FDA clears French syphilis drug imports to tackle shortage

syphilis treatment for pregnant women
Christian Bowen

Facing a sharp rise in the number of syphilis cases, the FDA has authorised the importation from France of a life-saving drug for the sexually transmitted infection (STI) that is in short supply in the domestic market.

The US regulator has cleared the way for imports of Laboratoires Delbert’s Extencilline (benzathine benzylpenicillin), a long-acting form of penicillin that has been used for decades to treat syphilis in Europe, but has never been approved in the US.

Extencilline will be used as an alternative to Pfizer’s FDA-approved product Bicillin L-A, another long-acting product based on the same active ingredient that has been subject to shortages in the US and other countries worldwide since the middle of last year.

According to the American Society of Hospital Pharmacists (ASHP), the reason for the shortage is “increased demand […] due to increased syphilis infection rates.”

The organisation has said it is particularly concerned about supplies of formulations of the drug used to treat pregnant women with syphilis, so they do not transmit the infection to their newborns, which causes a congenital form of the disease that can lead to serious disability and death.

The US is currently facing a 27-year high in syphilis cases that, according to media reports, has resulted in horse-trading of available supplies and off-label use of other antibiotics to try to treat patients, which could be less effective and raise the risk of resistance.

For example, while doxycycline is an effective drug for syphilis, patients can struggle to complete treatment courses with the drug, due to tolerability issues, leaving their infection untreated and risking continued community transmission.

In November, the Centres for Disease Control and Prevention (CDC) sounded the alarm about an increase in cases of newborn syphilis fuelled by “a rapidly accelerating epidemic of sexually transmitted infections in the US.”

It said 3,761 babies were recorded as being born with syphilis in 2022, which was more than 10 times the number in 2012 and follows rising syphilis cases among women of reproductive age, combined with “social and economic factors that create barriers to high-quality prenatal care and ongoing declines in the prevention infrastructure and resources.”

Pfizer has said it is taking steps to ramp up manufacturing of Bicillin L-A, but production cycles mean that the situation isn’t likely to be resolved until the spring at the earliest. It makes the product at a facility in Rochester, New York, so the supply problems are not related to the tornado that hit its Rocky Mount facility in North Carolina last year.

Millions of doses of Labs Delbert’s product are being imported into the US via an initiative with Provepharm, Direct Success, and the FDA, and the regulator has published instructions on how the drug should be used by US healthcare providers, as its labelling does not comply with national standards.

The National Coalition of STD Directors (NCSD) said after the FDA announcement that the emergency import plan is an “important step” to protect pregnant people and babies by ensuring US doctors have the essential medicine they need to treat and prevent congenital syphilis.

“We hope this is the first step towards seeing a resolution to this shortage, and that HHS and FDA will continue to take steps to ensure that communities never experience a syphilis treatment shortage again,” said David Harvey, executive director of the NCSD.