Cloudbreak Pharma completes final visits for Phase 3 pterygium trial

Cloudbreak Pharma has announced that the last patient has completed the 12-month primary endpoint visit in its Phase 3 trial of CBT-001, an investigational multi-kinase inhibitor (MKI) eye drop for pterygium. The California and Hong Kong-listed company said topline data from the 660-patient study are now anticipated in the third quarter of 2026.

Pterygium is a fibrovascular growth that extends from the conjunctiva onto the cornea, most commonly caused by chronic UV exposure. The condition can cause redness, irritation and, in progressive cases, impaired vision. Cloudbreak estimates it affects just under one billion people worldwide, with approximately 15 million in the United States. Despite this prevalence, there are currently no FDA-approved disease-modifying pharmacological treatments; existing management relies on symptom relief via artificial tears, off-label anti-inflammatories and, for severe cases, surgery — a procedure costing around $11,500 per episode and associated with recurrence rates of up to 38%.

Trial design and mechanism

The Phase 3 study is a multicenter, double-masked, randomised, vehicle-controlled trial evaluating two doses of CBT-001 emulsion administered twice daily over 24 months. Primary efficacy is assessed at the three-month and 12-month timepoints, with endpoints centred on reducing conjunctival hyperaemia and preventing pterygium lesion progression. Enrolment began in the United States in June 2022 and subsequently expanded to China, New Zealand, Australia and India, reaching its full complement of 660 patients in May 2025.

CBT-001 is designed to inhibit multiple receptor tyrosine kinases simultaneously — specifically PDGF, VEGF and FGF receptors — targeting the angiogenic and fibrogenic pathways thought to drive pterygium growth rather than providing symptomatic relief alone. Abu Abraham, chief medical officer at Cloudbreak, said the approach "addresses the root cause of this fibrovascular disease rather than merely treating symptoms," adding that Phase 2 data had already demonstrated meaningful disease modification.

Market context and competitive landscape

The absence of any approved pharmacological option for pterygium represents a genuine regulatory white space rather than a crowded therapeutic category. If CBT-001's topline data are positive, Cloudbreak intends to pursue multiple simultaneous regulatory filings, a strategy that could accelerate global commercialisation but also exposes the programme to parallel review timelines across agencies including the FDA, and potentially those in Australia, New Zealand and China. The company is also advancing a second MKI asset, CBT-004, into Phase 3 for pinguecula — a related but distinct conjunctival condition — suggesting a broader ambition to establish MKI as a platform rather than a single-product story.

Ophthalmic drug development has seen renewed investor interest in recent years, driven partly by the commercial success of anti-VEGF agents in retinal disease and, more recently, by approvals in dry eye and presbyopia. Pterygium sits at the front-of-eye surface disease end of the spectrum and has historically attracted limited pharmaceutical investment given the availability of surgical options; CBT-001's Phase 3 readout will test whether a drug-based alternative can demonstrate sufficient lesion reduction to shift clinical practice.

With topline data expected within months, the near-term focus for Cloudbreak will be on whether primary endpoints are met and whether the magnitude of lesion size reduction is clinically meaningful. Safety and durability data across the full 24-month treatment period will also be closely watched by regulators and potential commercial partners.