<prompt> Drugs or biological products for diagnosis, treatment or prevention of a rare disease or condition are called?Orphan drugsRare drugsExtinct drugsEssential drugs  <response>: Ans. is a i.e., Orphan drugs Orphan drugs These are drugs or biological products for diagnosisprevention of a rare disease or condition, or a more common disease endemic only in resource poor countries for which there is no reasonable expectation that the cost of developing and marketing it will be recovered from the sales of that drug. The list includes sodium nitrite, fomepizole, liposomal amphotericin B, miltefosine, rifabutin, succimer, somatropin, digoxin immune Fab digoxin antibody, liothyronine T3 and many more. Though these drugs may be life saving for some patients, they are commercially difficult to obtain as a medicinal product. Government in developed countries offer tax benefits and other incentives to pharmaceutical companies for developing and marketing orphan drugs e.g. Orphan Drug Act in USA. 