Points to consider when doing a trial primarily involving the heart

Assessment of myocardial fibrosis in patients with systemic sclerosis using [68Ga]Ga-FAPI-04-PET-CT

PURPOSE

Myocardial fibrosis (MF) is a factor of poor prognosis in systemic sclerosis (SSc). Direct in-vivo visualization of fibroblast activation as early readout of MF has not been feasible to date. Here, we characterize 68Gallium-labeled-Fibroblast-Activation-Inhibitor-04 ([68Ga]Ga-FAPI-04)-PET-CT as a diagnostic tool in SSc-related MF.

METHODS

In this proof-of-concept trial, six SSc patients with and eight without MF of the EUSTAR cohort Erlangen underwent [68Ga]Ga-FAPI-04-PET-CT and cardiac MRI (cMRI) and clinical and serologic investigations just before baseline and during follow-up between January 2020 and December 2020. Myocardial biopsy was performed as clinically indicated.

RESULTS

[68Ga]Ga-FAPI-04 tracer uptake was increased in SSc-related MF with higher uptake in SSc patients with arrhythmias, elevated serum-NT-pro-BNP, and increased late gadolinium enhancement (LGE) in cMRI. Histologically, myocardial biopsies from cMRI- and [68Ga]Ga-FAPI-04-positive regions confirmed the accumulation of FAP+ fibroblasts surrounded by collagen deposits. We observed similar but not equal spatial distributions of [68Ga]Ga-FAPI-04 uptake and quantitative cMRI-based techniques. Using sequential [68Ga]Ga-FAPI-04-PET-CTs, we observed dynamic changes of [68Ga]Ga-FAPI-04 uptake associated with changes in the activity of SSc-related MF, while cMRI parameters remained stable after regression of molecular activity and rather indicated tissue damage.

CONCLUSIONS

We present first in-human evidence that [68Ga]Ga-FAPI-04 uptake visualizes fibroblast activation in SSc-related MF and may be a diagnostic option to monitor cardiac fibroblast activity in situ.

Systemic sclerosis: Recent insight in clinical management

Systemic sclerosis (SSc) is a connective tissue disease characterized by diffuse microangiopathy and immune dysregulation which ultimately result in widespread fibrosis of skin and internal organs. Although the 2013 EULAR/ACR criteria have allowed to improve the sensitivity for SSc diagnosis, it has recently come to light that the traditional subclassification into limited and diffuse cutaneous forms does not appear to fully capture the different phenotypes of the scleroderma spectrum. In this regard, a recent large cluster analysis-based study and other ongoing projects are trying to achieve a better stratification of SSc patients, as the disease course remains largely unpredictable to date. Recent preclinical studies and randomized controlled trials have yielded encouraging results with new drugs targeting inflammatory/immunological and fibrotic pathways. One of the main unmet needs in SSc remains the early identification of patients at high mortality risk, for whom aggressiveness of therapies ought to be determined and weighed against disease prognosis. Furthermore, lung and cardiac transplantation may also be taken into account in some carefully selected patients. Though the prognosis of SSc remains poor, an optimized stratification of patients along with the recent and ongoing advances in therapies could greatly impact the natural course of the disease in the near future. Moreover, it is envisioned that there will be an increasing need in the future to further develop combination therapies to better fight against this complex disease. In this review we discussed new insights into organ involvements and therapeutic options.

Systemic sclerosis: state of the art on clinical practice guidelines

Systemic sclerosis (SSc) is an orphan disease characterised by autoimmunity, fibrosis of the skin and internal organs, and vasculopathy. SSc may be associated with high morbidity and mortality. In this narrative review we summarise the results of a systematic literature research, which was performed as part of the European Reference Network on Rare and Complex Connective Tissue and Musculoskeletal Diseases project, aimed at evaluating existing clinical practice guidelines or recommendations. Only in the domains ‘Vascular & Ulcers’ (ie, non-pharmacological approach to digital ulcer), ‘PAH’ (ie, screening and treatment), ‘Treatment’ and ‘Juveniles’ (ie, evaluation of juveniles with Raynaud’s phenomenon) evidence-based and consensus-based guidelines could be included. Hence there is a preponderance of unmet needs in SSc referring to the diagnosis and (non-)pharmacological treatment of several SSc-specific complications. Patients with SSc experience significant uncertainty concerning SSc-related taxonomy, management (both pharmacological and non-pharmacological) and education. Day-to-day impact of the disease (loss of self-esteem, fatigue, sexual dysfunction, and occupational, nutritional and relational problems) is underestimated and needs evaluation.