Management of MDA-5 antibody-positive dermatomyositis with interstitial lung disease-an Auckland case series.

Objective: The aim was to present our experience of managing six cases of anti-melanoma differentiation-associated gene 5 (anti-MDA-5) DM with associated interstitial lung disease (ILD), presenting between June 2017 and October 2020.

Methods: The electronic notes were reviewed for six patients being followed up by the Rheumatology service at Auckland District Health Board. Three patients were initially diagnosed and treated in neighbouring Counties Manukau District Health Board and later transferred to Auckland District Health Board. All had different initial treating clinicians at a time before any predefined treatment algorithm. Emphasis was placed on initial diagnosis and treatment, subsequent disease activity and changes in management. Local management was compared retrospectively with existing evidence relating to the treatment of anti-MDA-5 DM with ILD. Ethical approval was not obtained, according to the New Zealand Health and Disability Ethics Committee exemption for audits and related activities.

Results: Six patients with a variety of clinical presentations were identified appropriately as having anti-MDA-5 DM with ILD. They were commenced on different immunosuppressive regimens, with treatment adjusted according to response and on-going disease activity. Four have achieved clinical and biochemical remission, a fifth has improving active disease, and the sixth is in the early stages of their illness.

Conclusion: Anti-MDA-5 DM is commonly associated with ILD. This can be rapidly progressive, with a poor prognosis in spite of treatment, particularly among Asian patients. Disease activity can seemingly be monitored with serum ferritin. The most effective management of this condition remains poorly researched; however, increasing retrospective evidence favours early aggressive multi-agent immunosuppression and a low threshold for escalation of therapy.