Novartis’ HRO761 is an oral allosteric WRN helicase inhibitor, aimed at treating MSI-high and dMMR tumors. This article details the discovery of HRO761 and highlights the importance of selecting appropriate assays during early HTS as well as transferable medicinal chemistry strategies to optimize permeability and solubility through the modulation of LipE, neutral TPSA, chameleonicity, and non-classical zwitterions. It also explores the X-ray structure of HRO761 bound to WRN, how it differentiates from Vividion's VVD-214, its preclinical activity, clinical status, chemical synthesis, and more!

ORIC-944 is a second-generation, orally bioavailable PRC2 inhibitor, targeting the allosteric EED subunit. EZH2 inhibitors typically require frequent dosing due to poor drug-like properties. This article describes the previously undisclosed structure-based design of ORIC-944 into a potential best-in-class PRC2 inhibitor with enhanced solubility, metabolic stability, and prolonged clinical half-life compared to EZH2 inhibitors. It also highlights ORIC-944's capability to reprogram refractory, AR-independent prostate tumors to an AR-dependent state, the synthesis, clinical data, and more!

Pfizer’s oral, CDK4-selective inhibitor PF-07220060 has the potential to revolutionize treatment of HR+/HER2- breast cancer through avoiding the neutropenia DLTs associated with SoC CDK4/6 drugs and permitting greater coverage of the desired CDK4 target. Our full article outlines data presented at AACR 2024, covering the molecule’s course from in silico-informed screen, through structurally enabled optimization against CDK6 and GSK-3β to promising preclinical profile. Fresh clinical data showed efficacy and tolerability supporting PF-07220060's clinical progression.

Cerevance’s CVN293 is an oral, CNS-penetrant, selective inhibitor of potassium efflux-mediated NLRP3-inflammasome activation in microglia for the treatment of neurodegenerative disorders. Cerevance’s NETSseq platform was used to discover a microglia-specific potassium efflux channel, KCNK13, which allows modulation of the NLRP3-inflammasome in the CNS without affecting peripheral innate immunity. Read the full article to discover highlights on the CNS-penetration of highly polar compounds and how particle size can be key to oral bioavailability

TNG348 is a synthetic lethal inhibitor of USP1 by Tango Therapeutics. Inhibiting USP1 disrupts DNA repair and replication mechanisms leading to the selective death of BRCA1/2-mutant cancer cells. Despite the clinical benefit of PARPi in treating BRCA-mutated or HRD+ tumors, some patients exhibit an inadequate response or develop resistance. USP1 inhibitors may hold promise in meeting this unmet clinical demand. This case study highlights USP1 as a synthetic lethal target, the current competitive landscape, how the Tango team overcame high microsomal clearance and hERG liabilities, and more.

AstraZeneca has joined the race to gain approval for a first-in-class, orally bioavailable selective inhibitor of CDK2 with AZD8421, which was recently disclosed at the AACR San Diego 2024 “New Drugs on the Horizon” series. CDK2-selective inhibitors are a hot area right now, with their promise to overcome the resistance against approved CDK4/6 inhibitors. Read the full case study to learn about the CDK2-selective competitive landscape, the structural and kinetic data which underpin AZD8421’s CDK-selectivity and the preclinical activity data which has propelled it into the clinic.

BLU-222 is a potential first-in-class, orally bioavailable selective inhibitor of CDK2 discovered and currently in development by Blueprint Medicines for the treatment of advanced solid tumors. Read the full case study to learn about the competitive landscape of CDK inhibitors, the discovery story enabled by the DiscoveRx KINOMEscan screening platform, how exquisite kinome selectivity can be achieved despite ~100% active site sequence similarity between CDK1/2, how this molecule can potentially treat CCNE1-amplified and CDK4/6i-resistant tumor models, interim clinical data, and more.

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.

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.

Deciphera’s DCC-3116 is an oral ULK1/2 inhibitor targeting the autophagy pathway, a key mechanism of tumor survival and resistance to targeted therapy. Currently in two open-label Ph. I/II trials as a monotherapy and in combination with RTK pathway inhibitors, the structure and discovery of this first-in-class compound were recently presented at the ACS Spring 2024 meeting.

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.

ORIC-533, a potential best-in-class oral inhibitor of CD73 from ORIC Pharmaceuticals, is currently in a Ph. Ib trial for relapsed/refractory multiple myeloma (MM). It inhibits the CD73-mediated conversion of AMP to adenosine which generates an immunosuppressive tumor microenvironment and has the potential to be a next-generation immunotherapy. The in-depth use of X-ray structures led the team to discover a novel set of phosphonate bioisosteres which acheived bioavailability in a polar scaffold. The structure and discovery of ORIC-533 were recently disclosed at the ACS Spring 2024 Meeting.

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.

Zilucoplan is a macrocyclic peptide-containing drug with 15 amino acids in total, targeting the challenging-to-drug C5 complement protein and formulated for self-administered once-daily SC injection. In Sept. 2023, zilucoplan received its first global approval in Japan, followed in Oct. 2023 by FDA approval for gMG patients who are AChR antibody-positive, making zilucoplan the first drug derived from mRNA display for cyclic peptides to be approved. This case study discusses how zilucoplan was discovered and why it’s an important scientific milestone for the industry.

Inaxaplin (VX-147), developed by Vertex, is an inhibitor of APOL1 channel activity currently in a Ph. II/III pivotal study for the treatment of chronic kidney disease caused by specific variants of the APOL1 gene. It was recently granted Breakthrough Therapy designation by the FDA and PRIME designation by the EMA. The discovery story, which is an excellent case study for the use of MetID. Inaxaplin has been called “the most important genomic-driven drug discovery for chronic kidney disease this century”, acting on a target with a fascinating human genetic validation story.

Vertex’s VX-548 is a potential first-in-class, exquisitely selective, oral NaV1.8 inhibitor that recently captured headlines for its positive Ph. III data. With the ongoing opioid epidemic throughout the US, there is an urgent unmet medical need for non-addictive pain medications as alternatives to opioids. They plan to file an NDA by mid-2024 for the treatment of moderate-to-severe acute pain. This case study highlights what’s publicly known about Vertex’s journey in pain leading up to the Ph. III readout for VX-548, and why this is such a watershed moment for pain management.

STX-478 is a wild-type-sparing, oral, CNS-penetrant, novel allosteric inhibitor of mutant phosphatidylinositol-3 kinase α (PI3Kα), targeting a cryptic pocket near the ATP-binding site. PI3Kα plays a central role in many cancers, and has been recently highlighted in coverage of 2021 Molecule of the Year nominee and PI3Kα degrader inavolisib. Currently approved PI3Kα modulators are limited by their off-target activities on WT PI3Kα and other kinases, leading to significant side effects including hyperglycemia and rash.

Genentech’s GDC-6599 is the first oral TRP Ankyrin 1 (TRPA1) antagonist to reach Ph. IIa (NCT05660850) for chronic cough after preclinical studies and a Ph. I trial showed it was well-tolerated, in contrast to prior molecules. The transient receptor potential (TRP) family of ion channels has been the subject of intensive drug discovery efforts due to their critical role in the development and progression of pain, itch, and respiratory conditions.

Last year, Biogen announced that it would acquire Texas biotech Reata Pharmaceuticals for $7.3B. Reata’s lead molecule, omaveloxolone (SKYCLARYS®), an oral, reversible covalent inhibitor of the E3 ligase KEAP1, became the first drug approved for Friedrich’s Ataxia. Omaveloxolone was previously highlighted as a Molecule of the Month in July 2023. Now, this 2023 Molecule of the Year nominee reflects a historic milestone for neurological drug discovery. This comprehensive explainer dives into Nrf2 target rationale, how it works, how the drug was discovered, its synthesis, and why it’s a big deal.

The FGFR family of receptors are well-validated targets in cancer. While specific FGFRs like FGFR2 can drive cancers like cholangiocarcinoma, broad inhibition of FGFRs leads to significant off-target toxicities. Relay Therapeutics captured industry attention when they announced the discovery of an FGFR2 isoform-selective inhibitor, lirafugratinib, using a molecular dynamics simulations approach. This article provides an overview of the pan-FGFR landscape, explores the specifics of the FGFR2 selectivity, preclinical pharmacology, and early clinical data for this remarkable molecule.

Pfizer’s ritlecitinib, a first-in-class, selective, oral covalent inhibitor of JAK3 and the TEC family of kinases, was FDA-approved in June 2023 for the treatment of severe alopecia areata. Ritlecitinib derives its JAK-family kinase selectivity from the covalent modification of a unique cysteine on JAK3. This annotation reviews the discovery of ritlecitinib, highlighting the interpretation of selectivity assays, the PK optimization, the evolution of the JAK3 therapeutic hypothesis, and how this 2023 Molecule of the Year nominee has become a classic case study for covalent drug discovery.

The accelerated approvals of Ras(OFF)-targeting KRAS G12C inhibitors sotorasib and adagrasib, decades in the making, marked the beginning of a new phase of KRAS drug discovery. While an increasing number of follow-on KRAS inhibitors are emerging with similar mechanisms of action, Revolution Medicines’ 2023 Molecule of the Year Nominee, RMC-6291, is representative of a completely novel approach that could become a strong addition to the clinical toolbox for KRAS, but also serves as proof-of-concept for a new class of small molecule therapeutics entirely.

Merck’s macrocyclic PCSK9 protein-protein interaction (PPI) inhibitor, MK-0616, is a once-daily PCSK9-lowering and LDL-cholesterol-lowering small molecule that has recently demonstrated antibody-like efficacy as an oral agent in the clinic. The program highlights numerous technical achievements at the forefront of modern drug discovery, and will set a standard for modern “classics in drug discovery” for some time.

Gamma-secretase is most well-known as a target for Alzheimer’s disease, though such programs have not been successful to date. Nirogacestat is a gamma-secretase inhibitor that Pfizer originally intended to treat AD, but found life at Springworks Therapeutics as a treatment as a first-in-class drug for rare and aggressive desmoid tumors (DTs). Nirogacestat received the first FDA approval for a treatment for desmoid tumors in Nov. 2023, and this article reviews how it was discovered, how the therapeutic hypothesis emerged after confusing assay disconnects, and lessons learned from the program.

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.

Bexotegrast is a dual-selective αvβ6-αvβ1 integrin inhibitor with surprising efficacy and safety data from a Ph. II trial in idiopathic pulmonary fibrosis (IPF). The αv integrins have been studied for decades in indications such as cancer and IPF. Both small molecule and antibody-based integrin inhibitors have demonstrated preclinical toxicities in non-human primates. This article highlights the unmet need for effective therapies for IPF and related conditions, a comparison of bexotegrast with other integrin binders, and possible reasons why bexotegrast is different in terms of safety.