Matthew L Fidler

One of the things I often get asked is if you can use #nlmixr2 in submissions. We were invited to meet with some of the FDA reviewers, and they confirmed they have received submissions in nlmixr2 and no issues were raised about its use

https://blog.nlmixr2.org/blog/2026-04-29-fda/

We are excited to announce a new feature in nlmixr2: mceta for FOCEi. This is a hybrid approach combines Monte-Carlo sampling with the classical FOCEi algorithm bringing flexibility & robustness to nonlinear mixed-effects modeling in pharmacometrics. #nlmixr2 #rstats

New features in #nlmixr2 4.0, a #rstats package include a vere-style loading, importing models from older versions of nlmixr2 and Rstudio bug fixes. See https://blog.nlmixr2.org/blog/2025-08-29-nlmixr2-verse/

In this month's Blog, I discuss a new feature in the nlmixr2 ecosystem (in babelmixr2) -- translating and using nlmixr2 models in optimal design. They are fast and easy to use making this my go to tool when doing optimal design. #nlmixr2 #rstats

https://blog.nlmixr2.org/blog/2024-11-06-poped/

nlmixr2 and rxode2 3.0 is out. It is a major release since there are some backward-incompatible changes. #nlmixr2 #rxode2 #rstats

https://blog.nlmixr2.org/blog/2024-09-18-nlmixr2-3.0.0-release/

We have a new nlmixr2 blog entry courtesy of Hitesh Mistry and Nicola Melillo (@NicolaMelillo) detailing how to upscale nlmixr2 using AWS. This is helpful for long running SAEM models. In the future it may be even more interesting with other methods parallelized. (#nlmixr2 #rstats)

https://blog.nlmixr2.org/blog/2024-03-05-aws/

A new version of #nlmixr2 was released on CRAN today. I will talk about a few features in the future:

- More flexible mu referencing

- User defined functions can now be used with nlmixr2 and rxode2

- Event handling changes

- Many new estimation methods for population only fitting
I am very grateful for both the nlmixr2 team and the nlmixr2 users who have helped me get to this point in nlmixr2's development.

See the blog for more details about the release.

https://blog.nlmixr2.org/blog/2024-01-09-nlmixr2-2.1.0-release/

- It is also validated against the #nlmixr2 / #rxode2 model so you know if it is working immediately

Want a single language for a few pharmcometric applications? How about giving #babelmixr2, an extension of #nlmixr2 a try?

I would like to mention a new release of #nlmixr2. I haven't posted about it but I would like to mention my favorite new features: