PFIZER’s ZOLOFT IS SECOND SEROTONIN REUPTAKE INHIBITOR ANTIDEPRESSANT APPROVED BY FDA AFTER LILLY’s PROZAC; LAUNCH SCHEDULED FOR FIRST QUARTER 1992

Pfizer will back its first quarter launch of the antidepressant Zoloft (sertraline) with over 1,200 sales reps from the company's Roerig and Pratt marketing subsidiaries. Zoloft was approved by FDA on Dec. 30. Zoloft enters a potentially large and growing antidepressant market as the second serotonin reuptake inhibitor to be approved after Lilly's Prozac (fluoxetine). FDA designated Zoloft (sertraline) a "1C" drug, indicating a new chemical entity with little or no gain over existing therapies. Pfizer did not disclose its pricing plans for the drug. The Zoloft NDA underwent a three-and-a-half year review at FDA; Pfizer submitted the NDA on April 13, 1988. The company received a positive review by FDA's Psychopharmacological Drugs Advisory Committee on Nov. 19, 1990 ("The Pink Sheet" Nov. 26, p. 3). Sertraline is already marketed in the U.K. and Ireland under the trade name Lustral. According to the approved labeling, the recommended starting dose for Zoloft is 50 mg once a day. The labeling adds: "While a relationship between dose and antidepressant effect has not been established, patients were dosed in a rage of 50-200 mg/day in the clinical trials demonstrating the antidepressant effectiveness of Zoloft. Consequently, patients not responding to a 50 mg dose may benefit from dose increases up to a maximum of 200 mg/day." The drug is available in both 50 mg and 100 mg scored tablets. Zoloft can be administered either in the morning or the evening. The possible difference between morning and evening dosage regimens was an issue that concerned the advisory committee at its November 1990 meeting, but was apparently resolved by Pfizer in subsequent studies. The advisory committee also found Pfizer's long-term maintenance study data inconclusive. The labeling notes that "while there are insufficient data regarding any benefits from treatment beyond 16 weeks, it is generally agreed among expert psychopharmacologists that acute episodes of depression require several months or longer of sustained pharmacological therapy. Whether the dose of antidepressant needed to induce remission is identical to the dose needed to maintain and/or sustain euthymia is unknown." The labeling recommends that physicians who prescribe Zoloft for periods longer than 16 weeks "should periodically reevaluate the long-term usefulness of the drug for the individual patient." Zoloft's approval follows a storm of controversy directed at Prozac by the Church of Scientology in an aggressive media campaign seeking removal of the drug from the market because of its alleged potential to increase suicidal ideation in patients. However, FDA's Psychopharmacological Drugs Advisory Committee determined at a Sept. 20 meeting that there was no credible evidence to show a causative link between Prozac and suicidal ideation or behavior ("The Pink Sheet" Sept. 23, p. 3). The committee did not recommend any changes to Prozac's labeling. The "Precautions" portion of the Zoloft labeling contains a notice on suicide similar to the labeling for Prozac. The Zoloft precaution states that "the possibility of suicide attempt is inherent in depression and may persist until significant remission occurs" and recommends "close supervision" of at-risk patients. The principle adverse reactions in 2,710 Zoloft-treated patients were nausea, headaches, and diarrhea. The psychiatric adverse reactions reported in Zoloft's labeling include insomnia (16.4% vs. 8.8% for placebo), agitation (5.6% vs 4%) and nervousness (3.4% vs. 1.9%). Overall, 15% of Zoloft-treated patients discontinued therapy due to adverse events. The approval letter for Zoloft asks Pfizer to perform safety and efficacy studies of the drug in children and adolescents. The agency said "it is likely that sertraline will be used in children and adolescents, despite the absence of any relevant data" and that studies "would be useful." The letter also states that Pfizer has agreed to carry out post-marketing studies of the effects of hepatic and renal impairment on sertraline's pharmacokinetics.