OrganoTherapeutics S.a.r.l. (OT) makes use of a proprietary human-specific 3D in vitro model, the so-called midbrain organoids, for the discovery and development of effective drug candidates, which target neurodegeneration in Parkinson`s disease (PD) patients. We develop own small molecule compounds as therapeutics but also partner with our biotech and pharma companies to support their therapeutics development. The main pathologic event in PD is the loss of dopaminergic neurons in the midbrain. However, this key feature is not recapitulated in animal (rodent) models for PD. Importantly, also patient specific dopaminergic neurons cultured in normal 2D cell culture conditions do not recapitulate this. However, our data show that this key pathological PD hallmark is recapitulated in patient specific 3D midbrain organoids. Our recent publication, Smits et al., 2019 in npj Parkinson’s disease for the first time has shown PD specific phenotypes in 3D midbrain organoids. Importantly, this was replicated independently by another study (Kim et al., 2019; Stem Cell Reports). Additionally, we have data showing that the second key hallmark of PD, the appearance of alpha-Synuclein containing protein aggregates, can be recapitulated in patient specific midbrain organoids. After demonstrating that midbrain organoids recapitulate key disease features, we aimed at showing that these features can be ameliorated by treatment with small molecule compounds, which hence potentially can become drugs for treatment of PD. This is the proof-of-principle of the applicability of the midbrain organoid system for drug development. We have now several examples where treatment with small molecule compounds was able to rescue the key disease characteristic (e.g. loss of dopaminergic neurons) in PD specific midbrain organoids. Importantly, these example results just have been accepted for publication in the prestigious journal Science Translational Medicine (Boussaad et al., 2020).