MX-100 (also known as PL-100) is a benzenesulfonamide derivative patented by Pharmacor Inc as HIV aspartyl protease inhibitor. MX-100 retained excellent antiviral activity against almost all of these protease inhibitor-resistant viruses and that its performance in this regard was superior to those of atazanavir, amprenavir, indinavir, lopinavir, nelfinavir, and saquinavir. In almost every case, the increase in the EC50 for MX-100 observed with viruses containing multiple mutations in protease was far less than that obtained with the other drugs. Preclinical studies showed that MX-100 possessed suboptimal solubility and pharmacokinetic, (PK) properties, possibly hindering further development. MX-100 successfully completed preclinical and clinical development (phase I in healthy volunteers) and have been licensed to Merck in 2006

APD668 is a novel, highly potent and orally active glucose-dependent insulinotropic receptor (GDIR) agonist intended to more efficiently stimulate insulin release by beta cells in response to elevated blood glucose levels, and to avoid hypoglycemia. Ortho-McNeil's initial clinical studies evaluated healthy volunteers and patients with type 2 diabetes in randomized, double-blind, placebo-controlled trials evaluating the safety, tolerability, pharmacokinetics and pharmacodynamics of single and multiple (14 day) escalating doses of APD668. Based on the data from those studies, Ortho-McNeil has decided to put APD668 on hold and has advanced a potentially more potent Arena discovered GDIR agonist into preclinical development.