Acanthamoeba KeratitisPhase 2NCT03484507
Parasitic Ulcer Treatment Trial Pilot
A Phase 2 study testing Chlorhexidine, Povidone-Iodine and Prednisolone Sodium Phosphate in people with Acanthamoeba Keratitis, run by University of California, San Francisco at 2 sites in India.
Trial summary
This is a study of optimal treatments for acanthamoeba keratitis. In the first part of the study, participants will be randomized to chlorhexidine monotherapy or chlorhexidine plus povidone iodine. Read more about this study
- Who is it for?
- Ages 13 years and older
- Conditions the study is for
- Acanthamoeba Keratitis
- What is being tested?
- Chlorhexidine, Povidone-Iodine and Prednisolone Sodium Phosphate
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 49 participants
- Where
- 2 sitesIndia
- Study dates
- 1 Jan 2018to 15 Nov 2022
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 13 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Trial 1 Inclusion Criteria:
- Smear or culture positive for acanthamoeba
- Age 13 years or greater
Trial 1 Exclusion Criteria:
- Interstitial or viral keratitis on history or examination
- Corneal perforation
- Therapeutic keratoplasty for acanthamoeba keratitis
- Unwillingness or inability to follow-up (e.g., living too far from hospital)
Trial 2 Inclusion Criteria
- Smear or culture positive for acanthamoeba, with 4 weeks of anti-amoebic treatment
- Age 13 years or greater
- Willing to participate in study
Trial 2 Exclusion Criteria
- Interstitial or viral keratitis on history or examination
- Fungus identified on culture and smear after 2 weeks of anti-amoebic treatment
- Corneal perforation
- Therapeutic keratoplasty for acanthamoeba keratitis
- Unwillingness or inability to follow-up (e.g., living too far from hospital)
Trial locations and contacts
2 sites in 1 country.
India2 sites
Aravind Eye Hospital
Coimbatore, Tamil Nadu
Aravind Eye Hospital
Madurai, Tamil Nadu
About this study
This is a study of optimal treatments for acanthamoeba keratitis. In the first part of the study, participants will be randomized to chlorhexidine monotherapy or chlorhexidine plus povidone iodine. After four weeks of therapy, participants will be re-randomized to early corticosteroids, later corticosteroids, or placebo.
Read the detailed description
Acanthamoeba keratitis is a rare eye infection that is difficult to treat. The mainstay of therapy is a biguanide agent such as chlorhexidine, though recent studies have found povidone iodine to be effective for killing acanthamoeba organisms in vitro. Thus, we randomize participants to topical chlorhexidine 0.04% monotherapy (i.e., routine care) versus topical chlorhexidine 0.04% plus topical poviodine iodine 2.5%. The primary outcome is clearance of acanthamoeba from the ocular surface at 4 weeks.
The role of topical corticosteroids in acanthamoeba keratitis is controversial. Topical corticosteroids can promote growth of acanthamoeba, but may also reduce inflammation and vision-threatening complications of infection. Here, we randomize participants who have completed a course of anti-amoebic therapy to one of three groups: early prednisolone sodium phosphate 1% (started at 4 weeks), late prednisolone sodium phosphate 1% (started at 6 weeks) or placebo (started at 4 weeks). The primary outcome will be visual acuity at 6 months.
- Conditions
- Acanthamoeba Keratitis
- Being tested
- Chlorhexidine, Povidone-Iodine, Prednisolone Sodium Phosphate, Hydroxypropyl Methylcellulose
- Medical subject headings
- Acanthamoeba Keratitis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ChlorhexidineDrug
1 drop half-hourly for days 1-2, then hourly for days 3-6, then 8 times daily until the 4-week visit
Povidone-IodineDrug
1 drop half-hourly for days 1-2, then hourly for days 3-6, then 8 times daily until the 4-week visit
Prednisolone Sodium PhosphateDrug
1 drop 4 times daily for weeks 4-9, then 2 times daily for weeks 10-11
Hydroxypropyl MethylcelluloseDrug
1 drop 4 times daily for weeks 4-9, then 2 times daily for weeks 10-11
Prednisolone Sodium PhosphateDrug
1 drop 4 times daily for weeks 6-9, then 2 times daily for weeks 10-11
Hydroxypropyl MethylcelluloseDrug
1 drop 4 times daily for weeks 4-5
| Study group | Role | What they receive |
|---|---|---|
| Chlorhexidine monotherapy | Active comparator | Topical chlorhexidine 0.04% Receives: Drug: Chlorhexidine |
| Chlorhexidine plus povidone iodine | Experimental | Topical chlorhexidine 0.04% plus povidone iodine 2.5% Receives: Drug: Chlorhexidine; Drug: Povidone-Iodine |
| Early corticosteroids | Experimental | Topical prednisolone sodium phosophate 1% for weeks 4-11 Receives: Drug: Prednisolone Sodium Phosphate |
| Late corticosteroids | Experimental | Artificial tears for weeks 4-5, then topical prednisolone sodium phosophate 1% for weeks 6-11 Receives: Drug: Prednisolone Sodium Phosphate; Drug: Hydroxypropyl Methylcellulose |
| Placebo | Placebo comparator | Artificial tears for weeks 4-11 Receives: Drug: Hydroxypropyl Methylcellulose |
What is being measured
The primary outcome is the main question the study is designed to answer.
Trial 1: Microbial clearance
Acanthamoeba culture
Measured: 4 weeks
Trial 2: Best spectacle corrected visual acuity
Measured: 6 months
Secondary outcomes (4)
Trial 1: Best spectacle corrected visual acuity
Measured: 4 weeks
Trial 1: Time to re-epithelialization
Measured: 4 weeks
Trial 1: Clinical cure
Measured: 4 weeks
Trial 2: Time to clinical cure
Measured: 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Mar 2018
- Study start1 Jan 2018
- Primary completion15 Nov 2022
- Study completion15 Nov 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Acanthamoeba KeratitisStudies of the same condition, open and under way.
- More trials run by University of California, San FranciscoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Outcomes assessor
- Enrolment
- 49 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of California, San Francisco
- Sponsor type
- University, hospital or other
- Collaborators
- Research to Prevent Blindness
- Responsible party
- Sponsor
- Investigators
- Jeremy D Keenan, MD, Principal investigator, University of California, San Francisco
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03484507
- Sponsor's protocol ID
- UCSF-IRB-17-23895
- Status last verified
- May 2026
- First submitted
- 24 Mar 2018
- Last updated
- 7 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Rajaraman R, Kassaye I, Sharma SS, Prajna NV, Lalitha P, Panigrahi A, Rammohan R, Aromin KM, Cook C, Porco TC, Lietman TM, Seitzman GD, Keenan JD. Adjunctive povidone-iodine for Acanthamoeba keratitis: a randomized trial. Antimicrob Agents Chemother. 2026 May 6;70(5):e0151225. doi: 10.1128/aac.01512-25. Epub 2026 Mar 31.
PubMed 41914638
Study at a glance
From the registry record, last updated by the sponsor on 7 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Parasitic Ulcer Treatment Trial Pilot
- ClinicalTrials.gov ID
- NCT03484507
- Acronym / sponsor ID
- UCSF-IRB-17-23895
- Conditions
- Acanthamoeba Keratitis
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 49 participants (actual)
- Lead sponsor
- University of California, San FranciscoUniversity, hospital or other
- Collaborators
- Research to Prevent Blindness
- Study start
- 1 Jan 2018 (actual)
- Primary completion
- 15 Nov 2022 (actual)
- Study completion
- 15 Nov 2022 (actual)
- First posted
- 30 Mar 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a study of optimal treatments for acanthamoeba keratitis. In the first part of the study, participants will be randomized to chlorhexidine monotherapy or chlorhexidine plus povidone iodine. After four weeks of therapy, participants will be re-randomized to early corticosteroids, later corticosteroids, or placebo.
Detailed description
Acanthamoeba keratitis is a rare eye infection that is difficult to treat. The mainstay of therapy is a biguanide agent such as chlorhexidine, though recent studies have found povidone iodine to be effective for killing acanthamoeba organisms in vitro. Thus, we randomize participants to topical chlorhexidine 0.04% monotherapy (i.e., routine care) versus topical chlorhexidine 0.04% plus topical poviodine iodine 2.5%. The primary outcome is clearance of acanthamoeba from the ocular surface at 4 weeks.
The role of topical corticosteroids in acanthamoeba keratitis is controversial. Topical corticosteroids can promote growth of acanthamoeba, but may also reduce inflammation and vision-threatening complications of infection. Here, we randomize participants who have completed a course of anti-amoebic therapy to one of three groups: early prednisolone sodium phosphate 1% (started at 4 weeks), late prednisolone sodium phosphate 1% (started at 6 weeks) or placebo (started at 4 weeks). The primary outcome will be visual acuity at 6 months.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, outcomes assessor)
- Number of arms
- 5
| Arm | Type | Receives |
|---|---|---|
| Chlorhexidine monotherapy | Active comparator | Drug: ChlorhexidineTopical chlorhexidine 0.04% |
| Chlorhexidine plus povidone iodine | Experimental | Drug: Chlorhexidine, Drug: Povidone-IodineTopical chlorhexidine 0.04% plus povidone iodine 2.5% |
| Early corticosteroids | Experimental | Drug: Prednisolone Sodium PhosphateTopical prednisolone sodium phosophate 1% for weeks 4-11 |
| Late corticosteroids | Experimental | Drug: Prednisolone Sodium Phosphate, Drug: Hydroxypropyl MethylcelluloseArtificial tears for weeks 4-5, then topical prednisolone sodium phosophate 1% for weeks 6-11 |
| Placebo | Placebo comparator | Drug: Hydroxypropyl MethylcelluloseArtificial tears for weeks 4-11 |
Who may qualify
- Ages
- 13 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Chlorhexidine1 drop half-hourly for days 1-2, then hourly for days 3-6, then 8 times daily until the 4-week visit | Drug | Chlorhexidine monotherapy, Chlorhexidine plus povidone iodine |
| Povidone-Iodine1 drop half-hourly for days 1-2, then hourly for days 3-6, then 8 times daily until the 4-week visit | Drug | Chlorhexidine plus povidone iodine |
| Prednisolone Sodium Phosphate1 drop 4 times daily for weeks 4-9, then 2 times daily for weeks 10-11 | Drug | Early corticosteroids |
| Hydroxypropyl Methylcellulose1 drop 4 times daily for weeks 4-9, then 2 times daily for weeks 10-11 | Drug | Placebo |
| Prednisolone Sodium Phosphate1 drop 4 times daily for weeks 6-9, then 2 times daily for weeks 10-11 | Drug | Late corticosteroids |
| Hydroxypropyl Methylcellulose1 drop 4 times daily for weeks 4-5 | Drug | Late corticosteroids |
Primary outcome
Trial 1: Microbial clearance
Time frame: 4 weeks
Acanthamoeba culture
Trial 2: Best spectacle corrected visual acuity
Time frame: 6 months
4 secondary outcomes
Trial 1: Best spectacle corrected visual acuity
Time frame: 4 weeks
Trial 1: Time to re-epithelialization
Time frame: 4 weeks
Trial 1: Clinical cure
Time frame: 4 weeks
Trial 2: Time to clinical cure
Time frame: 6 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 May 2026.
- Derived from this study: PubMed 41914638Rajaraman R, Kassaye I, Sharma SS, Prajna NV, Lalitha P, Panigrahi A, Rammohan R, Aromin KM, Cook C, Porco TC, Lietman TM, Seitzman GD, Keenan JD. Adjunctive povidone-iodine for Acanthamoeba keratitis: a randomized trial. Antimicrob Agents Chemother. 2026 May 6;70(5):e0151225. doi: 10.1128/aac.01512-25. Epub 2026 Mar 31.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Jeremy D Keenan, MD principal investigator
University of California, San Francisco
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Chlorhexidine, Povidone-Iodine and Prednisolone Sodium Phosphate in people with Acanthamoeba Keratitis, run by University of California, San Francisco at 2 sites in India.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 7 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in India. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Trial 1: Microbial clearance (time frame: 4 weeks). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03484507, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 May 2026.