Guillet S, Crickx E, Azzaoui I, Chappert P, Boutin E, Viallard JF, Rivière E, Gobert D, Galicier L, Malphettes M, Cheze S, Lefrere F, Audia S, Bonnotte B, Lambotte O, Noel N, Fain O, Moulis G, Hamidou M, Gerfaud-Valentin M, Marolleau JP, Terriou L, Martis N, Morin AS, Perlat A, Le Gallou T, Roy-Peaud F, Robbins A, Lega JC, Puyade M, Comont T, Limal N, Languille L, Zarrour A, Luka M, Menager M, Belmondo T, Hue S, Canoui-Poitrine F, Michel M, Godeau B, and Mahévas M
Sustained response off treatment (SROT) after thrombopoietin receptor agonist (TPO-RA) discontinuation has been reported in immune thrombocytopenia (ITP). This prospective multicenter interventional study enrolled adults with persistent or chronic primary ITP and complete response (CR) on TPO-RAs. The primary end point was the proportion of patients achieving SROT (platelet count >30 × 109/L and no bleeding) at week 24 (W24) with no other ITP-specific medications. Secondary end points included the proportion of sustained CR off-treatment (SCROT, platelet count >100 × 109/L and no bleeding) and SROT at W52, bleeding events, and pattern of response to a new course of TPO-RAs. We included 48 patients with a median age of 58.5 years; 30 of 48 had chronic ITP at TPO-RA initiation. In the intention-to-treat analysis, 27 of 48 achieved SROT, 15 of 48 achieved SCROT at W24; 25 of 48 achieved SROT, and 14 of 48 achieved SCROT at W52. No severe bleeding episode occurred in patients who relapsed. Among patients rechallenged with TPO-RA, 11 of 12 achieved CR. We found no significant clinical predictors of SROT at W24. Single-cell RNA sequencing revealed enrichment of a tumor necrosis factor α signaling via NF-κB signature in CD8+ T cells of patients with no sustained response after TPO-RA discontinuation, which was further confirmed by a significant overexpression of CD69 on CD8+ T cells at baseline in these patients as compared with those achieving SCROT/SROT. Our results strongly support a strategy based on progressive tapering and discontinuation of TPO-RAs for patients with chronic ITP who achieved a stable CR on treatment. This trial was registered at www.clinicaltrials.gov as #NCT03119974., (© 2023 by The American Society of Hematology.)