PRMT5 is an epigenetic “synthetic lethality” target that has attracted much attention among drug hunters. The first generation of PRMT5 inhibitors was limited by systemic toxicities resulting in a cooling of industry interest, until the recent identification of tumor-specific inhibitors. These second-generation compounds target the MTA:PRMT5 complex in MTAP-deleted cancers—15% of all tumors—leading to a revival of the target. Read on to find out which companies are prevailing in the search for a first-in-class PRMT5 inhibitor and how their clinical compounds differentiate.

In April 2024, there were promising examples of drug repurposing, significant clinical and regulatory milestones for therapies aimed at rare and pediatric diseases, the initiation of a rolling NDA submission for suzetrigine, substantial billion-dollar acquisitions, and positive trial results were reported for both a D1/D5 receptor agonist and a PARP1 inhibitor. However, the industry also had setbacks as demonstrated by the failed clinical trials for an MNK inhibitor and an NMDA receptor modulator. In case you missed anything, here’s a recap of the most notable news highlights from April 2024!

Zuranolone (ZURZUVAE™) is an oral positive allosteric modulator of CNS GABA signaling developed by Sage Therapeutics, in collaboration with Biogen, which was approved in August 2023 by the FDA for the treatment of postpartum depression (PPD). In 2019 Sage had received approval for brexanolone (ZULRESSO™), an IV formulation of the endogenous GABA PAM neurosteroid hormone for PPD, but an oral drug is expected to greatly increase access to treatment. Zuranolone was also investigated for major depressive disorder, although the FDA declined to extend approval for this indication.

M4205 (IDRX-42) is a highly selective type II receptor tyrosine kinase inhibitor of KIT, discovered by Merck KGaA and currently being developed by IDRx. The molecule is a notable example of kinase selectivity achieved with a non-classical hinge binder. M4205 (IDRX-42) has received an Orphan Drug designation and is currently being evaluated in a Ph. I/Ib FIH trial for GIST, one of the most common mesenchymal neoplasms in the GI tract.

SGR-1505, the first in-house clinical compound developed at Schrödinger, is an oral, allosteric MALT1 inhibitor currently in the clinic for the treatment of mature B cell malignancies. The discovery effort, disclosed at the ACS Spring 2024 meeting, was completed in an impressive 10 months, starting from a published scaffold. SGR-1505 demonstrated preclinical single-agent and combination activity as well as inducing resensitization in BTK and BCL-2 inhibitor-resistant tumors. The compound is currently progressing in a Ph. I trial in patients with mature B cell malignancies.