Therefore, development costs will be higher and there will be far fewer biosimilars developed than generic versions of small molecule drugs.

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Second, large drug companies are trying to avoid traditional small molecule drugs that will face large generic uptake after their patents expire.

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Now the company is focusing on testing whether can improve side effects and usefulness in small molecule drugs, including ones for several old chemotherapy medicines.

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The Genzyme acquisition is really a bet that in the future drug companies will need stable businesses like vaccines and consumer health that are insulated from the sudden drops of sales that happen with traditional small molecule drugs in the U.S. market.

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Protein drugs like Enbrel are much more expensive to make than traditional small-molecule drugs, and Thousand Oaks, Calif.

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And they might be more lucrative than generic versions of small-molecule drugs, if the complexity of developing these larger molecules limits competition.

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Similar expirations have spawned a large generic industry around so-called small-molecule drugs and the same can occur for genetically engineered products that are proprietary and highly profitable today, Konski said.

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Because most small-molecule drugs can be manufactured with easily replicable chemical processes that lead to a largely reproducible drug formulation, the clinical trial data that supported approval of the original version can be relied upon for the generic versions.

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