FDA Approves Another Fixed-Dose HIV-1 Treatment: Symfi Lo Tablets

On the heels of the US Food and Drug Administration (FDA) granting approval to Gilead Science Inc.’s Biktarvy for the treatment of individuals with HIV-1, another fixed-dose HIV treatment has received approval: Symfi Lo Tablets for the treatment of HIV-1 in adult and pediatric patients who weigh at least 35 kg.

Symfi Lo Tablets is a combination product comprised of efavirenz (EFV) 400 mg, lamivudine (3TC) 300 mg, and tenofovir disoproxil fumarate (TDF) 300 mg. The recommended dose is 1 tablet, taken once-daily, on an empty stomach right before bed. Taking the dose at bedtime may make nervous system symptoms more tolerable.

The FDA recommends that patients be tested for hepatitis B virus infection previous to initiating treatment with this product, as well as throughout treatment. Furthermore, creatinine clearance, urine glucose, and urine protein should also be collected.

The FDA warns against using Symfi Lo tablets in those with CrCL of less than 50 mL/min or individuals with end-stage renal disease who require hemodialysis. Furthermore, patients suffering from moderate to severe hepatic impairment should also not use the product. Prescribers should “use caution in patients with mild hepatic impairment,” according to the product label.

The tablets proved effective for the treatment of HIV-1 infection in treatment-naïve adult patients in the following 2 clinical trials: Trial 903 which assessed the effectiveness of the combination product, and ENCORE1 which compared the 400 mg of EFV included in the triple drug regimen with a 600 mg dose of EFV in a triple-drug regimen.

Specifically, the ENCORE1 compared these doses in a total of 630 antiretroviral-naïve adults. Those adults were randomly assigned into 2 groups: those receiving EFV 400 mg in combination with TDF 300 mg plus FTC 200 mg once-daily, and those receiving EFV 600 mg in combination with TDF 300 mg/FTC 200 mg, also once-daily.

The mean baseline CD4+ cell count was 273 cells/mm3, while the median baseline viral load was 56,469 copies/mL. Furthermore, approximately 34% of subjects had baseline viral load of ≥ 100,000 copies/mL, according to the release.

Slightly more patients who were taking the EFV 400-mg dose regimen responded to treatment at 48 weeks, while virologic failure was similar for both therapies. The mean increase at Week 48 from baseline in CD4+ cell count was 183 cells/mm3 for the EFV 400-mg group and 158 cells/mm3 for the EFV 600 mg group, according to the release.

During the 48-week period, 11 patients in the 400-mg group and 5 subjects in the 600-mg group experienced a new CDC Class C event, the FDA concluded.

The most common adverse reactions are rash and dizziness, according to the FDA.

The product should not be given with other ART medications for the treatment of HIV-1. Furthermore, the FDA notes that co-administration of this product could potentially change the concentrations of other drugs, and other drugs could potentially alter the concentration of Symfi Lo.

Health care providers should consider the potential for drug-drug interaction prior to beginning therapy.