Palbociclib, trastuzumab and endocrine therapy in pretreated HER2-positive and PAM50 luminal advanced breast cancer: randomised phase II, SOLTI-1303 PATRICIA trial
Mené sur 73 patientes atteintes d'un cancer du sein HER2+ HR+ de type luminal et de stade avancé, cet essai de phase II évalue l'efficacité, du point de vue de la survie sans progression, et la toxicité d'un traitement combinant palbociclib, trastuzumab et traitement endocrinien après l'échec de plusieurs lignes thérapeutiques
Purpose: Based on the results from SOLTI-PATRICIA trial (NCT02448420) cohorts A/B, a direct comparison with standard-of-care treatments is needed to evaluate the efficacy and safety of palbociclib, trastuzumab and endocrine therapy (ET) in PAM50-luminal A/B pretreated patients.
Patients and Methods: SOLTI-PATRICIA cohort C is a randomised, multicentre, prospective, open-label, phase II study. Pretreated patients with HER2-positive, HR-positive, and PAM50-Luminal A/B ABC were randomised 1:1 to receive either i) the triplet regimen or ii) trastuzumab-based treatment of physician’s choice (TPC). Patients allocated in the TPC arm were eligible for re-randomization upon disease progression, if the inclusion criteria were still met. The primary endpoint was investigator-assessed progression-free survival (PFS) per RECIST 1.1.
Results: 264 participants were pre-screened between August 2019-2023, and 73 patients were randomised (including seven re-randomisations). In the TPC arm: 48.5% were treated with trastuzumab plus chemotherapy, 39.4% with T-DM1 and 12.1 % with trastuzumab plus ET. The triplet was associated with a significantly better PFS compared to TPC (stratified hazard ratio=0.52 [95% CI 0.29–0.95]; two-sided p=0.03). PFS rates after 24 months were 24.0% with the triplet and 4.3% in the TPC arm. The overall response rate was 18.9% (95% CI 8.6–35.7) and 7.1% (95% CI 1.2–25.0), respectively. In the triplet arm, grade ≥3 adverse events occurred in 61.5% of patients, with neutropenia being the most frequent (53.9%). No permanent discontinuations due to toxicity were observed.
Conclusions: Combining palbociclib, trastuzumab, and ET was safe and improved significantly PFS, compared to TPC in previously treated HER2-positive, PAM50 luminal A/B ABC patients.
Clinical Cancer Research , résumé, 2025