Forodesine (BCX-1777) is an orally active and potent purine nucleoside phosphorylase (PNP) inhibitor, a new purine nucleoside analog, inhibitor of human lymphocyte proliferation, induces apoptosis in leukemic cells by increasing dGTP levels, and may be useful in the study of cutaneous T-cell lymphomas.

PNP (rat):1.24 nM, PNP (monkey ):0.66 nM, PNP (human):1.19 nM, PNP (dog):1.57 nM, PNP (mouse):0.48 nM

Formodicin (10-30 μM; 24 and 48 hours; RPMI-8226, MOLT-4 and 5T33MM cells) has no effect on MM cells at 24 hours, but decreases the percentage of viable cells in MOLT-4 cells by 40% [1]. Treatment with forodosine (10-30 μM; 24 and 48 h; RPMI-8226, MOLT-4 and 5T33MM cells) partially inhibited cell proliferation [1]. In the presence of 2'-deoxyguanosine (dGuo, 3-10 μM), fordifloxacin inhibits the proliferation of human lymphocytes activated by a variety of drugs such as interleukin-2 (IL-2), mixed lymphocyte reaction (MLR) and phytohemagglutinin (PHA) (IC50 values less than 0.1-0.38 μM) [2].

Forodesine has excellent oral bioavailability (63%) in mice[2]. Forodesine(single dose of 10 mg/kg; in mice ) treatment, elevates dGuo to approximately 5 μM[2]. Forodesine is effective in prolonging the life span 2-fold or more, in the human peripheral blood lymphocyte severe combined immunodeficiency (hu-PBL-SCID) mouse model[2].