title: A phase-1 trial of bexarotene and denileukin diftitox in patients with relapsed or refractory cutaneous T-cell lymphoma.
abstract: Denileukin diftitox, a genetically engineered fusion protein combining the enzymatically active domains of diphtheria toxin and the full-length sequence for interleukin-2 (IL-2), efficiently targets lymphoma cells expressing the high-affinity IL-2 receptor (IL-2R) consisting of the alpha/p55/CD25, beta/p75/CD122, and gamma/p64/CD132 chains. In vitro studies demonstrated that the retinoid X receptor (RXR) retinoid, bexarotene, at biologically relevant concentrations of 10(-6) M to 10(-8) M, upregulated both the p55 and p75 subunits of the IL-2R and enhanced 5- to 10-fold the susceptibility of T-cell leukemia cells to denileukin diftitox. To determine whether this biomodulatory effect could be recapitulated in vivo, we treated 14 patients with relapsed or refractory cutaneous T-cell lymphoma with escalating doses of bexarotene (75 mg/day-300 mg/day) and denileukin diftitox (18 mcg/kg per day x 3 days every 21 days) in a phase 1 trial. Overall response was 67% (4 complete responses, 4 partial responses). Modulation of IL-2R expression was observed at or above a bexarotene dose of 150 mg/day. Four patients experienced grade 2 or 3 leukopenia, and 2 had grade 4 lymphopenia. Our results demonstrate that the combination of denileukin diftitox and bexarotene is well tolerated and that even low doses (150 mg/day) of bexarotene are capable of in vivo upregulation of CD25 expression on circulating leukemia cells.
authors.affiliation: Hematology/Oncology Department, Tufts New England Medical Center, 750 Washington St, Boston, MA 02111, USA. ffoss@tufts-nemc.org
authors.forename: Francine
authors.initials: F
authors.lastname: Foss
authors.forename: Marie France
authors.initials: MF
authors.lastname: Demierre
authors.forename: Gina
authors.initials: G
authors.lastname: DiVenuti
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage* / Q000009:adverse effects; D000077610:Bexarotene; D004167:Diphtheria Toxin / Q000008:administration & dosage* / Q000009:adverse effects; D004361:Drug Tolerance; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000008:administration & dosage* / Q000009:adverse effects; D016410:Lymphoma, T-Cell, Cutaneous / Q000188:drug therapy* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage* / Q000009:adverse effects; D012008:Recurrence; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000276:immunology; D013764:Tetrahydronaphthalenes / Q000008:administration & dosage* / Q000009:adverse effects; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D004167:Diphtheria Toxin; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D011993:Recombinant Fusion Proteins; D013764:Tetrahydronaphthalenes; C078456:denileukin diftitox; D000077610:Bexarotene