Island Pharmaceuticals Ltd has made positive progress on its upcoming Phase 2a/b ISLA-101 clinical program in dengue fever, with the clinical trial protocol amendment now cleared with US Food and Drug Administration (US FDA).
ISLA-101 is a drug with a well-established safety profile that Island is repurposing for the prevention and treatment of dengue fever and other mosquito-borne diseases.
"We are very pleased to have now locked down our protocol for the ISLA-101 PROTECT study and have it registered, in preparation for final ethics approvals. We have worked hard to bolster our internal capabilities and as a result have not needed to engage a CRO for this study,” Island CEO and managing director Dr David Foster said.
“This strategy not only has streamlined efforts on protocol revisions, FDA communications and trial execution, but has substantially reduced costs enabling us to complete the Phase 2a, prophylactic cohort of the PROTECT study with existing funds.”
Clinical trial protocol amendment cleared
Following its last trial progress update, on July 3, 2024, the Australian antiviral drug development company filed its final Single Ascending Dose Clinical Study Report from the recently completed Phase 1 clinical study with the US FDA.
Island also filed the proposed protocol for the upcoming ISLA-101 Phase 2 Clinical Study. This trial protocol amendment proposed that ISLA-101 would be administered at a single dose level, twice daily across multiple days.
Additionally, the company proposed that both a prophylactic (preventative) and therapeutic arm be included in the study, as opposed to just the previously proposed prophylactic arm.
All protocol amendments have now been cleared by the US FDA and the protocol has been revised to include two cohorts.
The 'A' cohort (Phase 2a) is a prophylactic, or 'preventative', arm that will include four subjects randomised 3:1 (active: placebo). The 'B' cohort (Phase 2b) is a therapeutic arm that will include 10 subjects randomised 8:2 (active: placebo).
To reflect the new (prophylactic and therapeutic) trial strategy, Island has renamed the Phase 2a/b study as 'PROTECT', which stands for PROphylactic and TrEatment Challenge Trial.
Dosing to begin late-September
As part of the consultation process on the protocol, the FDA requested that Island wait to start infecting subjects until the end of mosquito season, which occurs on October 1 — to ensure that the public is protected from unwanted transmission of the virus by mosquitoes.
Island agreed, despite there having been no recorded instances of a dengue-carrying mosquito in the part of New York where the trial will be conducted.
With IRB approval received from SUNY Upstate Medical Hospital in Syracuse, NY, the trial can now be advertised to healthy volunteers. Enrolment will begin as soon as IRB approval is received from the US Army and Island expects to start prophylactic dosing in late September and to start infecting on or after October 1.
The trial’s first cohort will be the prophylactic (prevention) arm. Island will pre-treat subjects with ISLA-101 before infecting them with the attenuated challenge virus.
The company says this timing will enable it to provide a full readout of the Phase 2a cohort well before the end of this calendar year. The Phase 2b cohort will begin being dosed in January 2025.
Study costs reduced substantially
Island has advised that its remaining cost for the full study is now substantially lower than prior estimates, at around US $1.08 million.
This follows the US$625,000 (A$962,000) in funding from a Congressionally Directed Medical Research Programs grant, as announced in May, that was allocated by SUNY Upstate New York to directly support the coming ISLA-101 clinical study.