A brand-name drug maker such as GlaxoSmithKline (GSK) which makes Zofran has the exclusive right to sell and market that drug so long as it enjoys patent protection. Zofran enjoyed this privilege in the United States between January 4, 1991 and mid-2007. By that time the relevant patents had expired and the 180 day grace period following patent expiration had also lapsed.
There were several generic drug manufacturers who were ready and willing to make generic Zofran right away. It is important to remember that Zofran is just a brand name for the drug substance is chemically known as ondansetron. GSK copyrighted the name Zofran, and no other drug company--generic or otherwise--can use the name Zofran without its permission. That is why all the generic companies making this drug use the name ondansetron.
Compared with getting FDA approval for a brand new drug, the process for getting generic drug approval from the FDA a is relatively easy. The generic maker files what is called an Abbreviated New Drug Application (ANDA). To receive the FDA permission to sell a generic drug, that company's ANDA must establish that the generic drug is identical to the brand name drug (also called the reference listed drug or RLD) with respect to: (1) route of administration, (2) active ingredients, (3) strength, (4) dosage form, and (5) conditions of use recommended in the labeling.
The FDA approves an ANDA application only if the generic drug is the "same as" the brand name drug. The FDA has defined "same as" to mean "identical." Generic drugs' labeling must also remain the "same as" the brand name drug at all times after the ANDA approval.
Since 2007, there have been nearly 50 approved ANDAs to sell generic Zofran (ondansetron). Sadly, and due to the FDA regulation requiring generic Zofran labeling to be the "same as" brand name Zofran, there is no difference in the generic drug information that is provided about expectant mothers taking Zofran during pregnancy. It is identical to the brand name label.
The FDA has recommended a change in the labeling rules that would give generic drug makers the latitude to change their labels whenever they think it is prudent to do so. A final decision on that rule will be made later this year.