OP0221 EFFICACY OF SECUKINUMAB IN ENTHESITIS-RELATED ARTHRITIS: RESULTS FROM A RANDOMISED, DOUBLE-BLIND, PLACEBO-CONTROLLED, TREATMENT WITHDRAWAL, PHASE 3 STUDY (JUNIPERA)

Background

Enthesitis-related Arthritis (ERA) is a category of juvenile idiopathic arthritis (JIA) characterised by heterogeneous and insidious manifestations comprising axial and/or peripheral arthritis, and enthesitis.1 Secukinumab (SEC) demonstrated efficacy and safety in both ERA and juvenile psoriatic arthritis (JPsA) in the JUNIPERA trial.2

Objectives

To evaluate the rate of flare risk reduction and efficacy of SEC on axial and peripheral manifestations in patients (pts) with active ERA.

Methods

ERA pts (2 to <18 years of age) with active disease (both ≥3 active joints and ≥1 active enthesitis site) were included. In the open-label (OL) treatment-period (TP)1, s.c. SEC (75/150 mg in pts <50/ ≥50 kg) was administered at baseline (BL), and at Week (Wk) 1–4, 8 and 12. Pts who achieved at least JIA-ACR30 response at Wk 12 were randomised into the double-blinded TP2 to continue SEC or placebo (PBO) every 4 wk until a disease flare, or up to Wk 100. The primary endpoint was time to flare in ERA and JPsA pts. The juvenile spondyloarthritis disease activity Index (JSpADA) is a disease activity assessment tool that contains 8 items to measure axial and peripheral disease activity.3 Evaluation of axial and peripheral manifestations at the end of TP1 and TP2 in pts who experienced these symptoms at BL included modified Schober test (lumbar flexion), inflammatory back pain, FABER (Flexion, ABduction, External Rotation) test, JIA-ACR responses, Juvenile Arthritis Disease Activity Score (JADAS)-27, and resolution of enthesitis and dactylitis for peripheral disease. These outcomes were also used to assess JIA disease course at the end of TP2.

Results

A total of 52/86 (60.5%) pts with ERA were enrolled in the OL period TP1 (mean age, 13.7 years; male, 78.8%). In total, 51/52 (98.1%) pts completed TP1 and 41/44 (93.2%) completed TP2. At BL, mean JADAS-27 was 14.8, mean JSpADA index was 3.9, mean enthesitis and dactylitis counts were 2.7 and 0.4, respectively, mean number of active joints was 6.2 and of mean joints with limited range of motion 4.9. The relative risk reduction of experiencing a disease flare in TP2 was 55% (HR 0.45, 95% CI: 0.16–1.28, p=0.075) in ERA pts (Figure 1). The overall axial and peripheral disease symptoms improved over time and are presented in the Table 1. At the end of TP1, 84.6% (44/52) of pts achieved JIA-ACR 30 and 65.4% (34/52) achieved JIA-ACR 70. Clinically relevant reduction of functional ability as assessed by Childhood Health Assessment Questionnaire (CHAQ) also occurred (see Table 1).

Table 1.

Resolution of axial and peripheral disease symptoms and JIA ACR responses at the end of TP1 and 2

Clinical response, mean (SD) change from BL (unless otherwise stated)TP1-Wk 12End of TP2*SEC (N=52)SEC (N=22)PBO (N=22)JSpADA index−2.4 (1.7)−2.7 (1.7)−2.3 (2.1)JSpADA Schöber, %58.3100.0100.0Inflammatory back pain, %77.8100.050.0FABER test, %52.6100.083.3Clinical sacroiliitis, %53.3100.050.0Enthesitis−2.2 (1.9)−2.5 (2.1)−1.3 (1.8)Dactylitis−0.2 (0.8)−0.2 (1)−0.1 (0.4)JIA ACR30, %84.690.968.2JIA ACR50, %78.881.868.2JIA ACR70, %65.468.254.5JIA ACR90, %32.745.550.0JIA ACR100, %26.936.445.5Inactive disease, %38.550.050.0CHAQ−0.5 (0.5)−0.6 (0.7)−0.4 (0.5)CRP, median (SD) change from BL−1.8 (38.7)−5.8 (38.3)0 (35.9)JADAS-27−9.6 (7.5)−11.0 (8.9)−7.6 (8.9)Resolution of enthesitis#, %72.378.683.3Resolution of dactylitis#, %5066.70

*End of TP2 is based on individual pts’ last visit at TP2. #At BL, in TP1, enthesitis (n= 46); dactylitis (n=5). In TP2, no. of pts who had presence at BL and showed complete resolution at the end of TP2: enthesitis, SEC 14, PBO 18; dactylitis, SEC 3, PBO, 0. CRP, C-reactive protein

Conclusion

In pts with ERA, SEC demonstrated longer time to disease flare vs PBO and exhibited rapid and sustained improvement of axial and peripheral manifestations up to Wk 104.

References

[1]Pagnini I, et al. Front Med 2021;8:6673052.

[2]Brunner H, et al. Arthritis Rheumatol 2021;73 (suppl 10).

[3]Weiss PF, et al. Arthritis Care Res 2014;66:1775-82.

Disclosure of Interests

Nicolino Ruperto Speakers bureau: Eli Lilly, GlaxoSmith and Kline, Pfizer, SOBI and UCB, Paid instructor for: Eli Lilly and Pfizer, Consultant of: Ablynx, Amgen, Astrazeneca-Medimmune, Aurinia, Bayer, Bristol Myers and Squibb, Cambridge Healthcare Research (CHR), Celegene, Domain therapeutic, Eli Lilly, EMD Serono, GlaxoSmith and Kline, Idorsia, Janssen, Novartis, Pfizer, SOBI and UCB, Grant/research support from: Bristol Myers and Squibb, Eli Lilly, F Hoffmann-La Roche, Novartis, Pfizer and SOBI, Elena Chertok: None declared, Joke Dehoorne Speakers bureau: Abbvie, Roche, Consultant of: Abbvie, Roche, Pfizer, Grant/research support from: Abbvie, Roche, Gerd Horneff Speakers bureau: Novartis, Pfizer, Janssen, Grant/research support from: Pfizer, Novartis, Roche, MSD, Tilmann Kallinich Speakers bureau: Roche, Ingrid Louw Speakers bureau: Pfizer, Abbvie, BMS, Consultant of: Pfizer, Abbvie, Janssen, Amgen and Cipla, Sandrine Compeyrot-Lacassagne: None declared, Bernard Lauwerys Employee of: UCB Pharma, Neil Martin: None declared, Katherine Marzan Grant/research support from: Novartis, Sanofi, William Knibbe Speakers bureau: Novartis, Amgen, UCB, Abbvie, Ruvie Martin Shareholder of: Novartis, Employee of: Novartis, Xuan Zhu Shareholder of: Novartis, Employee of: Novartis, sarah whelan Shareholder of: Novartis, Employee of: Novartis, Luminita Pricop Shareholder of: Novartis, Employee of: Novartis, Alberto Martini Speakers bureau: Aurinia, Bristol Myers and Squibb, Eli Lilly, EMD, Janssen, Pfizer, Roche and Serono, Consultant of: Aurinia, Bristol Myers and Squibb, Eli Lilly and EMD, Daniel J Lovell Consultant of: Astra Zeneca, Boehringer Ingelheim, GSK, Hoffman LaRoche, Novartis, UBC, Grant/research support from: Astra Zeneca, Boehringer Ingelheim, GSK, Hoffman LaRoche, Novartis, UBC, Hermine Brunner Consultant of: Novartis, Grant/research support from: Novartis

LB0004 EFFICACY AND SAFETY OF SECUKINUMAB IN ENTHESITIS-RELATED ARTHRITIS AND JUVENILE PSORIATIC ARTHRITIS: PRIMARY RESULTS FROM A RANDOMISED, DOUBLE-BLIND, PLACEBO-CONTROLLED, TREATMENT WITHDRAWAL, PHASE 3 STUDY (JUNIPERA)

Background:

Enthesitis-related arthritis (ERA) and juvenile psoriatic arthritis (JPsA) are two ILAR categories of juvenile idiopathic arthritis (JIA) and represent paediatric correlates of axial spondyloarthritis (axSpA) and adult psoriatic arthritis (PsA), respectively.1,2 Secukinumab (SEC) has demonstrated efficacy and safety in adult patients (pts) with PsA, ankylosing spondylitis and non-radiographic axSpA.3-5

Objectives:

Evaluate efficacy and safety of SEC using a flare prevention design in pts with active ERA and JPsA.

Methods:

This 2-yr study consisted of an open-label (OL) s.c. SEC (75/150 mg in pts <50/ ≥50 kg) at baseline (BL), and at Weeks (Wk) 1, 2, 3, 4, 8 and 12 in treatment-period (TP) 1. Responder pts who achieved at least JIA ACR 30 response at Wk 12 were randomised into the double-blinded TP2 to continue SEC or placebo (PBO) q4w until a disease flare, or up to Wk 100. Pts (aged 2 to <18 yrs) classified as ERA or JPsA according to ILAR criteria of ≥6 months duration with active disease were included. Primary endpoint was time to flare in TP2 and key secondary endpoints were JIA ACR 30/50/70/90/100, inactive disease, JADAS, enthesitis count and safety. Analysis of time to flare in TP2 included proportion of disease flare, Kaplan-Meier (KM) estimate of median time to flare in days, hazard ratio (95% CI) from Cox model, and P-value for the Stratified log-rank test. KM estimates of the probability to disease flare by treatment groups in TP2 were plotted against days. Observed data were used in all analyses. Post-hoc analyses using non-responder imputation (NRI) were performed for JIA ACR 30/50/70/90/100 responses.

Results:

86/97 (89%) pts were enrolled in the OL period TP1 (mean age, 13.1 yrs; female, 33.7%; ERA, n=52; JPsA, n=34). At BL, mean JADAS-27 score was 15.1 and enthesitis count was 2.6. At the end of TP1, 90.4% (75/83) of pts achieved JIA ACR 30 and 69.9% (58/83) achieved JIA ACR 70. There were 21 and 10 flares in TP2, respectively in PBO and SEC treated pts with a significantly longer time to flare and 72% risk of flare reduction in SEC treatment vs PBO (HR: 0.28; 95% CI: 0.13–0.63; P<0.001) (Figure 1). JIA ACR responses, disease activity and enthesitis count are reported in Table 1. NRI analyses showed that 87.2%, 83.7%, 67.4%, 38.4% and 24.4% of pts achieved JIA ACR 30/50/70/90/100, respectively. Rates of adverse events (AEs; 91.7% vs 92.1%) and serious AEs (14.6% vs 10.5%) in SEC and PBO groups were comparable in the entire TP. No new safety signals were observed.

Table 1.

Efficacy of secukinumab in Treatment Periods 1 and 2 (Key secondary endpoints)

Efficacy Outcomes, %TP1TP2¥SEC (N=83)^SEC (N=37)PBO (N=37)P-valueJIA ACR 3090.489.264.90.014JIA ACR 5086.778.462.20.152JIA ACR 7069.967.643.20.042JIA ACR 9039.851.440.50.431JIA ACR 10025.343.237.80.745Inactive disease#36.147.237.80.500JADAS-27, mean (SD)15.1 (7.2)14.6 (8.1)13.3 (5.8)NAEnthesitis count, mean change from BL (SD)−1.8 (2.3)−2.1 (2.0)−1.9 (1.2)NA

P-values: Cochran-Mantel-Haenszel test, adjusted for analysis factors: JIA category (ERA/ JPsA) and MTX use at BL

¥The N numbers are values at the end of TP2

^Efficacy outcomes (%) in TP1 calculated in patients with evaluable data at Wk 12 (N=83)

#Inactive disease: Definition adapted from JIA ACR criteria of Wallace et al., 2011. N=36 for SEC at the end of TP2

JADAS, Juvenile Arthritis Disease Activity Score; N, total number of patients in the treatment group; NA, data not available

Figure 1.

Time to flare in Treatment Period 2 (Primary Endpoint)

Conclusion:

In children and adolescents with ERA and JPsA, efficacy of SEC was demonstrated with a significantly longer time to flare vs PBO with sustained improvement of signs and symptoms up to Wk 104 and a favourable safety profile.

References:

[1]Colbert RA. Nat Rev Rheumatol. 2010;6:477–85.

[2]Martini A, et al. J Rheumatol. 2019;46:190–7.

[3]McInnes IB, et al. Lancet. 2015;386:1137–46.

[4]Baeten D, et al. N Engl J Med. 2015;373:2534–48.

[5]Deodhar A, et al. Arthritis Rheumatol. 2021;73:110–20.

Disclosure of Interests:

Nicolino Ruperto Consultant of: Ablynx, Astrazeneca-Medimmune, Bayer, Biogen, Boehringer, Bristol Myers and Squibb, Celgene, Eli-Lilly, EMD Serono, Glaxo Smith and Kline, Hoffmann-La Roche, Janssen, Merck, Novartis, Pfizer, R-Pharma, Sinergie, Sobi and UCB, Grant/research support from: BMS, Eli-Lilly, GlaxoSmithKline, F Hoffmann-La Roche, Janssen, Novartis, Pfizer, Sobi, Speakers bureau: Ablynx, Astrazeneca-Medimmune, Bayer, Biogen, Boehringer, Bristol Myers and Squibb, Celgene, Eli-Lilly, EMD Serono, Glaxo Smith and Kline, Hoffmann-La Roche, Janssen, Merck, Novartis, Pfizer, R-Pharma, Sinergie, Sobi and UCB, Ivan Foeldvari Consultant of: Novartis, Speakers bureau: Novartis, Ekaterina Alexeeva Grant/research support from: Novartis, Pfizer, Sanofi, MSD, AMGEN, Eli Lilly, Roche, Speakers bureau: Novartis, Pfizer, Sanofi, MSD, AMGEN, Eli Lilly, Roche, NURAY AKTAY AYAZ: None declared, Inmaculada Calvo Consultant of: Sobi, Novartis, Abbvie, GlaxoSmithKline, Pfizer, Amgen, Clementia, Speakers bureau: Sobi, Novartis, Abbvie, GlaxoSmithKline, Pfizer, Amgen, Clementia, Ozgur KASAPCOPUR: None declared, Vyacheslav Chasnyk: None declared, Markus Hufnagel Grant/research support from: Astellas, F. Hoffmann-La Roche, Novartis, Zbigniew Żuber: None declared, Grant Schulert Consultant of: Sobi, Novartis, Seza Ozen: None declared, Artem Popov: None declared, Athimalaipet Ramanan Speakers bureau: Roche, Sobi, Eli Lilly, UCB, Novartis, Christiaan Scott: None declared, Betül Sözeri: None declared, Elena Zholobova Grant/research support from: Pfizer, Novartis, Speakers bureau: Abbvie, Pfizer, Roche, Novartis, Xuan Zhu Employee of: Novartis, sarah whelan Employee of: Novartis, Shareholder of: Novartis, Luminita Pricop Employee of: Novartis, Shareholder of: Novartis, Angelo Ravelli Consultant of: Abbvie, Bristol-Myers Squibb, Pfizer, Hoffmann-LaRoche, Novartis, Centocor, Angelini Holding, Reckitt Benckiser, Speakers bureau: Abbvie, Bristol-Myers Squibb, Pfizer, Hoffmann-LaRoche, Novartis, Centocor, Angelini Holding, Reckitt Benckiser, Alberto Martini Consultant of: Eli Lilly, EMD Serono, Janssen, Novartis, Pfizer, Abbvie, Speakers bureau: Eli Lilly, EMD Serono, Janssen, Novartis, Pfizer, Abbvie, Daniel J Lovell Consultant of: AstraZeneca, Wyeth, Amgen, Abbott, Pfizer, Hoffmann-La Roche, Novartis, UBC, Takeda, Janssen, GlaxoSmithKline, Boehringer Ingelheim, Celgene, Bristol Myers Squibb, AbbVie, Forest Research, Speakers bureau: AstraZeneca, Wyeth, Amgen, Abbott, Pfizer, Hoffmann-La Roche, Novartis, UBC, Takeda, Janssen, GlaxoSmithKline, Boehringer Ingelheim, Celgene, Bristol Myers Squibb, AbbVie, Forest Research, Hermine Brunner Consultant of: Aurina, AbbVie, Astra Zeneca-Medimmune, Biogen, Boehringer, Bristol-Myers Squibb, Celgene, Eli Lilly, EMD Serono, GlaxoSmithKline, F. Hoffmann-La Roche, Merck, Novartis, R-Pharm, Sanofi, Pfizer, Grant/research support from: Bristol-Myers Squibb, Eli Lilly, GlaxoSmithKline, F. Hoffmann-La Roche, Janssen, Novartis, and Pfizer, Speakers bureau: Pfizer, Roche and GlaxoSmithKline

Efficacy of secukinumab and adalimumab in patients with psoriatic arthritis and concomitant moderate-to-severe plaque psoriasis: results from EXCEED, a randomized, double-blind head-to-head monotherapy study

Background

Secukinumab [an interleukin (IL)‐17A inhibitor] has demonstrated significantly higher efficacy vs. etanercept (a tumour necrosis factor inhibitor) and ustekinumab (an IL‐12/23 inhibitor) in patients with moderate‐to‐severe plaque psoriasis.

Objectives

To report 52‐week results from a prespecified analysis of patients with active psoriatic arthritis (PsA) having concomitant moderate‐to‐severe plaque psoriasis from the head‐to‐head EXCEED monotherapy study comparing secukinumab with adalimumab.

Methods

Patients were randomized to receive secukinumab 300 mg via subcutaneous injection at baseline, week 1–4, and then every 4 weeks until week 48 or adalimumab 40 mg via subcutaneous injection every 2 weeks from baseline until week 50. Assessments in patients with concomitant moderate‐to‐severe psoriasis, defined as having affected body surface area > 10% or Psoriasis Area and Severity Index (PASI) ≥ 10 at baseline, included musculoskeletal, skin and quality‐of‐life outcomes. Missing data were handled using multiple imputation.

Results

Of the 853 patients [secukinumab (N = 426), adalimumab (N = 427)], 211 (24·7%) had concomitant moderate‐to‐severe psoriasis [secukinumab (N = 110, 25·8%), adalimumab (N = 101, 23·7%)]. Up to week 50, 5·5% of patients discontinued secukinumab vs.17·8% in the adalimumab group. The proportion of patients who achieved American College of Rheumatology (ACR) 20 response was 76·4% with secukinumab vs. 68·3% with adalimumab (P = 0·175), PASI 100 response was 39·1% vs. 23·8% (P = 0·013), and simultaneous improvement in ACR 50 and PASI 100 response at week 52 was 28·2% vs. 17·7%, respectively (P = 0·06). Secukinumab demonstrated consistently higher responses vs. adalimumab across skin endpoints.

Conclusions

This prespecified analysis in PsA patients with concomitant moderate‐to‐severe plaque psoriasis in the EXCEED study provides further evidence that IL‐17 inhibitors offer a comprehensive biological treatment to manage the concomitant features of psoriasis and PsA.

What is already known about this topic?

Secukinumab, an interleukin‐17A inhibitor, has previously been reported to have significantly higher efficacy in head‐to‐head trials vs. etanercept and ustekinumab in patients with moderate‐to‐severe plaque psoriasis.

What does this study add?

The results of the study provide valuable head‐to‐head data on the efficacy of two biologics with different mechanisms of action (secukinumab and adalimumab) as first‐line biological monotherapy for patients with psoriatic arthritis and concomitant moderate‐to‐severe plaque psoriasis.

The findings of this study can further help physicians to make informed and evidence‐based decisions for the treatment of patients with active psoriatic arthritis who have concomitant moderate‐to‐severe plaque psoriasis.

Linked Comment: E. Sbidian and L. Pina‐Vegas. Br J Dermatol 2021; 185:1085.

OP0227 SECUKINUMAB VERSUS ADALIMUMAB HEAD-TO-HEAD COMPARISON IN BIOLOGIC-NAÏVE PATIENTS WITH ACTIVE PSORIATIC ARTHRITIS THROUGH 52-WEEKS (EXCEED): A RANDOMISED, DOUBLE-BLIND, PHASE-3B STUDY

Background:

Secukinumab (SEC), an interleukin-17A inhibitor, has demonstrated improvements on multiple domains of psoriatic arthritis (PsA).1Adalimumab (ADA), a TNF inhibitor, is widely used as a first–line biologic in PsA.

Objectives:

To report efficacy and safety outcomes from the head-to-head EXCEED trial (NCT02745080) that compares SECvs.ADA as first–line biologic monotherapy through 52-weeks (wks), with a musculoskeletal primary endpoint in pts with active PsA.

Methods:

Head-to-head, phase-3b, randomised, double-blind trial: biologic naïve active PsA pts were randomised to receive SEC 300mg subcutaneous at baseline, Wk1-4, and then every 4wks (q4w) until Wk48 or ADA 40mg subcutaneous at baseline and then q2w until Wk50. The primary endpoint was superiority of SECvs.ADA on ACR20 response at Wk52. Binary and continuous variables were analysed using logistic-regression model and MMRM, respectively. Safety analysis included patients who received ≥1 dose of study-drug.

Results:

853 pts were randomised to receive SEC (n=426) or ADA (n=427). Baseline demographics and disease characteristics were comparable between treatment-groups except higher proportion of female pts and pts without enthesitis in the SEC group. ACR20 response at Wk52 for SECvs.ADA were 67·4%vs.61·5%, respectively (p=0·0719) (Figure). Higher clinical responses were observed with SECvs.ADA for a range of musculoskeletal, skin, and higher-hurdle outcomes (Table). A higher retention rate was observed for SEC (85.7%)vs.ADA (76.3%). Safety profiles of SEC and ADA were consistent with previous reports.2,3

Conclusion:

Results suggest that SEC is at least as efficacious as ADA on musculoskeletal endpoints whilst providing higher responses on skin endpoints, and is associated with a higher retention rate. No new safety signals were reported.

References:

[1]van der Heijde, et al. Rheumatol. (Oxford).2019; DOI10.1093/rheumatology/kez420.

[2]Deodhar A, et al. Arthritis Res Ther. 2019;21:111.

[3]Burmester GR, et al. Ann Rheum Dis.2013; 72:517-24.

Figure.

ACR20 Response through Wk 52

Table.

Efficacy Outcomes at Wk 52

Endpoints, % response unless specified otherwiseSEC 300 mg(N=426)ADA 40 mg(N=427)P-value (unadjusted)*ACR2067·461·50·0719aACR2066·959·50·0239Key SecondarybPASI 9065·443·2<0·0001ACR5049·044·80·2251HAQ-DI mean change from baseline ± SE-0·58 ± 0.03-0·56 ± 0.030·5465cResolution of enthesitis (based on LEI)60·554·20·1498ExploratoryMDA43·037·90·1498VLDA18·116·60·6107DAPSA LDA+Remission61·753·10·0178PASDAS LDA+Remission51·144·10·0557

*Unadjusted P-valuesvsADA

Binary variables were analysed using logistic regression. Pts who discontinued study treatment prematurely or took csDMARDs after week-36 were considered non-responders. Multiple imputation was used for all other missing data. HAQ-DI mean change from baseline was analysed using mixed-effect model repeated measures

aNon-responder imputation was used for pre-specified sensitivity analysis

bN=215 in SEC and N=202 in ADA in psoriasis subset

cN=234 in SEC and N=264 in ADA in enthesitis subset

Disclosure of Interests:

Iain McInnes Grant/research support from: Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Janssen, and UCB, Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Gilead, Janssen, Novartis, Pfizer, and UCB, Frank Behrens Grant/research support from: Pfizer, Janssen, Chugai, Celgene, Lilly and Roche, Consultant of: Pfizer, AbbVie, Sanofi, Lilly, Novartis, Genzyme, Boehringer, Janssen, MSD, Celgene, Roche and Chugai, Philip J Mease Grant/research support from: Abbott, Amgen, Biogen Idec, BMS, Celgene Corporation, Eli Lilly, Novartis, Pfizer, Sun Pharmaceutical, UCB – grant/research support, Consultant of: Abbott, Amgen, Biogen Idec, BMS, Celgene Corporation, Eli Lilly, Novartis, Pfizer, Sun Pharmaceutical, UCB – consultant, Speakers bureau: Abbott, Amgen, Biogen Idec, BMS, Eli Lilly, Genentech, Janssen, Pfizer, UCB – speakers bureau, Arthur Kavanaugh Grant/research support from: Abbott, Amgen, AstraZeneca, BMS, Celgene Corporation, Centocor-Janssen, Pfizer, Roche, UCB – grant/research support, Christopher T. Ritchlin Grant/research support from: UCB Pharma, AbbVie, Amgen, Consultant of: UCB Pharma, Amgen, AbbVie, Lilly, Pfizer, Novartis, Gilead, Janssen, Peter Nash Grant/research support from: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Gilead, Janssen, MSD, Novartis, Pfizer Inc, Roche, Sanofi, UCB, Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Gilead, Janssen, MSD, Novartis, Pfizer Inc, Roche, Sanofi, UCB, Speakers bureau: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Gilead, Janssen, MSD, Novartis, Pfizer Inc, Roche, Sanofi, UCB, Jordi Gratacos-Masmitja Grant/research support from: a grant from Pfizzer to study implementation of multidisciplinary units to manage PSA in SPAIN, Consultant of: Pfizzer, MSD, ABBVIE, Janssen, Amgen, BMS, Novartis, Lilly, Speakers bureau: Pfizzer, MSD, ABBVIE, Janssen, Amgen, BMS, Novartis, Lilly, Philippe Goupille Grant/research support from: AbbVie, Amgen, Biogen, BMS, Celgene, Chugai, Lilly, Janssen, Medac, MSD France, Nordic Pharma, Novartis, Pfizer, Sanofi and UCB, Consultant of: AbbVie, Amgen, Biogen, BMS, Celgene, Chugai, Lilly, Janssen, Medac, MSD France, Nordic Pharma, Novartis, Pfizer, Sanofi and UCB, Speakers bureau: AbbVie, Amgen, Biogen, BMS, Celgene, Chugai, Lilly, Janssen, Medac, MSD France, Nordic Pharma, Novartis, Pfizer, Sanofi and UCB, Tatiana Korotaeva Grant/research support from: Pfizer, Consultant of: Abbvie, BIOCAD, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Novartis-Sandoz, Pfizer, UCB, Speakers bureau: Abbvie, BIOCAD, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Novartis-Sandoz, Pfizer, UCB, Alice B Gottlieb Grant/research support from:: Research grants, consultation fees, or speaker honoraria for lectures from: Pfizer, AbbVie, BMS, Lilly, MSD, Novartis, Roche, Sanofi, Sandoz, Nordic, Celltrion and UCB., Consultant of:: Research grants, consultation fees, or speaker honoraria for lectures from: Pfizer, AbbVie, BMS, Lilly, MSD, Novartis, Roche, Sanofi, Sandoz, Nordic, Celltrion and UCB., Speakers bureau:: Research grants, consultation fees, or speaker honoraria for lectures from: Pfizer, AbbVie, BMS, Lilly, MSD, Novartis, Roche, Sanofi, Sandoz, Nordic, Celltrion and UCB., Ruvie Martin Shareholder of: Novartis, Employee of: Novartis, Kevin Ding Employee of: Novartis, Pascale Pellet Shareholder of: Novartis, Employee of: Novartis, Shephard Mpofu Shareholder of: Novartis, Employee of: Novartis, Luminita Pricop Shareholder of: Novartis, Employee of: Novartis

FRI0272 SECUKINUMAB DEMONSTRATES A CONSISTENT SAFETY PROFILE IN PATIENTS WITH PSORIASIS, PSORIATIC ARTHRITIS AND ANKYLOSING SPONDYLITIS OVER LONG TERM: UPDATED POOLED SAFETY ANALYSES

Background:

Pooled safety data has been reported with secukinumab (SEC) in patients (pts) with Psoriatic arthritis (PsA), Ankylosing Spondylitis (AS) and Psoriasis (PsO).1

Objectives:

To report longer-term safety data of SEC treatment in PsA, AS, PsO pts up to 5 years.

Methods:

The integrated clinical trial safety dataset included data pooled from 28 randomised controlled clinical trials of SEC 300 or 150 or 75 mg in PsO (11 Phase 3 and 8 Phase 4 trials), PsA (5 Phase 3 trials), and AS (4 Phase 3 trials), along with post-marketing safety surveillance data with a cut-off date of 25 December 2018. Adverse events (AEs) were reported as exposure-adjusted incident rates (EAIRs) per 100 pt-years. Analyses included all pts who received ≥1 dose of SEC.

Results:

A total of 12637 pts (8819, 2678 and 1140 pts with PsO, PsA and AS, with an exposure of 15063.1, 5984.6 and 3527.2 pt-years, respectively) were included. The most frequent AE was upper respiratory tract infection and EAIR per 100 pt-years for IBD, malignancies and MACE remained low. The EAIR per 100 pt-years for adverse events (AEs) of special interest are reported in Table 1. The cumulative post-marketing exposure to SEC was estimated to be ~285,811 pt-years across the approved indications. Safety data from post-marketing surveillance are reported in Table 2.

Table 1.

Selected AEs of interest with SEC across pooled clinical trials

VariablePsOPsAASSECN=8819SECN=2678SECN=1140Exposure (Days), Mean (SD)623.9 (567.7)816.2 (580.7)1130.1 (583.0)Death, n (%)15 (0.2)13 (0.5)10 (0.9)Selected AE’s of interest, EAIR (95% CI)Serious infections11.4 (1.2, 1.6)1.8 (1.5, 2.2)1.2 (0.9, 1.6)Candidainfections22.9 (2.7, 3.2)1.5 (1.2, 1.9)0.7 (0.5, 1.1)IBD3Crohn’s disease3Ulcerative colitis30.01 (0.0, 0.05)0.1 (0.05, 0.2)0.1 (0.08, 0.2)0.03 (0.0, 0.1)0.1 (0.04, 0.2)0.1 (0.04, 0.2)0.03 (0.0, 0.2)0.4 (0.24, 0.7)0.2 (0.1, 0.5)MACE40.4 (0.31, 0.5)0.4 (0.3, 0.6)0.7 (0.4, 1.0)Uveitis30.01 (0.0, 0.05)0.1 (0.04, 0.2)1.2 (0.9, 1.7)Malignancy50.9 (0.7, 1.0)1.0 (0.77, 1.3)0.5 (0.3, 0.8)

1Rates for system organ class;2Rates for high level term;3Rates for preferred term (PT; IBD for unspecified IBD);4Rates for Novartis MedDRA Query term;5Rates for standardized MedDRA query term – ‘malignancies and unspecified tumour’; EAIR, exposure adjusted incidence rate per 100 pt-years; N, number of pts in the analysis

Table 2.

Summary of SEC post-marketing safety

Exposure (PTY)PSUR126Dec14 -25Jun15PSUR226 Jun - 25Dec15PSUR326Dec15 -25Jun16PSUR426Jun -25Dec16PSUR526Dec16 -25Dec17PSUR626Dec17 -25Dec18Cumulative18387450168712854993744137325285811                    n (Reporting rate PTY)Serious infections89 (4.8)149 (2.0)232 (1.4)475 (1.7)649 (0.7)1841 (1.3)3980 (1.4)Malignancy2 (0.1)15 (0.2)21 (0.1)50 (0.2)225 (0.2)422 (0.3)788 (0.3)Total IBD4 (0.2)12 (0.2)37(0.2)46 (0.2)185 (0.2)340 (0.3)693 (0.2)MACE6 (0.3)15 (0.2)16 (0.1)39 (0.1)151 (0.2)238 (0.2)504 (0.2)

PSUR, periodic safety update report; PTY, pt-treatment years

Conclusion:

In this long-term analysis across clinical trials and post-marketing surveillance, of pts with PsO, PsA and AS, SEC was well tolerated, with a safety profile consistent with previous reports.1

Reference:

[1]Deodhar et al. Arthritis Research & Therapy (2019) 21:111.

Disclosure of Interests:

Atul Deodhar Grant/research support from: AbbVie, Eli Lilly, GSK, Novartis, Pfizer, UCB, Consultant of: AbbVie, Amgen, Boehringer Ingelheim, Bristol Myer Squibb (BMS), Eli Lilly, GSK, Janssen, Novartis, Pfizer, UCB, Speakers bureau: AbbVie, Amgen, Boehringer Ingelheim, Bristol Myer Squibb (BMS), Eli Lilly, GSK, Janssen, Novartis, Pfizer, UCB, Iain McInnes Grant/research support from: Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Janssen, and UCB, Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Gilead, Janssen, Novartis, Pfizer, and UCB, Xenofon Baraliakos Grant/research support from: Grant/research support from: AbbVie, BMS, Celgene, Chugai, Merck, Novartis, Pfizer, UCB and Werfen, Consultant of: AbbVie, BMS, Celgene, Chugai, Merck, Novartis, Pfizer, UCB and Werfen, Speakers bureau: AbbVie, BMS, Celgene, Chugai, Merck, Novartis, Pfizer, UCB and Werfen, Kristian Reich Grant/research support from: Affibody; Almirall; Amgen; Biogen; Boehringer Ingelheim; Celgene; Centocor; Covagen; Eli Lilly; Forward Pharma; Fresenius Medical Care; GlaxoSmithKline; Janssen; Kyowa Kirin; LEO Pharma; Medac; Merck; Novartis; Miltenyi Biotec; Ocean Pharma; Pfizer; Regeneron; Samsung Bioepis; Sanofi Genzyme; Takeda; UCB; Valeant and Xenoport., Consultant of: Affibody; Almirall; Amgen; Biogen; Boehringer Ingelheim; Celgene; Centocor; Covagen; Eli Lilly; Forward Pharma; Fresenius Medical Care; GlaxoSmithKline; Janssen; Kyowa Kirin; LEO Pharma; Medac; Merck; Novartis; Miltenyi Biotec; Ocean Pharma; Pfizer; Regeneron; Samsung Bioepis; Sanofi Genzyme; Takeda; UCB; Valeant and Xenoport., Speakers bureau: Affibody; Almirall; Amgen; Biogen; Boehringer Ingelheim; Celgene; Centocor; Covagen; Eli Lilly; Forward Pharma; Fresenius Medical Care; GlaxoSmithKline; Janssen; Kyowa Kirin; LEO Pharma; Medac; Merck; Novartis; Miltenyi Biotec; Ocean Pharma; Pfizer; Regeneron; Samsung Bioepis; Sanofi Genzyme; Takeda; UCB; Valeant and Xenoport., Alice B Gottlieb Grant/research support from:: Research grants, consultation fees, or speaker honoraria for lectures from: Pfizer, AbbVie, BMS, Lilly, MSD, Novartis, Roche, Sanofi, Sandoz, Nordic, Celltrion and UCB., Consultant of:: Research grants, consultation fees, or speaker honoraria for lectures from: Pfizer, AbbVie, BMS, Lilly, MSD, Novartis, Roche, Sanofi, Sandoz, Nordic, Celltrion and UCB., Speakers bureau:: Research grants, consultation fees, or speaker honoraria for lectures from: Pfizer, AbbVie, BMS, Lilly, MSD, Novartis, Roche, Sanofi, Sandoz, Nordic, Celltrion and UCB., Mark Lebwohl Grant/research support from: AbbVie, Amgen, Arcutis, AstraZeneca, Boehringer Ingelheim, Celgene, Clinuvel, Eli Lilly, Incyte, Janssen Research & Development, LLC, Kadmon Corp., LLC, Leo Pharmaceutucals, Medimmune, Novartis, Ortho Dermatologics, Pfizer, Sciderm, UCB, Inc., and ViDac, Consultant of: Allergan, Almirall, Arcutis, Inc., Avotres Therapeutics, BirchBioMed Inc., Boehringer-Ingelheim, Bristol-Myers Squibb, Cara Therapeutics, Castle Biosciences, Corrona, Dermavant Sciences, Evelo, Foundation for Research and Education in Dermatology, Inozyme Pharma, LEO Pharma, Meiji Seika Pharma, Menlo, Mitsubishi, Neuroderm, Pfizer, Promius/Dr. Reddy’s Laboratories, Theravance, and Verrica, Stefan Schreiber Consultant of: AbbVie, Arena, BMS, Biogen, Celltrion, Celgene, IMAB, Gilead, MSD, Mylan, Pfizer, Fresenius, Janssen, Takeda, Theravance, provention Bio, Protagonist and Falk, Weibin Bao Shareholder of: Novartis, Employee of: Novartis, Kwaku Marfo Shareholder of: Novartis, Employee of: Novartis, Hanno Richards Shareholder of: Novartis, Employee of: Novartis, Luminita Pricop Shareholder of: Novartis, Employee of: Novartis, Abhijit Shete Shareholder of: Novartis, Employee of: Novartis, Jorge Safi Shareholder of: Novartis, Employee of: Novartis, Philip J Mease Grant/research support from: Abbott, Amgen, Biogen Idec, BMS, Celgene Corporation, Eli Lilly, Novartis, Pfizer, Sun Pharmaceutical, UCB – grant/research support, Consultant of: Abbott, Amgen, Biogen Idec, BMS, Celgene Corporation, Eli Lilly, Novartis, Pfizer, Sun Pharmaceutical, UCB – consultant, Speakers bureau: Abbott, Amgen, Biogen Idec, BMS, Eli Lilly, Genentech, Janssen, Pfizer, UCB – speakers bureau

FRI0340 COMPARISON OF SECUKINUMAB VERSUS ADALIMUMAB EFFICACY ON SKIN OUTCOMES IN PSORIATIC ARTHRITIS: 52-WEEK RESULTS FROM THE EXCEED STUDY

Background:

Psoriatic arthritis (PsA) is a heterogeneous disease comprising musculoskeletal and dermatological manifestations, especially plaque psoriasis.1Secukinumab (SEC), an IL-17A inhibitor, provided significantly greater PASI 75/100 responses in a head-to-head trialversus (vs.) etanercept, a TNF inhibitor, in patients (pts) with moderate-to-severe plaque psoriasis.2The objective of the EXCEED study (NCT02745080) was to investigate whether SEC is superior to adalimumab (ADA), a TNF inhibitor, as monotherapy in biologic-naive active PsA pts with active plaque psoriasis (defined as having at least one psoriatic plaque of ≥2 cm diameter or nail changes consistent with psoriasis or documented history of plaque psoriasis).

Objectives:

To report the pre-specified skin outcomes from the EXCEED study in the subset of pts with at least 3% body surface area (BSA) affected with psoriasis at baseline.

Methods:

Head-to-head, phase-3b, randomised, double-blind, active-controlled, multicentre, parallel-group trial: pts were randomised to receive SEC 300 mg subcutaneous at baseline, Week 1-4, followed by dosing every 4 weeks (q4w) until Week 48 or ADA 40 mg subcutaneous at baseline followed by same dosing q2w until Week 50. The primary endpoint was superiority of SECvs.ADA on ACR20 response at Week 52. Pre-specified outcomes included the proportion of pts achieving a combined ACR50 and PASI 100 response, PASI 100 response, and absolute PASI score ≤3. Missing data was handled using multiple imputation.

Results:

853 pts were randomised to receive SEC (n=426) or ADA (n=427). At baseline, there were 215 and 202 pts having at least 3% BSA affected with psoriasis in the SEC and ADA groups, respectively. A higher proportion of patients achieved simultaneous improvement in ACR50 and PASI 100 response with SECvs.ADA (30·7%vs.19·2%; P=0·0087 [Figure]). Higher efficacy was demonstrated for SECvs.ADA for PASI 100 responses and for the proportion of pts achieving absolute PASI score ≤3 (Table).

Conclusion:

In this pre-specified analysis, SEC provided higher responses compared to ADA in achievement of simultaneous improvement of joint and skin disease (combined ACR50 and PASI 100 response) and in skin specific endpoints (PASI 100 and PASI score ≤3) at Week 52.

References:

[1]Coates LC and Helliwell PS.Clinical Med.2017;17:65–70.

[2]Langley RG et al.N Engl J Med.2014;371:326–38.

Figure.

Combined ACR50 and PASI 100 Response through Week 52

Table.

Skin Specific Outcomes at Week 52

Endpoints, data is presented as % responseSEC 300 mg(N = 215)ADA 40 mg(N = 202)P-value (unadjusted)PASI 10046·029·70·0007Absolute PASI score ≤379·265·00·0015

P value vs. adalimumab; Unadjusted P values are presented

N, number of patients in psoriasis subset

Multiple imputation was used for handling missing data

ADA, adalimumab; BSA, body surface area; PASI, psoriasis area severity index; SEC, secukinumab

Acknowledgments:

Suchita Dubey (Novartis) provided medical writing support.

Disclosure of Interests:

Alice B Gottlieb Grant/research support from:: Research grants, consultation fees, or speaker honoraria for lectures from: Pfizer, AbbVie, BMS, Lilly, MSD, Novartis, Roche, Sanofi, Sandoz, Nordic, Celltrion and UCB., Consultant of:: Research grants, consultation fees, or speaker honoraria for lectures from: Pfizer, AbbVie, BMS, Lilly, MSD, Novartis, Roche, Sanofi, Sandoz, Nordic, Celltrion and UCB., Speakers bureau:: Research grants, consultation fees, or speaker honoraria for lectures from: Pfizer, AbbVie, BMS, Lilly, MSD, Novartis, Roche, Sanofi, Sandoz, Nordic, Celltrion and UCB., Frank Behrens Grant/research support from: Pfizer, Janssen, Chugai, Celgene, Lilly and Roche, Consultant of: Pfizer, AbbVie, Sanofi, Lilly, Novartis, Genzyme, Boehringer, Janssen, MSD, Celgene, Roche and Chugai, Peter Nash Grant/research support from: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Gilead, Janssen, MSD, Novartis, Pfizer Inc, Roche, Sanofi, UCB, Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Gilead, Janssen, MSD, Novartis, Pfizer Inc, Roche, Sanofi, UCB, Speakers bureau: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Gilead, Janssen, MSD, Novartis, Pfizer Inc, Roche, Sanofi, UCB, Joseph F. Merola Consultant of: Merck, AbbVie, Dermavant, Eli Lilly, Novartis, Janssen, UCB Pharma, Celgene, Sanofi, Regeneron, Arena, Sun Pharma, Biogen, Pfizer, EMD Sorono, Avotres and LEO Pharma, Kevin Ding Employee of: Novartis, Pascale Pellet Shareholder of: Novartis, Employee of: Novartis, Luminita Pricop Shareholder of: Novartis, Employee of: Novartis, Iain McInnes Grant/research support from: Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Janssen, and UCB, Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Gilead, Janssen, Novartis, Pfizer, and UCB

THU0373 SECUKINUMAB DOSE ESCALATION ON ACR RESPONSES IN ANTI-TUMOUR NECROSIS FACTOR NAÏVE PATIENTS WITH PSORIATIC ARTHRITIS: 2-YEAR DATA FROM THE PHASE 3 FUTURE 4 AND FUTURE 5 STUDIES

Background:

Secukinumab (SEC) 150 and 300 mg doses are approved for the treatment of psoriatic arthritis (PsA). SEC 300 mg is the recommended dose for patients (pts) with concomitant moderate-to-severe plaque psoriasis or who are anti-tumour necrosis factor (TNF) inadequate responders. An increase from 150 mg to 300 mg has been reported to be beneficial in some patients with a suboptimal response to SEC 150 mg.1Here, we present a post hoc analysis in anti-TNF naïve pts who escalated from SEC 150 to 300 mg dose in two Phase 3 studies, FUTURE 4 (NCT02294227) and FUTURE 5 (NCT02404350).

Objectives:

To evaluate the clinical efficacy on joints following dose escalation from SEC 150 to 300 mg on ACR responses in anti-TNF naïve pts with PsA.

Methods:

Study design, patient inclusion and exclusion criteria of the FUTURE 4 and FUTURE 5 studies have been reported previously.1–3In FUTURE 4, 341 pts were randomised in a 1:1:1 ratio to SEC 150 mg with loading dose (LD), SEC 150 mg without LD, or placebo. In FUTURE 5, 996 pts were randomised in a 2:2:2:3 ratio to SEC 300 mg with LD, SEC 150 mg with LD, SEC 150 mg without LD or placebo. Following a protocol amendment, pts were allowed to escalate from 150 mg to the 300 mg dose, in the event of suboptimal response based on investigator’s judgment, starting at Week 36 in FUTURE 4 and at Week 52 in FUTURE 5. ACR responses in anti-TNF naïve pts were evaluated pre- and up to 32 and 40 weeks post-escalation, in FUTURE 4 and FUTURE 5, respectively: pts were grouped into four ranges based on their response: no (< 20); low (≥ 20 to < 50); moderate (≥ 50 to < 70); high (≥ 70) ACR responses. Data presented are as observed in the Sankey-style overlay plot.

Results:

Dose escalation from SEC 150 to 300 mg occurred in 136 pts in FUTURE 4 and in 236 pts in FUTURE 5. The proportion of ACR responders increased and the proportion of non-responders decreased in anti-TNF naïve pts who escalated from SEC 150 to 300 mg in the two studies. The proportion of anti-TNF naïve pts with a response ≥ACR50 increased from 20% to 41% in FUTURE 4 and 28% to 46% in FUTURE 5, post dose escalation. The ACR responses in anti-TNF naïve pts up to 40 weeks after escalation from SEC 150 to 300 mg are presented in the Sankey-style overlay (Figure).

Figure.

ACR Response bar chart with Sankey-style overlays up to 40 weeks, after dose escalation from SEC 150 mg to 300 mg, in anti-TNF naïve pts in FUTURE 4 and 5

Conclusion:

The proportion of ACR responders increased within 12-16 weeks and was sustained up to 40 weeks following dose escalation in anti-TNF naïve pts with PsA. These results suggest that dose escalation from SEC 150 to 300 mg may be beneficial in anti-TNF naïve pts with a suboptimal response on SEC 150 mg.

References:

[1]Kivitz AJ, et al. Rheumatol Ther. 2019;6(3):393–407;

[2]Mease PJ, et al. Ann Rheum Dis. 2018;77:890–7;

[3]Mease, P.J., et al. ACR Open Rheumatology. 2019 [ePub ahead of print] doi:10.1002/acr2.11097.

Disclosure of Interests:

Paul Emery Grant/research support from: AbbVie, Bristol-Myers Squibb, Merck Sharp & Dohme, Pfizer, Roche (all paid to employer), Consultant of: AbbVie (consultant, clinical trials, advisor), Bristol-Myers Squibb (consultant, clinical trials, advisor), Lilly (clinical trials, advisor), Merck Sharp & Dohme (consultant, clinical trials, advisor), Novartis (consultant, clinical trials, advisor), Pfizer (consultant, clinical trials, advisor), Roche (consultant, clinical trials, advisor), Samsung (clinical trials, advisor), Sandoz (clinical trials, advisor), UCB (consultant, clinical trials, advisor), Mikkel Ǿstergaard Grant/research support from: AbbVie, Bristol-Myers Squibb, Celgene, Merck, and Novartis, Consultant of: AbbVie, Bristol-Myers Squibb, Boehringer Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo Nordisk, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi, and UCB, Speakers bureau: AbbVie, Bristol-Myers Squibb, Boehringer Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo Nordisk, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi, and UCB, Laura C Coates: None declared, Atul Deodhar Grant/research support from: AbbVie, Eli Lilly, GSK, Novartis, Pfizer, UCB, Consultant of: AbbVie, Amgen, Boehringer Ingelheim, Bristol Myer Squibb (BMS), Eli Lilly, GSK, Janssen, Novartis, Pfizer, UCB, Speakers bureau: AbbVie, Amgen, Boehringer Ingelheim, Bristol Myer Squibb (BMS), Eli Lilly, GSK, Janssen, Novartis, Pfizer, UCB, Erhard Quebe-Fehling Shareholder of: Novartis, Employee of: Novartis, Pascale Pellet Shareholder of: Novartis, Employee of: Novartis, Luminita Pricop Shareholder of: Novartis, Employee of: Novartis, Corine Gaillez Shareholder of: Novartis, Employee of: Novartis, Filip van den Bosch Consultant of: AbbVie, Celgene Corporation, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, and UCB, Speakers bureau: AbbVie, Celgene Corporation, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, and UCB

Long-term safety of secukinumab in patients with moderate-to-severe plaque psoriasis, psoriatic arthritis, and ankylosing spondylitis: integrated pooled clinical trial and post-marketing surveillance data

BACKGROUND

Secukinumab, a fully human immunoglobulin G1-kappa monoclonal antibody that directly inhibits interleukin (IL)-17A, has been shown to have robust efficacy in the treatment of moderate-to-severe psoriasis (PsO), psoriatic arthritis (PsA), and ankylosing spondylitis (AS) demonstrating a rapid onset of action and sustained long-term clinical responses with a consistently favorable safety profile in multiple Phase 2 and 3 trials. Here, we report longer-term pooled safety and tolerability data for secukinumab across three indications (up to 5 years of treatment in PsO and PsA; up to 4 years in AS).

METHODS

The integrated clinical trial safety dataset included data pooled from 21 randomized controlled clinical trials of secukinumab 300 or 150 or 75 mg in PsO (14 Phase 3 trials and 1 Phase 4 trial), PsA (3 Phase 3 trials), and AS (3 Phase 3 trials), along with post-marketing safety surveillance data with a cut-off date of June 25, 2017. Adverse events (AEs) were reported as exposure-adjusted incident rates (EAIRs) per 100 patient-years. Analyses included all patients who received ≥ 1 dose of secukinumab.

RESULTS

A total of 5181, 1380, and 794 patients from PsO, PsA, and AS clinical trials representing secukinumab exposures of 10,416.9, 3866.9, and 1943.1 patient-years, respectively, and post-marketing data from patients with a cumulative exposure to secukinumab of ~ 96,054 patient-years were included in the analysis. The most frequent AE was upper respiratory tract infection. EAIRs across PsO, PsA, and AS indications were generally low for serious infections (1.4, 1.9, and 1.2, respectively), Candida infections (2.2, 1.5, and 0.7, respectively), inflammatory bowel disease (0.01, 0.05, and 0.1, respectively), and major adverse cardiac events (0.3, 0.4, and 0.6, respectively). No cases of tuberculosis reactivation were reported. The incidence of treatment-emergent anti-drug antibodies was low with secukinumab across all studies, with no discernible loss of efficacy, unexpected alterations in pharmacokinetics, or association with immunogenicity-related AEs.

CONCLUSIONS

Secukinumab demonstrated a favorable safety profile over long-term treatment in patients with PsO, PsA, and AS. This comprehensive assessment demonstrated that the safety profile of secukinumab was consistent with previous reports in patients with PsO, PsA, and AS, supporting its long-term use in these chronic conditions.

Interpenetrating poly(urethane-urea)–polydimethylsiloxane networks designed as active elements in electromechanical transducers

Original interpenetrating polymer networks suitable for active dielectric elements in actuation devices were prepared by using a dual compatibilization pathway.

Characterization of the FcgammaRIIA promoter and 5'UTR sequences in patients with systemic lupus erythematosus

FcgammaRIIA is a candidate gene involved in the predisposition to systemic lupus erythematosus (SLE). The presence of low binding alleles in patients with SLE is not sufficient to explain the lower phagocytic capacity observed in SLE patients. We considered the possibility that nucleotide polymorphisms in the FcgammaRIIA promoter that cause alterations in receptor expression might be present in SLE patients. In the present study, a 2.0 kb region of the human FcgammaRIIA 5'UTR from 20 normal donors and 53 SLE patients was examined. The results demonstrate that the sequence of the human FcgammaRIIA 5' region differs from the published sequence. Two novel SNPs have been identified in the distal region of the FcgammaRIIA promoter. The polymorphisms are present in both disease-free and SLE donors and do not associate with quantitative changes in FcgammaRIIa phagocytic function.

Human receptors for immunoglobulin G: key elements in the pathogenesis of rheumatic disease

The structural diversity of Fc gammaR provides a mechanism by which IgG can elicit a broad range of cell responses. Fc gammaR vary in their affinity for IgG, their preference for IgG subclasses, the cell types in which they are expressed, and the intracellular signals which they elicit--stimulatory or inhibitory. Expansion in our knowledge of structure-function relationships among Fc gammaR has identified them as heritable risk factors for disease susceptibility and valuable targets for therapeutic modulation of the immune system.

Differential modulation of stimulatory and inhibitory Fc gamma receptors on human monocytes by Th1 and Th2 cytokines

Immune complex-mediated inflammatory responses are initiated by Fc gamma R on phagocytes. We report in this study that an inhibitory receptor, Fc gamma RIIb2, is expressed on circulating human monocytes, and when co-cross-linked with stimulatory Fc gamma R it down-regulates effector function. Fc gamma RIIb2 expression is increased by IL-4 and decreased by IFN-gamma, in contrast to the activating receptor, Fc gamma RIIa, which is increased by IFN-gamma and decreased by IL-4. Thus, Th1 and Th2 cytokines differentially regulate the opposing Fc gamma R systems, altering the balance of activating and inhibiting Fc gamma R. The detection and cytokine modulation of Fc gamma RIIb2 in human myeloid cells provide evidence of a negative regulator of immune complex-mediated responses in human phagocytes and offer a new approach to limit Ab-triggered inflammation in autoimmune disease.

Reactive oxygen intermediates enhance Fc gamma receptor signaling and amplify phagocytic capacity

Receptors for the Fc region of IgG (Fc gamma R) mediate internalization of opsonized particles by human neutrophils (PMN) and mononuclear phagocytes. Cross-linking of Fc gamma R leads to activation of protein tyrosine kinases and phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs) within Fc gamma R subunits, both obligatory early signals for phagocytosis. Human PMN constitutively express two structurally distinct Fc gamma R, Fc gamma RIIa and Fc gamma RIIIb, and can be induced to express Fc gamma RI by IFN-gamma. We have previously shown that stimulation of PMN through Fc gamma RIIIb results in enhanced Fc gamma RIIa-mediated phagocytic activity that is inhibited by catalase. In the present study, we have tested the hypothesis that reactive oxygen intermediates (ROI) have the capacity to regulate Fc gamma R responses and defined a mechanism for this effect. We show that H2O2 augmented phagocytosis mediated by Fc gamma RIIa and Fc gamma RI in PMN and amplified receptor-triggered tyrosine phosphorylation of Fc gamma R-associated ITAMs and signaling elements. Generation of endogenous oxidants in PMN by cross-linking Fc gamma RIIIb similarly enhanced phosphorylation of Fc gamma RIIa and Syk, a tyrosine kinase required for phagocytic function, in a catalase-sensitive manner. Our results provide a mechanism for priming phagocytes for enhanced responses to receptor-driven effects. ROI generated in an inflammatory milieu may stimulate quiescent cells to rapidly increase the magnitude of their effector function. Indeed, human monocytes incubated in the presence of stimulated PMN showed oxidant-induced increases in Fc gamma RIIa-mediated phagocytosis. Definition of the role of oxidants as amplifiers of Fc gamma R signaling identifies a target for therapeutic intervention in immune complex-mediated tissue injury.

A naturally occurring mutation in Fc gamma RIIA: a Q to K127 change confers unique IgG binding properties to the R131 allelic form of the receptor

Fc gamma RIIa is widely expressed on hematopoietic cells. There are two known allelic polymorphic forms of Fc gamma RIIa, Fc gamma RIIa-R131 and Fc gamma RIIa-H131, which differ in the amino acid at position 131 in the second lg-like domain. In contrast to Fc gamma RIIa-R131, Fc gamma RIIa-H131 binds hlgG2 but not mIgG1, and this differential binding has clinical implications for host defense, autoimmune disease, immunohematologic disease, and response to therapeutic monoclonal antibodies. We identified a novel Fc gamma RIIA genotype in a healthy individual homozygous for Fc gamma RIIA R/R131 in whom a C to A substitution at codon 127 changes glutamine (Q) to lysine (K) in one of the two Fc gamma RIIA genes. This individual's homozygosity for Fc gamma RIIA-R/R131 leads to the prediction that the receptors on her cells would not bind hIgG2. Monocyte and neutrophil phagocytosis of hIgG2-opsonized erythrocytes was significantly higher (P < .05) for cells from this K/Q127, R/R131 individual than for Q/Q127, R/R131 donors. Platelet aggregation stimulated by an mIgG1 anti-CD9 antibody in this individual was significantly different (P < .05) from Q/Q127, H/R131 and Q/Q127, H/H131 donors and similar to Q/Q127, R/R131. Our data show that the K127/R131 receptors have a unique phenotype, binding both hIgG2 and mIgG1. Further functionally significant mutations in human Fc gamma receptors and possible novel mechanisms for inherited differences in disease susceptibility should be sought with unbiased screening methods.

Flow cytometric quantitation of attachment and phagocytosis in phenotypically-defined subpopulations of cells using PKH26-labeled Fc gamma R-specific probes

Human receptors for IgG (Fc gamma R) are characterized by diverse structure and function. We describe a flow cytometric technique to quantitate receptor-specific Fc gamma R-mediated attachment and phagocytosis in phenotypically-defined subsets of cells using erythrocytes (E) labeled with the lipophilic dye PKH26 and coupled with biotin/avidin to either human IgG (myeloma proteins) or anti-Fc gamma R mAb. Using this technique and Fc gamma RIIa as a model, (1) we demonstrate sensitive and specific quantitation of attached and internalized E coupled to receptor-specific mAb or natural ligand by monocytes within a peripheral blood leukocyte preparation; (2) we show the capacity to detect subtle allelic differences in Fc gamma R function; and (3) we demonstrate oxidant-induced enhancement of binding and internalization.

V lambda-light chain genes reconstitute immune responses to defined carbohydrate antigens or haptens by utilizing different VH genes

The contribution of the lambda-light chain to the development of peripheral B cell repertoire and generation of specific antibodies to haptens and polysaccharide antigens was studied in genetically manipulated kappa-deficient and lambda 2-transgenic mice. The results clearly demonstrate a non-stoichiometric VH gene family expression in the absence of k-light chain and suggest a non-stochastic pairing between VH and V lambda genes, expressed in the peripheral B cell repertoire. A shift in VH gene utilization in the case of VI lambda + antibodies was evident in response to beta 2-6 fructosan and TNP hapten. These observations demonstrate the availability of compensatory mechanisms in the absence of VK genes and are consistent with the hypothesis that VH gene family expression is controlled by genetic factors from inside the VH locus. Furthermore, genetic factors from outside the VH locus, namely restricted available light chain diversity, may lead to a shift in VH gene utilization in the peripheral B cell repertoire.

Repertoires of antigen receptors in Tdt congenitally deficient mice

Tdt deficient mice show lack of N region in V(D)J junctions of immunoglobulin and T cell receptor genes and revealed that "immature recombinase" in fetal stage would boil down to no more than a lack of Tdt. Although particular junctions which are thought to be created by homology-mediated joining are frequently observed, one fourth of junctions lacked even one bp of overlap, indicating the existence of a V(D)J joining pathway that is homology independent. Lymphocyte repertoire which express VH81X gene without N region is negatively selected, which shows that the repertoire of Tdt deficient mice is not a truly fetal repertoire. Positive selection of thymocytes is more efficient in Tdt deficient mice. Furthermore Tdt-/- mice produce significant amounts of anti-dsDNA antibodies as Tdt+/+ mice, indicating that increased diversity of the third complementarity-determining region (CDR3) by Tdt is not essential for the expansion of precursor B cells programmed to produce anti-DNA antibodies.

Antibody response against poly (Glu60Ala30Tyr10) terpolymer and bacterial levan in kappa-deficient mice

In murine species, the kappa (+)-bearing immunoglobulins dominate the antibody (Ab) repertoire with a kappa/lambda ratio of 95:5. The aim of the present study is to investigate the characteristics of the antibody response in kappa-deficient (K-/-) mice immunized with a T-dependent synthetic antigen, poly(Glu60Ala30Tyr10) (GAT) and a T-independent antigen, bacterial levan (BL). K-/- mice were obtained by targeted deletion of the J kappa C kappa gene segments. In response to GAT, K-/- mice respond by producing increasing amounts of anti-GAT Ig lambda 1 and Ig lambda 2 in the primary as well as secondary response, although anti-GAT specific monoclonal antibodies (mAb) raised in K-/- mice are mostly of IgM isotype. The GAT public idiotype, GATIdX, present on all GAT-specific Ab bearing kappa light chain, is not detected in the sera of K-/- mice or on any of the anti-GAT lambda 1 mAb. In response to BL, the amount of Ig lambda 1+ Ab in K-/- mice is comparable to the amount of Ig kappa + Ab in normal mice. However, lambda 2+ Ab are detected neither in wild-type nor in K-/- mice. Like kappa + Ab, the majority of lambda 1+ mAb are specific for beta 2-6 fructosan present in BL and rye levan and, to some extent, express the BL-specific idiotype, A48ld. Our results show that important compensatory mechanisms occur in kappa-deficient mice, restoring their ability to mount immune responses against a variety of T-dependent and T-independent antigens by the alternative usage of the clonally restricted lambda repertoire.

Study of self reactive antibodies in kappa-light chain deficient mice

The kappa chain deficient mouse strain represents an excellent experimental system for studying the contribution of lambda light chains to the antibody repertoire. Here, we have studied the contribution of lambda chains to the generation of self reactive antibodies including RFs in kappa deficient mice with 129/sv background. These mutant mice produce rheumatoid factors similar to 129/sv mice and these antibodies are primarily encoded by lambda 2. This may be due to the production of RF by peritoneal B lymphocytes which belong to Ly1 B subset. Peritoneal B cell selectively produce lambda 2 and lambda 3 isotypes. Though lambda 1 positive RF is not detectable in the sera, lambda 1 positive specific precursor B cells are present in these mice and they can be activated by T-independent antigens. Our studies show that these mice also spontaneously produce anti-dsDNA antibodies bearing lambda 1 light chain but do not produce self reactive antibodies specific for eight different autoantigens. However, B cell precursors expressing lambda chains specific for autoantigens like collagen II, III, IV and histone 2A are present in the B cell repertoire of kappa-deficient mice. Thus, our results demonstrate that lambda light chain can compensate, to some extent, the lack of kappa chain repertoire, not only against foreign antigens, as observed previously, but also against a number of autoantigens.

Antibody response elicited by T-dependent and T-independent antigens in gene targeted kappa-deficient mice

Animal models substantially contribute to the understanding of the pathogenesis of various human diseases, including those associated with genetic defects. Our study investigated the characteristics of antibody responses elicited by T-dependent and T-independent antigens in mice rendered kappa-deficient by targeted deletion of the J kappa C kappa gene segments. It is known that in normal murine species the kappa repertoire dominates the antibody repertoire (kappa/lambda ratio = 95:5). Our results indicate that the kappa gene deletion causes the alternative usage of lambda 1 (93%) and lambda 2 (7%) light chains, confirming previous studies demonstrating that in kappa-deficient mice all B cells express Ig lambda receptors. The anti-trinitrophenylbenzene (TNP) response in K-/- mice was compensated for by lambda 1 and lambda 2 bearing Igs. However, isoelectric focusing analysis of anti-TNP antibodies showed a considerably more restricted pattern of lambda anti-TNP antibodies in K-/- as compared with kappa antibodies in normal mice. No major differences were observed in the affinity for the hapten of kappa or lambda 1 or lambda 2 mAbs obtained from 129/Sv and K-/- mice. Furthermore, lambda 1 and lambda 2 chains can reconstitute the expression of an idiotype (460Id) borne on kappa anti-TNP antibodies. The 460Id was detected both in polyclonal and monoclonal anti-TNP antibodies obtained from K-/- mice. Our results clearly showed that the kappa anti-TNP repertoire is compensated by the lambda repertoire even though the latter is clonally restricted in K-/- mice.

Expression and function of CD7 molecule on human natural killer cells

The CD7 molecule, one of the earliest T-lymphocyte Ag expressed during ontogeny, has recently been demonstrated to facilitate activation of T cells and to preferentially activate TCR-gamma/delta + subset of T cells. The CD7 Ag is also expressed on human NK cells, but its function has not been determined. In this study, expression and function of CD7 Ag on highly enriched NK cells (94 +/- 3% mean +/- SD, n = 12) obtained by negative selection from peripheral blood of normal donors were investigated. The CD7 Ag was found to be expressed at a significantly (p < 0.002) higher level on fresh NK cells than on IL-2-activated, NK cells. CD7 on human NK cells was found to be a signal-transducing molecule with a rapid increase in cytoplasmic free calcium observed on binding of anti-CD7 mAb to the surface of NK cells. Cross-linking of CD7 induced expression of surface activation molecules such as CD25, CD71, HLA-DR, CD69, and CD54. Activation by anti-CD7 mAb cross-linked to plastic or through goat anti-mouse Ig also induced a variety of NK cell functions: it stimulated secretion of IFN-gamma, led to proliferation of NK cells, as measured by [3H]thymidine incorporation, and significantly enhanced cytotoxicity of NK cells against K562 targets (p < 0.03). However, CD7 on NK cells did not seem to transduce a lytic signal, because it neither mediated redirected killing of Fc gamma R+ murine mastocytoma P815 cells nor triggered lysis of a hybridoma expressing the antibody in a membrane-bound form. CD7 molecules appeared to have a regulatory role in adhesion of NK cells to fibronectin, because cross-linking of CD7 on resting NK cells significantly augmented their adhesion to fibronectin-coated plastic surfaces. However, this induced adhesion was not associated with increased expression of beta 1-integrins on NK cells. Thus, CD7-mediated signals appear to augment function of adhesion molecules on NK cells, which may be involved in NK cell activation by providing both anchorage and costimulatory triggering.

Expression and function of CD7 molecule on human natural killer cells

The CD7 molecule, one of the earliest T-lymphocyte Ag expressed during ontogeny, has recently been demonstrated to facilitate activation of T cells and to preferentially activate TCR-gamma/delta + subset of T cells. The CD7 Ag is also expressed on human NK cells, but its function has not been determined. In this study, expression and function of CD7 Ag on highly enriched NK cells (94 +/- 3% mean +/- SD, n = 12) obtained by negative selection from peripheral blood of normal donors were investigated. The CD7 Ag was found to be expressed at a significantly (p &lt; 0.002) higher level on fresh NK cells than on IL-2-activated, NK cells. CD7 on human NK cells was found to be a signal-transducing molecule with a rapid increase in cytoplasmic free calcium observed on binding of anti-CD7 mAb to the surface of NK cells. Cross-linking of CD7 induced expression of surface activation molecules such as CD25, CD71, HLA-DR, CD69, and CD54. Activation by anti-CD7 mAb cross-linked to plastic or through goat anti-mouse Ig also induced a variety of NK cell functions: it stimulated secretion of IFN-gamma, led to proliferation of NK cells, as measured by [3H]thymidine incorporation, and significantly enhanced cytotoxicity of NK cells against K562 targets (p &lt; 0.03). However, CD7 on NK cells did not seem to transduce a lytic signal, because it neither mediated redirected killing of Fc gamma R+ murine mastocytoma P815 cells nor triggered lysis of a hybridoma expressing the antibody in a membrane-bound form. CD7 molecules appeared to have a regulatory role in adhesion of NK cells to fibronectin, because cross-linking of CD7 on resting NK cells significantly augmented their adhesion to fibronectin-coated plastic surfaces. However, this induced adhesion was not associated with increased expression of beta 1-integrins on NK cells. Thus, CD7-mediated signals appear to augment function of adhesion molecules on NK cells, which may be involved in NK cell activation by providing both anchorage and costimulatory triggering.

Characterization of the Fc mu receptor on human natural killer cells. Interaction with its physiologic ligand, human normal IgM, specificity of binding, and functional effects

After treatment with human normal IgM, 78 +/- 8% of purified CD3-CD56+ resting human NK cells and 93 +/- 6% of IL-2-activated NK cells selected by adherence to plastic reacted with FITC-goat anti-human IgM. Binding of IgM to the FcR for IgM (Fc mu R) on human NK cells was not species specific because mouse myeloma IgM also bound to these cells. The percentage of CD56+ cells binding IgM after incubation with anti-CD16 mAb was similar to that of cells incubated with medium alone (95 +/- 1% vs 93 +/- 4%). Binding of anti-CD16 mAb to Fc gamma RIII on NK cells was unaffected by pretreatment with IgM (65 +/- 12% vs 69 +/- 4%). The CD7 molecule has been reported to be the Fc mu R on the surface of T cells. Two-color flow cytometry showed that 94 +/- 3% of CD3-CD56+ resting NK cells and 71 +/- 16% of activated NK cells were CD7+. Preincubation of NK cells with three anti-CD7 mAb (Leu-9, 8H8-1, and LAU-A1) failed to block the binding of IgM to the Fc mu R. Modulation of the CD7 molecule off the cell surface (CD7+ = 1.5% +/- 0.3) did not reduce IgM binding, thus excluding the possibility that IgM anti-CD7 might bind to different epitopes of the same molecule. These data indicate that the Fc mu R is a specific Ig-binding structure, distinct from the Fc gamma RIII (CD16) or CD7. The Fc mu R on NK cells functions as a signal-transducing molecule because the addition of 0.2 mg/ml IgM to R-NK cells caused a rapid increase in [Ca2+]i (delta = 40 nM). One of the early events that followed signaling through the Fc mu R was the down-modulation of IFN-gamma gene expression and IFN gamma production in NK cells. The presence of IgM during culture of NK cells consistently decreased the expression of HLA-DR (16% vs 40% in control). Thus, the Fc mu R, a constitutively-expressed receptor on human NK cells, seems to be an important functional molecule, which delivers negative regulatory signals to NK cells.

Characterization of the Fc mu receptor on human natural killer cells. Interaction with its physiologic ligand, human normal IgM, specificity of binding, and functional effects

After treatment with human normal IgM, 78 +/- 8% of purified CD3-CD56+ resting human NK cells and 93 +/- 6% of IL-2-activated NK cells selected by adherence to plastic reacted with FITC-goat anti-human IgM. Binding of IgM to the FcR for IgM (Fc mu R) on human NK cells was not species specific because mouse myeloma IgM also bound to these cells. The percentage of CD56+ cells binding IgM after incubation with anti-CD16 mAb was similar to that of cells incubated with medium alone (95 +/- 1% vs 93 +/- 4%). Binding of anti-CD16 mAb to Fc gamma RIII on NK cells was unaffected by pretreatment with IgM (65 +/- 12% vs 69 +/- 4%). The CD7 molecule has been reported to be the Fc mu R on the surface of T cells. Two-color flow cytometry showed that 94 +/- 3% of CD3-CD56+ resting NK cells and 71 +/- 16% of activated NK cells were CD7+. Preincubation of NK cells with three anti-CD7 mAb (Leu-9, 8H8-1, and LAU-A1) failed to block the binding of IgM to the Fc mu R. Modulation of the CD7 molecule off the cell surface (CD7+ = 1.5% +/- 0.3) did not reduce IgM binding, thus excluding the possibility that IgM anti-CD7 might bind to different epitopes of the same molecule. These data indicate that the Fc mu R is a specific Ig-binding structure, distinct from the Fc gamma RIII (CD16) or CD7. The Fc mu R on NK cells functions as a signal-transducing molecule because the addition of 0.2 mg/ml IgM to R-NK cells caused a rapid increase in [Ca2+]i (delta = 40 nM). One of the early events that followed signaling through the Fc mu R was the down-modulation of IFN-gamma gene expression and IFN gamma production in NK cells. The presence of IgM during culture of NK cells consistently decreased the expression of HLA-DR (16% vs 40% in control). Thus, the Fc mu R, a constitutively-expressed receptor on human NK cells, seems to be an important functional molecule, which delivers negative regulatory signals to NK cells.

Expression of Fc mu receptors on human natural killer cells

Fc receptors for IgG (CD16) have been described as the only type of immunoglobulin receptor on large granular lymphocytes (LGL). However, the ability of natural killer (NK) cells to mediate antibody-dependent cellular cytotoxicity (ADCC) in the presence of monoclonal or polyclonal IgM and the inhibition of NK activity by highly purified IgM could not be explained on the basis of FcR for IgG. In order to directly assess the expression of Fc receptors for IgM (Fc mu R), NK cells were treated with human polyclonal IgM, and its binding was visualized by a direct anti-globulin rosette assay with identification of rosette-forming LGL on Giemsa-stained smears. The data indicated that a high proportion of LGL (up to 68%) were Fc mu R-positive cells. However, this percentage varied depending on the IgM preparation (polyclonal or monoclonal), the indicator reagent used for the rosette assays, and the cell preparations studied. Two-color flow cytometry of human nonadherent lymphocyte preparations confirmed the presence of CD56+IgM+ cells, which represented from 43 to 78% of CD56+ cells. Flow cytometry was also performed using highly enriched preparations of human NK cells (the mean percentage of CD3-CD56+ cells was 84%). Up to 88% of purified NK cells bound FITC-labeled monoclonal IgM at a saturating concentration. By indirect immunofluorescence, from 34 to 62% of NK cells purified from the peripheral blood of normal donors were able to bind polyclonal IgM. Similar results were obtained with LGL from a patient with NK lymphoproliferative disease. Thus the presence of Fc mu R on a majority of human NK cells was demonstrated by different techniques, using unseparated peripheral blood mononuclear leukocytes, purified normal NK cells, and also LGL from a patient with NK lymphoproliferative disease.

Inhibition of human natural killer cell activity by polyclonal IgM

Pretreatment of effector cells with normal human IgM induced strong dose-dependent inhibition of NK activity. The degree of inhibition by normal IgM was stronger than that induced by monomeric IgG, which has previously been reported to be a negative regulator of NK activity. For 100% inhibition, 1.1 x 10(-6) M of IgM was required, whereas 66.6 x 10(-6) M of IgG was needed to abolish NK activity. This inhibitory property of polyclonal IgM appeared to be localized in the Fc region of the molecule, and also was significantly reduced upon mild reduction of disulfide bonds. Monoclonal IgM purified from sera of five patients with Waldenström's macroglobulinemia and tested in parallel with normal IgM lacked or had a decreased capacity to inhibit the cytotoxic reaction. As with IgG, IgM interfered mainly with the lytic event, after binding of effector cells to target cells. The inhibition by IgM appeared to be a direct effect on NK cells, since similar effects were observed with purified large granular lymphocytes as with non-adherent lymphocytes. These results indicate a new mechanism for negative regulation of NK cells and suggest the presence of Fcmu receptors on these effector cells.