Table 2.

Characteristics of each drug therapy for ILDs with PM/DM.

DRUG THERAPY	CHARACTERISTICS
Corticosteroids	First-line therapy for ILD with PM/DM.
	Corticosteroids monotherapy is generally not effective for RP-ILD with PM/DM.
MTX	Inhibitor of folic acid metabolism.
	Useful for corticosteroid-sparing agents.
AZA	A prodrug of 6-mercaptopurine, inhibition of purine synthesis.
	Useful for corticosteroid-sparing agents.
CY	Alkylating agent, nitrogen mustard derivative. IVCY is administered in RP-ILD or refractory ILD.
MMF	Anti-metabolite that blocks de novo purine synthesis and the production of B and T cells.
	Efficacy for corticosteroid-resistant ILD with PM/DM has been shown.
IVIG	The mechanism of drug action is variable.
	Efficacy for refractory myositis has been demonstrated.
	Efficacy was also found in several PM/DM cases with ILD.
CSA	CNI, one of the T-cell-targeting therapies.
	Cornerstone for the PM/DM-ILD treatment.
	Usually administered in antisynthetase syndrome or RP-ILD.
TAC	CNI. TAC has a 100-fold greater potency than CSA in inhibiting T-cell activation.
	Efficacy for CSA-refractory ILD in PM/DM has been demonstrated.
RTX	Chimeric monoclonal anti-CD20 antibody, B-cell targeting agent.
	Efficacy for refractory ILD or antisynthetase syndrome has been shown.

Abbreviation: CD, cluster of differentiation.