LISINOPRIL CLEARS FDA AFTER 20-MONTH REVIEW; MERCK SECOND-GENERATION ACE PRODUCT WILL BE COMARKETED BY STUART; FIRMS HEAVILY PROMOTING BRANDS TO MDs

Merck's Prinivil (lisinopril), enters the market as the first ACE inhibitor to carry a one-a-day dosage schedule. The drug will be comarketed by its developer/sponsor Merck as Prinivil and licensee Stuart under the brand name Zestril. Lisinopril, the third ACE inhibitor to reach the market, was approved by FDA on Dec. 30. "Prinivil is indicated for the treatment of hypertension," approved labeling states. "It may be used alone as initial therapy or concomitantly with other classes of antihypertensive agents. The labeling notes that lisinopril "was approximately equivalent to atenolol (Stuart's Ternomin) and metoprolol (Ciba-Geigy's Lopressor) in effects on diastolic blood pressure and had somewhat greater effects on systolic blood pressure." The approval of the second generation ACE inhibitor marks another quick trip for Merck through the FDA review process. Lisinopril's NDA for both congestive heart failure and hypertension was filed in April 1986. At its October meeting, FDA's Cardio-Renal Drugs Advisory Committee did not review the hypertension claim but requested an additional placebo-controlled study for approval of the congestive heart failure indication. Merck and Stuart have been aggressively promoting the brands for the upcoming launch into the $1 bil. ACE inhibitor market. In an attempt to establish brand identity among prescribing physicians, both firms have been running full and half-page pre-approval ads in the major medical journals. One example of the pre-approval promotion is a three-page Merck ad appearing in the Dec. 25 edition of The New England Journal of Medicine. The ad instructs doctors to write the brandname "Prinivil" in a cutaway and offers a character analysis of the physician's writing sample. Stuart said it will promote Zestril with the ICI Pharma sales force it established in March. At that time, the company announced plans to add another 150 reps to its existing 750-rep detail force. Merck has about the same number of sales reps in its cardiovascular products marketing group. Merck, which has a one-price policy, is pricing 100-tablet bottles of 5 mg, 10 mg and 20 mg Prinivil at $54.36, $56.05 and $58.85, respectively. Stuart said its suggested prices to wholesalers for similar doses and package sizes of Zestril are $47.71, $53.02 and $55.67, respectively. Both products should reach pharmacy shelves by mid-January. For hypertension, lisinopril's once-a-day dosing offers a distinct advantage over the other two ACE inhibitors on the market, Squibb's Capoten (captopril) and Merck's Vasotec (enalapril), both of which require administration three or four times daily. Merck faces a positioning dilemma with Vasotec, the fast-growing product with estimated 1987 worldwide sales of $500 mil., mostly for hypertension. The company must try to build physician acceptance of Prinivil without cannibalizing Vasotec. Vasotec's indication as a last-resort treatment of congestive heart failure may be upgraded to primary therapy. MERCK's PRINIVIL -- DOSAGE AND ADMINISTRATION [Information excerpted from FDA-approved labeling] Initial Therapy: In patients with uncomplicated essential hypertension not on diuretic therapy, the recommended initial dose is 10 mg once a day. Dosage should be adjusted according to blood pressure response. The usual dosage range is 20 to 40 mg per day administered in a single daily dose. The antihypertensive effect may diminish toward the end of the dosing interval regardless of the administered dose, but most commonly with a dose of 10 mg daily. This can be evaluated by measuring blood pressure just prior to dosing to determine whether satisfactory control is being maintained for 24 hours. If it is not, an increase in dose should be considered. Doses up to 80 mg have been used but do not appear to give a greater effect. If blood pressure is not controlled with Prinivil alone, a low dose of a diuretic may be added. Hydrochlorothlazide 12.5 mg has been shown to provide an additive effect. After the addition of a diuretic, it may be possible to reduce the dose of Prinivil.