The drug: Gleevec
The company: Novartis
Estimated worldwide sales 2012: $4.72 billion

Gleevec has been referred to as a miracle drug, and some might say that is has been such for Novartis ($NVS) as well as for patients. It is one of the revolutionary drugs that has transformed some blood cancers into chronic illnesses rather than death sentences.

And it is a drug the gift that just keeps on giving. It was approved for gastrointestinal stromal tumors in 2002, and every few years it seems to get approval for a new use. There were a string of them in 2006. In 2011, it was OK'd for chronic myelogenous leukemia, and this year it was as an adjuvant GIST treatment.

And researchers keep looking for new uses. For example, a recent study found that Gleevec as well as Novartis' ($NVS) leukemia drug Tasigna, attacked the highly lethal Ebola virus in lab tests, providing clues  about what it might take to finally march forward with a treatment  against the killer bug.

With more uses has come increasing sales and IMS Health estimates Gleevec sales will actually grow this year, from $4.1 billion last year. The  drug will stay on patent until 2015, which should keep earnings stable.

For more:
Special Report: Gleevec - Top 10 Best-selling Cancer Drugs in 2011
Novartis swings for fences in battle over Gleevec patent in India
Pfizer nabs another targeted cancer drug OK from FDA
Novartis cancer drugs stymie deadly Ebola virus
Kedem adapting Novartis' Gleevec to dissolve under tongue