The follow-on patent would cover not only Alimta's basic compound but a method of administering that drug along with certain vitamins designed to mitigate side effects. So The Wall Street Journal reports.
Defending “secondary patents” like the patent on Alimta's vitamin regimen is a way for Big Pharma companies to extend their exclusive rights to sell successful drugs. However, generic-drug companies have historically had significant success arguing that such follow-on patents should be struck down because their claims were anticipated by prior, publicly available research.