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

Pyrazolo[3,4-d]pyrimidines have become of significant interest for the medicinal chemistry community as aprivileged scaffold for the development of kinase inhibitors to treat a range of diseases, including cancer.This fused nitrogen-containing heterocycle is an isostere of the adenine ring of ATP, allowing themolecules to mimic hinge region binding interactions in kinase active sites. Similarities in kinase ATP sitescan be exploited to direct the activity and selectivity of pyrazolo[3,4-d]pyrimidines to multiple oncogenictargets through focussed chemical modification. As a result, pharma and academic efforts have succeededin progressing several pyrazolo[3,4-d]pyrimidines to clinical trials, including the BTK inhibitor ibrutinib,which has been approved for the treatment of several B-cell cancers. In this review, we examine thepyrazolo[3,4-d]pyrimidines currently in clinical trials for oncology patients, as well as those published in theliterature during the last 5 years for different anticancer indications.