ALBERT

Description: Vemurafenib and dabrafenib selectively inhibit the v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) kinase, resulting in high response rates and increased survival in melanoma. Approximately 22% of individuals treated with vemurafenib develop cutaneous squamous cell carcinoma (cSCC) during therapy. The prevailing explanation for this is drug-induced paradoxical ERK activation, resulting in hyperproliferation. Here we show an unexpected and novel effect of vemurafenib/PLX4720 in suppressing apoptosis through the inhibition of multiple off-target kinases upstream of c-Jun N-terminal kinase (JNK), principally ZAK. JNK signaling is suppressed in multiple contexts, including in cSCC of vemurafenib-treated patients, as well as in mice. Expression of a mutant ZAK that cannot be inhibited reverses the suppression of JNK activation and apoptosis. Our results implicate suppression of JNK-dependent apoptosis as a significant, independent mechanism that cooperates with paradoxical ERK activation to induce cSCC, suggesting broad implications for understanding toxicities associated with BRAF inhibitors and for their use in combination therapies.

Description: Cutaneous T cell lymphoma—CTCL is a malignancy of skin-tropic T cells. CTCL cells have ubiquitous overexpression of CD3. Although uncommon, CTCL has been estimated to affect 1,500 patients per year in the United States. There are multiple approved systemic therapies for CTCL, but responses are brief lasting months. Allogeneic stem cell transplantation may provide long-term remissions, but is suitable for only rare CTCL patients. Overall, CTCL has a long clinical course with relentless progression over months to years with estimated median survival of 3-5 years for stage IB-IIB patients. The CD3 targeted agent, Resimmune, was synthesized and prepared for clinical use. It consists of the catalytic and translocation domains of diphtheria toxin fused to two anti-human CD3 Fv fragments. DNA encoding Resimmune protein was integrated into the Pichia pastoris genome, and recombinant protein was produced in Pichia pastoris via the secretory route (Woo, Protein Expr Purif 25, 270, 2002). Protein was purified by anion exchange and size exclusion chromatography. The CD3+ Jurkat cell line incubated with Resimmune yielded an IC50 for protein synthesis inhibition of 0.017pM. The CD3- Vero cell line incubated with Resimmune showed an IC50 〉10pM. Mice, rats, and monkeys given total doses of 〉200mg/kg over four days showed only transient transaminasemia without histopathologic tissue injury or clinical signs or symptoms (Woo, Cancer Immunol Immunother 57, 1225, 2008). In a mouse model with human CD3e transfected lymphocytes, four logs of antigen positive cells were reproducibly depleted from nodes and spleen with 100mg/kg total dose of Resimmune (Thompson, Protein Eng 14, 1035, 2001). Based on these findings, a phase 1 study was initiated and this report serves to update the results of a single cycle of Resimmune given at 2.5-11.25mg/kg 15 min IV infusion twice daily for 8 doses to 18 CTCL patients. There were 10 females and 8 males with ages 20-81 years. Two patients were naïve to systemic therapies, and all others had failed 1-4 prior treatments including interferon, bexarotene, gemcitabine, vorinostat, chlorambucil, etoposide, pralatrexate, doxil, romidepsin, methotrexate, CHOP, and brentuximab vedotin. None of the Resimmune treated CTCL patients had dose-limiting toxicities. Side effects were mild-moderate and transient with fevers, chills, nausea, transaminasemia, hypoalbuminemia, lymphopenia, reactivation of EBV and CMV, and hypophosphatemia. Toxicities responded to antipyretics, anti-emetics, albumin infusions, rituximab treatment and valgancyclovir. Among measured patients, there was a 3 log decline in normal, circulating T cells by day 5 that recovered by day 14. Because of vascular leak syndrome toxicities in non-CTCL patients, the MTD was defined as 7.5mg/kg x 8 doses. Cmax ranged from 1.9-40.7ng/mL and half-life from 5-66min. Pretreatment anti-DT titers were 0.9-251mg/mL and day 30 post-therapy increased to 5-4059 mg/mL. 17 CTCL patients were evaluable for response. There were six responses for a response rate of 35%. There were four CRs (24% CR rate). Three of the CRs are over 4-years duration. Patients with IB or IIB disease and mSWAT

Description: Abstract 2800 Background: Pralatrexate (FOLOTYN®) is an antifolate designed for preferential tumor uptake and accumulation. Pralatrexate was granted accelerated approval by the US Food and Drug Administration at a dose of 30 mg/m2 weekly for 6/7 weeks for relapsed or refractory peripheral T-cell lymphoma. Given that cutaneous T-cell lymphoma (CTCL) is often an indolent disease treated in a maintenance fashion, the goal of this trial was to identify a dose with clinical activity and minimal toxicity to allow continuous or maintenance treatment. In the present study, designated PDX-010, the initial dose of pralatrexate for relapsed or refractory CTCL was based on data showing that 30 mg/m2 demonstrated activity in patients with aggressive lymphoma. A dose de-escalation strategy was used in PDX-010 to identify an optimal dose for CTCL. Methods: Eligibility included CTCL histology of mycosis fungoides, Sézary syndrome, or primary cutaneous anaplastic large-cell lymphoma, with disease progression after at least 1 prior systemic therapy, and written informed consent. The starting dose and schedule was 30 mg/m2 of pralatrexate by intravenous (IV) push weekly for 3/4 weeks. If toxicity as defined per the protocol was observed, subsequent cohorts received reduced doses (20, 15, 10 mg/m2) and/or schedules (weekly for 3/4 or 2/3 weeks). All patients received supplementation with vitamin B12 1 mg intramuscularly every 8 to10 weeks, and folic acid 1 mg orally once daily (QD). Response was evaluated by the modified severity weighted adjustment tool (mSWAT) every 2 cycles for 6 months, and then every 4 cycles. For patients with lymph node involvement, scans were completed at baseline and upon clinical response or end of treatment, whichever occurred first. Results: Fifty-four patients were treated across 2 stages of this study. In the dose-finding phase, 31 patients were sequentially enrolled into 6 cohorts and treated at varying doses and schedules. The optimal dose and schedule, as defined in the protocol, was identified as 15 mg/m2 weekly for 3/4 weeks, based on the tolerability and efficacy (overall response rate [ORR] of 50%) observed in the initial 6 patients in that cohort. Among the 31 patients in the dose-finding stage, the ORR for patients treated at a dose intensity ≥15 mg/m2 weekly for 3/4 weeks was 61% (11/18), and the ORR for those patients treated in lower-dose cohorts was 8% (1/13). The second stage of the study included 23 additional patients treated at 15 mg/m2 weekly for 3/4 weeks, for a total of n = 29 patients treated at this optimal dose. Among these 29 patients, the median number of prior systemic therapies was 4.5 (range 1 to 11), and patients received pralatrexate for a median of 4 cycles (range 1 to 23). Patients enrolled in this cohort could be dose-escalated at investigator discretion if there was an absence of toxicity and a response 〈 CR. At this time 53/54 patients treated in this study are evaluable for efficacy, including 28/29 patients treated at 15 mg/m2 for 3/4 weeks. At the optimal dose, the ORR was 43% (12/28) and 50% (20/40) in patients treated at a dose intensity ≥15 mg/m2 weekly for 3/4 weeks. At the optimal dose/schedule, grade 1–2 adverse events (AEs) occurring in 〉10% were fatigue (34%), mucositis (28%), nausea (24%), edema (24%), epistaxis (21%), pyrexia (17%), constipation (14%), and vomiting (14%). The only grade 3 AE in 〉10% was mucositis (17%). Hematologic toxicities were limited to grade 3 neutropenia (3%), grade 1–2 anemia (14%), grade 3 anemia (3%), grade 1–2 thrombocytopenia (7%), grade 3 thrombocytopenia (3%), grade 1–2 leukopenia (3%), and grade 4 leukopenia (3%). No grade 4 nonhematological toxicities were observed. Conclusions: Pralatrexate shows high activity with acceptable toxicity in patients with relapsed or refractory CTCL at the identified optimal dose and schedule of 15 mg/m2 weekly for 3/4 weeks. The lack of significant hematologic toxicity or cumulative toxicity seen in this study suggests that pralatrexate should be further evaluated as continuous or maintenance therapy for patients with CTCL. Final efficacy and tolerability data will be reported. Disclosures: Horwitz: Allos Therapeutics, Inc.: Consultancy, Research Funding. Foss:Allos Therapeutics, Inc.: Consultancy, Speaker. Zain:Allos Therapeutics, Inc. : Speakers Bureau. Lechowicz:Allos Therapeutics, Inc.: Consultancy; Celgene Corporation : Consultancy. Shustov:Allos Therapeutics, Inc.: Honoraria, Research Funding. Koutsoukos:Allos Therapeutics, Inc.: Employment. Fruchtman:Allos Therapeutics, Inc.: Employment. O'Connor:Allos Therapeutics, Inc.: Research Funding. Duvic:Allos Therapeutics, Inc.: Research Funding.

Description: Introduction Brentuximab vedotin, an antibody drug conjugate comprising of an anti-CD30 monoclonal antibody (cAC10) attached by a protease-cleavable linker to a microtubule-disrupting agent monomethyl auristatin E (MMAE), was approved for relapsed Hodgkin lymphoma (ORR 75%) and systemic anaplastic large T-cell lymphoma (ALCL; ORR 86%) and the naked cAC10 antibody was shown active in CD30+ skin lymphomas (ORR 70%). Study design To determine safety and activity of Brentuximab vedotin we completed a Phase II open-label trial of 48 patients with primary cutaneous CD30+ lymphoproliferative disorders including lymphomatoid papulosis (LyP) and primary cutaneous pc-ALCL (pc-ALCL) or CD30+ mycosis fungoides (MF). Eligibility required skin lesion expression of CD30, 〉 10 Lyp lesions, one or more tumors, and need for systemic therapy. Patients with CD30+ MF were stage IB or higher and had received one or more prior topical or systemic therapies. The antibody conjugate was infused at 1.8 mg/kg every 21 days. Patients achieving a complete response (CR) received two additional doses and those achieving partial responses (PR) after 8 cycles could receive up to 16 doses. Response criteria for LyP were a 50% decrease in lesions, for pc-ALCL were 50 % tumor reduction, and for MF were 50% decrease in modified skin weighted assessment tool mSWAT. CD30 pretreatment skin biopsies and serum sCD30 were correlated with response. Results The 48 evaluable patients who received 〉2 doses of brentuximab vedotin included 22 females and 26 males with median age of 59.5 years (range 31-86). Their clinical diagnoses are in Table 1: 28 with MF, 2 with pc-ALCL, 9 with only LyP, 7 LyP with MF, and 2 with pc-ALCL/LyP/MF. Overall response rate (ORR) was 71% (34/48) with CR of 35% (17/48). The intent to treat response rate for all 56 patients receiving at least one dose was 61% (34/56). ORR was 50% in 28 MF patients regardless of whether their lesions had low, medium, or high CD30 at baseline. LyP and pc-ALCL patients had a 100% ORR and two pc-ALCL patients had CRs. For LyP, time to response (TTR) was 3 wks (range 3-6) and median duration of response (DOR) of 23 wks (range 6-44). For MF, TTR was 10.5 wks (range 3-39) and DOR was 13.5 wks (range 3-56 wks). Relapse rates in Lyp and pc-ALCL was 40% (8/20) with TTR of 25 wks (range 6-41). In MF responders, 5/14 (36%) relapsed and MTR was 3 wks (range 3-40). Median ORR and disease specific response (DSS) were not reached from date of diagnosis or from first dose. Median progression free survival (PFS) was 9.7 years from diagnosis and 1.68 years from first dose. Soluble CD30 levels from baseline to end of study differed significantly among those patients achieving a CR compared to those with PR or SD (p=.036). The most common related adverse event (AE) of any grade was peripheral neuropathy (PN) in 29/48 (60%): resolved in 14/29 (48%) and ongoing in 15/29 (52%) with 5 grade 2 and 10 grade one. Other AE 〉 10% were drug rashes (27%), diarrhea (24%), fatigue (30%), alopecia (16%), myalgias (16%), and nausea (14%). Grade 3-4 events included neutropenia (n=5), nausea (n=2), chest pain (n=2), deep vein thrombosis (n=1), transaminitis (n=1) and dehydration (n=1). Dose reductions to 1.2 mg/kg were for grade 2 neuropathy (n=2), transaminitis (n=1) and arthralgia/ fatigue (n=2). There were two deaths from untreated sepsis after one dose. Conclusion This phase II clinical trial demonstrates that brentuximab vedotin is active for mycosis fungoides (ORR 50%) irrespective of level of CD30+ expression. The ORR was 100% for CD30+ pc-ALCL, and LyP patients and was 71% with a CR of 36% for all evaluable patients. Disclosures: Duvic: Seattle Genetics: Research Funding. Off Label Use: This is an open label study for Cutaneous T-cell lymphoma and lymphoproliferative disorder. Brentuximab is approved for relapsed and refractory Hodgkins lymphoma. Tetzlaff:Seattle Genetic: Consultancy.

Description: Because syndecan-4 (SD-4) on effector and memory T cells inhibits T-cell activation by binding dendritic cell–associated heparan sulfate proteoglycan-integrin ligand (DC-HIL) on antigen presenting cells and because malignant cells of the cutaneous T-cell lymphoma (CTCL) subset, Sézary syndrome (SS), exhibit memory T-cell phenotype, we posited SS cells to express SD-4. Indeed, malignant T cells from patients with SS and from CTCL cell lines constitutively expressed SD-4 at high levels, in contrast to T cells from healthy volunteers and patients with other inflammatory skin diseases and to non-CTCL cell lines that did not. SS cells also bound to DC-HIL at a level higher than normal T cells activated in vitro, resulting in their inhibited proliferation to anti–CD3 antibody. SD-4 on SS cells also trapped transforming growth factor-β1 to their cell surface, enhancing their ability to inhibit activation of syngeneic and allogeneic normal T cells. All of these inhibitory properties were dependent on overexpression of distinct heparan sulfate (HS) moieties by SD-4 on SS cells. Finally, we showed toxin-conjugated DC-HIL to abrogate the ability of SS cells to proliferate in vitro. These findings indicate that SD-4 bearing distinct HS moieties plays a pathogenic role in SS and may be targeted for treatment.

Description: Systemic treatment for cutaneous T-cell lymphoma (CTCL) involves the use of less aggressive, well-tolerated therapies. Pralatrexate is a novel antifolate with high affinity for reduced folate carrier-1. A dose de-escalation strategy identified recommended pralatrexate dosing for patients with CTCL that demonstrated high activity, good rates of disease control, and an acceptable toxicity profile for continuous long-term dosing. Eligibility included mycosis fungoides, Sézary syndrome, or primary cutaneous anaplastic large cell lymphoma, with disease progression after ≥ 1 prior systemic therapy. The starting dose and schedule was 30 mg/m2/wk intravenously for 3 of 4 (3/4) weeks. Subsequent starting doses were 20, 15, and 10 mg/m2/wk for 3/4 or 2 of 3 (2/3) weeks. Response was evaluated by the modified severity-weighted adjustment tool. Fifty-four patients were treated. The recommended regimen was identified as 15 mg/m2/wk for 3/4 weeks and was explored in the expansion cohort. In 29 patients treated overall with the recommended dosing regimen, the median number of prior systemic therapies was 4. Pralatrexate was administered for a median of 4 cycles; response rate was 45%. The most common grade 3 adverse event (AE) was mucositis (17%); the only grade 4 AE was leukopenia (3%). Pralatrexate 15 mg/m2/wk for 3/4 weeks shows high activity with acceptable toxicity in patients with relapsed/refractory CTCL.

Description: Abstract 2863 Introduction: Cutaneous T-cell lymphoma (CTCL) is a heterogeneous group of non-Hodgkin's lymphomas typically characterized by skin patches, plaques, and tumors. Although CTCL primarily develops in the skin, it may progress to involve lymph nodes, blood, and visceral organs. Denileukin diftitox (DD) is a recombinant fusion protein that targets the interleukin-2 receptor found on malignant T lymphocytes. In a Phase III trial in DD-naïve patients with CD25 assay-positive CTCL (the approved indication for DD), patients treated with DD 9 and 18 μg/kg/day had overall response rates (ORR) of 37% and 46%, respectively, compared with 15% in the placebo arm. Here we analyze results from a multicenter, international, open-label phase 3 study that included a cohort of patients previously treated with DD to determine the benefit of DD retreatment following disease progression. Methods: Study L4389-14 was designed to ascertain the efficacy and safety of DD in patients with stage IA-III CTCL, receipt of ≤3 previous therapies, and life expectancy ≥12 months. The current analysis focuses on the subgroup of CD25-positive patients who experienced response to DD 9 or 18 μg/kg/day in previous clinical trials but who then relapsed. Retreatment consisted of DD 18 μg/kg/day intravenously on Days 1–5 of a 21-day cycle for up to 8 courses. Response assessment was based on the percentage change in tumor burden at each study visit based on a global, weighted score of skin, lymph node, and blood involvement, and responses were confirmed in 3 consecutive DD courses. The primary endpoint was overall response rate (ORR); secondary endpoints included progression-free survival (PFS), time to treatment failure (TTF), and safety. Results: Twenty patients with CD25-positive CTCL received DD retreatment (4 had complete response to the prior DD treatment, 13 had partial response to prior treatment, 1 had stable disease as prior response, and 2 had unrecorded prior response). At baseline, these patients had a median age of 59.5 years, 70% were male, 80% were white, and 80% had early-stage disease (stage ≤IIA). The 20 patients received a median of 8 courses of DD retreatment. Overall, 40% (8/20) of patients had a secondary response, the majority of which were partial responses (30%; 6/20). Secondary response rates for patients with baseline CTCL stages ≤IIA and ≥IIB were 38% (6/16) and 50% (2/4), respectively. Kaplan-Meier estimated median time to response for the intent-to-treat population was 102 days, and the median duration of response was 274 days. Progression events were observed for 9 patients, all of whom had stage ≤IIA disease at baseline. Kaplan-Meier estimated median PFS for the intent-to-treat population was 205 days (95% CI: 170–429 days), and the median TTF was 189 days (95% CI: 72–429 days). In total, 85% of patients had a treatment-related adverse event (AE), 55% had a treatment-related grade 3/4 AE, and 5% had a treatment-related serious AE. The most common treatment-related AEs were nausea (35%), fatigue (25%), headache (15%), rigors (20%), and pyrexia (10%). The 1 treatment-related serious AE involved pleural effusion. Conclusion: Patients with CD25-positive CTCL who had been treated previously with DD and subsequently relapsed were able to show durable responses upon retreatment. The observed ORR of 40% was similar to that seen with primary treatment with an estimated median duration of response of 9.8 months. Disclosures: Duvic: Eisai: Consultancy, Research Funding, Speakers Bureau. Olsen:Eisai: Research Funding; Merck: Consultancy, Research Funding; Gloucester: Consultancy; Yaupon: Research Funding; Biocryst: Research Funding; Johnson & Johnson : Consultancy, Research Funding. Fivenson:Amgen: Honoraria, Research Funding, Speakers Bureau; Dermik: Research Funding; Centrocor: Honoraria, Research Funding; Abbott: Honoraria, Research Funding, Speakers Bureau; Warner Chilcott: Honoraria, Speakers Bureau; Allergan: Research Funding; Ferndale: Research Funding; Graceway: Research Funding; Biolife: Consultancy, Research Funding; Merck: Honoraria, Research Funding; Pfizer: Research Funding; Galderma: Honoraria, Research Funding; Aspreva: Research Funding; Astellas: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Genentech: Honoraria, Research Funding; Perrigo: Research Funding; Organogenesis: Research Funding; Ligand: Research Funding; Connetics: Research Funding; Stiefel/GSK: Honoraria; Clay-Park Labs: Research Funding; Jacobus: Research Funding; Smith and Nephew: Research Funding; Dow Pharma: Research Funding; Therakos: Research Funding; Seragen: Research Funding; Convatec: Research Funding. Prince:Eisai: Consultancy, Honoraria.

Description: Abstract 3973 Histone deacetylase inhibitors (HDACi), including vorinostat (SAHA), depsipeptide (FK228), panobinostat (LBH589), belinostat (PXD101), and entinostat (SNDX275), show in-vitro and clinical activity against cutaneous T-cell lymphoma (CTCL) cell lines and patients' skin lesions [Zhang & Duvic, Expert Rev Dermatol 5: 393–401, 2010]. Vorinostat and depsipeptide were recently approved [Duvic et al, Blood 109: 31-9, 2007; Olsen et al, J Clin Oncol 25: 3109-15, 2007; Piekarz et al, J Clin Oncol 27: 5410-7, 2009], at response rates of 29% and 42%, respectively, but development of resistance remains an important clinical problem. Because we have shown that curcumin, the active ingredient of turmeric, exhibits anti-cancer activity through selective induction of tumor T-cell apoptosis and inhibition of NF-κB signaling in CTCL [Zhang et al, J Invest Dermatol 130: 2110-9, 2010], we now investigated whether curcumin combined with HDACi has synergistic anti-tumor effects in CTCL. HDACi-resistant MJ, HDACi-sensitive HH and HDACi cross-resistant HH/VOR CTCL cells were treated with HDACi (panobinostat, vorinostat, or enlinostat) plus or minus curcumin for up to 48 hrs. Cell viability was examined by the MTS assay and apoptosis by FACS analysis of annexin V/PI binding populations and/or cell cycle distribution. The NF-κB signaling pathway was analyzed by electrophoretic mobility gel shift assay and Western blotting. In MJ and HH cell lines, 5 nM panobinostat induced 1.4% and 11.4% apoptosis and 10 μM curcumin induced 24.5% and 29% apoptosis compared to vehicle controls. Panobinostat combined with curcumin induced 46.9% and 83.4% apoptosis in MJ and HH cell lines, respectively. Of interest, the HDACi cross-resistant HH/VOR CTCL cells were sensitive to curcumin alone and curcumin further enhanced panobinostat-induced apoptosis by 30% in the HH/VOR CTCL cells. Moreover, panobinostat combined with curcumin synergistically suppressed the DNA binding of NF-κB and decreased protein expression of the NF-κB activator RANK and NF-κBp65. Synergism was associated with down-regulation of NF-κB-regulated anti-apoptotic proteins (bcl-2, bcl-xL, and survivin), anti-proliferative proteins (c-myc and cyclooxygenase-2), and pro-invasive protein matrix metalloproteinase-9. Similar synergism was also seen when vorinostat or entinostat was combined with curcumin. These results suggest that HDACi could be combined with curcumin to enhance apoptosis of malignant T-cells through inhibition of NF-κB signaling in CTCL. Curcumin alone and in combination with HDACi may be an attractive strategy for the treatment of HDACi-refractory CTCL patients. Disclosures: Zhang: Novartis: Research Funding. Duvic:Novartis: Research Funding.