Adenosine deaminase-resistant purine analog

Class

Lymphocyte-depleting purine nucleoside analog

This mechanism describes a purine nucleoside analog engineered to resist breakdown by adenosine deaminase, an enzyme that normally degrades naturally occurring purine nucleosides. By evading this enzyme, the analog persists long enough to be taken up preferentially by lymphocytes, the white blood cells responsible for adaptive immunity, including T and B cells implicated in autoimmune attack on tissue. Once inside these cells, the compound is converted into an active triphosphate form that is incorporated into DNA, disrupting synthesis and repair and triggering programmed cell death. Because lymphocytes have a metabolic profile that favors activation of this analog relative to other cell types, the depletion is relatively selective, sparing much of the rest of the hematopoietic and immune system. This selective, pulsed depletion strategy is used therapeutically to interrupt pathological immune activity in diseases driven by autoreactive lymphocytes, such as certain relapsing neurological autoimmune conditions, and in some lymphoid malignancies where uncontrolled lymphocyte proliferation is the core problem. The broader pharmacological rationale is to achieve durable immune modulation through periodic dosing rather than continuous suppression, distinguishing this class from agents that require ongoing administration to maintain effect.