In the early 1990s Dutch scientists Arnold Reuser and Ans van der Ploeg were able to show that using alpha-glucosidase containing phosphorylated mannose residues purified from bovine testes increased the enzymes activity in normal mouse muscles.Later in 1998, Dr. Yuan-Tsong Chen and colleagues at Duke University, using the enzyme produced in Chinese Hamster Ovary cells  demonstrated for the first time that the enzyme can clear the glycogen and improved the muscle function in Pompe disease quail. The results of the work at Duke were impressive with one treated bird recovering to the point of being able to fly again.This was followed by production of clinical grade alpha-glucosidase in Chinese hamster ovary (CHO) cells and in the milk of transgenic rabbits. This work eventually culminated in the start of clinical trials with the first clinical trial including 4 babies receiving enzyme from rabbit milk at Erasmus MC Sophia Childrens Hospital and 3 babies receiving enzyme grown in CHO cells at Duke University in 1999. The currently approved Myozyme is manufactured by Genzyme Corp. in Cambridge, Massachusetts. Its development was a complex process. Genzyme first partnered with Pharming Group NV who had managed to produce acid alpha-glucosidase from the milk of transgenic rabbits. They also partnered with a second group based at Duke University using Chinese hamster ovary cells. In 2001, Genzyme acquired Novazyme which was also working on this enzyme. Genzyme also had its own product (Myozyme) grown in CHO cells under development.
Fosphenytoin, also known as fosphenytoin sodium, and sold under the brand name Cerebyx among others, is a water-soluble phenytoin prodrug that is administered intravenously to deliver phenytoin, potentially more safely than intravenous phenytoin. It is used in the acute treatment of convulsive status epilepticus. Fosphenytoin was developed in 1996. On 18 November 2004, Sicor (a subsidiary of Teva) received a tentative approval letter from the United States Food and Drug Administration for a generic version of fosphenytoin. Medical uses
Fosphenytoin is approved in the United States for the short-term (five days or fewer) treatment of epilepsy when more widely used means of phenytoin administration are not possible or are ill-advised, such as endotracheal intubation, status epilepticus or some other type of repeated seizures; cluster seizure, vomiting, and/or the patient is unalert or not awake or both. Other
In 2003, it was reported that even though anticonvulsants are often very effective in mania, and acute mania requires rapid treatment, fosphenytoin had no antimanic effect. Metabolism
One millimole of phenytoin is produced for every millimole of fosphenytoin administered; the hydrolysis of fosphenytoin also yields phosphate and formaldehyde, the latter of which is subsequently metabolized to formate, which is in turn metabolized by a folate dependent mechanism. Side effects
Side effects are similar to intravenous phenytoin and include hypotension, cardiac arrhythmias, CNS adverse events (nystagmus, dizziness, sedation/somnolence, ataxia and stupor), and local dermatological reactions. Purple glove syndrome probably occurs with fosphenytoin but possibly at lower frequency than with intravenous phenytoin. Fosphenytoin can cause hyperphosphatemia in end-stage renal failure patients.