The present invention pertains generally to the field of therapeutic compounds. More specifically the present invention pertains to certain pyrazolo[1,5-a]pyrimidine-5,7- diamine compounds (referred to herein as "PPDA compounds") that, inter alia, inhibit (e.g., selectively inhibit) CDK (e.g., CDK1, CDK2, CDK4, CDK5, CDK6, CDK7, CDK8, CDK9, CDK10, CDK11, CDK12, CDK13, etc.). The present invention also pertains to pharmaceutical compositions comprising such compounds, and the use of such compounds and compositions, both in vitro and in vivo, to inhibit CDK； and to treat disorders including: disorders that are associated with CDK； disorders that result from an inappropriate activity of a cyclin-dependent kinase (CDK)； disorders that are associated with CDK mutation； disorders that are associated with CDK overexpression； disorders that are associated with upstream pathway activation of CDK； disorders that are ameliorated by the inhibition of CDK； proliferative disorders； cancer； viral infections (including HIV)； neurodegenerative disorders (including Alzheimer's disease and Parkinson's disease)； ischaemia； renal diseases； and cardiovascular disorders (including atherosclerosis). Optionally, the treatment further comprises treatment (e.g., simultaneous or sequential treatment) with a further active agent which is, e.g., an aromatase inhibitor, an anti-estrogen, a Her2 blocker, a cytotoxic chemotherapeutic agent, etc.
