Effectiveness of dorzolamide–timolol (COSOPT) in patients who were treatment naive for open-angle glaucoma or ocular hypertension: the COSOPT first-line study.
OBJECTIVE
The aim of this study was to assess the effectiveness of dorzolamide-timolol (DT) in the management of open-angle glaucoma (OAG) and ocular hypertension.


METHODS
An open-label, 12-week, multicenter, Canadian study was conducted. Patients with untreated OAG or ocular hypertension received DT for 12 weeks to reduce intraocular pressure (IOP). If target IOP was not reached after the first 6-week treatment period, a prostaglandin (PG) (latanoprost) was added for the remaining 6 weeks. Primary outcome measures were changes in IOP from baseline to 6 and 12 weeks of treatment, and secondary outcome measures included the proportion of patients achieving target IOP and the proportion of patients achieving therapeutic response defined as a reduction of 5.0 mmHg or 20% in IOP from baseline. IOP values were the mean of 2 measures taken before and at least 2 h after patients administered the study medication.


RESULTS
A total of 164 patients were enrolled. Mean [standard deviation (SD)] population age was 63.0 (12.3) years and 53.0% of the patients were men. At week 6, the mean (SD) absolute and percent change in IOP for the total population was (-11.1) (4.9) and (-36.4)% (13.9%), respectively, and 92.1% of the patients achieved a reduction in IOP of at least 5 mmHg. Therapeutic target was achieved by 136 (82.9%) patients (DT subgroup) at 6 weeks, whereas 28 (17.1%) patients were changed to a combination therapy of DT and latanoprost [DT plus PG (DT & PG) subgroup]. Between weeks 6 and 12, DT was effective in sustaining the IOP within therapeutic target, whereas addition of latanoprost reduced the IOP of the DT & PG subgroup by an additional 6.3 mmHg or 22.1% (20.1%). At week 12, patients in the DT subgroup experienced a clinically and statistically significant mean (SD) decrease in IOP from a baseline of 12.2 mmHg or 40.4% (11.9%) (P < 0.001), whereas these values corresponded to 13.4 mmHg and 39.7% (15.7%) (P < 0.001), respectively, in the DT & PG subgroup. The proportion of patients who achieved therapeutic response during the entire 12-week study period was over 82%. Treatment-related adverse events (AEs) were reported by 19 (14.0%) patients in the DT subgroup and by 6 (21.4%) patients in the combination subgroup. Eye disorders and nervous system disorders were among the most common treatment-related AEs in both subgroups. No serious AEs were reported during the study period.


CONCLUSIONS
DT alone and DT in combination with a PG are effective in significantly reducing IOP in patients with untreated OAG or ocular hypertension. The treatment was safe and well tolerated with a low incidence of AEs.
Crichton
Andrew C S
AC
Faculty of Medicine, University of Calgary , Calgary, Canada.
Harasymowycz
Paul
P
Hutnik
Cindy M L
CM
Behki
Rama
R
Boucher
Serge
S
Ibrahim
Fahim
F
Rifkind
Aaron W
AW
Solomon
Leon
L
Liao
Chuanhong
C
Bastien
Natacha R
NR
Sampalis
John S
JS
D000368:Aged; D004338:Drug Combinations; D005123:Eye / Q000503:physiopathology; D005260:Female; D005901:Glaucoma / Q000188:drug therapy; D005902:Glaucoma, Open-Angle / Q000188:drug therapy*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D000077338:Latanoprost; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D009798:Ocular Hypertension / Q000188:drug therapy*; D009883:Ophthalmic Solutions / Q000008:administration & dosage / Q000494:pharmacology; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D013449:Sulfonamides / Q000009:adverse effects / Q000494:pharmacology*; D013876:Thiophenes / Q000009:adverse effects / Q000494:pharmacology*; D013999:Timolol / Q000009:adverse effects / Q000494:pharmacology*; D014065:Tonometry, Ocular; D016896:Treatment Outcome
D004338:Drug Combinations; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic; D013449:Sulfonamides; D013876:Thiophenes; C479140:dorzolamide-timolol combination; D000077338:Latanoprost; D013999:Timolol