A study in today’s Lancet suggests that Merck’s Mectizan (ivermectin) is beginning to develop resistance issues. Mectizan has been the primary weapon in the world’s fight against river blindness, or onchocerciasis.

Mectizan has also been at the cornerstone of Merck’s public image efforts. The company has donated hundreds of millions of dollars worth of the product over the last 20 years and ingratiated itself with the likes of Jimmy Carter. More detail in What Ever Happened to Mectizan?

The issue of emerging resistance calls for the need for new and varied drugs to treat a host of microbial pathogens. Relying on a single agent is a recipe for resistance.