Dennis C. Koester

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.

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.

TNG462, developed by Tango Therapeutics, is a potential best-in-class, oral, protein arginine methyltransferase 5 (PRMT5) inhibitor currently in Ph. I/II clinical trial for MTAP-deleted solid tumors. TNG462 is designed to cooperatively bind to PRMT5 when complexed with its endogenous inhibitor methylthioadenosine (MTA), which accumulates in MTAP-deleted tumors. This triggers synthetic lethality in cells with an MTAP-deletion and spares healthy tissues with low MTA levels. A CNS-permeable analogue, TNG908, is also entering clinical trials for MTAP-deleted glioblastoma.

VVD-214/RO7589831 is an oral covalent, reversible, and allosteric inhibitor of WRN helicase discovered by the San Diego-based biotech Vividion Therapeutics and being developed by Roche for tumors marked by microsatellite instability and/or mismatch repair deficiency. Vividion has utilized its chemoproteomics platform to discover and develop novel treatment options for oncology targets. The structure and initial preclinical pharmacology data for VVD-214 were recently disclosed at the AACR Annual Meeting 2024 in San Diego. VVD-214 is currently being evaluated in a Ph. I trial.

Peptidic GLP-1R agonists have received significant media coverage over the past year for their astounding efficacy in several indications. While most of the recent fanfare has been related to their role in weight loss, GLP-1R agonists have been a mainstay of the type 2 diabetes treatment landscape for the past 2 decades. GLP-1R agonists have also recently shown efficacy in reducing heart disease risk and treating certain chronic kidney diseases. Here’s a recap of the March 14th, 2024, Flash Talk, from Oliver Philps.

Minipigs have recently gained prominence as an alternative non-rodent in vivo model for pharmacokinetic (PK), efficacy, and toxicology studies supporting human dose predictions. This article provides an overview of the use of minipigs in small molecule preclinical drug discovery research, tracing their historical background and outlining practical considerations for selecting them in studies focusing on hepatic metabolism, oral bioavailability, CNS penetration, and toxicology. It highlights minipigs' unique advantages and makes a compelling case for their continued use in preclinical research.

February 2024 saw numerous notable patent disclosures aimed at a variety of therapeutic targets across different disease areas. The Drug Hunter team has compiled a searchable table that includes more than 200 patents of relevance to the drug discovery industry. Accompanying the table are detailed notes, as well as standout features from some of our top picks, including MTA-cooperative PRMT5 inhibitors, heterobifunctional TYK2 degraders, strategies for engaging and reactivating mutant p53, and more.

Nrf2/KEAP1 modulation has been pursued since the discovery that dimethyl fumarate and its metabolite protect CNS neurons via up-regulation of Nrf2-depdendent activities. Compounds with greater selectivity have been sought for many years, culminating with the approval of the KEAP1 inhibitor, omaveloxolone. Vividion disclosed their efforts to identify the covalent KEAP1 inhibitor, VVD-702. This ACS Spring 2024 disclosure is an excellent case study for covalent hit finding using chemoproteomics, covalent compound optimization, and the use of an uncommon but surprisingly stable covalent warhead.

With increasingly tight timelines between bench and clinic, considering formulation strategies early on can give your program a competitive edge. This succinct formulations guide provides specific clinically-used examples of common formulations, and can help you select a formulation strategy most likely to succeed based on the properties of your compound.

The impact of small and mid-sized biotech companies has become increasingly important. The shift from large pharma dominance to a biotech-driven era of drug discovery presents challenges to the traditional model of education for emerging medicinal chemists. Industry leader Dean Brown recently highlighted challenges for modern medicinal chemists starting in biotech who face fewer mentoring opportunities and are often propelled into leadership positions sooner than their counterparts in big pharma. Here we share how our team of former industry scientists at Drug Hunter can help.

PF-07817883 (ibuzatrelvir) is an oral, second-generation SARS-CoV-2 M^pro inhibitor developed by Pfizer. These efforts follow the success of Pfizer's antiviral combination drug, Paxlovid, which was granted Emergency Use Authorization by the FDA for the treatment of COVID-19. PF-07817883 was granted Fast Track designation and recently completed a Ph. II clinical trial in outpatient adults with COVID-19 symptoms. This article details the discovery strategy for PF-07817883, which includes addressing metabolic soft spots identified through MetID studies, recent clinical developments, and more.

PF-9363 (CTx-648) is a first-in-class, oral inhibitor of the KAT6A/B histone lysine acetyltransferases (HATs) for the treatment of ER+/luminal & KAT6A+ breast cancer discovered by Melbourne’s Cancer Therapeutics CRC (CTxT) and Pfizer, San Diego. This article discusses why the molecule is scientifically notable in drug discovery for epigenetic targets and transferable scientific insights from its decade-long KAT6 campaign including its target rationale, hit-finding and lead optimization, synthesis and relevant clinical data.

Obtaining adequate drug exposure in the brain is key to treating CNS diseases effectively. Recently, Dennis Koester gave us a crash course in CNS drug discovery in a Drug Hunter Flash Talk. Here, he sums up some key points on how to find compounds that cross the blood-brain barrier.

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.

“Compound 25” is a selective, CNS-penetrant, ATP-competitive LRRK2 inhibitor that entered preclinical candidate enabling studies but was discontinued for undisclosed reasons. The molecule possesses two interesting chemical features: a “bow-tie” spirocyclopropyl group that made a significant impact on potency and overall properties [...]

Vadadustat (Vafseo) from Akebia Therapeutics is an oral hypoxia-inducible factor prolyl-4-hydroxylase domain (HIF-PHD) inhibitor developed for anemia in patients with chronic kidney disease (CKD). It received FDA approval on March 27th, 2024 for patients on dialysis for at least three months, after regulatory challenges including an earlier complete response letter due to safety concerns. This makes vadadustat the second FDA-approved HIF-PHD inhibitor for the treatment of anemia in CKD for dialysis-dependent patients after GSK’s daprodustat’s approval in Feb. 2023.

“Compound 3” (UCSF) is a covalent KRAS G12R inhibitor used as a proof-of-concept for covalent arginine modification. KRAS is the first oncoprotein to be identified and is a well-known cancer-driving protein. As one of the most frequently mutated proteins in pancreatic and colorectal cancers, residues that are frequently mutated are [...]

In this highlight, Dr. Dennis C. Koester reviews treatment options for HIV and explains how small molecule long-acting injectables (LAIs) are offering significant promise in both HIV treatment and prophylaxis. A Coming Paradigm Shift for HIV Treatment and Prophylaxis By Dennis C. Koester The surge of the coronavirus pandemic has made our [...]

INE963 (Novartis Institute for Tropical Diseases) is an oral, single dose, fast-acting blood-stage antimalarial candidate . The molecule was identified using a phenotypic high-throughput screening approach which has been successfully used to identify new antimalarial chemotypes . Phenotypic screens can be preferable to target-based [...]

One of the privileges that have come with building Drug Hunter has been all the insightful thoughts and commentary our readers share. We also appreciate how readers help catch mistakes and offer corrections. This new series of “ Drug Hunter Letters” highlights recent insightful communications from drug hunters, which includes this time: Dr [...]

We asked the global drug discovery community to nominate and vote on their favorite molecule from 2021, and the results are in. The 2021 choice for Drug Hunter’s Small Molecule of the Year is Pfizer’s CoV-2 M pro Inhibitor, PF-07321332 (nirmatrelvir, Paxlovid) . Published in a November 2021 Science article , the molecule was praised for its [...]