Recommendations for postremission laboratory surveillance and preemptive treatment of patients with iTTP
| Timing of follow-up . | ADAMTS13 activity and CBC . | Preemptive rituximab . |
|---|---|---|
| First 3 mo after stopping TPE | ADAMTS13 monthly; CBC every 1-2 wk until steroids have been discontinued and then monthly | Consider treatment when ADAMTS13 activity drops to 10-20% during follow-up in remission |
| 3 to 24 mo | Every 3 mo | Optimal dose and schedule have not been determined; most studies have used the standard regimen for B-cell neoplasia (375 mg/m2 per wk for 4 wk).† |
| 24 to 60 mo | Continue every 3 mo or extend interval to every 6-12 mo* | Associated favorable risk-benefit ratio. |
| 61+ mo | No evidence, but recommend ongoing (yearly) surveillance* |
| Timing of follow-up . | ADAMTS13 activity and CBC . | Preemptive rituximab . |
|---|---|---|
| First 3 mo after stopping TPE | ADAMTS13 monthly; CBC every 1-2 wk until steroids have been discontinued and then monthly | Consider treatment when ADAMTS13 activity drops to 10-20% during follow-up in remission |
| 3 to 24 mo | Every 3 mo | Optimal dose and schedule have not been determined; most studies have used the standard regimen for B-cell neoplasia (375 mg/m2 per wk for 4 wk).† |
| 24 to 60 mo | Continue every 3 mo or extend interval to every 6-12 mo* | Associated favorable risk-benefit ratio. |
| 61+ mo | No evidence, but recommend ongoing (yearly) surveillance* |
CBC, complete blood count.
The patient’s preference has to be taken into account; consider demographic risk factors of relapsing courses2,3 in decision making.
†Other doses and <4 weekly infusions of rituximab may be effective in normalizing ADAMTS13 activity. Administration of 1 rituximab infusion (fixed or body weight–adapted dose), followed by re-measurement of ADAMTS13 activity after 1 month, is an alternative approach. However, according to Jestin et al,8 the median time to first retreatment in patients receiving 4 rituximab infusions was 40 months (IQR, 18.1-57) compared with 18.9 months (IQR, 14.3-26) and 18.1 mo (IQR, 11.3-22) in those receiving 2 or 1 infusion(s), respectively (P = 0.01). Similarly, Westwood et al9 documented a lower incidence rate for retreatment following preemptive rituximab in standard-dose regimens (0.17 per year) compared with reduced-dose regimens (0.38 per year) (P = 0.039).