Efficacy and tolerability of the dorzolamide 2%/timolol 0.5% combination (COSOPT) versus 0.005% (XALATAN) in the treatment of ocular hypertension or glaucoma: results from two randomized clinical trials.
OBJECTIVE
To compare the efficacy of the fixed dorzolamide 2%/timolol 0.5% combination (COSOPT) versus latanoprost 0.005% (XALATAN).


METHODS
Two 3-month, parallel group, randomized, observer-masked and patient-masked, multicentre, clinical trials were performed in patients with ocular hypertension or open-angle glaucoma. Study 1 (n=256) was conducted in the United States and Study 2 (n=288) was conducted in Europe/Israel. Patients could be included whether or not they were currently taking ocular hypotensive therapy, and regardless of the effectiveness of any previous therapy. Patients were washed out from their usual ocular hypotensive medications and then those with a baseline intraocular pressure (IOP) >/= 24 mmHg were randomized to either the dorzolamide/timolol combination eye drops twice daily or latanoprost eye drops once daily in both eyes. Efficacy was assessed by daytime diurnal IOP (the mean of measurements made at 0800, 1000, 1400 and 1600 h).


RESULTS
At baseline, the mean daytime diurnal IOP was 26.1 mmHg in the dorzolamide/timolol combination group versus 25.6 mmHg in the latanoprost group in Study 1, and 25.3 mmHg in the dorzolamide/timolol combination group versus 24.7 mmHg in the latanoprost group in Study 2. After 3 months, the mean daytime diurnal IOP was 18.9 mmHg for the dorzolamide/timolol combination versus 18.4 mmHg for latanoprost in Study 1, and 17.4 mmHg for the dorzolamide/timolol combination versus 17.5 for latanoprost in Study 2. The difference between treatments in mean IOP change at 3 months was -0.04 mmHg [95% confidence interval (CI) -0.85, 0.77] in Study 1, and -0.57 mmHg (95% CI -1.31, 0.16) in Study 2. The probability that the true difference lay between -1.5 and 1.5 mmHg, the predefined bounds for equivalence, was >0.950 in both studies. Both treatments were well tolerated over 3 months, although ocular stinging occurred more frequently with the dorzolamide/timolol combination.


CONCLUSIONS
The dorzolamide/timolol combination and latanoprost were equally effective at lowering IOP.
Glaucoma Division, New Jersey Medical School, UMDNJ, Newark, NJ 07101-1709, USA. Fechtner@UMDNJ.edu
Robert D
RD
Fechtner
P Juhani
PJ
Airaksinen
Albert J
AJ
Getson
Christopher R
CR
Lines
Ingrid A
IA
Adamsons
D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D004338:Drug Combinations; D005260:Female; D005902:Glaucoma, Open-Angle / Q000188:drug therapy*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D000077338:Latanoprost; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000188:drug therapy; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D012449:Safety; D013449:Sulfonamides / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D013876:Thiophenes / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D013999:Timolol / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D016896:Treatment Outcome
D000959:Antihypertensive Agents; D004338:Drug Combinations; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic; D013449:Sulfonamides; D013876:Thiophenes; C479140:dorzolamide-timolol combination; D000077338:Latanoprost; D013999:Timolol