Pfizer Group B strep vaccine for infants returns strong trial results

Pfizer on Wednesday said its experimental vaccine targeting the doubtless deadly bacterial disease Group B Streptococcus returned strong mid-stage clinical trial results, a promising step because the drug inches toward potential approval.

Pfizer is amongst several drugmakers racing to develop the world’s first shot targeting Group B strep disease, which is linked to just about 150,000 infant deaths worldwide annually, especially in lower-income countries.

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The Food and Drug Administration in September granted breakthrough therapy designation to Pfizer’s vaccine, which is meant to expedite the event and review of the shot. 

Pfizer’s single-dose shot generated antibodies that will provide infants with meaningful protection against the disease, based on the data released Wednesday from a phase two clinical trial.

The jab is administered to expectant moms, who pass vaccine-induced antibodies to their fetuses. One in all the corporate’s vaccines targeting respiratory syncytial virus also uses that maternal vaccination method. 

Pfizer’s encouraging phase two trial results provide hope that maternal vaccination against the disease, also often known as GBS, could help prevent 1000’s of cases in babies. 

The outcomes may even help the corporate plan its phase three clinical trials on the shot, that are typically required before the FDA approves a drug.

The Bill & Melinda Gates Foundation, which supported the phase two trial, provided a further $100 million grant to Pfizer last yr that may fund late-stage trials and help facilitate the delivery of shots to lower-income countries following a possible approval.

GBS disease is brought on by a common and frequently harmless bacteria that many adults carry of their bodies.

But an expectant mother can pass that bacteria to a newborn during labor and delivery, which may cause severe infections in the course of the baby’s first few weeks or months of life.  

About 1 out of each 4 women carries GBS bacteria, based on the Centers for Disease Control and Prevention. 

Infants with GBS infections can experience symptoms including fever and difficulty respiratory.

Some infants can experience invasive GBS infections, which cause more serious complications resembling pneumonia, infections within the bloodstream, and meningitis, or the inflammation of tissues surrounding the brain and spinal cord.

There are 10 different GBS serotypes, meaning distinct variations of the bacteria that causes the disease. Pfizer’s vaccine targets six of essentially the most outstanding serotypes, which collectively account for 98% of GBS disease cases worldwide. 

Pfizer’s trial followed 360 healthy pregnant individuals in South Africa. The moms were randomly assigned to receive a single shot at three different dosage levels, with or with out a specific adjuvant, or a placebo. 

The trial found that Pfizer’s shot generated robust antibodies against the six GBS serotypes in moms. Those antibodies were “efficiently transferred” to infants at ratios between 0.4 and 1.3, depending on the dose. 

Meaning some infants received only a fraction of antibodies from their moms, while others received higher antibody levels than even what their moms had. 

Pfizer said those antibody transfer levels are related to a reduced risk of GBS disease. That conclusion was based on a parallel natural history conducted in South Africa.

The protection profile for each moms and infants gave the impression to be similar between the vaccine and placebo groups, based on the trial results, suggesting that the shot was generally well tolerated in the course of the phase two trial.

Reactions amongst moms following vaccination were generally mild or moderate and short in duration. Between 2% to eight% of participants who received the shot reported fever, compared with 5% within the placebo group, based on the outcomes. 

Around 45% to 70% of pregnant individuals who received the vaccine experienced more hostile reactions resembling headache and vomiting. However the placebo group wasn’t much different, with greater than 60% of expectant moms experiencing those hostile events. 

About 62% to 75% of infants within the vaccine group and 74% of those within the placebo group experienced hostile events, including upper respiratory tract infection. There have been three infant deaths within the vaccine group and two within the placebo group.

The study authors determined that no hostile events or deaths amongst infants were related to the vaccine.

The outcomes come as Pfizer braces for a continued decline in Covid-related sales this yr.