France's Exonhit Therapeutics and U.S. drugmaker Allergan (AGN) have renewed their partnership and extended it to developing treatments that target neurological diseases like Alzheimer's and Parkinson's.

The French biotechnology company did not disclose financial terms of the three-year agreement but said on Tuesday it would receive annual research and development payments as well as payments for milestones it reaches in its development.

Allergan, maker of Botox anti-wrinkle treatment, and Exonhit already worked together on developing drugs that combat pain and eye diseases and amyothropic lateral sclerosis, which affects nerve cells in the brain and spinal cord.

It is the second time the two companies have renewed their partnership in those areas, Exonhit said in a statement.