Challenges to determine synergistic drug interactions in mice
Bart A. Westerman, Yoran Broersma, Tom Würdinger, David P. Noske, Peter Sminia, Bakhos A. Tannous · Nature Communications · 2025
Synergistic drug interactions can be assessed in a laboratory setting by multiple methods that do not necessarily lead to the same outcome; hence, the optimal way to determine synergy is a matter of an ongoing debate. Drug synergy assessment in animal experiments is even more complex, not only because of the existence of multiple methods but especially because of their experimental conditions and their practical limitations, which affects their interpretation 1 . Inevitably, no clear and standardized method or guideline exists for these experiments as yet. We appreciate the opportunity to discuss this and will highlight several fundamental and practical considerations associated with the determination of synergy in mouse experiments and will discuss these concerning our chosen approach. We will provide recommendations to determine synergy in vivo which might be valuable for future research. We will also point out how we used a published and accepted method in our publication, that has led to an evaluation bias in our publication 1 which we will put here into perspective. This evaluation shows that, upon re-analysis using four different synergy assessment methods, similar frequencies are seen between in vivo, in vitro and in silico experiments 1 , 2 , 3 , confirming the validity of our prediction method in different model systems. Given the high number of parameters and decision steps involved in the evaluation of drug combinations in mice, we think that insights of our re-evaluation can be valuable to the scientific community. Below, we provide a number of considerations that should be taken into account when drug interactions are assessed in mice.