Pharmaceutical company PKC Pharma has published list of companies known to have sold the incorrect isomer of the kinase inhibitor bosutinib, which researchers are studying as a potential chemotherapeutic agent. As The Scientist reported earlier this month (see Mismarketed Chemical Causes Concern), inconsistent NMR spectra alerted the biochemical community that an incorrect isomer of bosutinib had entered the marketplace. PKC Pharma, after being notified that its own bosutinib was actually the incorrect isomer, began purchasing and testing bosutinib from different vendors to learn how many may have unwittingly sold an incorrect form of bosutinib. This week (May 23), the company listed 17 vendors on its website that it says sold the incorrect isomer, verified by several tests including proton NMR.
PKC Pharma, which had distributed bostunib bought from other suppliers, will seek refunds from companies that supplied the incorrect isomer, said President Paul Driedger, and has already sent letters offering refunds or replacements to PKC Pharma’s customers. One company on PKC Pharma’s list, Selleckchem, has already switched to the correct isomer. General Manager Graham Dong said that to his knowledge, any incorrect isomer purchased had already been replaced with the correct bosutinib isomer synthesized by Selleckchem. Although companies may not welcome appearing on PKC Pharma’s list, “We’re willing to stand by our data,” said Driedger, who noted that his company had also produced an X-ray crystallography of the incorrect isomer, verified by three experts.