Structure-Guided Development of Covalent and Mutant-Selective Pyrazolopyrimidines to Target T790M Drug Resistance in Epidermal Growth Factor Receptor

Abstract

Reversible epidermal growth factor receptor (EGFR) inhibitors prompt a beneficial clinical response in non-small cell lung cancer patients who harbor activating mutations in EGFR. However, resistance mutations, particularly the gatekeeper mutation T790M, limit this efficacy. Here, we describe a structure-guided development of a series of covalent and mutant-selective EGFR inhibitors that effectively target the T790M mutant. The pyrazolopyrimidine-based core differs structurally from that of aminopyrimidine-based third-generation EGFR inhibitors and therefore constitutes a new set of inhibitors that target this mechanism of drug resistance. These inhibitors exhibited strong inhibitory effects toward EGFR kinase activity and excellent inhibition of cell growth in the drug-resistant cell line H1975, without significantly affecting EGFR wild-type cell lines. Additionally, we present the in vitro ADME/DMPK parameters for a subset of the inhibitors as well as in vivo pharmacokinetics in mice for a candidate with promising activity profile.

Recent developments in anticancer kinase inhibitors based on the pyrazolo[3,4-d]pyrimidine scaffold

“…Further analysis of the physicochemical properties in vitro and in vivo demonstrated that 23 possessed the best overall profile, displaying a high kinetic solubility as well as an excellent permeability. 71 Maher et al designed a series of dual EGFR/ErbB2 inhibitors through the isosteric replacement of the quinazoline core of lapatinib and erlotinib, with a pyrazolo[3,4-d]pyrimidine core. The substitutions around this core primarily focussed on the incorporation of a library of substituted arenes in the C4-position linked by a variety of different nitrogen-containing moieties.…”

Synthesis of [13C6]‐ibrutinib

“…The coupling reaction proceeded smoothly with both unlabeled and labeled boronic acids using excess of reagents at room temperature. The crude product was deprotected with TFA in DCM and acylated with acryoyl chloride according to the known procedures 18–20 . 2.6 mg of [ 13 C 6 ]‐1 was then obtained by LC‐MS purification in 24% yield over three steps (10% yield based on the 21 and 7% based on [ 13 C 6 ]‐bromobenzene).…”

“…Our attempts started again with commercially available tert ‐butyl ( R )‐3‐(4‐amino‐3‐iodo‐1H‐pyrazolo[3,4‐d]pyrimidin‐1‐yl)piperidine‐1‐carboxylate 21 , which was converted into known hydroxyphenyl derivative 27 under Suzuki conditions (Scheme 7). 19 Purification by column chromatography provided the product in 72% yield.…”

A Review on Fused Pyrimidine Systems as EGFR Inhibitors and Their Structure–Activity Relationship

“…These compounds were further screened against the third-generation EGFR inhibitor gefitinib and were found to be superior, concluding that the compounds synthesized were selective third-generation EGFR inhibitors. Further, 223 was taken up for preclinical study using the mice model and results showed good activity by the intraperitoneal route compared to that by intravenous ( Engel et al, 2017 ).…”