Nurix Therapeutics’ NX-1607 is the first oral small molecule inhibitor of CBL-B to enter clinical trials. CBL-B negatively regulates immune activation in T, B, and NK cells; while immune checkpoint inhibitors are often effective, they have limitations, including lack of efficacy in certain cancers, patient variability, and resistance. NX-1607 enhances T cell activation by gluing CBL-B in an inactive conformation and, driven by preclincial data, NX-1607 is currently in a Ph. I trial. This article details its discovery story and initial clincial results, presented at the ACS Spring 2024 meeting.

Nuvalent’s lead compound, NVL-520, is an oral, brain-penetrant, TRK-sparing, and potential best-in-class ROS1 kinase inhibitor that recently entered Ph. II of the ARROS-1 trial (NCT05118789) in patients with advanced ROS1-positive NSCLC. This article highlights what makes the Nuvalent’s NVL-520 program scientifically notable, including what gives it a potential best-in-class profile as a ROS1 inhibitor, the emerging toxicology of hard-to-avoid off-targets, an interesting synthetic route to the small macrocycle, and more.

BMS-986365 is a potential best-in-class heterobifunctional ligand-directed degrader of WT AR. This full case study details how this heterobifunctional degrader was engineered to have low intrinsic agonism and exert direct antagonism of WT AR through occupancy of its ligand-binding domain, how the dual modality of BMS-986365 results in deep AR pathway inhibition and allows antagonism to reinforce degradation to combat compensatory resistance mechanisms, its attractive preclinical profile, interim clinical data, how it differentiates from Arvinas’ first-to-clinic AR degraders, and more!

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.

AbbVie’s ABBV-467 is a highly potent, selective MCL-1 (myeloid cell leukemia-1) inhibitor which entered the clinic in 2022 in a Ph. I trial in patients with advanced hematologic cancers. MCL-1 has had a rough time in the clinic with multiple trials being halted or terminated due to cardiac toxicity, which is suspected to be an on-target effect. AbbVie’s approach with ABBV-467 was to target a highly potent/short half-life compound which could induce rapid apoptosis and tumor regressions in a short exposure period before the onset of any adverse events. Is this the end for MCL-1?