Paliroden is an orally active drug that activates the synthesis of endogenous neurotrophins or nerve growth factors. Paliroden was investigated in phase II clinical trial in patients with Alzheimer's disease and to evaluate its effect on 18F-Dopa PET imaging in patients with Parkinson's disease. The further development of paliroden was discontinued due to its insufficient efficacy.

Befiradol (also known as NLX-112) was initially developed by Pierre Fabre as a selective serotonin-1A receptor agonist for the treatment of cancer pain and neuropathic pain. However, these trials were discontinued. In 2013, the development and commercialization rights were licensed to Neurolixis. Neurolixis studied befiradol in Parkinson’s disease (PD) patients that exhibit dyskinesia. Dyskinesia is a side effect that appears after several years of action Levodopa, a drug that remains the gold standard treatment for PD. In 2019, FDA gave a positive response to Neurolixis’s befiradol to be tested in Phase 2 clinical in Parkinson's disease patients suffering from debilitating levodopa-induced dyskinesia.