GBS is a leading killer of infants worldwide, especially in Sub-Saharan Africa. Pic: Getty Images
Health & Biotech
The paradox of group B streptococcus (GBS) is that it is easily treated and yet is a leading cause of death among infants because the standard laboratory-based pathology tests often are hard to access.
Slated to list on the ASX next year, Nexsen Biotech’s solution is a simple rapid point-of-care test, Strepsure, that can be used by non-medical individuals with a result obtained in minutes.
The claimed accuracy is similar to – if not better than – the lab tests.
“Our priority is to build an effective test that is available to anyone, anywhere in the world,” says CEO and co-founder Tom Hanly.
The Melbourne-based Nexsen is raising $2-3 million in a pre-IPO round to develop Strepsure, as well as a variant called Vetstrep to detect mastitis in cattle.
The company is also developing over-the-counter assays for creatinine levels (kidney function) and the prostate specific antigen (the key prostate cancer biomarker).
GBS is present in about 20% of humanity and in most cases is harmless. The exception is the immunocompromised and newborns.
“The most vulnerable are newborn babies,” says Hanly. “If the mum has GBS and passes it on to the baby, the baby has a chance of getting sepsis, pneumonia or meningitis.
“It is one of the leading causes of infant mortality and disability.”
This is especially the case in sub-Saharan Africa, which accounts for half of the world’s early-onset GBS deaths and pre-term births. The bacterial infections linked to GBS result in around 2.9 million neonatal deaths globally every year.
In Australia, pregnant women present at 36 weeks for a lab-based test, but this screening could miss pre-term babies, or women who have missed the appointment.
Being transient, GBS can re-present in someone who has screened negative. The disease can be treated with inexpensive antibiotics, but because of antimicrobial resistance it is not a good idea to use them as a blanket prophylactic.
Likewise, an easy diagnosis of bovine mastitis could prevent the mass dosing of beef and dairy cattle, a common practice in the US which risks increasing antibiotic resistance through the food chain.
“If a penicillin-resistant GBS arises, the impact will be horrific,” Hanly says.
Strepsure’s background tech emanated from the RMIT University-based Sir Ian Potter Nonosensing Facility, led by nanotech guru Professor Vipul Bansal.
Strepsure looks like an advanced lateral-flow device, a cross between a Covid and pregnancy test.
While Covid tests use an antibody biomarker, Strepsure is based on aptamers. Aptamers are short-chain synthetic sequences of DNA RNA, nucleic acids that carry crucial genetic information.
The company has patented ten such sequences.
In the case of Covid tests, the urgency of the situation meant that the rapid-flow tests were accepted, despite being considerably less reliance than the lab-based polymerase chain reaction (PCR) tests.
Many of us would remember waiting days for a result.
“To achieve optimum accuracy the device has a magnetic preconcentration step of GBS and improved a group of nanoparticles to give a better result,” Hanly says. “It’s all within the device, you don’t need vials of liquid as with a Covid test.”
Based on lab assessments, Nexsen claims a sensitivity (an ability to detect GBS) of 97.5%, equal to that of a pathology-based test.
The test is cheap, has a long shelf life and doesn’t have to be stored at a particular temperature.
Hanly says targeting GBS first wasn’t a case of plucking the low-hanging fruit, because the requisite accuracy rate is higher than for the other planned devices.
But the unmet need was clear as evidenced by agencies such as the World Health Organisation, which sees GBS as a public health priority.
Locally, Nexsen has attracted $7.7 million of funding from grants and other non-dilutive sources.
These include $3m from Ausindustry’s Cooperative Research Centres Program (CRCP) and $1.75m from the Australian Research Council (for cattle mastitis testing).
“With the CRCP we got 100% of what we asked for and government used the grant to promote the program,” Hanly says.
RMIT University has provided $1.35m of cash in kind, while other collaboration partners have chipped in $1m.
To support a planned US Food & Drug Administration (FDA) approval application, the Melbourne hospital network Northern Health will host a clinical trial.
The trial aims to screen 400 to 500 pregnant women, who will undergo the Strepsure test at 36 weeks alongside the standard test. The tests will be compared side-by-side.
Nexsen is confident the trial data will be sufficient to seek FDA marketing approval, under the 510k (predicate device) route. FDA approval would streamline applications in other geographies including Australia, Canada, Brazil and Japan.
As a prostate cancer survivor, Hanly knows the importance of early and easily accessible testing.
While Australian men are entitled to one free prostate check a year, his informal polling of over 50s blokes shows that “virtually none of them” had availed of the opportunity.
But they might be more willing to obtain a cheap over-the-counter alternative at a pharmacy and use it in the comfort of their home.
“Rather than getting one at 54, I should have had one at 50 and might not have had 28 courses of radiation and hormone treatment,” Hanly says.
“So, this one is clearly near and dear to me”.
While clear of the disease years later, Hanly says his body never will be the same again.
It’s a moot point why big pharma has not tackled GBS.
Maybe it’s perceived as a ‘woman’s disease’ – a traditional area of underinvestment – or an uneconomic proposition, given that antibiotics are so cheap.
“I keep waking up thinking Johnson & Johnson will soon announce their rapid GBS point-of-care test but … our research suggests there is no other device we are aware of,” Hanly says.
The UK experience shows why GBS should not be pigeon-holed as a third world problem.
Unusually for a developed country, Britain does not have routine GBS pregnancy screening – a situation partly attributable to National Health Service (NHS) funding woes.
But this will change as plaintiff law firms gear up to sue the NHS for GBS complications in infants. These include our own Slater & Gordon, which has an entire GBS division in the UK.
Facilitated by Alpine Capital, Nexsen’s pre-seed round is expected to be done by the end of the week, with the planned IPO likely to raise a further $6 million. Depending on market conditions – which currently are improving – the IPO is expected in mid-2025.
Health & Biotech
Health & Biotech
Health & Biotech
