Statistical Framework for in Vivo Drug Combination Studies R package SynergyLMM version 1.1.3 A framework for evaluating drug combination effects in preclinical in vivo studies. 'SynergyLMM' provides functions to analyze longitudinal tumor growth experiments using mixed-effects models, perform time-resolved analyses of synergy and antagonism, evaluate model diagnostics and performance, and assess both post-hoc and a priori statistical power. The calculation of drug combination synergy follows the statistical framework provided by Demidenko and Miller (2019, <doi:10.1371/journal.pone.0224137>). The implementation and analysis of linear mixed-effect models is based on the methods described by Pinheiro and Bates (2000, <doi:10.1007/b98882>), and Gałecki and Burzykowski (2013, <doi:10.1007/978-1-4614-3900-4>). Software Depends: R (>= 4.0) Imports: magrittr (>= 2.0.3), rlang, dplyr (>= 1.1.4), ggplot2 (>= 3.5.1), cowplot (>= 1.1.3), nlme (>= 3.1-165), nlmeU, fBasics, car, MASS, performance, lattice, marginaleffects, clubSandwich Suggests: lme4, knitr, rmarkdown, testthat (>= 3.0.0) Rafael Romero-Becerra <rafrombec@gmail.com> Comprehensive R Archive Network (CRAN) Rafael Romero-Becerra [aut, cre] (ORCID: <https://orcid.org/0000-0003-3935-2647>), Zhi Zhao [ctb], Tero Aittokallio [ctb] GPL (>= 3) 2026-05-12 application/tgz https://CRAN.R-project.org/package=SynergyLMM doi:10.32614/CRAN.package.SynergyLMM