Hi cheri,
Amgen makes both drugs. Neulasta is a modern drug and stays longer in the body because it has a large chemical called polyethylene glycol (or PEG) added to one end of the Neupogen molecule. At the same time Neulasta is difficult to monitor - if you for example get pain from the joints the adverse effect will last much longer.
http://www.neulasta.com/patient/howc..._neupogen.html
When I have tried different drugs for iron overload like Ferriprox (not approved in the US) and a normal dose of Exjade I have been taking Neupogen every day to increase the very low WBCs. The same thing happened when I started to take Thalidomide 50 mg/day - I can only take 50 mg 4 times/week.
Kind regards
Birgitta-A