Results of Two Phase 3 Studies of Investigational Prostate Cancer Drug in Early and Late-Stage Patients Announced at AUA
ANAHEIM, Calif.--(BUSINESS WIRE)--June 4, 2001--Amgen (NASDAQ: AMGN - news) and PRAECIS PHARMACEUTICALS INCORPORATED (NASDAQ: PRCS - news) today announced data from two phase 3 clinical trials that assess the ability of abarelix for injectable suspension to reduce serum prostate specific antigen (PSA) levels and testosterone levels compared with standard hormonal therapy. Both studies also evaluated the frequency of hormonal ``surge,'' an initial increase in testosterone and other hormonal levels, at the start of therapy. The results were presented at the annual meeting of the American Urological Association.
Abarelix, a gonadotropin releasing hormone (GnRH) antagonist, is under priority review by the U.S. Food and Drug Administration for the treatment of prostate cancer.
In a head-to-head, randomized, multicenter phase 3 study (Zinner et al) of 271 patients with early and late-stage prostate cancer, those administered abarelix (n=180) experienced a median percent reduction from baseline in serum PSA of 50 percent after two weeks of treatment and 75 percent after four weeks compared with a median percent reduction of 15 percent after two weeks and 61 percent after four weeks for those treated with the comparator, leuprolide acetate (n=91). At day 85, both patient groups had achieved a greater than 90 percent reduction in serum PSA levels.
In measuring time to reduce testosterone to a targeted level (less than or equal to 50 ng/dL), 72 percent of abarelix-treated patients achieved the level by day eight compared with none of the leuprolide acetate-treated patients. None of the abarelix patients experienced a surge of testosterone compared with 82 percent of the leuprolide acetate patients. On day two, patients treated with abarelix had median changes compared to baseline of 84 percent reduction for testosterone, 80 percent reduction for luteinizing hormone (LH) and 38 percent reduction for follicle-stimulating hormone (FSH). Patients treated with leuprolide acetate experienced a median change compared to baseline of 45 percent increase for testosterone, 369 percent increase for LH and 100 percent increase for FSH. From day 29 through day 85, both patient groups achieved the targeted testosterone level.
``Testosterone fuels the growth of prostate cancer cells,'' said Dr. Norm Zinner, a urologist at Western Clinical Research, Inc., in Torrance, Calif. ``A surge in testosterone may stimulate tumor cell growth, elevate PSA levels and potentially worsen the symptoms of cancer during the first weeks of treatment.''
In a second head-to-head, randomized, multicenter phase 3 study (Pessis et al) of 251 early and late-stage prostate cancer patients, 68 percent of patients administered abarelix (n=168) achieved a reduction in testosterone to a targeted level (less than or equal to 50 ng/dL) after one week of therapy versus none of the patients administered a combination of leuprolide acetate plus bicalutamide (n=83). All patients receiving abarelix avoided testosterone surge compared with 14 percent of patients receiving the combination. All patients in each treatment group achieved a 50 percent reduction from baseline in serum PSA at 24 weeks.
In these clinical trials, the most frequently reported adverse events were associated with physiological effects of lowered testosterone and included hot flashes, breast enlargement, breast pain/nipple tenderness and headache. The incidence of allergic events that required medical intervention was similar in the active control and abarelix groups.
Measuring Testosterone, Pain and Other Symptoms in Advanced Metastatic Disease
A separate single-arm study (Koch et al) evaluated 72 advanced symptomatic prostate cancer patients with bone pain from skeletal metastases (n=31), enlarged prostate gland or pelvic mass (n=25), urinary tract obstruction (n=9), or impending neurological compromise (n=6). Of these, 57 patients (79 percent) achieved a targeted level (less than or equal to 50 ng/dL) of testosterone after one week on abarelix and 68 patients (94 percent) after four weeks. In addition, serum levels of PSA, LH and FSH were suppressed from baseline levels throughout treatment. All patients avoided surgical removal of the testicles through day 85.
This study also evaluated the level of pain and need for narcotic analgesic use in 36 patients who had pain. The median Visual Analog Scale (VAS) pain score, measured on a continuous scale of zero (no pain) to 10 (worse pain), declined from 4.4 at baseline to 0.7 on day 85. The frequency, dose and/or potency of analgesic use decreased in 13 of the 19 patients using these medications at study entry.
Prostate cancer is the most common cancer (excluding skin cancer) in American men. One out of 10 American men will develop the disease at some point in his life, most after age 65. This year alone in the United States, an estimated 198,100 new cases of prostate cancer will be diagnosed and 31,500 men in this country will die of the disease. The prostate is a small, walnut-shaped gland at the base of the male bladder that secretes a major constituent of ejaculatory fluid.
Amgen is a global biotechnology company that discovers, develops, manufactures and markets important human therapeutics based on advances in cellular and molecular biology.
PRAECIS PHARMACEUTICALS INCORPORATED is a biotechnology company focused on the discovery and development of pharmaceutical products using its proprietary LEAP(TM) (Ligand Evolution to Active Pharmaceuticals) technology. |
