Three StrepSure enhancements push FDA submission back by roughly one quarter

Shares Suspended Pending Device Contract

Nexsen Limited (ASX:NXN) has put its shares into voluntary suspension while it prepares an announcement on the execution of a contract for an additional device that could have a material impact on the company’s share price or value. The suspension took effect before trading on 24 September and is expected to end when the contract announcement is released, or when trading resumes on 25 September unless ASX determines otherwise.

The market-sensitive contract disclosure arrived a day after Nexsen revealed that its lead StrepSure Group B Streptococcus test would not proceed in its current configuration towards the previously targeted fourth-quarter 2026 FDA submission. That programme will now absorb an approximately one-quarter delay while the company incorporates lessons from an interim clinical review.

Interim Review Changes StrepSure Path

The study at Northern Health in Melbourne tested StrepSure in women in labour, the real-world setting for which the device is intended. Enrolment has been suspended under the study protocol and assessment of the current configuration has ceased. Nexsen said there was no adverse safety signal or event, but the review identified a need to strengthen performance before the company commits to a larger US regulatory study.

The trial site recorded GBS prevalence of about 11%, below the 18% to 25% prevalence reported at many US study sites. Nexsen said the lower prevalence did not make the test perform worse, but increased the need to avoid false positives for a positive result to remain reliable. The filing does not disclose case numbers or detailed interim sensitivity, specificity, positive predictive value or negative predictive value, leaving the scale of the performance gap difficult to assess from the announcement alone.

Three Technical Enhancements Planned

Nexsen described the next step as a targeted improvement to the existing platform rather than a fundamental redesign, and said it does not expect material additional development expenditure. The planned work will concentrate GBS from each swab using magnetic beads, strengthen the quantitative electronic readout through upconversion nanoparticle reader technology, and use dual recognition to identify GBS through two independent methods.

The stated aim is to improve sensitivity, specificity and consistency while retaining StrepSure’s rapid, portable lateral-flow format. The company will then undertake broader clinical evaluation and validate the integrated design before returning to the US regulatory pathway. Both the revised timing and the expected cost profile remain forward-looking company estimates.

Asia-Pacific Programme Remains Active

Nexsen said the timetable change applies only to StrepSure’s US pathway. Its Asia-Pacific work on antenatal screening and decentralised care is continuing through the Hong Kong R&D facility, research and clinical validation support from The University of Hong Kong, and its hospital partnership with IHH Healthcare’s Gleneagles Hospital Hong Kong. The company also said its kidney disease, traumatic brain injury, neonatal sepsis and biosecurity programmes remain in progress.

That leaves two separate questions for the market: what the suspended device contract contains, and whether the StrepSure enhancements can be validated without turning a roughly one-quarter delay into a longer regulatory reset. Until those details emerge, the filing offers a clearer development plan but not yet the performance data needed to judge whether the revised US pathway is on firmer ground.