Table 1.
Baseline clinical and laboratory characteristics of WM patients who progressed on ibrutinib
| Baseline characteristics | WM1 | WM2 | WM3 | WM4 | WM5 | WM6 |
|---|---|---|---|---|---|---|
| Age (y) | 77 | 92 | 61 | 66 | 78 | 73 |
| Sex | Male | Male | Male | Male | Male | Male |
| Serum IgM (mg/dL) | 4130 | 921 | 3630 | 2490 | 1300 | 5790 |
| Serum IgM M-spike (g/dL) | 2.21 | 0.86 | 2.09 | 1.41 | 0.98 | 3.62 |
| Hb (g/dL) | 10.3 | 8.0 | 12.3 | 9.1 | 8.9 | 10.8 |
| Serum β2-microglobulin (mg/L) | 4.5 | N/A | 2.5 | 5.6 | 14.2 | 3.9 |
| BM involvement (%) | 30 | N/A | 70 | 40 | 5 | 30 |
| Prior therapies | Fludarabine, R, CPR, bendamustine-R, bortezomib/dex, tositumomab | R | R, ofatumumab, C, pentostatin | R | Cladribine, C, R, IFN-α, bendamustine, bortezomib/dex | R, chlorambucil, bendamustine |
| Time on ibrutinib (mo) | 9.6 | 7.7 | 37.1 | 36.4 | 9.1 | 23.0 |
| Best response to ibrutinib | PR | PR | PR | VGPR | VGPR | PR |
| Events supporting progressive disease from best response | BM 30%→70% IgM M-spike 0.55→1.12 Hb 11.8→10.5 | IgM M-spike NQ→0.55 Hb 9.5→7.3 | BM 20%→90% Hb 13.4→10.7 | Splenic enlargement Hb 10.6→7.8 New pleural effusion | BM 5%→60% IgM M-spike 0.23→0.81 Hb 9.6→8.4 | BM 15→80% IgM 2647→3970 Hb 15.1→7.7 |
| MYD88 status | L265P | L265P | L265P | S243N | L265P | L265P |
| CXCR4 status | WT | S339fs | S338X | WT | WT | S338fs |
C, cyclophosphamide; dex, dexamethasone; fs, denotes frameshift mutation present at this amino acid site; Hb, hemoglobin; IFN, interferon; IgM, immunoglobulin M; N/A, not available; NQ, faint, not quantifiable; P, prednisone; PR, partial response; R, rituximab; VGPR, very good partial response.