Infectious Disease Treatments on FDA’s Watchlist for Q2 2025
Novavax’s COVID-19 vaccine, Merck’s RSV antibody, and Innoviva’s gonorrhea antibiotic await regulatory decisions this quarter.
As we enter the second quarter of 2025, the FDA is reviewing treatments in infectious disease. Novavax is seeking full approval for its COVID-19 vaccine, Merck’s monoclonal antibody for RSV prevention is under review, and Innoviva has applied an oral antibiotic for gonorrhea. Here is what to expect in the coming months.
Novavax COVID-19 Vaccine
PDUFA Date: April 2025
Company: Novavax
The Novavax COVID-19 vaccine is a protein-based vaccine that has received Emergency Use Authorization (EUA) and is now seeking full approval for the prevention of COVID-19 infections. It offers an alternative to mRNA-based vaccines and is designed for individuals who prefer a more traditional vaccine platform.
We recently interviewed Robert Walker, MD, Novavax’s Chief Medical Officer, about the latest findings from the Phase 2/3 trial of NVX-CoV2601, the company’s updated COVID-19 vaccine. The study demonstrated that NVX-CoV2601 elicited significantly higher neutralizing antibody responses than its predecessor, with a geometric mean titer nearly six times greater than NVX-CoV2373. These results highlight the importance of updating vaccines to match circulating variants and reinforce Novavax’s commitment to developing effective, adaptable booster options in the fight against COVID-19.
According to a recent Morbidity and Mortality Weekly Report (MMWR) from February 2025, the FDA has authorized a monovalent 2024–2025 COVID-19 vaccine from Novavax for individuals aged 12 and older.
Clesrovimab
PDUFA Date: June 10, 2025
Company: Merck
Merck's investigational monoclonal antibody, Clesrovimab (MK-1654), has been accepted by the FDA for review. If approved, it will be the first single-dose immunization for infants, regardless of weight, offering protection throughout their first RSV season.
In a Phase 2b/3 trial, Clesrovimab showed promising results in preventing respiratory syncytial virus (RSV). The treatment reduced RSV-associated medically attended lower respiratory infections by 60.4% and hospitalizations by 84.2%, with severe cases of MALRI declining by 91.7%. The trial enrolled 3,632 infants, and results indicated a safety profile comparable to placebo.
In an interview, Anushua Sinha, MD, discussed the trial's findings and Clesrovimab's potential to improve RSV prevention. Additionally, a Phase 3 trial comparing Clesrovimab with Palivizumab in high-risk infants demonstrated similar safety profiles and efficacy. This treatment simplifies RSV prevention with a fixed dose for all infants, which could improve efficiency in pediatric care settings.
Clesrovimab represents a new approach to RSV prevention, potentially extending protection beyond high-risk infants to all babies during their first RSV season.
Zoliflodacin
PDUFA Date: Q1 2025 (Exact date TBD)
Company: Innoviva Specialty Therapeutics
Zoliflodacin is an investigational oral antibiotic designed to treat uncomplicated gonorrhea, including strains resistant to existing antibiotics. As antimicrobial resistance continues to pose a global health threat, zoliflodacin offers a promising single-dose alternative for combating this sexually transmitted infection (STI).
In a late-stage Phase 3 trial, zoliflodacin demonstrated non-inferiority to the standard dual therapy of ceftriaxone and azithromycin. The study, which included a global, randomized, controlled design, showed a 90.9% microbiological cure rate, compared to 96.2% with the standard treatment. The antibiotic also exhibited a favorable safety profile with comparable adverse event rates across treatment arms.
The rise of multidrug-resistant gonorrhea, particularly the penA 60.001 allele, has intensified the need for new treatment options. Given its success in clinical trials, Innoviva Specialty Therapeutics plans to submit a New Drug Application (NDA) to the FDA in Q1 2025. Zoliflodacin has already received qualified infectious disease product (QIDP) and fast track designations, which could expedite its regulatory review.
David Altarac, MD, Chief Medical Officer at Innoviva, highlighted that zoliflodacin’s development is specifically focused on uncomplicated gonorrhea, ensuring its responsible use while addressing an urgent medical need.
Several key regulatory decisions are expected in the second quarter of 2025. The FDA’s review of these treatments will determine their availability and potential role in infectious disease prevention and treatment.
