Rovunaptabin neutralises functional autoantibodies targeting G-Protein coupled receptors (GPCR-fAAbs), observed in patients with Post-COVID syndrome. As we hypothesise an improvement of PCS by rovunaptabin, the aim of reCOVer was to investigate safety, tolerability, and clinical effects of rovunaptabin in PCS patients. reCOVer is a prospective, exploratory, placebo-controlled, double-blind, randomised phase IIa clinical investigator initiated trial with 1350 mg rovunaptabin with additional cross-over at the Universitätsklinikum Erlangen, Germany. The trial was registered in EudraCT, 2022-001781-35. Screening was done between 21·11·2023 and 25·06·2024. Eligible participants (18–80 years) showed GPCR-fAAbs, at least 3/8 defined PCS symptoms persisting ≥3 months after COVID-19 and fatigue as major symptom. Participants were randomly assigned (1:1) to either receive rovunaptabin or placebo at day 0 (d0) and d48 with a follow-up of 28 days, respectively. Primary endpoint was the number of treatment emergent adverse events (TEAE) at d28 (co-primary endpoint: TEAE at d70); secondary endpoint focused on fatigue and quality of life. Thirty PCS patients were randomised and analysed. RCT analysis showed nine (rovunaptabin) and five TEAEs (placebo), yet without statistically significance (p = 0·1299; CI −14·80%; 63·02%); one serious adverse event, not related to treatment, was recorded. Rovunaptabin showed a neutralisation of GPCR-fAAb and a significant improvement of FACIT Fatigue Scale (effect size = 2·10, p = 0·0378), Bell score (effect size = 3·64, p = 0·0004), Fatigue Severity Scale (effect size = −2·66, p = 0·0088), and quality of life (4/8 items). As this proof-of-concept study showed effects on the patient-centred endpoint PCS and a good safety profil, subsequent studies are needed to confirm these results in a larger cohort. 10.13039/501100002347 German Federal Ministry of Education and Research , 10.13039/501100001659 German Research Foundation .

Long-COVID (LC) is characterized by diverse and persistent symptoms, potentially mirroring different molecular pathways. Recent data might offer that one of them is mediated by functional autoantibodies (fAAb) targeting G protein-coupled receptors (GPCR). Thus, the aim of this study was to investigate the clinical phenotype of patients with LC in relation to their GPCR-fAAb seropositivity. The present study recruited 194 patients with LC and profiled them based on self-reported symptoms. GPCR-fAAb seropositivity was identified by using a cardiomyocyte bioassay, testing the presence and functionality of the AAbs. Logistic regression, clustering, and decision tree analyses were applied to examine associations between GPCR-fAAb profiles and self-reported symptoms considering age and gender. The most prevalent GPCR-fAAbs in patients with LC were fAAB targeting the β2 adrenergic receptor (β2-fAAb, 92.8%), the muscarinergic M2 receptor (M2-fAAb, 87.1%), the Angiotensin II type 1 receptor (AT1-fAAb, 85.6%), and angiotensin (1–7) Mas receptor (MAS-fAAb, 85.6%). β2-fAAb showed a significant relation with dizziness, lack of concentration, and POTS, while Endothelin Type A receptor functional autoantibody (ET-A-fAAb) was significantly related to deterioration of pre-existing neurological disorders. Statistical analysis indicated a strong positive correlation between M2- and β2-fAAb; as in addition, an association of β2-fAAb and gender was observed to one of the major clinical symptoms (fatigue/PEM), a critical impact of GPCR-fAAb on LC-pathogenesis can be assumed. Summing up, the present data show that specific GPCR-fAAb are associated with distinct clinical phenotypes. Especially, the combination of M2- and β2-fAAb seemed to be essential for the LC-phenotype with a combination of fatigue/PEM and lack of concentration as major clinical symptoms.