AB0663 Bicentric observational study on the therapeutic management of patients with rheumatoid arthritis and systemic sclerosis overlap syndrome

Background

The rheumatoid arthritis (RA)/systemic sclerosis (SSc) overlap syndrome is a rare and understudied association. It affects 5% of patients with SSc. Only open studies evaluating biological drugs (bDMARDs) have reported encouraging results, particularly on joint involvement. The management of these patients is therefore not codified.

Objectives

The objective was to analyze in real conditions the therapeutic strategy and the response to bDMARDs, with a focus on joint involvement.

Methods

We retrospectively analyzed over a 10-year period the clinical, biological, radiographic characteristics and therapeutic management of patients meeting the ACR/EULAR diagnostic criteria for RA and SSc in two academic centers. Response to bDMARDs was assessed according to EULAR and if unavailable according to therapeutic maintenance. The evolution of lung function test was also evaluated.

Results

Twenty-two patients were identified. Interstitial lung involvement was common (n=11). Only 7 patients were treated with csDMARD alone. The most commonly used drug was methotrexate. The use of bDMARDs was frequent (15/22), significantly greater in patients with rheumatoid factors (OR 26.7; p=0.004) and with a trend in patients with higher levels of anti-CCP (160 vs 15 IU; p=0.11) or diffuse interstitial lung disease (OR 10.6; p=0.063). Tocilizumab was the most selected therapy (n = 8) followed by rituximab (n = 5), abatacept, and anti-TNFs (n = 4 respectively). We evaluated 21 treatment sequences, 19 of which were evaluated according to EULAR response criteria. bDMARDS that inhibits the activation of lymphocytes (abatacept, rituximab) generally resulted in a good or moderate response (n = 9/10) with a significant decrease in DAS28 at 6 months (-1.75; p = 0.016). Cytokine inhibitors (tocilizumab, etanercept, infliximab) were less likely to achieve good or moderate control of joint involvement (n = 3/9) with a smaller decrease in DAS28 at 6 months (-0.79; p = 0.36). Two tocilizumab sequences were stopped early due to intolerance and could not be evaluated. One patient received tofacitinib with a good clinical response but was discontinued at 9 months for intolerance. Lung function test data did not change significantly on bDMARD.

Conclusion

In patients with rheumatoid arthritis (RA)/systemic sclerosis (SSc) overlap syndrome, bDMARDS that inhibits the activation of lymphocytes (abatacept, rituximab) resulted in more frequent and greater improvement in joint involvement than cytokine inhibitors (tocilizumab, etanercept, infliximab).

Disclosure of Interests

None declared

Biological and molecular analyses of structurally reduced analogues of endothelin-1

Structurally reduced analogues of endothelin-1 (ET-1) were synthesized through linking with an aliphatic spacer [aminocaproic acid (Aca)], segment 3-11 of ET-1 to carboxyl-terminal fragments of various lengths (16-21, 17-21,...,21). The peptides were prepared in their linear or cyclic form, and a formyl group was or was not introduced on the Trp21 side chain. Pharmacological studies were carried out with the guinea pig lung parenchyma paradigm and the rat thoracic aorta bioassay. In the rat aorta, an ET(A) receptor preparation, all of the analogues were inactive. However, in the lung parenchyma, we observed that among the linear formylated derivatives, [Cys(Acm)3,11,Trp(For)21]-(3-11)-Aca-(17-21)ET was a partial agonist. In this series, the presence of His16, as in [Cys(Acm)3,11,Trp(For)21]-(3-11)-Aca-(16-21)ET, caused a decrease in contractile activity, suggesting that the imidazole group disfavors the proper interaction of the linear molecule with the ETB receptors of the lung parenchyma. The loss of biological activity of the deformylated linear analogues strongly suggested that the formyl group played a stabilizing role in the structure of the linear molecules. Interestingly, molecular modeling studies indicated the adoption of different conformations by the formylated and the nonformylated analogues. In contrast, the stabilizing effect of the formyl group was not observed with the cyclic compounds. Furthermore, the presence of His16 favored the contractile activity of the cyclic peptides. Finally, the results demonstrated that the carboxyl-terminal residues 18-21 are required for the activity in the guinea pig lung parenchyma ETB receptors.

Role of the neutral endopeptidase 24.11 in the conversion of big endothelins in guinea-pig lung parenchyma

1. We have studied the conversion of big endothelin-1 (big ET-1), big endothelin-2 (big ET-2) and big endothelin-3 (big ET-3) and characterized the enzyme involved in the conversion of the three peptides in guinea-pig lung parenchyma (GPLP). 2. Endothelin-1 (ET-1), endothelin-2 (ET-2) and endothelin-3 (ET-3) (10 nM to 100 nM) caused similar concentration-dependent contractions of strips of GPLP. 3. Big ET-1 and big ET-2 also elicited concentration-dependent contractions of GPLP strips. In contrast, big ET-3, up to a concentration of 100 nM, failed to induce a contraction of the GPLP. 4. Incubation of strips of GPLP with the dual endothelin converting enzyme (ECE) and neutral endopeptidase (NEP) inhibitor, phosphoramidon (10 microM), as well as two other NEP inhibitors thiorphan (10 microM) or SQ 28,603 (10 microM) decreased by 43% (P < 0.05), 42% (P < 0.05) and 40% (P < 0.05) the contractions induced by 30 nM of big ET-1 respectively. Captopril (10 microM), an angiotensin-converting enzyme inhibitor, had no effect on the contractions induced by big ET-1. 5. The incubation of strips of GPLP with phosphoramidon (10 microM), thiorphan (10 microM) or SQ 28,603 (10 microM) also decreased by 74% (P < 0.05), 34% and 50% (P < 0.05) the contractions induced by 30 nM big ET-2 respectively. As for the contractions induced by big ET-1, captopril (10 microM) had no effect on the concentration-dependent contractions induced by big ET-2. 6. Phosphoramidon (10 microM), thiorphan (10 microM) and SQ 28,603 (10 microM) significantly potentiated the contractions of strips of GPLP induced by both ET-1 (30 nM) and ET-3 (30 nM). However, the enzymatic inhibitors did not significantly affect the contractions induced by ET-2 (30 nM) in this tissue. 7. These results suggest that the effects of big ET-1 and big ET-2 result from the conversion to ET-1 and ET-2 by at least one enzyme sensitive to phosphoramidon, thiorphan and SQ 28,603. This enzyme corresponds possibly to EC 3.4.24.11 (NEP 24.11) and could also be responsible for the degradation of ETs in the GPLP.