GDC-9545 (Giredestrant): A Potent and Orally Bioavailable Selective Estrogen Receptor Antagonist and Degrader with an Exceptional Preclinical Profile for ER+ Breast Cancer.

Breast cancer remains a leading cause of cancer death in women, representing a significant unmet medical need. Here, we disclose our discovery efforts culminating in a clinical candidate, (GDC-9545 or giredestrant). is an efficient and potent selective estrogen receptor degrader (SERD) and a full antagonist, which translates into better antiproliferation activity than known SERDs (, , , and ) across multiple cell lines.

Discovery of a C-8 hydroxychromene as a potent degrader of estrogen receptor alpha with improved rat oral exposure over GDC-0927.

Phenolic groups are responsible for the high clearance and low oral bioavailability of the estrogen receptor alpha (ERα) clinical candidate GDC-0927. An exhaustive search for a backup molecule with improved pharmacokinetic (PK) properties identified several metabolically stable analogs, although in general at the expense of the desired potency and degradation efficiency. C-8 hydroxychromene 30 is the first example of a phenol-containing chromene that not only maintained excellent potency but also exhibited 10-fold higher oral exposure in rats.

Discovery of a Noncovalent, Mutant-Selective Epidermal Growth Factor Receptor Inhibitor.

Inhibitors targeting the activating mutants of the epidermal growth factor receptor (EGFR) have found success in the treatment of EGFR mutant positive non-small-cell lung cancer. A secondary point mutation (T790M) in the inhibitor binding site has been linked to the acquired resistance against those first generation therapeutics. Herein, we describe the lead optimization of a series of reversible, pan-mutant (L858R, del T790M/L858R, and T790M/del) EGFR inhibitors.

Discovery of selective and noncovalent diaminopyrimidine-based inhibitors of epidermal growth factor receptor containing the T790M resistance mutation.

Activating mutations within the epidermal growth factor receptor (EGFR) kinase domain, commonly L858R or deletions within exon 19, increase EGFR-driven cell proliferation and survival and are correlated with impressive responses to the EGFR inhibitors erlotinib and gefitinib in nonsmall cell lung cancer patients. Approximately 60% of acquired resistance to these agents is driven by a single secondary mutation within the EGFR kinase domain, specifically substitution of the gatekeeper residue threonine-790 with methionine (T790M). Due to dose-limiting toxicities associated with inhibition of wild-type EGFR (wtEGFR), we sought inhibitors of T790M-containing EGFR mutants with selectivity over wtEGFR.

Designing compound subsets: comparison of random and rational approaches using statistical simulation.

Compound subsets, which may be screened where it is not feasible or desirable to screen all available compounds, may be designed using rational or random selection. Literature on the relative performance of random versus rational selection reports conflicting observations, possibly because some random subsets might be more representative than others and perform better than subsets designed by rational means, or vice versa. In order to address this likelihood, we simulated a large number of rationally designed subsets for evaluation against an equally large number of randomly generated subsets.