cPrPMEDAP

cPrPMEDAP is an intermediate metabolite of GS-9219. cpr-PMEDAP functions as a proagent of the guanine nucleotide analog PMEG and has antiproliferative activity. cPrPMEDAP is negatively charged at physiologic pH and has poor permeability into the skin.

cPrPMEDAP shows antiproliferative activity in SiHa cells with an EC₅₀ of 290 nM (SiHa cells: HPV-transformed cervical carcinoma cell lines)^[1].
PMEG forms an active phosphorylated metabolite, PMEG diphosphate (PMEG-DP), in cells, which inhibits the growth of various transformed cell lines due to potent inhibition of the nuclear DNA polymerases α, δ and ɛ, resulting in inhibition of DNA synthesis and/or DNA repair. In animal models, PMEG has antiproliferative effects; the utility of PMEG as an antiproliferative agent is limited by its poor cellular permeability and toxicity. cPrPMEDAP has similar antiproliferative effects in vitro and reduced toxicity in vivo but, like PMEG, is negatively charged at physiologic pH and has poor permeability into the skin^[1].

References:
[1]. Compton ML, et al. 9-(2-Phosphonylmethoxyethyl)-N6-cyclopropyl-2,6-diaminopurine (cpr-PMEDAP) as a prodrug of 9-(2-phosphonylmethoxyethyl)guanine (PMEG). Biochem Pharmacol. 1999;58(4):709-714.
[2]. Wolfgang GH, et al. GS-9191 is a novel topical prodrug of the nucleotide analog 9-(2-phosphonylmethoxyethyl)guanine with antiproliferative activity and possible utility in the treatment of human papillomavirus lesions. Antimicrob Agents Chemother. 2009;53(7):2777-2784.