Duration of response in cutaneous T-cell lymphoma patients treated with denileukin diftitox: results from 3 phase III studies.

BACKGROUND

We aimed to determine duration of response in patients with CTCL treated using DD who experienced partial response, complete clinical response, or complete response.

PATIENTS AND

METHODS

Data from 3 phase III studies were pooled. Patients received up to 8 courses of 9 or 18 μg/kg intravenous DD daily for 5 days every 21 days, or placebo. Data on DD-treated patients were analyzed by dose and CD25 status. Kaplan-Meier product limit estimates and 95% confidence intervals were calculated for duration of response and time to response.

RESULTS

The pooled population comprised 263 DD-treated and 44 placebo-treated patients, and 100 and 7, respectively, had at least a partial response. Median duration of response using DD was 277 days vs. 81 days using placebo. Overall response vs. placebo (n = 7; 16%) as (n = 25; 31%) for DD 9 μg/kg (P = .05), (n = 56; 47%) for DD 18 μg/kg (P = .004), (n = 8; 28%) for re-treated patients (DD 18 μg/kg; P = .21), and (n = 11; 31%) for CD25 low-expression patients (DD 18 μg/kg; P = .14). Overall response rates were similar between patients who did (n = 95; 36%) and did not (n = 105; 40%) develop capillary leak syndrome (CLS); median duration of response was longer in patients who developed CLS, but was not significant (619 vs. 267 days, respectively; P = .28). Adverse events occurred in 98% of DD-treated patients; most frequent were nausea, pyrexia, fatigue, CLS, and rigors.

CONCLUSION

These data indicate a durable response with DD in CTCL, even in heavily pretreated patients and those with CD25 low-expression disease.