ORTHO’s SUPPRELIN HISTRELIN ACETATE INJECTION FOR PRECOCIOUS PUBERTY APPROVED DEC. 24; CONDITION AFFECTS 6,000 IN U.S. WITH 2,000 NEW DIAGNOSES ANNUALLY

Ortho Pharmaceutical's Supprelin (histrelin acetate) injection was approved by FDA on Dec. 24 for the treatment of children who develop secondary sexual characteristics before puberty. Central or unexplained precocious puberty affects an estimated 6,000 children in the U.S., with 2,000 more diagnosed each year, FDA noted in a Dec. 30 press release on the approval of Supprelin. The drug was granted orphan status in 1988. Histrelin acetate was given a "1A" (new molecular entity representing an important therapeutic gain over existing therapies) designation by FDA. Current therapies for precocious puberty have included the use of anti-androgens and progestins. However, the agency said, these other synthetic female and male hormones "have been more effective in reducing the early sexual changes than in slowing accelerated bone maturation." Ortho says it is "finalizing" marketing plans and pricing for Supprelin. Histrelin acetate is being manufactured for Ortho by Schering-Plough in Manati, Puerto Rico. Histrelin acetate, a synthetic nonapeptide agonist of the naturally-occurring gonatropin-releasing hormone (GnRH or LHRH -- leutenizing hormone/releasing hormone), has been shown in chronic administration studies to "control the secretion of pituitary gonadotropins resulting in decreased sex steroid levels and in the regression of secondary sexual characteristics in children with precocious puberty," approved labeling states. The decreases in sex steroids "are evident within three months of initiation of therapy," and "skeletal maturation is slowed and adult height predictions increase," labeling states. The most common form of the condition, idiopathic central precocious puberty, may occur in girls before the age of eight and in boys before the age of nine-and-one-half. For no known cause, secondary sexual characteristics may develop, such as enlarged breasts and menstruation in girls and penile growth and testicular development in boys. FDA noted that "although these children initially grow faster than other children, their bones mature only to a certain stage after which no further growth occurs, often resulting in failure to reach full adult height." Supprelin is to be administered once daily via a subcutaneous injection of 10 mcg/kg of body weight with the injection site varied daily. A patient insert and physician labeling stress the need to give the injection at the same time each day. Variance from the injection schedule or non-compliance "may result in inadequate control of the pubertal process," the warnings section states. Patients are to be monitored after three months and every six to 12 months thereafter, labeling notes. Therapy can be discontinued when the child reaches the appropriate age for puberty. The NDA (19-836) for Supprelin was filed on May 19, 1989. Histrelin acetate received an approval recommendation from FDA's Endocrinologic & Metabolic Drugs Advisory Committee on March 26, 1990 ("The Pink Sheet" April 2, 1990, T&G-4). The committee based its go-ahead recommendation on two pivotal open-label, uncontrolled trials in 183 children, of whom 80 were considered evaluable for efficacy. Treatment time ranged from 1.4 to 34 months. FDA's approval letter to the R. W. Johnson Pharmaceutical Research Institute, which conducted the clinical studies of Supprelin, notes that the company committed at the advisory committee meeting to "long-term follow-up of treated patients until each has achieved full reproductive potential and final height, i.e., until age 21 years or birth of first offspring." Adverse experiences reported in the clinical trials included: skin irritations at the injection sites (45%) and "vaginal bleeding (usually only one episode within one to three weeks after starting therapy lasting several days)" in 22% of the female patients. Other infrequent adverse reactions included hives, headache, nausea and vomiting.