Background/Purpose: Belimumab (Benlysta) is a human monoclonal antibody that inhibits soluble B-Lymphocyte Stimulator and improves SLE disease activity. This study was initiated to evaluate the use and efficacy of Belimumab in academic SLE clinical practices.

Methods: An invitation to participate was sent to 16 physicians experienced in SLE Phase III clinical trials. All agreeing to participate completed a one page questionnaire for each patient (pt) prescribed Belimumab. Information collected included: demographics (age, gender, race/ethnicity), SLE data (duration of disease, SELENA-SLEDAI, clinical manifestation(s) targeted, background medications), and Belimumab information (start date, clinical response, side effects). Clinical response was defined as the investigator’s impression of a ≥50% improvement in the initial manifestation being treated and no worsening in other organ systems.

Results: Of 16 invitations sent, nine investigators participated. Questionnaires on 151 treated pts were returned. The mean age was 43.1±11.8 years. 92.1% were female, 69.7% White, 21.2% Black, 6.1% Asian, and 4.5% Hispanic. The average SLE disease duration was 12.9±8.4 years. 3 pts (2.4%) were ANA negative. Concomitant medications included: antimalarials in 71.5%, immunosuppressants in 72.2% (Azathioprine 21.9%, Mycophenolate Mofetil 37.1%, Methotrexate 13.2%), and prednisone in 70.9% (mean dose of 12.3±11.3, 38.3% on ≥10 mg). Only 2.6% of pts were not on any background SLE medications. 12 pts (7.9%) were on anti-malarials alone. The dominant clinical manifestations driving treatment were arthritis in 73.5%, rash in 51.0%, and serositis in 17.2%. Other SLE manifestations were renal 12.0%, hematological 14.6%, and inability to taper steroids 20.5%. 70.2% of pts had ≥2 active manifestations. Data on 115 pts on Benlysta for at least 3 months (mos.) were available for analysis. Of those, 55 (47.8%) clinically responded by 3 mos. with marked improvement in arthritis and/or rash. Similarly, of the 79 pts on Benlysta for at least 6 mos., 46 (58.2%) clinically responded with improvements in arthritis, rash and/or nephritis. Clinical response for each of the SLE manifestations was also evaluated. At 3 mos., 36 of 61 (59.0%) pts with arthritis clinically responded with marked improvement and at 6 mos., 24 of 50 (48.0%). For rash, 19 of 57 (33.3%) pts responded at three mos. and 20 of 40 (50.0%) at six mos. Interestingly, of the 5 pts with renal involvement for whom follow up data are available, 4 of 5 (80.0%) improved at 3 mos. and 2 of 3 at 6 mos. Data on blacks shows a similar pattern of improvement. At 3 mos., 13 of 17 (76.5%) improved and at 6 mos., 13 of 16 (81.2%). Of the 20 (13.2%) pts overall in whom Benlysta was discontinued, 3 had CNS lupus, 1 MI, 3 losses of insurance, 3 infections, 3 infusion reactions, 1 severe arthritis flare, 1 stroke-like symptoms, 1 worsening neuropsychiatric condition, 1 worsening myositis, 1 elective surgery, and 2 no clinical response.

Conclusion: These early data support the use of Benlysta across all ethnic groups and efficacy similar to that reported in the Phase III trials. While the numbers are limited, black pts showed an improvement at 3 mos. Relevant to physician and pt decision-making, improvement was observed within 3 mos.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/favorable-clinical-response-to-belimumab-at-three-months/