Important trials in Glaucoma

IMPORTANT TRIALS IN GLAUCOMA

Presenter-Dr RavneetModerator- Dr Hetal Shah

Dr Rita Dhamankar Dr Vijay Shetty

Landmark studies in glaucoma

Ocular Hypertension Treatment study (OHTS)Collaborative Initial Glaucoma treatment Study

(CIGTS)

Advanced Glaucoma Intervention Study (AGIS)Early Manifest Glaucoma trial (EMGT)

Collaborative Normal Tension Glaucoma (CNTGS)Tube versus Trabeculectomy study (TVT)

European Glaucoma prevention study(EGPS)Low Tension Glaucoma prevention Study(LoGTS)

Ocular Hypertension Treatment study (OHTS)

3 Arch Ophthalmol 120: 701-713, 2002.


Objective:To evaluate the safety and efficacy of topical

ocular hypotensive medications in preventing or delaying onset of visual field loss and or optic nerve damage in subjects with ocular hypertension.

Identify baseline demographic and clinical factors that predict which participants will develop POAG

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Participants: 1637 patients with ocular hypertension

recruited between 1994 and 1996

Study design:Multicentre randomized controlled

clinical trial comparing observation with medical therapy for ocular hypertension.

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Methods:

1637 participants

no evidence of glaucomatous damage,

40 to 80 years

IOP 24 mmHg - 32 mmHg in one eye

21mmHg and 32 mmHg in other eye

The goal in the medication group was to reduce the IOP by 20% or more and to reach an IOP of 24 mmHg or less.


OHTS Phase 1Begins February 28, 1994

Eligibility Criteria

MedicationTopical treatment to lower IOP 20%

and IOP < 24 mm Hg

ObservationNo topical treatment to lower IOP

Randomization

Reproducible Abnormality3 consecutive visual fields and/or 2 consecutive sets of optic disc photographs

MonitoringHumphrey 30-2 q6 months

Stereoscopic disc photos annually

POAGVisual field and/or optic disc changes attributed to

POAG

Adjust therapy if target not met


Results :At 5 years followup

Incidence of POAG

9.5% in controls

4.4% in treatment group

22.5% decrease in IOP in the treatment group

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OHTS Summary of results

CCT < 555 & IOP > 25 CCT < 555 & CD > 0.5 Risk 36% Risk 22% CCT > 588 &IOP > 25 CCT > 588 & CD >0.5 Risk 6% Risk 8%


Increased risk of the onset of POAG was associated with:

Increased age

Vertical and horizontal cup disc ratio

Pattern standard deviation

IOP at baseline

Central corneal thickness (CCT) was found to be a powerful predictor for the development of POAG.


The corneas in OHTS subjects were thicker

lower corneal thickness in black subjects than whites.

The effect of CCT may influence the accuracy of applanation tonometry in the diagnosis, screening and management of patients with glaucoma and ocular hypertension.

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Clinical useful points from OHTS

OHT – What to do * Treat all * Treat no one * Treat some -- Is treatment effective

DOES OHTS HAVE ANSWERS FOR THIS

Clinical useful points from OHTSTreat only patients at high risk.

Risk factors – risk calculator www.discoveriesinsight.orgImportance of CCTONH & VF monitoring at every FUStudy – Rx effective , of the 9.6% that

converted half could be prevented by Rx

OHTS - ? Conversion after longer FU

Age Vertical C/D

IOP DM+

CCT PSD

If not high risk waiting to treat OHT till conversion- better strategy ( vision related QOL)

http://www.discoveriesinsight.org/

OHTS PHASE2

March 2010

OHTS Phase 2

Medication GroupN = 694

Medication is continued in the Medication group

OHTS Phase 2N = 672

Medication is Initiated in the Observation group

OHTS Phase 2: Rationale OHTS Phase 1 provides proof of

concept: medication reduces the incidence of POAG.

OHTS Phase 1 does not indicate when medication should begin.

OHTS Phase 1 does not indicate if all OHT patients should receive early medication.

OHTS Phase 2: MethodsAfter 7.5 years of observation, participants

originally randomized to observation group start medication.

This creates:Delayed treatment group Observation group followed for 7.5 years then treated for 5.5

years

Early treatment groupMedication group treated for median of 13 years from the

beginning

Compare incidence of POAG at 13.0 years

OHTS PHASE 2 RESULTS Median Time to develop POAG:Observation group-6 yrsMedication group-8.7 yrsIncreased cumulative incidence of POAG at

13 yrs(22% vs 16%)More eyes with structural and functional

damage(8% vs 5%)More participants with bilateral disease (6%

vs 4%)


The primary purpose of the follow up study was to determine whether delaying treatment resulted in persistently increased risk of conversion to glaucoma, even after the initiation of therapy.

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Implications:Ocular hypertensives can be seperated into

categories of high,medium & low risk.

People with high risk factors may benefit from close followup and early treatment

Low risk patients can have less frequent followup and may not need early treatment.

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Ocular Hypertension Treatment study (OHTS

Subjects with corneal thickness of 555μm or less had three times the risk of developing primary open-angle glaucoma compared with those who had corneal thickness of 588μm or more.

Therefore, measure central corneal thickness of all new glaucoma suspects.

Early Manifest Glaucoma trial (EMGT)

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Purpose:To compare the effect of immediate therapy

to lower the intraocular pressure versus late or no treatment on the progression of newly detected open-angle glaucoma,as measured by increasing visual field loss and or optic disc changes

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Participants:Newly diagnosed POAG patients (255)

50 to 80 years of age

255 patients were randomized between 1993 and 1997.

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Study design:

Multicenter randomized controlled

clinical trial comparing observation with

betaxolol and argon laser trabeculoplasty

for OAG.

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EMGT• Randomised to

-ALT and betaxolol-No treatment

• If IOP >25mmHg in treated (>35 untreated)→ Latanoprost added

• If remains high → individualised treatment


Results:At 6 years, 62% of untreated patients showed

progression, whereas 45% of treated patients progressed. Treatment reduced IOP by 25%.

Median time to progression 66 months in treated versus 48 months in untreated .

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EMGTS – results Progression

62% - control45% - treated group

25% IOP - risk of progression by 50%

Risk of progression less with larger initial IOP drop

Risk of progression by 10% / mm Hg IOP from baseline


In the control group , the rate of visual field progression was fastest in the subgroup of patients with exfoliation and slowest in those with normal IOPs at baseline.

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Baseline risk factors:Higher IOP

Exfoliation

Older age

Lower systolic perfusion pressure

Lower CCT among patients with higher IOPs

follow up higher IOP,

disc hemorrhages.32

Early Manifest Glaucoma trial (EMGT) Implications:In eyes with glaucoma ,IOP that was

lowered by an average of 25%, treatment was of benefit versus no treatment .

There is beneficial effect of immediate therapy to lower the intraocular pressure versus late or no treatment on the progression of newly detected OAG

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Clinical ImplicationsEven small reductions in IOP can make a

difference.Every 1mm of IOP reduction was associated

with a risk reduction of 10% to 13%, depending on the analysis,

But that doesn't necessarily mean all patients must be treated, because we can't know which patients will progress, in some cases, we can observe closely and tailor management to the individual patient

It's beneficial to lower pressure in patients progressing quickly, even if IOP levels have been in the range of 15 to 18mm Hg,

Clinical useful points from EMGTS

25% IOP - progression from 62 – 45%Regular FU every 3 – 6 months with ONH & VF must – not commonly practiced.Pts with low risk of progression left untreated – no effect on QOL till lifetimeDrawbacks – Rx options limited – better drugs now

Collaborative Initial Glaucoma treatment Study (CIGTS)

Am J Ophthalmol 1998;126:498-505


Purpose:

To determine whether patients with newly diagnosed open angle glaucoma (OAG) are better treated by initial treatment with medications or by immediate filtering surgery.

In addition, a secondary measure—a health-related quality of life questionnaire—looked at how the treatment affected the patient's lifestyle.

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Participants:607 patients with OAG ( primary, pigmentary,

or pseudoexfoliative) recruited between 1993 and 1997.

Study design:Multicenter randomized controlled clinical

trial comparing initial medical with initial surgical therapy for OAG.

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First time the concept of Target IOP was used.

March 2010

CIGTS

MEDICATION GROUPN = 307

SURGICAL GROUPN = 300

CIGTSRESULTS

At 5 yrs both effective

Control of IOP lower by surgery (48%), medical (35%)

VF loss greater in surgery (cataract)

QOL initially better with medical group

CIGTS – Results at 5yrsMedical

TreatmentSurgical

TreatmentIOP reduction 28mmHg→17-

18mmHg(38%)

27mmHg→14-15mmHg

(46%)Progression at 5

yearsNo progression No progression

• Surgical group is at increased risk of visual loss initially but by 4yrs both groups are comparable•The rate of cataract removal was greater in the surgically treated group.


Results

Patients with diabetes were more likely to

progress if treated with surgery first.

The quality of life (QOL) impact reported

by the 2 treatment groups was very similar.

Increased impact of local eye symptoms

reported by the surgery group

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Results

The overall rate of progression of OAG in CIGTS was lower than in many clinical trials, potentially the result of more aggressive IOP goals and the stage of the disease.

CIGTS summarySurgery resulted in

Lower IOPMore cataractMore ocular side effectsInitial ↓ visionInitial ↓ visual field


Implications In moderate to advanced disease initial surgical

therapy may be preferred. The results also revealed that either treatment

had a remarkably similar effect on patients' quality of life.

Though not associated with a particular treatment group, the fear of blindness was common, affecting 34% at diagnosis.

Patients who reported a decrease in visual functioning were more likely to experience depression and mood changes

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Clinical useful points from CIGTS

Early POAG – medical Rx effectiveOur scenario – compliance/cost – deciding factor for either modalityConcept of target IOP – must in our management.Drawback – study duration too short for Rx recommendation.

Advanced Glaucoma Intervention Study (AGIS)

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Purpose:

To compare the clinical outcomes of 2 treatment sequences in cases of advanced glaucoma

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Advanced glaucoma intervention study (AGIS)Objective – to determine if ALT or surgery

is preferred Rx for advanced glaucoma on max tolerated medical Rx.

789 eyes

ALTTRABTRAB(ATT)

TRABALTTRAB(TAT)


Participants: 789 eyes of 591 patients with medically

uncontrolled OAG recruited from 1988 to 1992.

POAG uncontrolled on maximum accepted and tolerated medical therapy(IOP ≥ 18 mm Hg)

35 to 80 yr

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Study design:Multicenter randomized controlled clinical trial

comparing 2 treatment sequences (TAT and ATT ) for patients with OAG uncontrolled by medical therapy.


Results: Black patients had less combined visual acuity

and visual field loss if treated with the ATT sequence.

White patients had less combined visual acuity and visual field loss at 7 years if treated with the TAT sequence.

Visual function scores improved after cataract surgery.

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AGIS - Results Relationship of IOP & VF progression.

Predictive analysis – IOP < 14 mm Hg did better

Associative analysis – low IOP & low IOP fluctuation - Decreased progression

Advanced Glaucoma Intervention Study (AGIS Results:

Lower IOP was associated with less visual field loss.

First 18 months after the first surgical intervention, or eyes with IOP of 18mmHg or less at all visits throughout the study had significantly less visual field loss

Approximately half of the study patients developed cataract in the first 5 years of follow up.

Trabeculectomy increases the relative risk of cataract formation by 78%.

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Results

ALT failure is associated with

-younger age

-higher IOP.

Trabeculectomy failure associated with

-younger age,

-higher IOP,

-diabetes, and postoperative complications such as particularly

elevated IOP and marked inflammation.

-IOP fluctuation was an independent predictor of progression of

OAG in eye with lower baseline IOPs.

Results - AGIS

TAT IOPBetter for whites

ATT FailureBetter for blacks

Risk of cataract after TRAB after 5 years – 78 %

AGISEffects of IOP on visual field progression

were also specifically evaluated from AGIS data, and it was found that patients with an average IOP of greater than 17.5mm Hg had greater worsening of their visual fields than those with an average IOP of less than 14mm Hg.

AGIS was one of the first studies to show that lower mean IOP results in a decreased risk of visual field progression.

AGISEach patient requires individualized care. AGIS demonstrated that race is an important

consideration for surgical intervention in advanced glaucoma.

This is not to say, for instance, that a white patient with medically-uncontrolled glaucoma should only be offered the option of trabeculectomy.

Potential operative complications associated with the more invasive surgery may sway the patient toward laser intervention as a first option.

AGISConversely, a black patient presented with

the option of laser intervention should be warned of the likely future need for both additional medications and additional glaucoma surgery after the laser procedure is completed.

AGISThere is no magic number for target IOP. Patients in the AGIS group who consistently

maintained IOP less than 18mm Hg at every visit over six years, with mean IOP of 12.3mm Hg as a group, had good preservation of visual field—yet a number of patients in this group still showed progressive visual field loss.


Implications:Keep race in mind when choosing therapy.

Lower IOP was associated with less visual field loss

IOP fluctuation was an independent predictor of progression of OAG in eye with lower baseline IOPs.

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Collaborative Normal Tension Glaucoma (CNTGS)

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Lowering IOP in patients with normal-tension glaucoma (NTG) can be challenging.

Is it even worth trying to lower an already-low IOP?


Purpose:To determine if IOP plays a part in the

pathogenic process of NTG by comparing a treatment group (with a 30% reduction in IOP) to a no treatment group. .

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Participants :230 patients

20-90 yrs

Patients had unilateral or bilateral NTG

Three reliable visual fields within 1 month

Average IOP ≤20 mmHg,no reading above 24 mmHg

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NTGS - methodsRandomised immediately if

VF defect threatening fixationPreviously documented disease progression

Others randomised when evidence of progression

NTGS145 (of 239) patients randomised One eye randomised to

Treatment Drops, ALT or surgery to achieve 30%

reduction in IOPNo treatment until evidence of progression Other eye could be treated in this group


Study design:

In both arms, neither eye could receive beta-adrenergic blockers or adrenergic agonists, because they might have systemic cardiovascular effects that could conceivably alter the course of the treated or untreated disease, confounding the analysis of data.

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CNTGS

RESULTS30% drop achieved in half without surgery

Once 30% drop achieved rate of progressive field loss was lower than group that did not receive treatment (after allowing for cataract effect which was higher in treated group)

CNTGS RESULTS:Rate of progression in untreated NTG highly

variableHalf did not progress on VF in 5 yearsFactors associated with progression

FemaleMigraineDisc haemorrhages on presentation

CNTG – results Prog in 12% of Rxed eyes & 35% in untreated group.30% reduction possible even by medicines.Treated pts that progressed

Non IOP related target IOP wrong

CNGTSOverall, lowering IOP in NTG slows

progression.

However, over half of patients did not progress without treatment at 5 years.


IMPLICATIONS:

The natural course of NTG is quite variable, some cases slow enough that they may never need treatment, but others progressing rapidly to potential blindness.

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Because of the variable natural course of NTG, it is important to distinguish between patients who have progressive vs. non-progressive disease.

In cases of mild NTG, consider monitoring until progression is confirmed.

However, factors that weigh more heavily for treatment are female gender, history of migraine and disc hemorrhage at diagnosis.

When you suspect progression, be sure to confirm that it is actual progression and not testing variability.

This may require multiple visual fields to prevent over-diagnosing progression.

Once the decision is made to begin treatment, set a goal (at least 30% IOP reduction) and be diligent in attaining it.

The large arsenal of IOP-lowering medications available today makes this goal much more achievable without surgery

TUBE V/S TRABECULECTOMY(TVT)

TVTPURPOSE: To report 5 year treatment

outcomes in the tube versus trabeculectomy study.

DESIGN: Multicenter randomized clinical trial

TVTSTUDY POPULATION: -Patients 18 to 85 years -Prior cataract or glaucoma filtering surgery- Uncontrolled glaucoma with IOP of 18mmHg

to 40 mmHg on maximum tolerated medical therapy

OUTCOME MEASURES-IOP, Visual acuity, visual fields, surgical

complications, glaucoma medications and treatment failure

TVTRESULTS:-Trabeculectomy with MMC and tube-shunt

surgery both produced sustained IOP reduction to the low teens during 5 years of followup

-Tube-shunt surgery was associated with use of more glaucoma medications than trabeculectomy with MMC during the first 2 yrs of study,but medical therapy equalized with longer followup

TVTRESULTS-Trabeculectomy with MMC had a higher

failure rate (46.9%)compared with tube shunt surgery(29.8%)

-Higher rate of reoperation for glaucoma(29%) compared to tube group(9%0

-vision loss occurred at similar rate in both groups

-Early postoperative complications occurred more frequently after trabeculectomy with MMC relative to tube shunt surgery.similar rate for late complications

TVTImplications-No procedure superior for treating glaucoma-Factors for selecting surgical procedureo Surgeons skill and experienceo Patients willingness to undergo repeat

glaucoma surgeryo Surgeons planned surgical approach should

failure occur

The researchers maintain that the TVT study does not demonstrate clear superiority of one glaucoma operation over the other, but that both surgeries are viable options.

Potential pitfalls exist with the use of tube shunts. Subsequent surgical options after failure of tube-shunt devices become limited—surgeons are left with the choice of a second, inferiorly placed tube or cyclophotocoagulation.

The TVT Study supports the expanding use of tube shunts beyond the surgical management of refractory glaucoma.

Tube shunt surgery was shown to be effective in a patient population at lower risk of surgical failure than has traditionally been designated for this procedure.

Trabeculectomy is not without its travails. It requires the surgeon to tailor the procedure to each patient (i.e., number of scleral flap sutures and dosage of an antifibrotic agent) whereas tube-shunt surgery is a more standardized procedure

Also, trabeculectomies require more frequent and more vigilant postoperative care than tube shunts.

OTHER IMPORTANT TRIALS

EUROPEAN GLAUCOMA PREVENTION STUDYOBJECTIVE Efficacy of reduction of IOP by dorzolamide

versus placebo in preventing or delaying POAG in patients affected by Ocular hypertension

EGPS PARTICIPANTS:-1081 patients-Age ≥30 yrs-IOP 22 to 29 mmHg-2 normal and reliable visual fields-Normal optic discsOutcome measures:Safety end point was IOP >35 mmHg on 2

consecutive examinations

EGPSRESULTS-Dorzolamide reduced IOP by 15-22% in 5 yrs

period-At 60 months ,cumulative probability of

converting to an efficacy end point was13.4%(dorzolamide group)14.1%(placebo group)-No statistically significant difference between

medical therapy and placebo group in reducing incidence of POAG

EGPSRisk factors for progression1.Older age2.Thinner CCT3.Higher vertical cup disc ratio4.Higher Pattern standard deviation

EGPSThe role of systemic blood pressure appears

importantRegression to the MeanMinimised by multiple IOP measurements at

different times of the day (diurnal variation) or on a different day.

For each mm Hg higher IOP per 12 months, the risk of converting to POAG in increased by 9% in the next 5 years.

LOW TENSION GLAUCOMA PREVENTION STUDYOBJECTIVE To evaluate visual field stability in low-

pressure glaucoma patients randomized to intraocular pressure reduction in both eyes with topical twice daily brimonidine tartrate 0.2% versus twice daily timolol maleate 0.5%

LOGTSPARTICIPANTS -Low-pressure glaucoma patients - 30 years of age or older -untreated pressure of more than 21 mmHg

and advanced visual field loss were excluded

Randomization of both eyes to double-masked monotherapy with brimonidine or timolol.

LOGTSFollow-up visits included Humphrey 24-2 full-

threshold perimetry, tonometry every 4 months, and annual optic disc photography.

MAIN OUTCOME MEASURE:- Progression of visual field loss.

LOGTS

RESULTSshowed similar IOP reduction for each

medication.patients on brimonidine had less visual field

loss (9.1%) compared with patients on timolol (39.2%) during an average of 30 months

28 of the 99 patients in the brimonidine arm of the study dropped out due to drug-related adverse events, compared with only 9 of the 79 timolol patients

LOGTS

RESULTSlow-pressure glaucoma patients treated with

brimonidine are less likely to have field progression than patients treated with timolol

Conclusion:Brimonidine better than Timolol??

The study attempted to find correlations between many other baseline factors of the 2 study groups and the slower progression of glaucoma in the group that received brimonidine.

Age, sex, family history, diabetes mellitus, risk factors for low-tension glaucoma (such as migraine and the Raynaud phenomenon), and ocular perfusion pressure were investigated..

LOGTS Drawbacks-Data may have been skewed due to the high

number of patients dropping out of the brimonidine group.

-No therapeutic goal for either medication -Baseline untreated IOP was just over 15mm

Hg and the mean treated IOP was around 14mm Hg

LOGTS For now,we should use the therapy that

reduces IOP in normal-tension patients to significant levels (minimum 30%), and modify treatment if the optic nerve, retinal nerve fiber layer or visual field changes.

Prostaglandins have superb efficacy and less effect than other agents in lowering heart rate. These should be used as a first-line treatment whenever possible.

Remember to check blood pressure and heart rate before initiating treatment with a beta-blocker such as timolol.

Also, check if the patient is already taking a systemic beta-blocker.

Be sure that patients use timolol earlier in the evening rather than before bedtime to avoid the hypotensive effect that might compromise ocular blood flow and induce systemic hypotension.

TAKE HOME MESSAGE

In OHT cases:Not all OHT need treatment – assess risk on

individual basis and then decidePeople with high risk factors may benefit from

close followup and early treatment

Low risk patients can have less frequent followup and may not need early treatment.

TAKE HOME MESSAGEIn NTG cases:Rate of progression in NTG highly variableOnly proven treatment is reducing IOPTreat if risk factors present

TAKE HOME MESSAGEPOAG casesStart early treatment in diagnosed cases of

POAGChoice of medical therapy first – change only

if target IOP not achieved.Surgical therapy safeIn moderate to advanced disease initial surgical

therapy may be preferred

TAKE HOME MESSAGEEfficient patient care – practice of evidence based

Rx

IOP is the main risk factor for all glaucomas

Recognize threat – lower IOP – lower risk of progression

Set a target IOP after assessing risk factors for progression

Healthcare

Important trials in Glaucoma