ALBERT

Description: The Retinoid-X-Receptor specific retinoid bexarotene is approved for treatment of cutaneous T-cell lymphoma (CTCL) in the United States and Europe. CTCL is a heterogeneous group of peripheral non-Hodgkin lymphomas with different prognosis and different response to treatment and the current WHO classification contains nine different entities with Mycosis fungoides (MF) as the most common subtype. Since most data on efficacy and tolerability are available from studies with MF, this Dermatologic Cooperative Oncology Group (DeCOG) trial (ADO-CTCL-3) evaluates treatment response to bexarotene in patients with non-MF CTCL, encompassing CD30+ primary cutaneous ALCL and severe lymphomatoid papulosis (LyP), CD-30 negative pleomorphic TCL, Sezary's syndrome (SS), subcutaneous panniculitis-like TCL, and other defined variants. Additionally, patients with different rare variants of MF, including folliculotropic (fMF), granulomatous, erythrodermic, and CD30+ transformed MF were included. 200 patients with CTCL stage IB or higher and at least one prior treatment failure were registered in this trial with bexarotene at an initial daily dose of 150mg/m² orally und prophylactic fenofibrate medication. Bexatrotene was increased to a target dosage of 300 mg/m² in patients with tolarable serum lipids under these conditions. Patients were evaluated according to a standardized evaluation tool (tumor burden index; TBI) up to 24 weeks of of treatment or until progression occured. In responding patients, treatment could be continued until progression. After a central pathology board review process 2 patients needed to be excluded from evaluation because of misdiagnoses. Additional 11 patients could not be evaluated for response due to early withdrawal. Among the remaining patients there were 18 patients with SS, 8 cutaneous CD30+ ALCL, 10 Lyp, 9 other rare entities. In addition MF cases with folliculotropic subtype (18), CD30+ transformation (11), CD30- transformation (4), and a variety of other MF subtypes could be compared to the response in classical MF. Response to bexarotene could be confirmed in classical MF with an objective response (OR) rate of 37 percent (5% CR; 32% PR). Response rates for the other entities were as follows: CD30+ ALCL 50% OR, LyP 60% OR, SS 33% OR, other forms of CTCL together 33% OR. In MF with CD30+ transformation 46% responded, in contrast to only 11% of cases with folliculotropic MF. Tolerability was as expected with most grade III/IV toxicities limited to hyperlipidemia. Side effect management anf the incidence of serious adverse events could be substantially improved using standard algorithms for lipid control. In conclusion, this is one of the largest CTCL cohorts with exact pathological review worldwide evaluated for treatment response with bexarotene. Bexarotene appears to be a safe and effective treatment option also in non-classical MF and CTCL variants. Folliculotropic MF proved to be a difficult-to-treat entity and CD30 expression seems to be a favourable prognostic marker for treatment response. Disclosures: Weichenthal: Cephalon GmbH: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; TEVA GmbH: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding. Goldinger:Cephalon: Travel costs Other; TEVA: Travel costs, Travel costs Other. Wehkamp:TEVA GmbH: Travel costs Other. Beyer:TEVA GmbH: Honoraria, Research Funding; Cephalon GmbH: Honoraria, Research Funding. Stein:Cephalon: Travel costs Other; TEVA: Travel costs, Travel costs Other. Tsianakas:Cephalon: Travel costs Other; TEVA: Travel costs, Travel costs Other. Koch:Cephalon: Travel costs Other. Yazdi:Cephalon: Travel costs Other; TEVA: Travel costs, Travel costs Other. Wobser:Cephalon: Travel costs Other; TEVA: Travel costs, Travel costs Other. Frambach:Cephalon: Travel costs Other; TEVA: Travel costs, Travel costs Other. Dippel:Cephalon GmbH: Honoraria, Travel costs Other; TEVA GmbH: Honoraria, Travel costs, Travel costs Other. Geißler:Cephalon GmbH: Travel costs Other; TEVA GmbH: Travel costs, Travel costs Other. Loquai:TEVA GmbH: Travel costs Other. Kurschat:Cephalon: Travel costs Other; TEVA GmbH: Honoraria, Travel costs, Travel costs Other. Pföhler:Cephalon: Travel costs Other. Hartmann:Cephalon GmbH: Travel costs Other; TEVA GmbH: Travel costs, Travel costs Other. Coors:Cephalon GmbH: Travel costs Other; TEVA GmbH: Honoraria, Travel costs, Travel costs Other. Hallermann:TEVA GmbH: Travel costs Other. Mohr:TEVA: Honoraria, Travel costs Other. Hillen:TEVA: Travel costs Other. Belloni:Cephalon GmbH: Travel costs Other. Mitteldorf:Cephalon: Travel costs Other. Assaf:TEVA: Honoraria, Research Funding, Travel costs Other. Klemke:TEVA GmbH: Consultancy, Honoraria; Cephalon GmbH: Honoraria. Becker:Cephalon GmbH: Honoraria, Research Funding; TEVA GmbH: Honoraria. Dummer:Cephalon GmbH: Honoraria, Research Funding; TEVA GmbH: Honoraria. Nicolay:TEVA: Travel costs Other.

Description: Cutaneous T-cell lymphomas (CTCLs) are malignancies of skin-homing lymphoid cells, which have so far not been investigated thoroughly for common oncogenic mutations. We screened 90 biopsy specimens from CTCL patients (41 mycosis fungoides, 36 Sézary syndrome, and 13 non–mycosis fungoides/Sézary syndrome CTCL) for somatic mutations using OncoMap technology. We detected oncogenic mutations for the RAS pathway in 4 of 90 samples. One mycosis fungoides and one pleomorphic CTCL harbored a KRASG13D mutation; one Sézary syndrome and one CD30+ CTCL harbored a NRASQ61K amino acid change. All mutations were found in stage IV patients (4 of 42) who showed significantly decreased overall survival compared with stage IV patients without mutations (P = .04). In addition, we detected a NRASQ61K mutation in the CTCL cell line Hut78. Knockdown of NRAS by siRNA induced apoptosis in mutant Hut78 cells but not in CTCL cell lines lacking RAS mutations. The NRASQ61K mutation sensitized Hut78 cells toward growth inhibition by the MEK inhibitors U0126, AZD6244, and PD0325901. Furthermore, we found that MEK inhibitors exclusively induce apoptosis in Hut78 cells. Taken together, we conclude that RAS mutations are rare events at a late stage of CTCL, and our preclinical results suggest that such late-stage patients profit from MEK inhibitors.