Efficacy and Safety of Filgotinib in Patients with High Risk of Poor Prognosis Who Showed Inadequate Response to MTX: A Post Hoc Analysis of the FINCH 1 Study.

INTRODUCTION: This exploratory analysis of FINCH 1 (NCT02889796) examined filgotinib (FIL) efficacy and safety in a subgroup of patients with rheumatoid arthritis (RA) and inadequate response to methotrexate (MTX; MTX-IR) who had four poor prognostic factors (PPFs). METHODS: Patients with MTX-IR received placebo up to week (W)24 or FIL200 mg, FIL100 mg, or adalimumab up to W52; all received MTX. Efficacy and safety data were stratified by four PPFs versus fewer than four PPFs: seropositivity, high-sensitivity C-reactive protein (CRP) ≥ 6 mg/L, Disease Activity Score in 28 joints with CRP > 5.1, and erosions on X-rays. RESULTS: At baseline, 687/1755 patients had four PPFs. At W12, whether with four PPFs or fewer than four PPFs, response rates on all American College of Rheumatology (ACR) measures were significantly greater with FIL200 and FIL100 versus placebo. At W52, FIL200 ACR20/50/70 response rates remained at least numerically higher versus adalimumab in both subgroups. At W52, FIL200 reduced modified total Sharp score (mTSS) change versus adalimumab in patients with four or fewer than four PPFs. CONCLUSIONS: In high-risk (four PPFs) patients with MTX-IR RA, FIL200 and FIL100 showed similar reductions in disease activity versus placebo at W12 as in patients with fewer than four PPFs. mTSS in patients receiving FIL200 changed little from W24 to W52, while that in patients receiving FIL100 progressed comparably to patients who received adalimumab. Tolerability was comparable across treatment arms and subgroups.

Monotherapy rapamycin allows an increase of CD4 CD25 FoxP3 T cells in renal recipients.

CD4(+) CD25(bright+) FoxP3(+) regulatory T cells (Tregs) may control donor-specific allogeneic responses in kidney transplant recipients. Recent evidence demonstrated that three phenotypical Treg-subsets, naive (CCR7(+)CD45RO(-)), central-memory (CCR7(+)CD45RO(+)) and effector-memory (CCR7(-)CD45RO(+)), are essential for the development and function of antigen-specific suppression in the lymphoid and peripheral tissues. Also, it has been appreciated that Tregs are affected by immunosuppressive agents. In clinical practice, however, the effect of a single drug remains to be determined. Therefore, we analyzed the effect of several immunosuppressive agents on the number, phenotype and function of peripheral Tregs from 46 stable kidney transplant recipients. These patients were converted to monotherapy with tacrolimus (n = 15), rapamycin (n = 17) or mycophenolate mofetil (n = 14). Blood was obtained at inclusion and 6 months thereafter. The number of Tregs increased significantly in patients on monotherapy with rapamycin (P < 0.001), which was caused by increased numbers of Tregs with a central-memory and an effector-memory phenotype (both P < 0.05). At 6 months after conversion, however, the suppressive function of Tregs did not significantly change in co-cultures stimulated with donor-Ag. Therefore, monotherapy with rapamycin allows the signals that are needed to increase the number of functional Tregs with a memory phenotype, thereby enhancing the potential capacity to regulate donor-specific responses in the lymphoid and the peripheral tissues.

Generation of donor-specific regulatory T-cell function in kidney transplant patients.

BACKGROUND: In the search for mechanisms that can induce and maintain transplant tolerance, donor-specific CD4CD25FoxP3 regulatory T cells have been frequently mentioned. However, it remains to be demonstrated, whether these cells are generated after clinical transplantation. METHODS: We prospectively analyzed the phenotype and function of peripheral regulatory CD4CD25 T cells of 79 patients before, 3, 6, and 12 months after kidney transplantation. The immune regulatory capacities of CD4CD25 T cells were assessed by their depletion from peripheral blood mononuclear cells and in co-culture with CD25 responder T-cells in the mixed lymphocyte reactions. RESULTS: In the first year after transplantation, the number and proportion of CD4CD25 T cells significantly decreased (P<0.05 and P<0.001, respectively). In the mixed lymphocyte reactions, we observed donor-specific hyporesponsiveness in the presence of significantly increased proliferation to third and fourth Party-Ag, (P<0.001 and P<0.05, respectively). Furthermore, functional analysis of CD25 cells showed that the effect of depletion of these cells from peripheral blood mononuclear cells, and their suppressive capacities in co-culture with donor-Ag stimulated CD25 responder T-cells (1:10 ratio) significantly improved (P<0.01 and P<0.001, respectively). Moreover, the difference between the stimulation with donor-Ag and third Party-Ag became apparent at 6 months after transplantation. CONCLUSIONS: These findings demonstrate that donor-specific CD4CD25 regulatory T-cell function is generated in fully immunosuppressed renal recipients in the first year after transplantation.

End-stage renal failure and regulatory activities of CD4+CD25bright+FoxP3+ T-cells.

BACKGROUND: The defensive immune system in patients with end-stage renal failure is impaired at multiple levels. This state of immune incompetence is associated with continuous activation of the immune system. An additional explanation for this state of activation may be the disturbed function of CD4(+)CD25(bright+)FoxP3(+) regulatory T-cells. METHODS: The phenotype and function of peripheral regulatory T-cells from patients with end-stage renal failure (N = 80) and healthy controls (N = 17) was studied by flow cytometry, RT-PCR and mixed lymphocyte reaction. Patients were on haemodialysis (N = 40), peritoneal dialysis (N = 26) or not treated with dialysis yet (N = 14). The latter group had a glomerular filtration rate of <20 ml/min/ 1.73 m(2). RESULTS: The basal IL-2 mRNA level was high in patient-PBMC (P = 0.0002 versus healthy controls). The absolute number of CD4(+)CD25(bright+) T-cells was low in patients (P < 0.05 versus healthy controls). Furthermore, proliferation of patient-PBMC upon allogeneic stimulation was impaired (P < 0.0001 versus healthy controls). The regulatory function of CD4(+)CD25(bright+) T-cells was determined in the setting of direct allorecognition. First, the effect of depletion of CD25(bright+) cells from patient-PBMC on proliferation was low. Second, co-culture of CD25(bright+) cells with CD25(neg/dim) cells (1:10 ratio) showed impaired regulatory function (P < 0.001 versus healthy controls), which was especially pronounced in patients on dialysis. The FOXP3 mRNA level was also low upon stimulation (P = 0.0002 versus healthy controls). CONCLUSIONS: In line with previous studies, we observed an overactivated but functionally compromised immune system in patients with end-stage renal failure. It now appears that in this setting, regulation by CD4(+)CD25(bright+)FoxP3(+) T-cells is also impaired.

The effect of rabbit anti-thymocyte globulin induction therapy on regulatory T cells in kidney transplant patients.

BACKGROUND: Prevention of alloreactivity by rabbit anti-thymocyte globulins (rATG) may not only result from immunodepletion but also from the induction of T cells that control allogeneic immune responses. In the present prospective and controlled study, we investigated the effect of rATG on the frequency, function and phenotype of peripheral immunoregulatory CD4+ T cells in kidney transplant (KTx) patients. METHODS: After transplantation, 16 patients received ATG-induction therapy and triple therapy consisting of tacrolimus, MMF and steroids. The control group (n = 18) received triple therapy only. By flow cytometry, T cells were analysed for CD25, FoxP3, CD127, CD45RO and CCR7. To study their suppressive capacities, CD25bright T cells were co-cultured with CD25(-/dim) effector T cells (Teff) in mixed lymphocyte reactions (MLR), stimulated with donor and third party (3P) antigens. RESULTS: Pre-transplant levels of FoxP3+CD127(-/low) T cells were 6% of CD4+ T cells. One week post-ATG treatment, no measurable numbers of regulatory T cells were present (P < 0.01). After 4 weeks, the cell numbers of CD4+FoxP3+CD127(-/low) T cells slowly reappeared and thereafter remained low (P < 0.01). At 14 weeks, a significant shift towards the CD45RO+CCR7+ (central memory) phenotype within CD4+FoxP3+ T cells was observed (P < 0.01). At 26 weeks, the proliferative alloresponses of the PBMC and CD25(-/dim) Teff profoundly decreased compared to pre-transplant (P = 0.01 and P = 0.02 respectively), while the regulatory capacity of the CD25bright T cells, of which 90% consisted of FoxP3+CD127(-/low) T cells, remained unaffected. The CD25bright T cells suppressed the anti-donor (94%) and 3P responses (93%). CONCLUSION: Our findings show that rATG therapy does not spare peripheral immunoregulatory T cells in vivo, but after regeneration preserves their suppressive activity.

Impact of immunosuppressive drugs on CD4+CD25+FOXP3+ regulatory T cells: does in vitro evidence translate to the clinical setting?

Success of solid-organ transplantation requires the continuous administration of immunosuppressive drugs to prevent graft rejection. The currently prescribed immunosuppressive medication targets the immune system in a nonspecific fashion, leading to debilitating side effects that diminish patient survival and quality of life. Therefore, it is important to minimize immunosuppression, but this requires the development of alternative therapeutic strategies to induce and maintain transplant tolerance. One such strategy would be to allow and facilitate the induction of alloantigen-specific immune regulation by regulatory T cells (Treg). Recent experimental studies indicate that several commonly used immunosuppressive drugs have detrimental effects on the induction and function of Treg, whereas other drugs appear to spare these cells or may even be beneficial. These differential effects may be explained by differences in signaling pathways between Treg and effector T cells. In this review, we provide a comprehensive overview of the current literature on the effects of immunosuppressive drugs on CD4+CD25+FOXP3+ Treg and discuss whether these in vitro data are substantiated by in vivo evidence from the clinic. A greater understanding of the impact of immunosuppression on Treg may help to create future opportunities to manipulate the host allo-immune response and achieve operational tolerance in transplantation.