Table 5.
Summary of change in serum tryptase levels.
| Unweighted samplea | IPTW-weighted sampleb | |||||||
|---|---|---|---|---|---|---|---|---|
| Avapritinib | BAT | Estimate (95% CI) | p | Avapritinib | BAT | Estimate (95% CI) | p | |
| Patients included in analysis of change from baseline to 2 monthsc, n | 154 | 43 | Effective N = 150 | Effective N = 34 | ||||
| Number of lines of therapy analyzed | 154 | 50 | Effective N = 150 | Effective N = 41 | ||||
| Absolute change | ||||||||
| Mean (SD) | −226.6 (218.9) | −48.6 (299.6) | −168.48 (−257.92, −79.05) | <0.001* | −234.9 (229.8) | −79.8 (209.3) | – | |
| Median (range) | −164.9 (−1056.0, 543.0) | −8.5 (−1050.0, 1137.7) | −166.3 (−1056.0, 543.0) | −33.0 (−1050.0, 1137.7) | ||||
| Percentage change | ||||||||
| Mean (SD) | −71.5 (35.9) | 37.9 (269.3) | −103.00 (−167.11, −38.90) | 0.002* | −71.3 (35.2) | 1.7 (148.8) | – | |
| Median (range) | −84.5 (−98.9, 129.3) | −12.1 (−94.2, 1826.2) | −84.6 (−98.9, 129.3) | −24.4 (−94.2, 1826.2) | ||||
| Maximum reduction | N = 175 | N = 116 | Effective N = 173 | Effective N = 106 | ||||
| Number of lines of therapy analyzed | N = 175 | N = 161 | Effective N = 173 | Effective N = 150 | ||||
| Absolute reduction | ||||||||
| Mean (SD) | −265.9 (232.5) | −108.4 (264.1) | −181.40 (−215.75, −147.04) | <0.001* | −278.4 (245.8) | −114.7 (245.1) | −211.94 (−266.74, −157.14) | <0.001* |
| Median (range) | −188.7 (−1284.1, −4.5) | −52.3 (−1050.0, 1137.7) | −194.1 (−1284.1, −4.5) | −54.0 (−1050.0, 1137.7) | ||||
| Percentage reduction | ||||||||
| Mean (SD) | −86.6 (18.2) | −9.2 (161.4) | −77.86 (−103.43, −52.29) | <0.001* | −87.1 (17.2) | −18.0 (123.9) | −60.34 (−72.81, −47.86) | <0.001* |
| Median (range) | −92.7 (−99.5, −7.8) | −36.3 (−99.4, 1826.2) | −92.7 (−99.5, −7.8) | −36.9 (−99.4, 1826.2) | ||||
| Time to maximum reduction | ||||||||
| Mean (SD) | 9.6 (9.7) | 7.0 (12.7) | 8.8 (9.2) | 8.5 (17.1) | ||||
| Median (range) | 5.6 (0.5, 49.4) | 3.2 (0.1, 115.4) | 5.6 (0.5, 49.4) | 3.2 (0.1, 115.4) | ||||
AdvSM advanced systemic mastocytosis, BAT best available therapy, CI confidence interval, DOT duration of treatment, HR hazard ratio, IPTW inverse probability of treatment weighting, LOT line of therapy, NE not estimable, NR not reached.
*p < 0.05.
aLOTs without a tryptase measurement at baseline or in the specified time window and LOTs with unknown discontinuation and last prescription date were excluded from the serum tryptase analyses.
bStabilized weights were generated using the following baseline characteristics: age, sex, region, ECOG score, anemia (hemoglobin <10 g/dl), thrombocytopenia (platelet count <100 × 109/l), AdvSM subtype, skin involvement, leukocyte count of 16 × 109/l or higher, serum tryptase level of 125 ng/ml or higher, number of mutated genes within the SRSF2/ASXL1/RUNX1 gene panel, number of prior LOTs, and prior use of tyrosine kinase inhibitor therapy.
cFor the BAT cohort, the serum tryptase level at 2 months was calculated as the serum tryptase level closest to 60 days (±11 days) from the LOT start date, which corresponds to the 3 day 1 of cycle (C3D1) assessment in the EXPLORER and PATHFINDER trials. For avapritinib patients, serum tryptase level at 2 months was defined as the measurement taken at the C3D1 assessment.