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.

EOS-984 is an oral, potential first-in-class, highly selective ENT1 inhibitor from iTeos currently in clinical trials for advanced solid tumors. The drug, which was identified through SBDD and optimization of the vasodilator dilazep, targets the immunosuppressive effects of adenosine, which helps tumors evade immune detection. This is an excellent case study on the importance of understanding a molecule's bioactive conformation to reduce the entropy of binding and enhance potency.

HiberCell recently disclosed the discovery of HC-7366, a potential first-in-class, intentionally discovered, orally bioavailable, potent, selective, small-molecule kinase activator of GCN2. HC-7366 has now progressed to Ph. I trials to treat ccRCC and AML. This case study is a fantastic example of how to mitigate CYP3A4 inhibition and improve oral bioavailability via judicious choice of salt formulation.

AZ-PRMT5i-1 is an orally bioavailable MTA-cooperative PRMT5 inhibitor that specifically targets MTAP-deleted cancers and is structurally related to AZ’s clinical candidate, AZ3470. This case study is an excellent example of utilizing bioisosteric replacements for polar guanidine headgroups, rigidifying scaffolds through spirocyclization to reduce rotatable bonds, and leveraging fluorine atoms beyond simply blocking metabolic soft spots.

Arvinas’ ARV-393 is an orally bioavailable PROTAC that degrades BCL6 via CRBN-mediated ubiquitination and proteasomal degradation intended for the treatment of NHL. At the AACR San Diego 2024 meeting, Arvinas disclosed the structure and discovery story of this molecule, which exhibits first-in-class potential. This article covers the key SAR observations that led to the invention of this orally bioavailable PROTAC®, its performance in a triple-hit, high-grade BCL and R-CHOP-resistant cell line, and why sustaining BCL6 knockdown beyond 24 hours was critical for the success of this program.