concomitant medications were reported in 308 (48.6%) patients. According to the MAP inclusion criteria, which allows only patients without an alternative treatment available, at treatment access most patients had stage II disease (602; 95%), stage IIA 366 (57.7%) and IIB 234 (36.9%). Stage III disease was reported in 31 patients (4.9%), with 1.9% each in stages IIIA and IIIC, and 1.1% in stage IIIB. The most common tumor classifications were T0-1N1 (34.9%) and T2N1 (33.3%). Among patients in stage T2N0 (22.9%), 91 (62.7%) were G3. 72.5% of patients had nodal involvement, mainly N1 (68.6%), and 27% had N0 disease. 296 (46.7%) patients received previous chemotherapy, 227 (76.7%) in the adjuvant setting and 69 (23.3%) in the neoadjuvant setting. Prior chemotherapy was administered to 41.5% of patients with lymph node involvement, compared to 61.4% of those without nodal metastases. Adjuvant radiotherapy was received by 312 (49.2%) patients, while an adjuvant CDK4/6 inhibitor was previously received by 15 (2.4%). Four patients originally eligible for abemaciclib were included in the MAP due to clinical conditions (50%) or because the treatment window had elapsed (50%). Conclusions: These real-world data underscore the need for additional adjuvant treatment options in patients with HR-positive/HER2-negative EBC in Italy. The population treated within the compassionate use program included a broad spectrum of disease stages, such as patients with stage II disease and those without nodal involvement—subgroups with limited current therapeutic alternatives.1Hortobagyi GN, et al. Ann Oncol. 20252 Fashing PA, et al. Ann Oncol 2024 Citation Format: I. Viganò, A. Lunello, D. Valsecchi, N. Viapiana, A. Martinez-Fernandez2. Addressing unmet clinical need in HR-positive/HER2-negative early breast cancer: baseline profile of Italian patients included in a compassionate use program ribociclib plus NSAI [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS3-10-07.