Table 5.
Proposed response criteria for ASM according to Pardanani and Tefferi (18)
| Response category | A: disease-related symptoms1 | B: organomegaly/lymphadenopathy2 | C: disease-related organopathy3 | D: BM findings4 |
|---|---|---|---|---|
| Complete response: A + B + C + D required (when present) | Complete resolution for 3 months | Complete resolution2 | Complete resolution5 | Absence of abnormal MC infiltration6 |
| Major response: A + B + C + D required (when present) | No progression (at a minimum) | No progression (at a minimum) | Complete resolution of ≥1 element of organopathy3,7 | >50% Decrease in BM MC (%) |
| Partial response: A or B or C (without progression in others) | Complete resolution for 3 months | Complete resolution2 | ≥2 Grade improvement in ≥1 element of organopathy7,8 | No progression (at a minimum) |
| Stable disease | None of the above responses | |||
| Progressive disease: B or C required | Not applicable9 | >50% Increase from baseline2 | ≥2 Grade worsening from baseline | Not applicable |
ASM, aggressive systemic mastocytosis; BM, bone marrow; MC, mast cell.
Responses were validated only if they lasted for ≥4 wk.
To be considered as a parameter for response measurement, symptoms must be frequent (≥1 time per month); severe enough to require treatment, despite prophylaxis (H1 and H2 histamine receptor antagonists, proton pump inhibitors, and/or oral cromolyn sodium); and accompanied by either organomegaly/lymphadenopathy or organopathy.
Palpable disease or measurable disease by imaging studies required at baseline; baseline and post-treatment status must be documented by imaging studies to allow third-party confirmation of response or progression.
Grade ≥2 ascites (not optimally controlled with medical therapy) or grade ≥2 weight loss or grade ≥2 osteoporosis (large osteolytic lesions or pathological fracture) or grade ≥2 anemia (hemoglobin <10 g/dL) or thrombocytopenia (platelet count <75 × 109/L) or grade ≥2 hyperbilirubinemia or hypoalbuminemia that is a disease-related change from baseline (grades are per National Cancer Institute Common Toxicity Criteria for reporting adverse events).
BM characteristics to be described: (i) BM MC burden (%) based on tryptase/CD117 (KIT) immunostaining, (ii) cytogenetics, and (iii) D816V KIT status.
Complete resolution of all evidence of organopathy unless observed changes are deemed related to treatment.
Cytogenetic remission is not required; cytogenetic response, if any, to be documented as follows: complete response, disappearance of previously documented chromosomal abnormality without appearance of new ones and partial response, ≥50% reduction of cytogenetic abnormality.
No progression in other elements of organopathy should be evident unless observed changes are deemed related to treatment.
Per National Cancer Institute Common Toxicity Criteria for reporting adverse events.
Given the difficulty in distinguishing treatment-related symptoms from disease-related symptoms.