Despite decades of research, there is still no effective vaccine against Group B streptococcus (GBS), a leading cause of infant mortality worldwide. But MinervaX thinks it’s on course to change that, and now it has the cash it needs to push its candidate into pivotal trials.
The Danish biotech has just raised $57 million in an upsized second-round financing that will allow the company to complete phase 2 trials of its GBS-NN vaccine and prepare the way for phase 3 as it goes head-to-head with Pfizer in the race to market.
MinervaX’s CEO and co-founder Per Fischer thinks the potential rewards are considerable, both from a health perspective and commercially.
“The WHO anticipates that some 100 million women will require the vaccine globally, with some 10% of those in Europe and the U.S.,” he says, adding that the market for the maternal vaccine could be worth $1 billion a year.
GBS is present in almost 1 in 5 women around the world and is responsible for nearly half of all life-threatening infections in newborns, and GBS-NN represents the best hope of tackling that public health issue.
Colonization can lead to late-term abortions, premature delivery or stillbirth, and in newborns can cause sepsis, pneumonia or meningitis—all of which carry significant risks of disability or death. Currently, prevention can only be provided through intravenous antibiotics, which aren’t very effective, are expensive and encourage antimicrobial resistance.
Efforts to develop a vaccine have been hampered by resistance to maternal vaccination and the low incidence of GBS disease, which means that massive trials would be required to demonstrate efficacy.
“When we first started in 2010 … one of the big hurdles was maternal vaccination—large companies were afraid of vaccinating pregnant women due to fear of large lawsuits in case of adverse events,” says Fischer.
That gradually changed after the 2009 H1N1 flu outbreak, but, because GBS neonatal disease still occurs relatively rarely, phase 3 trials would have to include 150,000 or so pregnant women to be powerful enough to show efficacy—costly and almost impossible to organize.
That remained a barrier until regulators like the FDA and the European Medicines Agency agreed—at least in principle—to accept surrogate markers such as GBS antibody levels, dramatically reducing the scale of trials needed to show that vaccines work as expected.
“The uncertainty about maternal immunization and uncertainty about [the] path to licensure has resulted in most companies and investors not being interested in GBS vaccines until the last few years,” according to Fischer.
There have also been disappointing results with capsular polysaccharide (CPS) conjugate GBS vaccines like GlaxoSmithKline’s CPS-CRM197, which was inherited from Novartis as part of their asset swap deal a few years back but seems to have stopped development.
“Those vaccines perform relatively poorly in individuals with low levels of pre-existing antibody levels, and giving multiple doses, higher doses or adding an adjuvant does not really help—so they are likely not particularly good at protecting those most at risk,” according to Fischer.
In contrast, MinervaX’s shot is based on two proteins (Rib and AlphaC) found on the surface of GBS and, according to the results of early-stage clinical trials, giving subsequent doses raises antibody levels above the level expected to be protective in almost all recipients—including those with low antibody levels at enrolment.
MinervaX's closest rival, Pfizer, is developing a CPS-conjugate vaccine similar to the one tested by GSK but with a broader coverage of GBS strains. Fischer says the phase 1 data look similar to those seen with CPS-CRM197, but Pfizer has nevertheless pressed ahead with a phase 1/2 trial in South Africa.
MinervaX has completed phase 1 studies in 300 healthy females, and the first five subjects have already been dosed with GBS-NN in a phase 2 trial in South Africa. The new cash injection means the biotech can now press ahead with a midstage trial in the U.S. and Europe.
The series B included new investors Sanofi Ventures, Wellington Partners, Adjuvant Capital and Industrifonden, along with existing investors Novo Holdings REPAIR Impact Fund, Sunstone Life Science Ventures and LF Investment.
The new funding was also welcomed by Jane Plumb, CEO and founder of the charity Group B Strep Support.
“MinervaX’s news today represents a significant step towards finding new ways of protecting mothers and babies from the devastating infections GBS can cause,” she said.
“It is vital that science continues to strive to find better ways of tackling what should be a hugely preventable infection and we fully support efforts to develop a new and effective vaccine.”