Adjuvant Trastuzumab Plus Pertuzumab Versus Trastuzumab Alone in Patients Achieving Pathologic Complete Response After Chemotherapy With Trastuzumab and Pertuzumab: A Retrospective Cohort Study.

BACKGROUND

For patients who achieve pathologic complete response (pCR) after neoadjuvant chemotherapy with trastuzumab (T) and pertuzumab (P), the benefit of adding P to T remains uncertain. We compared survival outcomes according to the type of adjuvant anti-HER2 therapy in patients with pCR after chemotherapy with TP.

METHOD

Patients who achieved pCR in both the breast and axilla after neoadjuvant chemotherapy with TP were included. Recurrence-free survival (RFS) and distant recurrence-free survival (DRFS) were evaluated. Univariate and multivariate Cox proportional hazards analyses were used to assess the impact of different adjuvant therapies on RFS and DRFS.

RESULTS

In total, 386 patients were included, with 69 (17.9%) receiving adjuvant TP and 317 (82.1%) receiving adjuvant T alone. At a median follow-up of 49 months, the 3-year RFS rate was 96.1%. There was no significant difference in the 3-year RFS between groups (94.2% in TP and 95.6% in T), with an adjusted hazard ratio (HR) of 1.15 (95% CI, 0.37-3.55, P = .806). In the clinical node-positive group (n = 294), there was no difference in survival between groups (HR 1.64, 95% CI, 0.58-4.65, P = .35). The multivariate analysis showed no significant predictors of recurrence or distant recurrence, including clinical tumor size, nodal status, ER/PR/HER2 status, and adjuvant radiotherapy receipt. Among 11 patients with brain metastasis after pCR, there was no difference according to the type of adjuvant anti-HER2 therapy.

CONCLUSIONS

In patients with pCR who responded to chemotherapy and dual HER2 blockade (TP), the 3-year RFS and brain metastasis-free survival did not differ according to the type of adjuvant anti-HER2 therapy.