Among therapies for immune thrombocytopenia (ITP) that achieve long unmaintained remissions, distant relapse rates have not been compared.
To compare relapse rates following umaintained remissions exceeding 1 year in patients with ITP treated with steroids versus anti-Rh(D) with/without steroids versus rituximab with/without steroids.
Institutional Review Board approval was obtained. The charts of 52 consecutive patients with ITP followed in a hematology practice between 07/01/03 and 06/30/13 were reviewed. Remission was defined as a platelet count > 100,000/µL. Patients with the aforementioned treatment and remission characteristics were identified. Steroids were administered alone as dexamethasone 40 mg PO daily for 4 days. Anti-Rh(D) was administered as 75 mcg/kg IV with or without prednisone 60-85 mg PO daily tapered over 4 weeks or dexamethasone 40 mg PO daily for 4 days. Rituximab was administered as 375 mg/m2 IV weekly for 4 weeks or as a single dose with or without dexamethasone 40 mg PO daily for 4 days. Relapse was defined as a platelet count < 30,000/µL. Statistical calculations included ANOVA to compare demographics and chi-square contingency table analysis to compare distant relapse rates (http://www.physics.csbsju.edu/stats).
There were 16 unmaintained remissions exceeding 1 year in 13 patients following treatment with steroids, anti-Rh(D) with/without steroids, or rituximab with/without steroids. Mean age on presentation, sex ratio, duration of ITP prior to therapy, and duration of follow-up after therapy were similar for the 3 groups (Table 1).
Demographics
| Steroids (n=2) | Anti-Rh(D) +/- steroids (n=8) | Rituximab +/- steroids (n=6) | P | |
| Age (y) Mean (range) | 25 (18-33) | 47 (29-70) | 54 (28-75) | 0.44 |
| M:F ratio | 1:1 | 1:1 | 1:1 | 1.0 |
| Duration of ITP prior to therapy (y) Mean (range) | 0.85 (0.31-2) | 2.47 (0.01-10) | 4.75 (1.67-9) | 0.26 |
| Duration of follow-up after therapy (y) Mean (range) | 2.17 (1.33-5.67) | 3.90 (1.73-8.63) | 3.89 (1.58-7.42) | 0.99 |
| Secondary ITP | None | HIV (n=1) | None |
| Steroids (n=2) | Anti-Rh(D) +/- steroids (n=8) | Rituximab +/- steroids (n=6) | P | |
| Age (y) Mean (range) | 25 (18-33) | 47 (29-70) | 54 (28-75) | 0.44 |
| M:F ratio | 1:1 | 1:1 | 1:1 | 1.0 |
| Duration of ITP prior to therapy (y) Mean (range) | 0.85 (0.31-2) | 2.47 (0.01-10) | 4.75 (1.67-9) | 0.26 |
| Duration of follow-up after therapy (y) Mean (range) | 2.17 (1.33-5.67) | 3.90 (1.73-8.63) | 3.89 (1.58-7.42) | 0.99 |
| Secondary ITP | None | HIV (n=1) | None |
Distant relapse rates were 100%, 14.2%, and 66.7% for the steroid, anti-Rh(D) with/without steroid, and rituximab with/without steroid groups, respectively, P = 0.03 (Table 2).
Distant relapse rates per treatment group
| Steroids (n=2) | Anti-Rh(D) +/- steroids (n=8) | Rituximab +/- steroids (n=6) | P | |
| With distant relapse (n) | 2 | 1 | 4 | 0.03 |
| Without distant relapse (n) | 0 | 7 | 2 |
| Steroids (n=2) | Anti-Rh(D) +/- steroids (n=8) | Rituximab +/- steroids (n=6) | P | |
| With distant relapse (n) | 2 | 1 | 4 | 0.03 |
| Without distant relapse (n) | 0 | 7 | 2 |
Among patients who achieve long unmaintained remissions of ITP with steroids, anti-Rh(D) with/without steroids, or rituximab with/without steroids, those treated with anti-Rh(D)-based therapy are the most likely to have extended remission.
Off Label Use: Rituximab therapy of ITP.
