Definition of success factors for acceptance of an indirect treatment comparison (ITC) as part of the Federal Joint Committee (German: Gemeinsamer Bundesausschuss, G-BA) benefit assessment according to §35a social code (SGB) in Germany.

Evaluation of all §35a assessments by the G-BA and IQWiG with ITC publicly available on the G‑BA website up to May 21^st, 2019. Evidence was screened on procedural level and analysed descriptively by two individual reviewers. Data was extracted into an a priori developed extraction sheet.

Until late May 2019, the G‑BA has recorded 323 procedures with ITC under §35a of which 21 have not yet been assessed. 72 % of the ITC were not approved by the G-BA, whereas the IQWIG even did not accept 84 %. Moreover, the G-BA certified an additional benefit for 58 % of all accepted ITC whereas the IQWiG has given an additional benefit in 71 %. The main reasons by the G-BA and IQWiG for refusing the ITC were insufficient similarity of the compared studies (31 % resp. 20 %), the wrong appropriate comparable therapy (ACT) (28 % resp. 20 %), and deviations from information in the summary of product characteristics (SmPC) (25 % resp. 23 %). In approx. 15 % of the procedures both, the G-BA and IQWiG, criticised the method of the comparison (mainly for non-adjusted comparisons) and a lack of data.

The evaluation has shown that there is no significant difference between the assessment of ITC by the G-BA and IQWiG. Beside the method of the comparison, the manufacturer should consider the similarity of the comparing study. Moreover, the indirect comparison should not be conducted against an ACT defined differently than proposed from the G-BA and the specifications in the SmPC should be followed to have a higher chance for acceptance of the ITC.