FDA Gives Nod to Dalvance (Dalbavancin) for Skin Infections
Treatment comparable with vancomycin in phase III trials
The FDA has given the "OK" to Dalvance (dalbavancin, Durata Therapeutics), a new antibacterial drug used to treat adults with skin infections.
Dalvance is intended to treat acute bacterial skin and skin-structure infections (ABSSSIs) caused by certain susceptible bacteria, such as Staphylococcus aureus (including methicillin-susceptible and methicillin-resistant strains) and Streptococcus pyogenes. The treatment is administered intravenously.
Dalvance is the first drug designated as a qualified infectious disease product (QIDP) to receive FDA approval. The treatment was granted the QIDP designation because it is an antibacterial or antifungal human drug intended to treat serious or life-threatening infections.
As part of its QIDP designation, Dalvance was given priority review, which provides an expedited review of the drug’s application. The QIDP designation also qualifies the drug for an additional 5 years of marketing exclusivity to be added to certain exclusivity periods already provided by the Food, Drug, and Cosmetic Act.
The safety and efficacy of dalbavancin were evaluated in two phase III clinical trials involving a total of 1,289 adults with ABSSSI. The participants were randomly assigned to receive 2 weeks of treatment with either dalbavancin (1,000 mg followed 1 week later by 500 mg) or vancomycin (1,000 mg or 15 mg/kg every 12 hours, with the option to switch to oral linezolid after 3 days).
The primary endpoint of the two studies was the clinical response rate, where responders were defined as patients who had no increase from baseline in lesion area 48 to 72 hours after the initiation of therapy, and had a temperature consistently at or below 37.6o C on repeated measurement.
The results showed that dalbavancin was as effective as vancomycin for the treatment of ABSSSI. In the first trial, the clinical response rates were 83.3% for dalbavancin compared with 81.8% for vancomycin/linezolid. In the second trial, the corresponding response rates were 76.8% and 78.3%.
A key secondary endpoint in both trials evaluated the percentage of intention-to-treat patients who achieved a 20% or greater reduction in lesion area from baseline at 48 to 72 hours after the initiation of therapy. In trial 1, 89.9% of the dalbavancin group met this endpoint compared with 90.9% of the vancomycin/linezolid group. In trial 2, the corresponding rates were 87.6% and 85.9%.
Another secondary endpoint in the two trials was the clinical success rate assessed at a follow-up visit occurring between days 26 to 30. Clinical success was defined as having a decrease in lesion size (in both length and width measurements), a temperature of 37.6o C or lower, and meeting pre-specified criteria for local signs.
In the first trial, the clinical success rates in evaluable patients were 93.8% for dalbavancin and 96.1% for vancomycin/linezolid. In the second trial, the corresponding rates were 96.3% and 94.5%.
The most common side effects identified in the two clinical studies were nausea, headache, and diarrhea. More participants in the dalbavancin group had elevations in one of their liver enzyme tests. The drug label for Dalvance provides recommendations on dosage adjustments in patients with renal impairment.