Chad Pecot: A First-in-Class EGFR-Directed KRAS G12V Selective Inhibitor

Chad Pecot, Founder and CEO of EnFuego Therapeutics and Director of the UNC RNA Discovery Center, shared a post on X about a paper he co-authored with colleagues published in Cancer Cell:

“Now in Cancer Cell, our group reports the development of a first-in-class EGFR-directed KRAS G12V selective inhibitor.

KRAS G12V mutations are the 2nd most common KRAS mutation in cancer, and there are still no approved inhibitors in the clinic.

We address two major challenges with RNAi therapeutics in cancer:

1. Delivery, delivery, delivery

2. Achieving mutation selectivity

To create a KRAS G12V mutant-selective siRNA, we utilized sequence optimization and leveraged the steric properties of 2OMe modifications to create EFTX-G12V V4 Hi2OMe. Thermodynamics, Ago2 modeling, RNAseq and assays with isogenic lines confirmed a highly mutant-selective KRAS G12V inhibitor that spares KRAS WT.

For delivery, recent scRNAseq profiling suggested EGFR is amongst the most highly differentially expressed cancer receptors compared with normal tissues. We confirmed this by profiling >500 lung cancer tumors and 27 somatic tissues. GE11 peptide, a 12 amino acid EGFR binding peptide without mitogenic activity, covalently linked to siRNAs could result in receptor-mediated endocytosis and a high efficiency of cancer cell delivery.

The GE11C-targeting EFTX-G12V siRNA = EFTX-G12V, an EGFR-directed KRAS G12V selective RNAi molecule

Pharmacodynamic profiling demonstrated that a single dose of EFTX-G12V resulted in up to ~80-90% KRAS mRNA and protein silencing throughout the tumor, and significant pERK inhibition.

Biodistribution studies showed EFTX-G12V also traffics to skin, kidneys and bladder. Due to the mutant-selectivity of EFTX-G12V, we observed minimal to no KRAS WT silencing in those tissues.

EFTX-G12V had significant anti-tumor activity in lung, colon and pancreatic cancer models.

Interestingly, compared with a more potent pan-KRAS siRNA molecule based on in vitro activity, EFTX-G12V unexpectedly outperformed pan-KRAS inhibition in vivo. This prompted us to investigate whether differences exist in the tumor microenvironment with mutant-selective targeting.

RNAseq profiling comparing EFTX-G12V with pan-KRAS silencing demonstrated mutant-selective silencing results in deep suppression of many cancer hallmarks. GSEA showed that tumor angiogenesis was uniquely suppressed by mutant-selective silencing. Consistent with this, we observed significant inhibition of microvessel density with EFTX-G12V, and inconsistent effects on tumor angiogenesis with pan-KRAS siR treatment.

We also observed less pEGFR reactivation in colon cancer models with EFTX-G12V, whereas pan-KRAS targeting had more robust pEGFR reactivation, increases in total EGFR. We did observe decreased p-YAP S127 with EFTX-G12V, consistent with activation of the YAP-TEAD pathway as a likely resistance pathway that emerges.

In a KRAS G12V colon model, we observed with prolonged EFTX-G12V treatment that pEGFR feedback activation occurs, and this was largely mitigated with the addition of an anti-EGFR antibody. This indicates that the GE11-mediated EGFR receptor uptake mechanism for siRNA delivery is compatible with an EGF/EGFR blocking antibody.

Using a syngeneic model from Mariano Barbacid’s lab, we observed EFTX-G12V phenocopies anti-tumor effects as tamoxifen-inducible KRAS G12V flox. Consistent with other reports of KRAS small molecule inhibitors, we observed highly significant and rapid increases of CD8+ T-cells and many granzyme B+ lymphocytes.

Because complete inhibition of mutant KRAS is challenging with any modality, we evaluated whether dual KRAS blockade with EFTX-G12V (RNAi-mediated silencing) and RMC-7977 (allosteric inhibition) could improve MAPK inhibition. We observed an additive or synergistic effect in several KRAS G12V mutant lines, and near complete pERK inhibition.

This was a massive effort over many years led by Lyla Stanland and Hayden Huggins. Grateful to the hard work of my lab and excellent collaborators, Justin Milner, Martin Egli, and Albert Bowers. Thanks so much to the reviewers who truly made the paper more robust and challenged us to go in new directions. Special thanks to Zhaodong Li a world-class editor at Cancer Cell, who did a fantastic job handling this paper. Grateful for funding sources from NCI, LungCancerInitiative, NCBiotech, and UNC Lineberger.

If you want to help bring EFTX-G12V to patients, please DM me.”

Title: A first-in-class EGFR-directed KRAS G12V selective inhibitor

Authors: Lyla J. Stanland, Hayden P. Huggins, Snehasudha S. Sahoo, Alessandro Porrello, Yogitha Chareddy, Salma H. Azam, Jillian L. Perry, Pradeep S. Pallan, Kristina Whately, Lincy Edatt, William D. Green, Matthew C. Fleming, Jonah Im, Christina Gutierrez-Ford, Imani Simmons, Alyaa Dawoud, Katherine I. Zhou, Vandanaa Jayaprakash, Rani S. Sellers, Gabriela de la Cruz, Albert Wielgus, Justin Milner, Martin Egli, Albert A. Bowers, Chad V. Pecot.

You can read the Full Article in Cancer Cell.

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