Biologic correlates of response and survival in patients with cutaneous T-cell lymphoma treated with denileukin diftitox.

BACKGROUND

Denileukin diftitox, a fusion protein consisting of peptide sequences for the enzymatically active and membrane translocation domains of diphtheria toxin and human interleukin, resulted in a response rate of 30% in the phase III registration trial in patients with recurrent or persistent cutaneous T-cell lymphoma (CTCL). Little is known with regard to the biologic correlates of response or the impact of denileukin diftitox on disease progression and survival.

PATIENTS AND

METHODS

In our single-center series of 37 patients with early- and advanced-stage disease with CTCL treated with denileukin diftitox at a dose of 9 microg/kg or 18 microg/kg per day, we observed an overall response rate of 51%.

RESULTS

In 8 patients with early-stage (< IIA) CTCL, there were 5 responses (62.5%), and the median survival has not been reached, with 70% of patients still alive at 46 months. In 29 patients with advanced-stage (>/= IIB) disease, there were 14 responses (49.3%), and the median survival was 31 months. Changes in the number of CD4+ CD25+ T-cell populations were observed in 7 of 19 responders, with no overall changes in the absolute lymphocyte counts during the course of therapy. Decrease in lactate dehydrogenase was strongly correlated with clinical response (P < 0.05).

CONCLUSION

Denilekin diftitox was a well-tolerated treatment in early- and advanced-stage CTCL and was not associated with detrimental immunologic efects on lymphocyte populations.