Adjuvant trastuzumab and vinorelbine (TV) for early-stage HER2+ breast cancer.

person Shannon McLaughlin Massachusetts General Hospital Cancer Center, Boston, MA info_outline Shannon McLaughlin, Erika Nakajima, Steven J. Isakoff, Jennifer Shin, Beverly Moy, Aditya Bardia, Irene Kuter, Laura Spring

Authors person Shannon McLaughlin Massachusetts General Hospital Cancer Center, Boston, MA info_outline Shannon McLaughlin, Erika Nakajima, Steven J. Isakoff, Jennifer Shin, Beverly Moy, Aditya Bardia, Irene Kuter, Laura Spring Organizations Massachusetts General Hospital Cancer Center, Boston, MA, Massachusetts General Hospital, Boston, MA, Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA Abstract Disclosures Research Funding No funding received Background: The anti-HER2 antibody trastuzumab has vastly improved outcomes for women with early stage and advanced HER2+ breast cancer (BC) when used in combination with chemotherapy. Anthracycline and taxane-based regimens have historically made up the chemotherapy backbone for patients with localized HER2+ BC, though recent evidence suggests anthracyclines can be safely omitted. The single arm phase II APT trial established trastuzumab and paclitaxel as the standard adjuvant regimen for small HER2+ tumors. However, paclitaxel requires weekly treatment, causes alopecia, and has high rates of neuropathy and hypersensitivity reactions. In patients with metastatic HER2+ BC, the combination of trastuzumab and vinorelbine (TV) is effective and well tolerated. There is a need for alternative regimens for patients with HER2+ early-stage BC, especially for those with contraindications to anthracycline and taxane-based regimens. We conducted a retrospective study of patients with early stage HER2+ BC treated with adjuvant TV to evaluate a non-anthracycline/taxane-based, alopecia-sparing regimen. Methods: Clinicopathological characteristics, treatment details, and outcomes of patients with localized HER2+ BC treated with adjuvant TV for from 2007 to 2021 at a large academic medical institution were collected. Study endpoints included invasive disease-free survival (IDFS), overall survival (OS), and safety/tolerability. IDFS and OS were measured from start date of TV treatment to date of event or last follow-up, respectively. 5-year survival rates were generated in GraphPad Prism. Results: A total of 25 patients were treated with TV. All patients received trastuzumab at standard dosing and vinorelbine at a starting dose of 25 mg/m2 on days 1/8 of a 21-day cycle with 4 planned cycles. Median age at diagnosis was 61 years (range: 36-81). 88% of patients had anatomic pathologic Stage IA BC and 12% Stage IIA BC. Of the 25 patients, 24 of them opted to pursue TV due to concerns over alopecia, neuropathy, and other toxicities while 1 patient had received prior adriamycin and therefore opted for TV. With a median follow-up time of 68 months (5.7 years), the 5-year rate of survival from invasive disease was 90.9%, with 1 local and 1 distant recurrence. The 5-year overall survival was 100%. 76% of patients completed 4 cycles of TV without dose holds or delays and 92% completed 4 cycles without dose reductions. 2 patients required hospitalization during treatment with TV due to toxicity (diarrhea attributed to V, rigors/fever attributed to T). No patients experienced alopecia or long-term neuropathy. Conclusions: Trastuzumab in combination with vinorelbine in the adjuvant, early-stage setting for HER2+ BC is effective and well-tolerated and warrants further exploration as an alternative to taxane-based regimen.