OBJECTIVES : This study aims to verify the equivalence or non-inferiority between biosimilar trastuzumab and reference in efficacy and safety outcomes in naive HER-2 positive breast cancer patients.

METHODS : Rapid review of the highest level of evidence, commissioned by the Department of Pharmaceutical Assistance of the Ministry of Health Brazil. We used the STARR decision tool (SelecTing Approaches for Rapid Reviews decision tool) to conduct discussions between the review group and the commissioners. The data sources used were PubMed, Embase and Cochrane CENTRAL.

RESULTS : We found four papers from three equivalence randomized clinical trials and one non-inferiority trial comparing four trastuzumab biosimilars (SB3, ABP 980, CT-P6 and R-TPR-016) with the reference biological drug. Overall, studies were assessed as moderate to low risk of bias. One study evaluated complete pathological breast response (bpCR) as the primary outcome of efficacy and the upper margin of pre-established therapeutic equivalence was exceeded by the SB3 biosimilar, suggesting its possible superiority over the reference. Two studies evaluated total pathological complete response (tpCR) as the primary outcome of efficacy. The result of CT-P6 was within the pre-established therapeutic equivalence margins, determining its equivalence. In the other study, the biosimilar ABP-980 exceeded the upper margin, suggesting non-equivalence between the drugs. For the study evaluating the non-inferiority of R-TPR-016 compared to the reference, the authors reported that there was no statistically significant difference in the proportion of patients who achieved the objective response rate (ORR), although they did not describe how they stipulated the margin used. Safety outcomes, which the Department of Pharmaceutical Assistance considered to be the most relevant for decision-making, were comparable to the reference.

CONCLUSIONS : The evidence was inconclusive regarding the statistical equivalence of efficacy between trastuzumab biosimilars and their reference. On the other hand, safety proved comparable.