Patrys Limited (ASX: PAB) Advances RLS-2202 Trial to Cohort 2

Patrys Limited has received clearance to advance its RLS-2202 Phase 1a trial to a second cohort after an independent safety review found the intravenous formulation had an acceptable safety and tolerability profile at the initial dose.

All four healthy volunteers in Cohort 1 completed dosing and the protocol-defined observation period. The Safety Review Committee assessed the available safety, tolerability and pharmacokinetic data before recommending dose escalation under the trial’s predefined design.

The selected dose for Cohort 2 was not disclosed. Recruitment is expected to begin shortly, with Patrys maintaining its target of completing dosing in the fourth quarter of 2026.

The result clears an early clinical checkpoint for RLS-2202, but it does not establish efficacy or a broader safety profile. The Phase 1a study is primarily designed to determine how the intravenous product behaves in the body and whether existing data for oral quetiapine can support its further development.

Comparing intravenous and oral delivery

Cohort 2 will enrol 12 healthy volunteers in a cross-over study. Each participant will receive both RLS-2202 and a reference oral quetiapine formulation, separated by a four-day washout period.

That structure allows researchers to compare the two formulations within the same participants, reducing the effect of individual metabolic differences on the results. Intravenous administration can produce a different exposure profile from oral delivery, including a faster onset, higher peak concentration and no first-pass metabolism.

RLS-2202 does not introduce a new active molecule. Instead, Patrys is seeking to establish an intravenous formulation of quetiapine as a potential treatment option for delirium, a condition the company says can develop rapidly and has limited options for rapid alleviation.

The trial’s strategic value rests on its potential to bridge established oral quetiapine safety and efficacy data to the intravenous formulation. If successful, that approach could reduce the clinical development work required compared with a program for an entirely new drug. The resulting data are also intended to guide the next clinical study and support future discussions with regulators, including the US Food and Drug Administration.

Dosing remains targeted for this quarter

Patrys expects the clinical-grade RLS-2202 supply for Cohort 2 to be released and delivered to trial operator CMAX during October. Screening, enrolment, validation of the bioanalytical assay and Cohort 2 dosing are all scheduled for the fourth quarter of 2026.

Completion of Cohort 2 will still leave the program at an early clinical stage. The key information for investors will be the resulting pharmacokinetic and safety data, which will determine how effectively Patrys can use the established oral quetiapine evidence to support the intravenous program’s next stage.