clinical improvement by measuring muscle
strength (normalisation or improvement with a
plateau). The normalisation of the CK level is
sometimes used to guide initiation of prednisone
taper; however, the decrease in CK level by itself
is not considered a sign of improvement. 5 A slow
prednisone taper is recommended after 3–4
weeks of high-dose prednisone in patients
showing clinical improvement. A proposed
prednisone taper is decrease prednisone by 10mg/
day every four weeks until the patient is on 20mg/
day; then decrease by 5mg/day every four weeks
until the patient is on 10mg/day; then decrease by
2.5mg/day every 4–12 weeks. Intravenous
methylprednisolone 1g/day for three days can be
used prior to initiation of high-dose prednisone in
patients with severe weakness, prominent
extramuscular disease or rapidly worsening
disease. 3
Steroid-sparing immunosuppressive or
immunomodulating therapy is usually used in
patients with moderate to severe diseases or those
with medical comorbidities making long-term
prednisone use undesirable. The second-line
agents usually used in patients with myositis
include azathioprine, methotrexate,
mycophenolate mofetil, tacrolimus, and
intravenous immunoglobulin (IVIg). Treatment of
IIMs is further complicated by the presence of
extramuscular manifestations of myositis, such as
interstitial lung disease (ILD), arthritis and typical
skin rashes in DM.
Novel agents
Novel agents being evaluated for treatment of
myositis include adrenocorticotropic hormone
(ACTH) gel, rituximab, IMO-8400, belimumab,
Octagam ® , tocilizumab, abatacept, siponimod,
JBT-101, IFN-kinoid, anakinra, bimagrumab,
follistatin gene therapy, rapamycin, and
arimoclomol.
interstitial lung disease (RECITAL,