Table 1. In vitro Profile of MRLB-11055.
| Category | Activity | IC50 (nM)a |
| Cell-free JAK2b | JAK2 (JH1)WT | 0.08 |
| JAK2 (JH1–JH2)WT | 0.78 | |
| JAK2 (JH1–JH2)V617F | 0.35 | |
| Cell pSTAT5c(1 hour) | BaF3d (JAK2 WT) | 23 |
| BaF3 (JAK2 V617F) | 11 | |
| CTLL-2e | 66 | |
| Cell Proliferationf(48 hour) | BaF3d (JAK2 WT) | 14 |
| BaF3 (JAK2 V617F) | 29 | |
| CTLL-2f | 13 | |
| H2122g | 1900 | |
| Cell Apoptosish(24 hour) | BaF3d (JAK2 WT) | 260 |
| BaF3 (JAK2 V617F) | 135 | |
| Cell-free Kinase Selectivity | TYK2 (JH1) | 0.18 |
| JAK1 (JH1) | 1.5 | |
| JAK3 (JH1) | 300 | |
| 198/220 kinasesi | >25-fold over JAK2 |
a) Mean value, n = 3.
b) Kinase activity, HTRF assay.
c) pJAK2 and pSTAT5 activity measured via AlphaScreen and BeadLyte assays.
d) EPO-stimulated.
e) IL2-stimulated CTLL-2 cells, JAK1 and JAK3 dependent.
f) Cell growth, Vialight assay.
g) Epithelial lung cancer cell line.
h) Apoptosis determined by ApoDirect measurement of fragmented DNA. Values shown are EC50.
i) See Table S1 for all kinases within 25-fold. Fold selectivity based on JAK2 (JH1-JH2) IC50.