The FDA has rejected Hyloris Pharmaceuticals antiviral valacyclovir, an oral suspension for infections caused by herpes simplex and varicella zoster viruses.
In a complete response letter (CRL), the FDA said it identified issues in an inspection of Hyloris’ third-party manufacturer. The U.S. regulator did not specify the problems in the CRL, explaining that they were itemized to a representative of the production facility.
The CRL was not a surprise. In a release last month, Belgium-based Hyloris explained (PDF) that the FDA had assigned an official action indicated (OAI) classification to the Greek facility after an inspection.
An OAI is the most severe of three FDA inspection classifications, indicating that the plant does not meet current good manufacturing practice (cGMP) standards and requires significant corrective actions.
“The manufacturer has a well-established track record of pharmaceutical production and supply, serving multiple clients in regulated markets, including the U.S.,” Hyloris explained in February of the plant. “Following the inspection outcome, the manufacturer has paused the manufacturing of products destined for the U.S. while currently still producing oral dosage forms for markets outside of the U.S.”
Hyloris added in February that it was working on a “manufacturing solution” for the product. The original target date for an FDA decision was in October.
In the CRL, the FDA said it would need to conduct a cGMP inspection plus a preapproval inspection before approving its new drug application. Additionally, the CRL spelled out that Hyloris needed to provide more safety information from all clinical and nonclinical studies of valacyclovir in all the indications in which it has been tested.
Three decades ago, GSK scored FDA approval of Valtrex, a tablet form of valacyclovir, for treating herpes zoster, with subsequent nods to include genital herpes and cold sores. It became available as a generic treatment in 2010.
In 2022, the FDA rejected (PDF) another Hyloris candidate because of a packaging problem. A year later, the U.S. regulator signed off on Maxigesic IV, an intravenous post-surgery pain relief medicine.
The FDA has sent out several manufacturing-related CRLs recently, including at least two on Feb. 27. One was to Ferring Pharmaceuticals for its human recombinant follicle stimulating hormone Rekovelle.
Another was to Incyte for its PD-1 inhibitor Zynyz. The rejection was over inspection findings at its third-party fill-finish facility, a former Catalent plant in Bloomington, Indiana, which is now owned by Novo Nordisk. The massive plant has been cited in several CRLs over the last several months.
