Clinical equivalence of intranasal and oral 17beta-estradiol for postmenopausal symptoms.
OBJECTIVE
The aim of this study was to demonstrate clinical equivalence between a novel intranasal estradiol formulation and a reference oral drug.


METHODS
In this multinational, double-blind, parallel-group study 659 postmenopausal women with moderate to severe postmenopausal symptoms were randomly assigned to receive either 300 microg/d intranasal 17beta-estradiol (S21400) or 2 mg/d oral micronized estradiol, plus the appropriate placebo, for 24 weeks. All patients also received 10 mg/d dydrogesterone for 14 days per 28-day cycle. Adjustment of intranasal dosage was permitted from week 14 on. The primary efficacy criterion was the Kupperman index at week 14, with a predefined limit of equivalence of 4.


RESULTS
Kupperman index scores improved similarly in the 2 groups, from 28.4 +/- 6.2 to 10.0 +/- 8.6 (mean +/- SD) for S21400 and from 28.1 +/- 6.0 to 8.9 +/- 8.0 for oral therapy, with a difference between groups at week 14 of 1.1 +/- 0.6 (90% confidence interval, 0. 0 to 2.2). This was below the predefined equivalence limit of +4 for statistical noninferiority (P <.001). The daily number and intensity of hot flushes decreased similarly in the two treatment groups. Withdrawal bleeding was 20% less frequent with intranasal therapy (90% confidence interval, 12.5 to 27.6). Severe mastalgia was less frequent in the S21400 group (1.0%) than in the group with oral therapy (5.2%; P <.01). Triglyceride and angiotensinogen levels increased significantly with oral therapy but not with S21400. The same number of patients required dose adaptation in the 2 groups (approximately 20%).


CONCLUSIONS
Intranasal administration of 300 microg/d estradiol was at least as effective as oral administration of 2 mg/d estradiol in alleviating postmenopausal symptoms, with less frequent mastalgia and uterine bleeding and without the metabolic consequences of the first-pass effect.
Mattsson
L A
LA
Department of Obstetrics and Gynecology, Sahlgrens University Hospital East, Göteborg, Sweden.
Christiansen
C
C
Colau
J C
JC
Palacios
S
S
Kenemans
P
P
Bergeron
C
C
Chevallier
O
O
Von Holst
T
T
Gangar
K
K
D000281:Administration, Intranasal; D000284:Administration, Oral; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D004394:Dydrogesterone / Q000627:therapeutic use; D004958:Estradiol / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000187:drug effects* / Q000502:physiology; D045167:Progesterone Congeners / Q000627:therapeutic use; D013810:Therapeutic Equivalency
D045167:Progesterone Congeners; D004958:Estradiol; D004394:Dydrogesterone