Table 1 Baseline characteristics and response to Bruton tyrosine kinase inhibitor (BTKi) therapy.

From: Long-term outcomes and treatment patterns in Waldenström macroglobulinemia patients who discontinue Bruton tyrosine kinase inhibitor (BTKi) therapy

Characteristics

Whole cohort (n = 150)

BTKi discontinued (n = 111)

Active BTKi therapy (n = 39)

P

Age, years

63 (23-93)

63 (24-93)

63 (23–91)

0.89

Female Sex, n (%)

58 (38.7%)

45 (40.5%)

13 (33.3%)

0.45

Baseline labs prior to BTKi

 Hb, g/dL

10.1 (6.1–14.2)

10.1 (6.1–14.2)

10.4 (7.1–13.5)

0.45

 Platelets, ×109/microL

194 (4–579)

186 (4–579)

238 (52–471)

0.1

 IgM, mg/dL

2420 (11–12064)

2027 (11–12064)

3133 (229–8236)

0.006

 B2M, mg/L

3.4 (1.4–19.0)

3.3 (1.4–16.6)

3.5 (1.5-19.0)

0.71

 Albumin, g/dL

3.7 ((1.9–4.8)

3.8 (1.9–4.8)

3.6 (3.0–4.6)

0.26

 LDH, U/L

206 (71–902)

215 (71–902)

197 (93–597)

0.13

 BM malignant cells, %

50.0 (0–100)

50.0 (0–100)

45.0 (7.0–100)

0.84

Splenomegaly, n (%)

28 (29.5%)

20 (29.0%)

8 (30.8%)

1

Lymphadenopathy, n (%)

54 (56.3%)

38 (54.3%)

16 (61.5%)

0.65

IPSS-WM score, n (%)

 0

3 (3.4%)

1 (1.8%)

2 (6.3%)

0.26

 1

21 (23.9%)

13 (23.2%)

8 (25.0%)

 

 2

36 (40.9%)

20 (35.7%)

16 (50.0%)

 

 3

26 (29.5%)

20 (35.7%)

6 (18.8%)

 

 4

2 (2.3%)

2 (3.6%)

0 (0%)

 

R-IPSS-WM score, n (%)

 0

12 (13.5%)

5 (8.9%)

7 (21.2%)

0.17

 1

32 (36.0%)

20 (35.7%)

12 (36.4%)

 

 2

23 (25.8%)

15 (26.8%)

8 (24.2%)

 

 3

17 (19.1%)

14 (25.0%)

3 (9.1%)

 

 4

5 (5.6%)

2 (3.6%)

3 (9.1%)

 

Genomic data before BTKi, n (%)

 MYD88 mutation

98 (86.7%)

68 (86.1%)

30 (88.2%)

1

 CXCR4 mutation

25 (33.8%)

16 (34.0%)

9 (33.3%)

1

 TP53 mutation

10 (16.9%)

9 (22.5%)

1 (5.3%)

0.15

Number of prior therapies, n (%)

 0

57 (38.0%)

40 (36.0%)

17 (43.6%)

0.07

 1

44 (29.3%)

29 (26.1%)

15 (38.5%)

 

 ≥2

49 (32.7%)

42 (37.8%)

7 (17.9%)

 

Prior therapy exposures, n (%)

 Anti-CD20

90 (60.0%)

70 (63.1%)

20 (51.3%)

0.25

 Proteasome-inhibitor

42 (28.0%)

36 (32.4%)

6 (15.4%)

0.06

 Chemotherapy

66 (44.0%)

50 (45.0%)

16 (41.0%)

0.71

BTKi therapy, n (%)

 Ibrutinib

113 (75.3%)

96 (86.5%)

17 (43.6%)

<0.001

 Zanubrutinib

26 (17.3%)

9 (8.1%)

17 (43.6%)

 

 Acalabrutinib

11 (7.3%)

6 (5.4%)

5 (12.8%)

 

BTKi best response, n (%)

 CR

3 (2.0%)

3 (2.7%)

0

0.009

 VGPR

27 (18.0%)

15 (13.5%)

12 (30.8%)

 

 PR

74 (49.3%)

52 (46.8%)

22 (56.4%)

 

 MR

16 (10.7%)

12 (10.8%)

4 (10.3%)

 

 SD

25 (16.7%)

24 (21.6%)

1 (2.6%)

 

 PD

5 (3.3%)

5 (4.5%)

0

 

Median time on BTKi, months

22.5 (0.3–136.3)

12.0 (0.3–130.0)

36.6 (13.2–136.3)

 
  1. Normal ranges: Hb, 12.2–15.3 g/dL; platelets, 160–397 ×109/μL; IgM, 35–242 mg/dL; B2M, 0.80–2.30 mg/L; albumin, 3.5–5.2 g/dL; LDH, 135–214 U/L. Range written in parentheses. Percentage calculated based on available data.
  2. BM bone marrow, BTKi bruton tyrosine kinase inhibitor, B2M beta 2 microglobulin, CR complete response, Hb hemoglobin, IgM immunoglobulin M, IPSS-WM International Prognostic Scoring System for Waldenström Macroglobulinemia, LDH lactate dehydrogenase, MR minimal response, PD progressive disease, PR partial response, R-IPSS-WM revised ISSWM, SD stable disease, VGPR very good partial response.
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