GlaxoSmithKline and Human Genome Sciences, Inc's Benlysta

Ths FDA approved Benlysta (belimumab) for the treatment of adults with active, autoantibody- positive systemic lupus.

Benlysta (belimumab) has been approved by the FDA for the treatment of adults with active, autoantibody-positive systemic lupus erythematosus (SLE) who are receiving standard therapy.

The approval carries the limitations that Benlysta has not been studied in patients with severe active lupus nephritis or severe active central nervous system lupus, nor has its use been evaluated in combination with other biologics or intravenous cyclophosphamide, and thus it should not be used in these situations. ¹

Each year in the United States, more than 16,000 individuals are diagnosed with SLE. ² Benlysta is marketed by GlaxoSmithKline and Human Genome Sciences, Inc, and is the first new treatment approved for SLE in more than 50 years. ³ PharmacoloGy and PharmacoKineticS Benlysta is a human immunoglobulin G1λ monoclonal antibody that is specific for soluble human B-lymphocyte stimulator protein (BLyS). Although Benlysta does not bind directly to B cells, it exerts its effect by blocking the binding of soluble BLyS to its B cell receptors, thus inhibiting the survival of B cells, including autoreactive B cells, and reducing the differentiation of B cells into immunoglobulin-producing plasma cells. ¹ Benlysta is the first in its class of BLyS-specific inhibitors. ³

The pharmacokinetics of Benlysta were not affected by age; however, none of the patients included in the study were younger than 18 years and only 1.4% of the study population was 65 years or older.

Although gender did not appear to impact the pharmacokinetics of Benlysta, 94% of the study population was female. Benlysta’s pharmacokinetics were not affected by race, renal impairment, or hepatic impairment. ¹

Dosing and Administration

Benlysta should only be administered by intravenous infusion after reconstitution and dilution. The dose should be given over 1 hour as 10 mg/kg at 2-week intervals for the first 3 doses and at 4-week intervals thereafter.

Consideration should be given to premedication against infusion and hypersensitivity reactions. Should a serious hypersensitivity reaction occur, Benlysta should be discontinued immediately. ¹

Clinical Trials

Benlysta was studied in 3 randomized, double-blind, placebo-controlled trials of 2133 patients with SLE. The first trial compared doses of Benlysta 1, 4, or 10 mg/ kg plus the standard of care with placebo plus the standard of care over 52 weeks. Although the results of this trial did not show Benlysta to have a benefit, it did influence the design of subsequent trials. Trials 2 and 3 evaluated Benlysta 1 or 10 mg/kg plus the standard of care or placebo plus the standard of care. Both trials 2 and 3 demonstrated a significant difference in patients achieving the SLE Responder Index between the 10 mg/kg dose and placebo. There was no significant difference with the 1 mg/kg dose. ¹

Contraindications, Warnings, and Precautions

Benlysta is contraindicated in patients who have previously had an anaphylactic reaction to it.

In clinical trials, more deaths were reported in the Benlysta arm than the placebo arm. Benlysta should be used cautiously in patients with chronic infections, as serious and sometimes fatal infections have been reported in patients using immunosuppressive agents, including Benlysta.

Serious hypersensitivity reactions and anaphylaxis have been reported in patients using Benlysta; it should only be administered by health care providers who are trained to manage such reactions. Patients should be monitored during and after administration. Depression and suicidality have been reported in patients using Benlysta. Live vaccines should not be administered 30 days prior to and during treatment with Benlysta.

Benlysta is pregnancy category C and a registry has been established to monitor maternal-fetal outcomes. It is not known if Benlysta is excreted into human breast milk; it should not be used by mothers who are nursing. Benlysta is not approved for pediatric patients. ¹

The most common adverse reactions are nausea, diarrhea, pyrexia, nasopharyngitis, bronchitis, insomnia, pain in extremities, depression, migraine, and pharyngitis. ³ PT

Dr. Holmberg is a pharmacist who resides in Phoenix, Arizona.

References

1. Benlysta complete prescribing information. www.hgsi.com/images/Benlysta/pdf/benlysta_pi.pdf. Accessed May 2011.

2. About lupus. www.lupus.org. Accessed May 2011.

3. GlaxoSmithKline and Human Genome Sciences announce FDA approval of Benlysta (belimumab) for the treatment of systemic lupus erythematosus.

www.gsk.com/media/pressreleases/2011/2011_us_pressrelease_10017.htm.Accessed May 2011.