The International Myeloma Working Group (IMWG) defines progressive disease as an increase of ≥25% from the lowest response value in any one or more of the following:

• Serum M component; the absolute increase must be ≥0.5 g/dL*
• Urine M component; the absolute increase must be ≥200 mg/24 h
• For patients without measurable serum and urine M protein levels, the difference between involved and uninvolved free light chain (FLC) levels; the absolute increase must be >10 mg/dL
• Bone marrow plasma cell percentage; the absolute percentage must be ≥10%^†
• Definite development of new bone lesions or soft tissue plasmacytomas or definite increase in the size of existing bone lesions or soft tissue plasmacytomas
• Development of hypercalcaemia (corrected serum calcium >11.5 mg/dL or 2.65 mmol/L) that can be attributed solely to the plasma cell proliferative disorder

Clinical relapse is defined as increasing disease and/or end organ dysfunction based on one or more indicators of CRAB (elevated calcium, renal failure, anaemia, or bone lesions).

NOTE: All relapse categories require 2 consecutive assessments made at any time before classification as relapse or disease progression and/or the institution of any new therapy. In the IMWG criteria, patients with complete response (CR) must also meet the criteria for progressive disease shown here to be classified as progressive disease for the purposes of calculating time to progression and progression-free survival (PFS). The definitions of relapse, clinical relapse, and relapse from CR are not to be used in calculation of time to progression or PFS.

It is important to note that these criteria may differ from what was used in the PANORAMA 1 trial.

*For progressive disease, serum M component increases of ≥1 gm/dL are sufficient to define relapse if starting M component is ≥5 g/dL.
†Relapse from CR has the 5% cut-off vs 10% for other categories of relapse.

Source: International Myeloma Working Group (IMWG) uniform response criteria for multiple myeloma. http://myeloma.org/pdfs/IMWG_Response_criteria.pdf. Accessed April 27, 2015.