In phase 1 and 1b clinical trials, DNL201 inhibited LRRK2 and was well tolerated in 122 healthy volunteers and in 28 patients with PD (Jennings et al. 2022), which led to the initiation of an international phase 2 clinical trial with the compound BIIB122, which is related to DNL201 (NCT05418673). The gene discussed is LRRK2; the disease is Parkinson disease.