ZENECA’s ZOLADEX SIDE EFFECTS IN ENDOMETRIOSIS PATIENTS

ZENECA's ZOLADEX SIDE EFFECTS IN ENDOMETRIOSIS PATIENTS "much more tolerated" than side effects from danazol, John Rock, MD, Emory University, declared at a Nov. 18 Zeneca press conference in New York City to launch gosarelin acetate for the endometriosis indication. Zoladex 3.6 mg once-monthly implant has been on the market for endometriosis since last month; the gonadotropin- releasing hormone agonist received a supplemental NDA approval on Feb. 2. Journal ads for endometriosis therapy began in the October/November issues of four major OB/GYN journals. At the press conference, Rock described one of three Zoladex studies submitted to FDA in the supplemental. The study found that Zoladex patients reported more frequent hypoestrogenic effects, such as hot flashes, vaginal dryness, headache and decreased libido; danazol patients in the study reported higher incidences of androgenic effects, such as acne, oily skin and hair, weight gain and hirsutism. The open, randomized, parallel, multicenter trial in the U.S. and Canada comprised 24 weeks of treatment and 48 weeks of follow- up with Zoladex and danazol in the treatment of endometriosis. In the study, 208 patients were treated with a Zoladex 3.6 mg implant every 28 days via subcutaneous injection and 107 women with danazol 400 mg orally twice a day for 24 weeks. In a standard regimen, Zoladex injections with the absorbable pellet are given every 28-30 days for six months. Treatment was deemed successful in patients who experienced a 50% or greater reduction in the revised American Fertility Society (AFS) score (an indicator of the degree of endometriosis) from the pretreatment value. The mean percent reduction in the revised AFS score after 24 weeks of treatment was 53% in the Zoladex group compared to 33% in the danazol group, which was not statistically significant. Another study did find a statistically significant difference in favor of Zoladex in AFS scores. A Zeneca fact sheet notes that Zoladex "may pose an additional risk...in women with major risk factors for decreased bone mineral density." After six months of treatment, 97 women had an average 4.6% decrease in vertebral trabecular bone mineral density (BMD) from pretreatment. Of the 44 patients assessed for BMD loss in a six-month post- treatment follow-up, the average loss was 2.6% compared to pretreatment values, suggesting a "possibility of partial reversibility." Fifteen patients (7.2%) in the Zoladex cohort and 18 (16.8%) in the danazol group withdrew from the study. Six (2.9%) Zoladex patients and 13 (12.1%) danazol patients withdrew because of adverse events. The study notes that the "most common reason for withdrawal after treatment was for ovulation induction therapy." The average wholesale price for Zoladex is $331.50, Zeneca said. This compares to $360.65 AWP for TAP's Lupron, a competing GnRH agonist for endometriosis, the firm noted. Zoladex has been marketed as an injectable since 1990 for advanced prostate cancer. Zeneca also presented the results of a study it commissioned Roper Starch Worldwide to conduct on endometriosis in America at the press conference. The condition has been diagnosed in approximately 5% of adult women (5 mil.) in the U.S. Results of the survey were presented by Roper Starch Senior VP Nicholas Tortorello, who said the survey found that among endometriosis patients, 46% suffered from symptoms for at least two years before diagnosis and 32% suffered for over three years. Tortorello commented that the "delay may often be due to misdiagnosis" or to a "general difficulty" in properly diagnosing the condition. One-quarter (26%) of patients reported having their condition misdiagnosed; ovarian cysts, pelvic inflammatory disease and psychological problems were some of these misdiagnoses. Nearly one-third (30%) of patients saw two or more health care providers before receiving the correct diagnosis, and 22% saw three or more, the survey found. Reporting time absent from work due to symptoms of the disease, 36% of patients said they miss two or more days per month, and 14% said they miss four or more days. On the whole 56% of patients said they have missed work because of endometriosis. Tortorello noted that Roper Starch will attempt to calculate the economic loss due to missed days. The survey also found that 31% of respondents said they were unable to conceive at some point because of endometriosis. Zeneca plans to incorporate the survey results into its marketing scheme for Zoladex.