Discovery of Highly Selective Brain-Penetrant Vasopressin 1a Antagonists for the Potential Treatment of Autism via a Chemogenomic and Scaffold Hopping Approach

From a micromolar high throughput screening hit <b>7</b>, the successful complementary application of a chemogenomic approach and of a scaffold hopping exercise rapidly led to a low single digit nanomolar human vasopressin 1a (hV1a) receptor antagonist <b>38</b>. Initial optimization of the mouse V1a activities delivered suitable tool compounds which demonstrated a V1a mediated central <i>in vivo</i> effect. This novel series was further optimized through parallel synthesis with a focus on balancing lipophilicity to achieve robust aqueous solubility while avoiding P-gp mediated efflux. These efforts led to the discovery of the highly potent and selective brain-penetrant hV1a antagonist RO5028442 (<b>8</b>) suitable for human clinical studies in people with autism

Specific Correction of Alternative Survival Motor Neuron 2 Splicing by Small Molecules: Discovery of a Potential Novel Medicine To Treat Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is the leading genetic cause of infant and toddler mortality, and there is currently no approved therapy available. SMA is caused by mutation or deletion of the survival motor neuron 1 (<i>SMN1</i>) gene. These mutations or deletions result in low levels of functional SMN protein. <i>SMN2</i>, a paralogous gene to <i>SMN1</i>, undergoes alternative splicing and exclusion of exon 7, producing an unstable, truncated SMNΔ7 protein. Herein, we report the identification of a pyridopyrimidinone series of small molecules that modify the alternative splicing of <i>SMN2</i>, increasing the production of full-length <i>SMN2</i> mRNA. Upon oral administration of our small molecules, the levels of full-length SMN protein were restored in two mouse models of SMA. In-depth lead optimization in the pyridopyrimidinone series culminated in the selection of compound <b>3</b> (RG7800), the first small molecule <i>SMN2</i> splicing modifier to enter human clinical trials

Discovery of Risdiplam, a Selective Survival of Motor Neuron‑2 (<i>SMN2</i>) Gene Splicing Modifier for the Treatment of Spinal Muscular Atrophy (SMA)

SMA is an inherited disease that leads to loss of motor function and ambulation and a reduced life expectancy. We have been working to develop orally administrated, systemically distributed small molecules to increase levels of functional SMN protein. Compound <b>2</b> was the first SMN2 splicing modifier tested in clinical trials in healthy volunteers and SMA patients. It was safe and well tolerated and increased SMN protein levels up to 2-fold in patients. Nevertheless, its development was stopped as a precautionary measure because retinal toxicity was observed in cynomolgus monkeys after chronic daily oral dosing (39 weeks) at exposures in excess of those investigated in patients. Herein, we describe the discovery of <b>1</b> (risdiplam, RG7916, RO7034067) that focused on thorough pharmacology, DMPK and safety characterization and optimization. This compound is undergoing pivotal clinical trials and is a promising medicine for the treatment of patients in all ages and stages with SMA

Discovery of Risdiplam, a Selective Survival of Motor Neuron‑2 (<i>SMN2</i>) Gene Splicing Modifier for the Treatment of Spinal Muscular Atrophy (SMA)

SMA is an inherited disease that leads to loss of motor function and ambulation and a reduced life expectancy. We have been working to develop orally administrated, systemically distributed small molecules to increase levels of functional SMN protein. Compound <b>2</b> was the first SMN2 splicing modifier tested in clinical trials in healthy volunteers and SMA patients. It was safe and well tolerated and increased SMN protein levels up to 2-fold in patients. Nevertheless, its development was stopped as a precautionary measure because retinal toxicity was observed in cynomolgus monkeys after chronic daily oral dosing (39 weeks) at exposures in excess of those investigated in patients. Herein, we describe the discovery of <b>1</b> (risdiplam, RG7916, RO7034067) that focused on thorough pharmacology, DMPK and safety characterization and optimization. This compound is undergoing pivotal clinical trials and is a promising medicine for the treatment of patients in all ages and stages with SMA