And Pegasys is the only product in its class approved for use in patients who already have cirrhosis of the liver, meaning that nonfunctioning scar tissue has replaced normal liver tissue.

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In Peyronie's disease, problems in the normal wound-healing process result in permanent scar tissue.

CNN: Peyronie's disease

Tissue cells, instead of performing the normal self-repair of damaged tissue, begin laying down excessive layers of collagen to help build a scar.

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