The pharmaceuticals company, Roche, has won regulatory approval from the Swiss authorities for its hepatitis C treatment, Pegasys.
Switzerland is the first country to admit the drug, which was supposed to be the Basel-based firm's major launch this year.
Analysts in the pharmaceuticals sector say the development is important as it paves the way for the medicine to be passed in many Latin American countries which recognise Swiss decisions.
The verdict could help speed up global sales of the Interferon drug that it expected to generate turnover of up to SFr1 billion ($580 million) a year. It will be an important addition to Roche's palette at a time when the company has been hit by sluggish sales.
Pegasys uses a molecule developed by the US company, Shearwater Corporation. It received a setback in April when the US Food and Drug Administration said it wanted to see more information on its clinical trials.
The delay has allowed US rival, Schering-Plough, to gain a head start with its hepatitis C treatment, Rebetol.
Hepatitis C, a viral infection that can cause fatal liver problems, affects around 170 million people around the world.
swissinfo with agencies