DSM265 is an experimental antimalarial that selectively inhibits the parasite dihydroorotate dehydrogenase (DHODH). DSM265 is the first DHODH inhibitor to reach clinical development for treatment of malaria. DSM265 is highly selective toward DHODH of the malaria parasite Plasmodium, efficacious against both blood and liver stages of P. falciparum, and active against drug-resistant parasite isolates. The only possible DSM265-related adverse event was a moderate transient elevation in serum bilirubin.

MK 3577 is an orally active glucagon receptor antagonist which was under development by Merck & Co for the treatment of type 2 diabetes mellitus. MK 3577 demonstrate activity in cellular models and preclinical trials. In phase II clinical trials MK 3577 shows good efficacy and acceptable level of adverse events, but no further development reports were published.

MK-1064 is an orexin 2 receptor antagonist patented by pharmaceutical company Merck & Co for the treatment of insomnia. MK-1064decreases the amount of time spent in active wake and increases the time spent in rapid eye movement (REM) sleep and slow-wave sleep (SMS) in mice, rats, dogs, and rhesus monkeys. MK-1064, even at the very high dose did not show signs of an enhanced predisposition to cataplexy in the food-elicited cataplexy test. MK-1064 has now completed two Phase I studies focused on pharmacokinetics, safety and sleep in healthy volunteers. The effects of MK-1064 on sleep parameters were moderate, but statistically significant, representing the first demonstration of PSG-quantified sleep induced in humans by an OX2R antagonist. MK-1064 at 50, 120 and 250 mg decreased latency to persistent sleep and wake after sleep onset, and increased total sleep time and sleep efficiency.

Bristol-Myers Squibb developed BMS-929075 as a selective, orally bioavailable hepatitis C virus (HCV) NS5B polymerase inhibitor for the treatment of chronic HCV infection. BMS-929075 was involved in phase I clinical trials for hepatitis C virus (HCV) infected patients; however, the company withdrew a study prior to enrolment.