It’s a toss-up: For patients with early, HER2-positive breast cancer, subcutaneous trastuzumab is comparable in efficacy and safety with intravenous trastuzumab, final results of the phase 3, randomized HannaH trial indicate.
The 6-year event-free survival (EFS) and overall survival (OS) rates were identical for patients randomized either to subcutaneously or intravenously delivered trastuzumab (Herceptin and biosimilars); adverse events rates also were similar, reported, from Sana Klinikum Offenbach, Germany, and his associates.
“Event-free survival and OS results after 6 years of follow-up continue to support the noninferiority of subcutaneous trastuzumab to intravenous trastuzumab observed in the primary analysis. Results for EFS were consistent with those observed in the Neoadjuvant Herceptin  trial of intravenous trastuzumab,” the investigators wrote in .
The(Enhanced Treatment With Neoadjuvant Herceptin) trial was designed to show whether subcutaneous trastuzumab was noninferior to intravenous trastuzumab for patients with HER2 (ERBB2)-positive early breast cancer.
Patients received four cycles of neoadjuvant docetaxel, followed by four cycles of combination chemotherapy with fluorouracil, epirubicin, and cyclophosphamide, plus either subcutaneous trastuzumab 600 mg delivered over 5 minutes or IV trastuzumab at a loading dose of 8 mg/kg and maintenance dose of 6 mg/kg every 3 weeks. Patients received an additional 10 cycles of trastuzumab post surgery.
The coprimary endpoints were pathologic complete response, defined as absence of invasive neoplastic cells in the breast (remaining ductal carcinoma in situ was accepted) and serum trough concentration predose on dose cycle 8.
The, published in 2012, showed that the subcutaneous formulation has pharmacokinetic, efficacy and safety profiles comparable with those of standard intravenous administration. Subsequent analyses showed similar 3-year EFS rates and safety profiles, Dr. Jackisch and colleagues noted.
The current, final analysis was conducted after a median follow-up of 5.9 years in an intention-to-treat population within the subcutaneous group (294 women), and 6.0 years in the intravenous group (297 women).
The 6-year EFS rate was 65% in each group, and the OS rate was 84% in each group. In both trial arms, 6-year EFS and OS rates were higher for patients with complete pathologic responses than for patients with residual disease.
Adverse events of any grade were reported in 97.6% in the subcutaneous group and 94.6% in the intravenous group. Grade 3 or greater adverse events occurred in 53.2% versus 53.7%, cardiac adverse events in 14.8% versus 14.1%, and serious adverse events in 21.9% versus 15.1%, respectively.
The HannaH trial was sponsored by Hoffman-La Roche. Dr. Jackisch and several coauthors reported receiving grants and personal fees from Hoffmann-La Roche.
SOURCE: Jackisch C et al. JAMA Oncol. 2019 Apr 18. .