Phase II Investigator-Initiated Study of Brentuximab Vedotin in Mycosis Fungoides or Sezary Syndrome: Final Results Show Significant Clinical Activity and Suggest Correlation with CD30 Expression

Abstract Background: Brentuximab vedotin (BV) is an anti-CD30 chimeric antibody conjugated by a protease-cleavable linker to the microtubule-disrupting agent, MMAE. While CD30 expression of malignant cells in HL and ALCL is uniform, in mycosis fungoides/Sezary syndrome (MF/SS), the CD30 expression is more variable. We reported previously (ASH 2012) that BV has clinical activity in MF/SS across all CD30 expression levels. In this final report, we update the clinical data and present new biomarker and correlative tissue analyses. Methods: Patients (pts) with MF/SS stages IB-IV, ECOG 0-2, with at least 1 prior systemic therapy were enrolled in this investigator-initiated, phase II, single-arm study. CD30 expression levels in the skin (% of total mononuclear cell infiltrate) were evaluated by routine immunohistochemistry (IHC) using the BerH2 antibody. At least 2 skin biopsies were obtained per pt and the max CD30 level was used for CD30 designation. All pts (CD30, 0-100%) were treated with up to 8 cycles of BV (1.8 mg/kg) administered every 3 weeks; optional extension of up to 8 additional cycles was allowed in responders with ongoing clinical improvement. Primary endpoint was overall response rate (ORR) by consensus global response criteria. CD30 expression and clinical response data were confirmed by independent review. Tumor microenvironment was assessed utilizing IHC for CD8, CD20, CD163, FoxP3, and PD-1. Multispectral image analysis was utilized to evaluate CD30 antigen co-expression. Results: 32 pts were enrolled and all received at least one dose of BV (Table); all included in safety data, 2 excluded in efficacy analyses (no response assessment). Median age was 62 (20-87). 28/32 (88%) had advanced disease, majority with adverse prognostic features (90% large cell transformation or folliculotropism). ORR was 70% (21/30) with responses in all clinical stages. Median best mSWAT reduction (response measure in the skin) was 73% (range, 100% to -54%) with 1 CR, 7 near CR in skin (>90% reduction) (Fig 1). Median time to response was 6.6 weeks (range 3.0-27.0). Kaplan-Meyer estimate shows 79% of responses ongoing and 54% progression-free at 12 months. Related AEs observed were mostly grade 1-2 and limited to AEs previously reported with BV. By IHC, median max CD30 expression level of all pts was 13% (range 0-100%; 6 had Conclusions: Our final analysis confirms significant clinical activity of BV in MF/SS with expected AE profile. Although clinical response was observed at all levels of CD30 expression, the likelihood of response was lower in those with negligible or very low ( Table . Characteristic All Pts n=32 Evaluable n=30 ORR n (%) n (%) CR PR SD PD Clinical Stage All pts IB IIB IV/SS 32 (100) 4 (13) 18 (56) 10 (31) 1 0 0 1 20 3 14 3 4 1 2 1 5 0 2 3 21/30 (70) 3/4 (75) 14/18 (78) 4/8 (50) Transformed or folliculotropic MF 29 (91) 1 19 3 5 20/28 (71) # prior systemic tx >=3 15 (47) 17(53) 0 1 8 12 2 2 4 1 8/14 (57) 13/16 (81) Download : Download high-res image (76KB) Download : Download full-size image Figure 1 . Download : Download high-res image (319KB) Download : Download full-size image Figure 2 . Disclosures Kim: Actelion: Consultancy; Celgene: Advisory, Advisory Other; Eisai: Research Funding, SAC/Advisory, SAC/Advisory Other; Galderma: Advisory, Advisory Other; Millennium/Takeda: Research Funding, SAC/Advisory Other; Kyowa-Hakko-Kirin: Research Funding, SAC/Advisory Other; Oncosec: Advisory Other; Seattle Genetics: Advisory, Advisory Other, Research Funding; SHAPE: Consultancy, Research Funding. Off Label Use: Treatment of cutaneous T-cell lymphoma, also recently added to NCCN NHL practice guidelines in CTCL. Wood: Millennium: IDMC Other. Advani: Seattle Genetics: Research Funding. Horwitz: Millennium: Consultancy, Research Funding; Infinity: Research Funding; Kiowa-Kirin: Research Funding; Seattle Genetics: Consultancy, Research Funding; Spectrum: Research Funding; Amgen: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy, Research Funding.