URINE DRUG SCREENING RESULTS FROM VOLUNTEERS IN PHASE-I CLINICAL-PHARMACOLOGY STUDIES - ARE WE BEING MISLED

The general intent of phase I clinical pharmacology studies is to demo nstrate the safety and tolerability of investigational new drugs in he althy human volunteers. There is emerging evidence that people who vol unteer for these studies are not always truthful with investigators du ring the screening process. All healthy volunteers who participate in studies at the SmithKline Beecham Clinical Pharmacology Unit in Philad elphia, Pennsylvania, are required to submit to urine drug testing. Du ring 11 months of 1996, a total of 1,469 urine samples were collected and tested for eight different drugs or classes of drugs of abuse. The urine samples collected during the first five months of 1996 were all analyzed using EMIT (Syva Corporation) and interpreted according to t he guidelines established by the National Institutes of Drug Abuse (NI DA). Of 534 samples, 12 (2.2%) were reported as positive. During the l ast 6 months of 1996, a new methodology using a fluorescence polarizat ion immunoassay (FPIA) was used. This assay had lower limits of quanti fication than EMIT, and more stringent interpretation guidelines than those of the NIDA were used. Of 935 samples analyzed by FPIA, 89 (9.5% ) were positive. Of the 89 positive test results, 59 were below the cu t-offs specified by the NIDA guidelines and would have been reported a s negative. Interpretation of urine drug screen results according to t he NIDA guidelines is not acceptable for clinical pharmacology investi gations. (C) 1998 The American College of Clinical Pharmacology.