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The development of human cancer is a multistep process characterized by the accumulation of genetic and epigenetic alterations that drive or reflect tumour progression. These changes distinguish cancer cells from their normal counterparts, allowing tumours to be recognized as foreign by the immune system. However, tumours are rarely rejected spontaneously, reflecting their ability to maintain an immunosuppressive microenvironment. Programmed death-ligand 1 (PD-L1; also called B7-H1 or CD274), which is expressed on many cancer and immune cells, plays an important part in blocking the 'cancer immunity cycle' by binding programmed death-1 (PD-1) and B7.1 (CD80), both of which are negative regulators of T-lymphocyte activation. Binding of PD-L1 to its receptors suppresses T-cell migration, proliferation and secretion of cytotoxic mediators, and restricts tumour cell killing. The PD-L1-PD-1 axis protects the host from overactive T-effector cells not only in cancer but also during microbial infections. Blocking PD-L1 should therefore enhance anticancer immunity, but little is known about predictive factors of efficacy. This study was designed to evaluate the safety, activity and biomarkers of PD-L1 inhibition using the engineered humanized antibody MPDL3280A. Here we show that across multiple cancer types, responses (as evaluated by Response Evaluation Criteria in Solid Tumours, version 1.1) were observed in patients with tumours expressing high levels of PD-L1, especially when PD-L1 was expressed by tumour-infiltrating immune cells. Furthermore, responses were associated with T-helper type 1 (TH1) gene expression, CTLA4 expression and the absence of fractalkine (CX3CL1) in baseline tumour specimens. Together, these data suggest that MPDL3280A is most effective in patients in which pre-existing immunity is suppressed by PD-L1, and is re-invigorated on antibody treatment.

Combined dabrafenib and trametinib (CombiDT) is an approved therapy for advanced BRAFV600E/K-mutant melanoma patients. This study shows that pyrexia is frequent and recurrent with CombiDT, but is not associated with baseline characteristics or drug efficacy. The etiology is unclear but may involve drug exposure. This requires further research, as do strategies to prevent recurrent pyrexia. Background Pyrexia is a frequent adverse event with combined dabrafenib and trametinib therapy (CombiDT), but little is known of its clinical associations, etiology, or appropriate management. Patients and methods All patients on the BRF133220 phase I/II trial of CombiDT treated at the standard dose (150/2) were included for assessment of pyrexia (n = 201). BRAF and MEK inhibitor-naive patients (n = 117) were included for efficacy analyses. Pyrexia was defined as temperature ≥38°C (≥100.4°F) or related symptoms. Results Fifty-nine percent of patients developed pyrexia during treatment, 24% of which had pyrexia symptoms without a recorded elevation in body temperature. Pyrexia was grade 2+ in 60% of pyrexia patients. Median time to onset of first pyrexia was 19 days, with a median duration of 9 days. Pyrexia patients had a median of two pyrexia events, but 21% had three or more events. Various pyrexia management approaches were conducted in this study. A trend was observed between dabrafenib and hydroxy-dabrafenib exposure and pyrexia. No baseline clinical characteristics predicted pyrexia, and pyrexia was not statistically significantly associated with treatment outcome. Conclusions Pyrexia is a frequent and recurrent toxicity with CombiDT treatment. No baseline features predict pyrexia, and it is not associated with clinical outcome. Dabrafenib and metabolite exposure may contribute to the etiology of pyrexia. The optimal secondary prophylaxis for pyrexia is best studied in a prospective trial.

Immunocompetent cells in bone marrow allografts have been associated with a graft-versus-leukemia (GVL) effect. To further characterize effector mechanisms that may be involved in this GVL phenomenon, we have previously established an in vitro model to identify allogeneic T- cell clones that selectively mediate cytotoxicity against a patient's leukemic cells, but not against nonleukemic lymphocytes from the same patient. We have modified this in vitro model to test whether the Ph1 chromosome and the P210 fusion protein it controls have a detectable role in leukemia-specific recognition by allogeneic T-cell clones. In this report, T-cell lines reactive with allogeneic Ph1 chromosome- bearing (Ph1+) chronic myeloid leukemia (CML) cell lines were derived and selected to be minimally reactive with Ph1 negative (Ph1-) lymphoid lines from the same patient. However, after prolonged culture, these same T-cell lines also mediated significant destruction of the Ph1- target cells from the same patients. These T-cell lines specifically recognized cells from the allogeneic CML patient to which they were sensitized, and were not contaminated by an outgrowth of natural killer cells. Furthermore, subclones could be derived from these T-cell lines, and some of these subclones again showed selective killing of the allogeneic Ph1+ leukemia cell lines, and not of the Ph1- cell line from the same patient. Analyses of T-cell receptor (TCR) genes showed the alloreactive T-cell lines and the Ph1+ selective subclones derived from them to be of the same clonal origin. This suggests that the same T cells reacting with antigens expressed on the nonleukemic Ph1- targets can at times selectively and preferentially kill the allogeneic Ph1+ cells. As the same TCR that recognizes Ph1+ cells also can recognize the Ph1- targets, it appears that the Ph1+ chromosome does not play a detectable role in recognition by these allogeneic T-cell clones. This in vitro observation may provide a model for evaluating the relationship between GVL and graft-versus-host disease effects.

Objective. To determine the effects of drug therapy (methotrexate [MTX] versus auranofin [AUR]) on radiographic progression in patients with active rheumatoid arthritis (RA). Methods. We conducted a 9-month randomized, multicenter, double-blind trial comparing MTX and AUR. Standardized radiographs of the hands and wrists were obtained at baseline and at completion of the study. Four experienced bone radiologists graded the radiographs for erosions, joint space narrowing, erosion healing, and reparative bone formation. Results. Two hundred eighty-one patients were enrolled in the study. Radiographs were available on 167 of the 183 who completed the trial. After 9 months of therapy, there was a significantly greater worsening of the erosion score in the AUR group (mean ± SEM change of 1.67 ± 0.4) compared with the change in the MTX group (0.60 ± 0.3) (P = 0.040). There was also a significantly greater worsening of the joint space narrowing score in the AUR group compared with the MTX group (1.36 ± 0.3 versus 0.42 ± 0.2) (P = 0.007). There was no difference demonstrated between groups in healing of erosions or in reparative bone formation. Conclusion. The rate of radiographic progression in patients with RA, as measured by erosion score and joint space narrowing score, was demonstrated to be lower in those treated with MTX, as compared with AUR, over a 36-week period.

9033 Background: AZD6244 is an orally available, potent, selective, ATP uncompetitive inhibitor of MEK1/2, with preclinical and phase I data suggesting it has the potential for anti-tumor activity in pts with melanoma. Here we evaluate the efficacy and safety of AZD6244 vs TMZ in an overall population of advanced melanoma pts and in mutated BRAF (BRAF+) or mutated NRAS (NRAS+) subgroups. Methods: Eligibility included AJCC stage 3/4 malignant melanoma, RECIST measurable disease, and no prior chemotherapy for advanced melanoma. Pts were randomized 1:1 to AZD6244 (100mg BD continuously) or TMZ (200 mg/m2 for 5 days, q28d). Pts randomized to TMZ could receive AZD6244 after disease progression. The primary outcome variable was progression-free survival (PFS), which was then adjusted for source of primary tumor (uveal vs non-uveal), mutation status, LDH (> or ≤2 x ULN), and WHO PS (0–2). Mutation status was assessed in archival or fresh tumor samples by DNA sequencing. Results: A total of 104 and 96 pts were ra...

with the nominal cost model, amounting to US$16.9 billion in 2015−35 (−US$14.9 billion in LIC; −US$18.7 billion LMIC, and US$50.5 billion in UMIC). The returns with the efficiency model were projected to be greater, however, amounting to US$104.2 billion (−US$2.4 billion in LIC, US$10.7 billion in LMIC and US$95.9 billion in UMIC). Conclusions: Our results provide compelling evidence that investment in radiotherapy not only enables treatment of large number of cancer cases to save lives it also brings positive economic benefits. No conflict of interest.

s S663 and refractory MM patients a significant humoral immune response against proteins related with these three conditions. Materials and Methods: We studied repository serum with clinical data included in MGUS, naive and refractory MM. We performed a systematic multivariate analysis of proteins overexpressed in monoclonal gammopathy as representative of a potential start to create preventive vaccines for MM and in refractory cancer patients who progress despite treatment. We found four potential oncogenic drivers such as HIF-1 alpha, RAD51, Sox2 and Mcl-1. Afterwards we performed an antigen–specific indirect ELISA for both IgG and IgA using recombinant proteins to interrogate human MGUS naive and refractory MM serum and demonstrated if they were immunogenic. Results: Using indirect ELISA both antigen specific IgG and IgA using recombinant proteins with the four proteins we only found a statistical difference for anti-Mcl-1 specific IgG in MGUS (p = 0.01), naive MM (p = 0.005) and relapsed MM (p = 0.05). For anti-Mcl-1 IgA we found in MGUS (p=0001), naive MM (p = 0.002) and relapsed MM (p = 0.01). Here, we showed that even in refractory MM the antigenspecific humoral immune response was detected and it was clear that patients with the highest immune responses had better clinical outcomes in terms of OS. Discussion: MM is a challenging hematological malignancy and immune therapy is a good possibility for treatment either to prevent recurrence or in combination to improve the outcomes of the current standard of care treatment. We showed that one out of the four proteins had biological and clinical relevance in MGUS, naive and relapsed MM is immunogenic both for IgG and IgA. We will move forward to prepare a peptide vaccine and test animal immunogenicity for Mcl-1. Also it could be a good approach in combination with standard of care treatment in progressive or active disease to improve clinical outcomes. No conflict of interest. Proffered Paper Session (Monday, 28 September) Melanoma and Skin Cancer

A physiological pharmacokinetic model was developed to describe the disposition of lycopene, delivered as a tomato beverage formulation in five graded doses (10, 30, 60, 90, or 120 mg), for a phase I study in healthy male subjects (five per dose). Blood was collected before dose administration (0 h) and at scheduled intervals until 672 h. Serum concentrations of carotenoids and vitamins were measured by high performance liquid chromatography analysis. The model was comprised of seven compartments: gastrointestinal tract, enterocytes, chylomicrons, plasma lipoproteins, fast-turnover liver, slow-turnover tissues, and a delay compartment before the enterocytes. As predicted, the percent absorption at the 10 mg dose (33.9 +/- 8.1%) was significantly greater than at the higher doses; however, the amount of lycopene absorbed (mg) was not statistically different (mean: 4.69 +/- 0.55 mg) between doses, suggesting a possible saturation of absorptive mechanisms. The slow-turnover tissue compartment served as a slow-depleting reservoir for lycopene, and the liver represented the fast-turnover pool. Independent of dose, 80% of the subjects absorbed less than 6 mg of lycopene. This may have important implications for planning clinical trials with pharmacological doses of lycopene in cancer control and prevention if absorption saturation occurs at levels that are already being consumed in the population.

Aim: PD-L1, which can mediate cancer immune evasion, is broadly expressed in RCC. As RCC can respond to immune-based therapy, blocking PD-L1 represents a strategy to restore tumor-specific T-cell immunity. MPDL3280A, a human mAb containing an engineered Fc-domain, targets PD-L1 to prevent binding to its receptors PD-1 and B7.1 on activated T cells. Interim results showed that MPDL3280A had a manageable safety profile and clinical activity in advanced NSCLC, melanoma and mRCC pts. Here, we report long term follow up and correlative data for the RCC cohort. Methods: mRCC pts were enrolled in a Ph I expansion study. All pts who received MPDL3280A IV q3w at doses of 3-20 mg/kg were evaluable for safety. Pts were treated for ≤ 1 y. Response was assessed by RECIST v1.1. PD-L1 IHC was centrally assessed in tumor biopsies. Results: As of Jan 1, 2014, among 69 mRCC pts evaluable for safety, median age was 61 y and all were ECOG PS 0-1 (48% PS 1). 94% of pts had prior nephrectomy and 87% received prior systemic therapy, including cytokines (39%), VEGF-inhibition (64%) and mTOR inhibitors (26%). Pts received MPDL3280A for a median duration of 7.7 m (0.7-24.3 m). 80% of pts had a treatment-related AE; however, the frequency of G3 related events was 16%, including anemia, dehydration, fatigue and hypophosphatemia (3% each). No related G4 AEs or deaths occurred. Clinical activity was evaluated in 58 pts with clear cell histology dosed prior to Jul 1, 2013; 51 pts (88%) had an evaluable baseline PD-L1 IHC status. The ORR was 14% (8/58 PRs, 95% CI: 6, 25) and the median duration of response was 54 wks (2.7+ to 68.1+ wks). The 24-wk PFS rate was 53% (95% CI: 40, 66). An association was seen between PD-L1 intensity and response to MPDL3280A. Finally, antitumor activity that included immune-related responses was observed in non-clear cell histology pts (n = 10). Updated data including biomarkers will be presented. Conclusions: MPDL3280A was well tolerated, with no treatment-related deaths. Evidence of increased activity was observed in pts with elevated PD-L1. Durable responses and prolonged SD were observed in mRCC pts, warranting further study. Disclosure: D.F. McDermott: has participated in advisory boards for Genentech, BMS and Merck; M. Sznol: has consulted for Immune Design, Merus, Lion Biotechnologies, Kyowa-Kirin, Aztra-Zeneca-Medimmune, BMS, Amgen, Medimmune, Genentech, Symphogen, Nektar, and Anaeropharma; J. Soria: has received honoraria from Genentech and Roche; M.S. Gordon: has served in an advisory/consultant role and has received research funding from Roche/Genentech; O. Hamid: has been a speaker and consultant for Genentech, and research funding has been provided by Genentech; M. Fasso, Y. Wang, J. Bruey and G. Fine: is employed by Genentech. All other authors have declared no conflicts of interest.

Aim: Nivolumab, a fully human IgG4 PD-1 immune checkpoint inhibitor antibody, is active and tolerable in pts with advanced MEL (Topalian et al. NEJM 366:2443, 2012). We report long-term clinical activity, response duration off-therapy, tumor PD-1 ligand (PD-L1) expression associated with survival endpoints, and 3-yr overall survival (OS) for the MEL pts in this phase 1 trial. Methods: Previously treated pts with advanced MEL and no prior ipilimumab therapy received nivolumab 0.1, 0.3, 1, 3 or 10 mg/kg IV Q2W for ≤96 wks and were evaluated for OS and progression-free survival (PFS). Tumor cell surface expression of PD-L1 was retrospectively assessed in archival pretreatment specimens by a Dako immunohistochemistry assay, with PD-L1+ defined as ≥5% tumor cells expressing this marker. Results: From 2008–2012, 107 MEL pts initiated treatment with nivolumab: 25% had ≥3 prior therapies. One-, 2- and 3-yr OS rates were 63%, 48% and 41%, respectively. For the 33/107 (31%) pts with objective responses (OR; RECIST), median response duration was 22.9 months. Twenty-four OR pts stopped nivolumab for reasons other than disease progression; 11 (46%) maintained responses for ≥24 wks off drug (range: 24, 56+ wks). Four (4%) additional pts had unconventional “immune-related” responses; overall survival for these pts was 21.1, 28.6 + , 43.1+ and 48.0+ months as of September 2013. In a subset of 41/107 pts with available tumor samples, median OS for pts with PD-L1+ (n = 18) and PD-L1– (n = 23) tumors was not reached and 12.5 months, respectively; median PFS was 9.1 and 1.9 months, respectively. Safety has been previously reported (Topalian et al. J Clin Oncol 32:1020, 2014). Conclusions: In pts with advanced MEL, nivolumab demonstrated notable 2- and 3-yr OS rates, durable responses with several persisting following discontinuation of therapy, and an acceptable safety profile. Additional analyses will be presented on the correlation between key pt characteristics and response to nivolumab. Ongoing phase 3 trials are further evaluating nivolumab for MEL pts and will also explore the role of PD-L1 as a potential predictive biomarker for nivolumab activity. Disclosure: D.F. McDermott: Consultant advisor, BMS advisory board; Research Funding BMS; M. Sznol: Paid consultant and scientific advisory board-Bristol-Myers Squibb, Genentech/Roche, MedImunne, Amgen, Nektar, Symphogen, Merus, Amphivena, NeoStem, Anaeropharma, BeiGene, Kyowa-Kirin, Immune Design, Lion Biotechnologies, Seattle Genetics; R. Carvajal: Consultant- Aura Biosciences; S.L. Topalian: Consultant-BMS(uncompensated), Jounce Therapeutics (comp.), Sanofi (comp.); Stock options: Compugen, Amplimmune, NexImmune, Jounce Therapuetics; Research funding BMS; Other remuneration-BMS and Amplimmune Inc., patent royalties through Johns Hopkins Univ; M.B. Atkins: Consultant advisor, honoraria- BMS; J.D. Powderly: Employment-Biologics Human Application Lab; Consultant advisor-BMS, Genetech, Amplimmune, Merck; Honoraria-BMS; Research Funding-BMS, Genetech, Amplimmune, Merck, AstraZeneca; Other Rumuneration-BMS Speakers Bureau and Advisory Boards; W.H. Sharfman: Consultant advisor, honoraria-MerckM; D.C. Smith: Research funding-BMS; J.M. Taube: Consultant advisor, research funding-BMS; R.A. Anders: Research Funding BMS; C. Horak: BMS-employee, stock; G. Kollia: BMS-employee, stock; J.A. Sosman: Consultant advisor-BMS; Honoraria-Glaxo Smith Kline, Amgen; Research funding-BMS, Novartis, Glaxo Smith Kline; F.S. Hodi: Consultant advisor BMS-uncompensated. All other authors have declared no conflicts of interest.

The HER-2/neu proto-oncogene is a useful prognostic and predictive biomarker in breast cancer. In addition, use of a humanized monoclonal antibody against HER-2/neu has recently been shown to have efficacy in the treatment of metastatic breast cancer. In order to examine the potential of HER-2/neu as a biomarker and as a target for HER-2/neu monoclonal antibody treatment in melanoma, we examined the HER-2/neu status in 40 advanced stage melanomas. Using fluorescence in situ hybridization for determining the gene amplification status and immunohistochemistry for detecting protein overexpression, we found that only one out of 40 cases of melanoma had an altered HER-2/neu status. These results demonstrated that HER-2/neu amplification and overexpression are not common in advanced stage melanoma and thus, HER-2/neu would have limited value as a biomarker or as a target for immunotherapy in melanoma.

To compare polytomography (PT) and computed tomography (CT) for visualizing fractures and arthrodeses, with and without metal hardware, to determine whether CT could adequately replace PT.An ex vivo bovine model containing fractures in three planes, reduced with metal hardware, was created to compare fractures using PT and CT. The radiation dose at the skin surface was calculated for both examinations. For in vivo assessment, images of 14 patients who underwent both PT and CT (15 fractures, five arthrodeses) were coded, sorted, and independently read by four musculoskeletal radiologists. They rated the degree of certainty of their assessment. Time factors for patients and personnel and financial costs were also compared.In the ex vivo model the fractures were well seen on both PT and CT. The radiation dose was higher for PT than for CT. In vivo, the degree of certainty in assessment of fractures and arthrodeses was higher for PT than CT in studies in which metal hardware was present, but there was no significant difference in studies without metal hardware or in the combined (with and without hardware) studies. The patient's and technologist's time required to perform a PT examination was greater than that for CT.In the assessment of fractures and arthrodeses containing metal hardware, PT is recommended. For studies without hardware, CT is equivalent and can replace PT.

Interleukin-12 (IL-12) is a key regulator of cell-mediated immunity that has therapeutic potential in cancer and infectious disease. In a previous Phase 1 dose escalation study of a single test dose of recombinant human IL-12 (rhIL-12) followed 14 days later by cycles of five consecutive daily intravenous injections every 3 weeks, we showed that a dose level up to 500 ng/kg could be administered with acceptable levels of safety. Based on these results, a Phase 2 study was conducted. In the Phase 2 study, however, administration of rhIL-12 at this same dose level resulted in severe toxicities with some patients unable to tolerate more than two successive doses. Of the 17 patients receiving rhIL-12 in the Phase 2 study, 12 patients were hospitalized and two patients died. A thorough scientific investigation to determine the cause of this unexpected toxicity failed to identify any difference in the drug products used or the patient populations enrolled in the Phase 1 and Phase 2 studies that could have accounted for the profound difference in toxicity. The focus of the investigation therefore shifted to the schedule of rhIL-12 administration. We determined that a single injection of rhIL-12 2 weeks before consecutive dosing included in the Phase 1 study, but not in the schedule of administration in the Phase 2 study, has a profound abrogating effect on IL-12-induced interferon-gamma (IFN-gamma) production and toxicity. This observation of schedule-dependent toxicity of IL-12 has been verified in mice, as well as nonhuman primates. In this regard, a single injection of IL-12 before consecutive daily dosing protected mice and cynomolgus monkeys from acute toxicity including mortality and was associated with an attenuated IFN-gamma response. Because of this unique biologic response, careful attention to the schedule of administration is required to assure safe and effective clinical development of this highly promising cytokine.

A phase II trial of outpatient subcutaneous (SC) interleukin-2 (rIL-2) plus interferon-alpha (IFN-alpha 2B) was performed in patients with metastatic renal cell cancer. A 5-year follow-up of that Cytokine Working Group study is presented.Forty-seven patients meeting eligibility criteria of previous Cytokine Working Group studies were treated on an outpatient basis with SC rIL-2 (Chiron, Emeryville, CA), 5 x 10(6) IU/m2/dose q 8 hr x 3, then daily, 5 days per week, and IFN-alpha 2B (Schering-Plough, Kenilworth, NJ), 5 x 10(6) IU/m2/dose three times weekly for 4 weeks. After a 2- to 4-week break, patients were scheduled to continue treatment for up to six cycles.There were two complete and six partial responders (17% response rate, 95% CI: 8%-31%). Median duration of response was 12 months (range 1-49+ months), with complete responses of 15 and 49+ months. Responding sites of disease included lung, nodes, soft tissue, bone, and liver. Dose and schedule were adjusted to control toxicity at grade 2/3 levels, with 50% requiring dosage alterations. Grade 2/3 toxicity included fatigue, nausea/vomiting, diarrhea, anorexia, fluid overload, rash, CNS, injection site pain, chest pain/palpitations (including atrial fibrillation requiring treatment, two patients), and hypotension. Grade 4 toxicity included dehydration (seven patients), vomiting (one patient), and irreversible renal failure with crescentic glomerulonephritis requiring dialysis (one patient).SC rIL-2 plus IFN-a2B is tolerated in the outpatient setting with frequent dose adjustments. The overall response rate of this regimen is similar to that seen with high-dose rIL-2 alone; however, the response duration appears to be shorter.

Interleukin 6 (IL-6) has antitumor activity comparable to IL-2 in murine models with less toxicity. Because the biological effects of intermittent and continuous infusions may differ, we conducted two concurrent Phase I trials of daily x5, 1-h, and continuous 120-h i.v. infusions to determine the toxicity, biological effects, and maximum tolerated dose of i.v. IL-6. Cohorts of six patients with advanced cancer received escalating doses (1, 3, 10, 30, 100, and 150 microgram/kg/day) of recombinant human IL-6 on days 1-5 and 8-12 of each 28-day course (1-h trial) or on days 1-5 of each 21-day course (120-h trial). Treatment was administered in regular inpatient wards and in outpatient clinics and was withheld in the event of grade 3 toxicity. Sixty-nine patients (1-h trial, n = 40; 120-h trial, n = 29) were enrolled, including 27 with renal cancer and 16 with melanoma. All were ambulatory, and 40 were asymptomatic. Fever (97%), anemia (78%), fatigue (56%), nausea or vomiting (49%), and elevated serum transaminase levels (42%) were the most frequent toxicities. Transient hypotension developed in 23 patients (33%). There were three deaths during the study due to progressive disease and/or infection. There were no objective responses. Dose-related increases in platelet counts and C-reactive protein levels were detected in most patients. Principal dose-limiting toxicities included atrial fibrillation (1 episode in the 1-h trial and 4 episodes in the 120-h trial) and neurological toxicities (3 episodes in the 1-h trial and 4 episodes in the 120-h trial). The neurological toxicities included confusion, slurred speech, blurred vision, proximal leg weakness, paraparesis, and ataxia. These effects were transient and reversed when IL-6 was discontinued. IL-6 can be given by i.v. infusion at biologically active doses with acceptable toxicity. Dose-limiting toxicities consisted mainly of a spectrum of severe but transient neurological toxicities and occasional episodes of atrial fibrillation. The maximum tolerated doses recommended for use with these i.v. schedules in Phase II trials are 100 microgram/kg/day by daily x5 1-h infusion and 30 microgram/kg/day by 120-h infusion. Phase II trials will be performed to determine the antitumor activity of IL-6 and better define its toxicity. Patients in these and other IL-6 studies should be monitored closely for neurological and cardiac effects.

In humans, interleukin 3 (IL-3) administration increases the cellularity and cycling of bone marrow progenitor cell populations. Initially, in primates and then in humans, IL-3 in sequence with GM-CSF has been shown to stimulate multilineage hematopoiesis. Based upon these effects, we designed a phase I trial of daily IL-3 administered subcutaneously for 10 days at dose levels of 2.5, 5.0, 10.0, 12.5, and 15.0 micrograms/kg followed within 72 h by bone marrow harvest, high-dose chemotherapy, and following chemotherapy, a fixed dose (5.0 micrograms/kg/day) of GM-CSF and bone marrow rescue. The study was designed to assess the toxicity and biological effects of IL-3 administered alone prior to bone marrow harvest and to determine the safety and clinical effects of IL-3 stimulated bone marrow with GM-CSF following high-dose combination chemotherapy. A total of 19 patients with chemotherapy-sensitive non-hematologic malignancies (13 breast, five ovarian, and one testicular cancer) were enrolled. IL-3 up to 15.0 micrograms/kg/day could be administered without dose-limiting toxicities. Flu-like symptoms and headaches were common and poorly tolerated at the highest IL-3 dose. Significant increases in neutrophil counts (P = 0.018) were observed following IL-3. Overall, IL-3 administration was associated with a modest, but significant increase in CFU-GM within the bone marrow (P = 0.034). IL-3 administration had no consistent effect on CD34+ cell number within bone marrow. For the entire group, engraftment of neutrophils to greater than 0.5 x 10(9)/l occurred at a median of 21 days (range of 13-63 days) and platelet independence occurred at a median of 17 days (range 11-120 days). When IL-3 dose levels were analyzed separately, engraftment of neutrophils and platelets, blood product (platelets and packed RBCs) utilization, and discharge date were not superior in those treated with the higher dose (15.0 micrograms/kg) of IL-3. While higher doses of IL-3 were associated with more toxicity, they did not appear to enhance the stem cell pool or speed engraftment later. The effects of pre-bone marrow harvest IL-3 are modest and likely not as impressive as other approaches aimed at enhancing hematologic recovery following high-dose chemotherapy.

Interleukin-4 (IL-4) is a T-cell-derived cytokine that may mediate murine tumor rejection through the activation of host eosinophils. In association with a Phase I clinical trial of IL-4 in cancer patients, we have examined changes in eosinophil counts and characterized systemic eosinophil degranulation. As previously reported, IL-4 administration induced a modest eosinophilia in all 17 evaluated patients. Here, we report that IL-4 therapy induced systemic eosinophil degranulation based on increases in serum major basic protein (MBP) (P = 0.018) and urine MBP (P = 0.031). The increase in serum MBP was IL-4 dose dependent (P = 0.001). Following the highest dose (600 microgram/m2/day) of IL-4 administered, mean serum MBP levels were2000 ng/ml. Skin biopsies of rashes from patients receiving IL-4 revealed MBP deposition. Sera from eight patients receiving IL-4 at 360 and 600 microgram/m2/day exhibited eosinophil survival-enhancing activity (on days 3, 5, 7, and 9) significantly above pretreatment (on day 1) activity (P values 0. 0469, 0.0039, 0.0395, and 0.0313, respectively). This enhanced eosinophil survival could be neutralized by antibodies to IL-5, granulocyte-macrophage-colony-stimulating factor, and IL-3. The eosinophil activation demonstrated in this trial may be relevant to the clinical effects of IL-4 in cancer patients. Furthermore, an association between IL-4 and eosinophil activation should be explored in other disease states.

Background Tumor EGFR and KRas mutations are both predictive and prognostic biomarkers in patients with advanced NSCLC. We analyzed the correlation between these biomarkers and treatment outcomes in a phase III trial of 3rd/4th line sorafenib in patients with NSCLC. Methods The global, randomized, placebo-controlled MISSION trial enrolled 703 patients with advanced relapsed/refractory NSCLC of predominantly non-squamous histology. The primary study endpoint was overall survival (OS). EGFR and KRas mutations were analyzed in archival tumor samples and in circulating tumor DNA isolated from plasma. Results Tumor and/or plasma mutation data were available from 347 patients (49%). EGFR and KRas mutations were detected in 89 (26%) and 68 (20%) patients, respectively, and were well balanced between treatment arms. Analysis of the interaction between EGFR mutation status and treatment effect on survival suggested that patients with EGFR mutations (mEGFR) benefitted from sorafenib, while those with wild-type EGFR (wtEGFR) did not (p = 0.023). Median OS was two-fold longer in mEGFR patients receiving sorafenib versus placebo (423 vs 197 days, HR 0.48, p = 0.002). There was no significant difference in OS between patients with wtEGFR receiving sorafenib or placebo (253 vs 256 days, HR 0.92, p = 0.559). An interaction was also seen between EGFR mutation status and the sorafenib effect on PFS (p = 0.015). Patients with mEGFR treated with sorafenib had better outcomes compared to placebo based on Cox regression analysis (HR 0.27, p Conclusion Post-hoc analyses of efficacy outcomes in MISSION suggest that advanced NSCLC patients with EGFR mutations may derive a survival benefit from receiving 3rd/4th line sorafenib. These results must be interpreted with caution due to the small, non-representative nature of the genetic biomarker subpopulation analyzed in this trial. Further prospective investigation may be warranted. Disclosure T.S.K. Mok: Honoraria: AstraZeneca, Roche, Eli Lilly, Merck Serono, Eisai, BMS, BeiGene, AVEO, Pfizer, Taiho, Boehringer Ingelheim, and GSK Biologicals Speaker: Astrazeneca, Roche, Eli Lilly, Boehringer Ingelheim, and Merck Serono Research funding: Astrazeneca. L. Paz-Ares: Dr. Paz-Ares has received honoraria from Bayer HealthCare Pharmaceuticals, Lilly, Roche and Pfizer. Y. Wu: Dr. Wu has received lecture fees from Roche, AstraZeneca, Eli Lilly, and Pfizer. V. Hirsh: Member of the steering committee for the MISSION trial. C. Lathia: Dr. Lathia is an employee of Bayer HealthCare. T.J. Ong: Dr. Ong is an employee of, and owns shares in, Bayer HealthCare. C. Pena: Dr. Pena is an employee of Bayer HealthCare. All other authors have declared no conflicts of interest.

Introduction Dabrafenib (D) combined with trametinib (T) shows enhanced activity in BRAF V600-mutated cancer cell lines and xenograft models compared with either drug alone. Preclinically, D + T delays resistance and prevents BRAFi-induced proliferative skin lesions. Safety and efficacy of D + T, were evaluated in a four-part Phase 1–2 study. Safety and efficacy from Part C, the randomised study of D + T vs D are presented. Methods BRAFV600E/K mutation-positive, MM, BRAFi and MEKi treatment-naive pts (≥ 18 yrs; ECOG PS Results Pt (n = 162) baseline characteristics were balanced across the three arms. Investigator assessed median PFS for 150/2 was 9.4 mo v 5.8 for D mono (HR 0.39, 95% CI 0.25–0.62; p Conclusions D + T provided a statistically significant and clinically meaningful improvement in PFS, RR and DoR compared to D mono in pts with BRAF V600 mutation-positive MM. The data is consistent to Part B reported with D + T. Increased incidence and severity of pyrexia and lower incidence of hyperproliferative skin lesions are observed with D + T compared to D mono. Phase 3 studies are ongoing. Disclosure G.V. Long: Has participated in advisory boards for GlaxoSmithKline, Bristol Myers Squibb and Roche. Has received research funding and honoraria from Roche. J.A. Sosman: Has received research funding from GlaxoSmithKline. J.S. Weber: Has participated in advisory boards for, and has received honoraria from, GlaxoSmithKline. K.T. Flaherty: Has acted as a data safety monitoring board member and consultant (compensated) for, and has received research funding from GlaxoSmithKline. J.R. Infante: Has participated in an advisory board for GlaxoSmithKline. O. Hamid: Has acted as a consultant (uncompensated) for GlaxoSmithKline. Has received research funding from Bristol Myers Squibb. L. Schuchter: Has participated in advisory boards for Merck and has received research funding from GlaxoSmithKline, Merck and Genentech. J.S. Cebon: Has participated in GlaxoSmithKline advisory boards, and has received research funding and honoraria from GlaxoSmithKline. I. Puzanov: Has acted as a paid consultant to GlaxoSmithKline. A.P. Algazi: Has received research funding from GlaxoSmithKline. K. Lewis: Has received research funding from GlaxoSmithKline. W. Hwu: Has acted as a compensated consultant for Merck. Has received research funding from Bristol Myers Squibb. R.F. Kefford: Has participated in an advisory board for GlaxoSmithKline. P. Sun: Is a GlaxoSmithKline employee (Statistician) and owns GlaxoSmithKline stocks and shares. S.M. Little: Is a GlaxoSmithKline employee (Clinical Development Manager) and owns GlaxoSmithKline stocks and shares. R. Gonzalez: Has acted as a consultant to, and has received research funding from, GlaxoSmithKline. K. Patel: Is a GlaxoSmithKline employee (Director, Oncology Clinical Development) and owns GlaxoSmithKline stocks and shares. K.B. Kim: Has received research funding from GlaxoSmithKline. All other authors have declared no conflicts of interest.

LBA4 Background: About 50% of melanomas have an activating V600EBRAF mutation which led to the hypothesis that inhibition of the mutated BRAF kinase may be of clinical benefit. Phase I and II trials with vemurafenib (previously PLX4032/RO5185426), an orally available inhibitor of oncogenic BRAF kinase, showed response rates (RR; CR+PR) >50% in V600EBRAF- mutated melanoma patients (pts). We conducted a phase III trial to determine if vemurafenib improved overall survival (OS) and progression-free survival (PFS) in melanoma pts with V600EBRAF mutation. Methods: Pts with previously untreated, unresectable stage IIIC or stage IV melanoma that tested positive for V600EBRAF mutation by the cobas 4800 BRAF V600 Mutation Test were randomized (1:1) to vemurafenib (960 mg po bid) or DTIC (1,000 mg/m2, IV, q3w). Randomization was stratified by PS, stage, LDH, and geographic region. Pts were assessed for tumor responses after weeks 6, 12, and then q9 weeks. Co-primary endpoints were OS and PFS on the intent-to-treat population; secondary endpoints included RR, response duration, and safety. Final analysis was planned at 196 deaths. Results: 675 pts were enrolled at 103 centers worldwide between Jan and Dec 2010. Treatment cohorts were well-balanced. At the pre-planned interim analysis (50% of deaths needed for final analysis), the hazard ratios for OS and PFS were 0.37 (95% CI 0.26 to 0.55; pV600EBRAF-mutated metastatic melanoma.

8509 Background: Most agents tested in large phase II trials in patients (pts) with metastatic melanoma have response rates of 10-20%. Approximately 50% of melanomas harbor a V600E activating mutation in the BRAF gene, which can now be targeted with specific inhibitors. In a Phase I study, treatment with vemurafenib (V), an orally available inhibitor of mutant BRAF, led to a high incidence of tumor regressions in BRAF-mutant melanoma (Flaherty et al. NEJM 2010). Here we report the results of BRIM-2, a pivotal Phase II trial of V in previously treated pts with BRAF-mutant melanoma. Methods: The primary endpoint was best overall response rate (BORR), with a target of 30% and a lower boundary of the exact 95% CI of at least 20% by independent review committee (IRC). BRAF mutation status was determined using a PCR-based investigational, companion diagnostic assay (cobas 4800 BRAF V600 Mutation Test, Roche Molecular Systems). Pts without active CNS metastasis who had received at least one prior line of therapy...

8520 Background: Vemurafenib (V; RG7204, PLX4032), an oral inhibitor of oncogenic V600E mutant BRAF, was evaluated for safety, efficacy, and pharmacokinetics in dose escalation and melanoma extensi...

8502 Background: Vemurafenib (PLX4032), an oral, selective inhibitor of oncogenic V600E mutant BRAF, was evaluated for safety and pharmacokinetics in the Phase I dose escalation (DE) study PLX06-02 (Flaherty, et al. NEJM, 2010). Exploratory analyses included the investigation of MOA, pathway inhibition, and primary or acquired drug resistance from pts participating in the DE and melanoma extension phase. Methods: Biopsies were taken at baseline (BL), on vemurafenib therapy Day 15 (D15), and at progressive disease (PD). Protein expression (PTEN, Cyclin D1, p27, and Ki67), phosphorylation (pERK, pMEK and pAKT), apoptosis (TUNEL), gene sequence (MEK1), and mutations in oncogenes and tumour suppressor genes (404 mutations incl. BRAF, H-, K-, N-RAS, and PIK3CA using Sequenom MassArray) were analyzed. Results: Tumor tissue of 5 pts from the DE and 17 pts from the extension cohort was obtained (total samples: 18 BL, 12 D15, 20 PD). In 7/7 pts with paired BL/D15 samples, high levels of pERK were observed at BL fo...

TPS145 Background: The Ras/Raf/MEK/ERK cascade is frequently activated in human cancers; MEK inhibition is an attractive therapeutic target for preventing tumor growth and angiogenesis. The investi...

8519 Background: Vemurafenib (V; RG7204, PLX4032), a BRAF inhibitor, induces responses in a majority of patients (pts) with V600EBRAF mutant melanoma, but most eventually progress. We report the pa...

8508 Background: RAF265 is an oral small molecule inhibitor of mutant (mut) BRAFV600E(EC50= 0.14µM) and VEGFR2 (EC50 = 0.19µM). It displays dose dependent inhibition of tumor growth and regression ...

3034 Background: ARQ 197 (A) is a selective, oral, non-ATP competitive inhibitor of c-MET, a RTK implicated in tumor cell proliferation, invasion and metastasis, currently in phase II/III clinical ...

331 Background: Programmed death-1 (PD-1), a T-cell inhibitory receptor, may suppress antitumor immunity. BMS-936558, a fully human PD-1 blocking antibody, has shown antitumor activity and manageable toxicity after biweekly dosing (Sznol, ASCO 2010, #2506). This report provides an update on safety and antitumor activity with special emphasis on RCC. Methods: An open-label phase I dose escalation study of BMS-936558 was conducted in patients (pts) with treatment refractory metastatic clear-cell renal cell carcinoma (RCC), castrate-resistant prostate cancer (CRPC), melanoma (MEL), non-small cell lung cancer, or colorectal cancer (CRC). Dose escalation continued to 10 mg/kg when an expansion cohort for pts (16) with each tumor type was opened for additional safety and efficacy information. Tumor response (RECIST) was evaluated every 8 weeks. Clinically stable pts with early PD could continue until further PD or clinical deterioration. Results: 126 pts (18 RCC) were treated with 1, 3, or 10 mg/kg. MTD was not reached. Across all doses, the most common AEs (Any/grade 3-4) were fatigue (45.2%/6.3%) and diarrhea (30.2%/0.8%) while the most common drug-related AEs (Any/grade 3-4) were fatigue (20.6%/0.8%), rash (11.9%/0%), pruritus (11.3%/0%), and diarrhea (10.3%/0.8%). There was no apparent relationship between dose and frequency of AEs. One pt died with sepsis while being treated for drug-related grade 4 pneumonitis. The median number of prior treatment regimens in the RCC cohort was 2 (range 1-6). Of the 18 RCC pts, 16 were treated with 10 mg/kg. The median duration of treatment was 7.6+mo. ORR was 5/16 (31.2%) and SD>4mo was 6/16 (37.5%). The median duration of response was 4.0+ mo (3.7-7.4+ mo). Of the 2 RCC pts treated with 1 mg/kg, 1 obtained a CR (12+ mo) and 1 had SD (21+ mo). For evaluable CRPC pts, 1/15 pts (6.7%) obtained a PR (2+ mo) and 3/15 (20%) had SD>4mo. Conclusions: BMS-936558 administered biweekly is tolerable and has encouraging antitumor activity in a previously treated patients with RCC. Data on baseline characteristics, long-term toxicity and response duration will be updated at the meeting. [Table: see text]

4 Background: Ipilimumab, a fully human monoclonal antibody against cytotoxic T-lymphocyte antigen-4, demonstrated activity in advanced melanoma. Gp100 vaccine showed immunological and clinical responses, and enhanced clinical activity when combined with other immunotherapy. This phase III study compared efficacy and safety of ipilimumab or gp100 monotherapy and combination. Methods: Eligible patients (HLA-A*0201+ previously treated adults with unresectable stage III/IV melanoma) were randomized 1:3:1 to ipilimumab (3 mg/kg q3w x 4 doses) + placebo (n=137), ipilimumab + gp100 (peptides 209-217[210M] and 280-288 [288V]; 1mg q3w x 4 doses; n=403), or gp100 + placebo (n=136). There was no maintenance phase. Primary endpoint was comparison of overall survival (OS) between patients who received combination versus gp100 alone; secondary endpoints were all other OS comparisons, best overall response rate (BORR), disease control rate (DCR) to W24, progression-free survival (PFS), and safety. Results: The study demonstrated statistically significant results for all efficacy endpoints (below). Ipilimumab alone or combined with gp100 resulted in a significant improvement in OS with risk reduction of 32-34% compared to gp100. Significant differences in DCR, BORR, and PFS were observed. Adverse events with ipilimumab were consistent with prior studies: generally mild, immune-related, and medically manageable. Conclusions: Ipilimumab is the first agent to improve median and long-term OS in a phase III study of previously treated patients with advanced melanoma. Addition of gp100 vaccine to ipilimumab did not improve outcome. [Table: see text] [Table: see text]

8529 Background: FDG-PET is an effective imaging modality at assessing early response to a variety of agents that target key driver mutations in human cancer. Reduction in FDG uptake reflects inhib...

8592 Background: Tumor regressions have been observed in a significant proportion of advanced melanoma patients treated with PLX4032 (RG7204), in a phase I trial with BRAF V600E mutated tumors. Tre...

8513 Background: In addition to known prognostic factors, the analysis of PB for expression of mel genes by RT-PCR (MRD) may provide insight into the likelihood of relapse and/or death in pts with high-risk mel and inform decisions regarding adjuvant therapy. Prior studies have provided conflicting results on the utility of PB RT-PCR testing. Methods: In Intergroup phase III trial S0008 of adjuvant therapy in pts with stage III mel (Txb+N1a or ≥N2a or N1b) MRD was assessed by RT-PCR of mel associated genes (tyrosinase, MART-1, gp-100 or MAGE-3) at baseline, day 90, and day 365. Pts were randomized to biochemotherapy (BCT) (9 wks) or standard adjuvant interferon (HD IFN) (52 wks). MRD monitoring was instituted after trial enrollment was initiated and represented data for 219 of 420 pts. Although survival data are not yet mature, the SWOG DSMC gave permission for a preliminary analysis of the impact of MRD on clinical outcomes blinded to treatment arm. Results: Two hundred nineteen of 420 enrolled pts had p...

4514 Background: HD IL-2 received FDA approval for mRCC in 1992, producing a 14% major response (CR + PR) rate and durable remissions in phase II trials. The Cytokine Working Group conducted the present trial to identify patients (pts) likely to respond to treatment in order to improve the therapeutic index of HD IL-2. Methods: In this multicenter, prospective study pts with histologically confirmed RCC that was metastatic or unresectable, measurable disease, age ≥ 18 years, ECOG PS 0-1 and adequate organ function received HD IL-2 (600,000 U/kg/dose intravenously every 8 hours on days 1 through 5 and 15 to 19 (maximum 28 doses) every 12 weeks. The primary endpoint of the study was to determine the major response rate (RR) of pts with “favorable” predictive features. All pts were consented to provide archived tumor tissue that would be used for pathology risk classification, carbonic anhydrase IX (CAIX) staining and in creation of a tissue microarray. Results: One hundred twenty eligible pts enrolled betwe...

8502 Background: BRAF and N-RAS mutations occur in 50% and 15%-20% of melanomas, respectively, while lack of functional PTEN enhances PI3 kinase/AKT/mTOR pathway signaling. Combinations that presum...

9021 Background: PLX4032 is an oral, highly selective inhibitor of oncogenic V600EBRAF kinase currently in phase I trial. V600EBRAF mutation activates Raf/MEK/ERK pathway in multiple tumor types. We evaluated the relationship between PK, PD (pERK, Ki67, FDG-PET), tumor histology and clinical activity following PLX4032 administration in a phase I trial. Methods: In the phase I trial, 6 melanoma pts with V600EBRAF were treated with PLX4032 daily at several dose levels and tumor biopsies (baseline vs. day 15) were assessed histologically and by semi-quantitative IHC analysis (modified H-score) for pERK and Ki67. The first 4 pts received a crystalline formulation of PLX4032; the last 2 pts received a formulation with increased bioavailability. Plasma PK parameters were collected at frequent time points on Days 1, 8 and 15. FDG-PET was performed on Days 1 and 15 on last 2 pts. Results: In the first 4 pts, no histological changes were observed with treatment and all developed disease progression. All had decreased percentage of Ki67 positive nuclei (pre-Rx, range 20–60%, median 45%; post-Rx, range 5–25%, median 12.5%) and 3 of the 4 had decreased pERK levels (pre-Rx, range 50–100, median 60; post-Rx, range 10–40, median 11). Mean PLX4032 AUC0–24h ∼ 126 μM*h was in the range for preclinical tumor stasis but below the threshold for shrinkage. In the last 2 pts, striking tumor necrosis and tumor melanosis was observed in the post-Rx samples. One pt remains on study with a confirmed PR, the other showed a clinical response before disease progression occurred in cycle 2. The percentage of Ki67 positive nuclei declined substantially (pre-Rx, 30% and 50% to post-Rx, 5% and 3%), as did the levels of pERK in the pt with PR (pre-Rx: 70 to post-Rx: 2). Mean PLX4032 AUC0–24h was well above the preclinical threshold in the range of 500 - 1000 μM*h. Both pts had decreased FDG uptake on D15. Conclusions: Clinical activity of PLX4032 treatment correlates with drug exposure levels as measured by AUC0–24h and was associated with histological changes in V600EBRAF positive melanomas on Day 15. Reduction of pERK, along with evidence of reduced proliferation and FDG uptake was observed. Further analysis of PD markers with additional pts at the MTD is planned. [Table: see text]

5101 Background: The recently demonstrated activity of inhibitors of TORC1 in RCC has raised the possibility that even greater effects may be achieved by targeting upstream of this pathway. Perifosine is a synthetic alkylphospholipid which inhibits Akt activity and also has cell-dependent effects upon the MAP-kinase pathway. Prior single-agent trials showed disease stabilization/regression in patients (pts) with advanced RCC; however, few pts were previously treated with a TKI. Therefore, we conducted a multi-center phase II trial to determine the safety and efficacy of perifosine in pts with advanced RCC refractory to VEGFR TKI. Methods: Primary objectives were to measure the % of pts progression-free at 12 weeks (wks) and overall progression-free survival (PFS) of perifosine (100 mg qhs). Secondary objectives included overall response rate (> PR), and safety, Eligibility: ECOG PS 0–1, pts with metastatic RCC who have RECIST defined progression on either sunitinib or sorafenib. Prior Rx with immunotherapy and bevacizumab was permitted. Normal organ and marrow function required. Results: From 4/07–10/08, 24 pts were treated at four sites. Median age 67 (range 47–78) and 16 were male; 90% of pts had predominantly clear cell histology. Prior sunitinib = 12; prior sorafenib = 12 (1.5 avg prior Rx). As of 12/08, all 24 pts were evaluable for PFS, response and toxicity as follows in the table . 6/24 pts remain on treatment (range 7 - 84 wks). Therapy was well tolerated with primarily Grade (G) 1 & 2 adverse events. G 3 & 4 events were: dyspnea (8%), hyponatremia (8%), pulmonary embolism (4%) and arthalgia (4%). Conclusions: Perifosine has promising activity in pts with RCC who have failed prior TKI therapy. The favorable toxicity profile suggests potential for combinational therapies with VEGF-targeted agents. Additional studies are under consideration to evaluate perifosine for clinical benefit in pts with previously treated RCC. [Table: see text] [Table: see text]

An anti-leukemic effect of allogeneic bone marrow has been repeatedly demonstrated in experimental animal models. Clinical data supporting this "graft versus leukemia" (GVL) effect are derived from several different observations which include: 1) the association of GVHD (acute and chronic) with decreased leukemic relapses; 2) identical twin transplants are associated with a higher relapse rate compared to allogeneic MHC-matched sibling transplants; 3) T cell depletion of donor bone marrow decreases GVHD and increases leukemic relapse rates; 4) Allogeneic BMT without GVHD have a lower leukemic relapse rate compared to identical twin transplants and T cell depleted transplants. The mechanisms of this GVL effect remain poorly understood, but clearly involve the immune system. It is hoped that current advances in basic understanding of the immune system and its activation will enable the "antileukemic" components of the GVL effect to be prospectively controlled and intentionally used as leukemia therapy.

5011 Background: We conducted a Phase I trial of S and B to study inhibition of the vascular endothelial growth factor (VEGF) pathway at both the ligand (B) and receptor (S), and platelet derived growth factor receptor (S) in mRCC. Methods: Pts with measurable mRCC, adequate organ function, and PS 0–1 were eligible. Cohorts of at least 6 pts were enrolled to define the MTD and DLT of B given IV q 2wks and S po QD on 28-day cycles. Response and toxicity were assessed after 2 cycles. Initial doses were S at 200mg BID and B at 5 mg/kg with modification based on observed toxicities. High dose pyridoxine was administered in some cohorts attempting to ameliorate hand-foot syndrome (HFS) symptoms. Results: 47/48 pts completed their 1st response evaluation. Median age was 61 yrs (35–83 ); M/F: 40/8; PS: 0/1= 32/16; 41 clear cell, 7 non-clear cell; 41 had prior nephrectomy; 6 prior IFN and 9 prior IL-2. The table summarizes dose levels explored and toxicities. Toxicities included PUD, rash, weight loss, proteinuri...

Interleukin 2 (IL-2) induced activation of unstimulated resting natural killer (NK) cells or resting T-cells initially occurs following binding of IL-2 through the p75 receptor that is expressed primarily by these cells. However, this IL-2/p75 interaction induces TAC chain synthesis and formation of high affinity IL-2 receptor required for the proliferation of resting peripheral blood lymphocytes. In this study, we present data indicating that NK cells activated by in vivo IL-2 treatment, in contrast to resting NK cells, respond and proliferate to further IL-2 in vitro using primarily the p75 receptor with only a minor component of cells responding through the high affinity receptor. These in vivo activated NK cells minimally expressed the TAC chain and maintained this TAC negative phenotype while proliferating in response to IL-2. The primary involvement of the p75 receptor in the proliferative response of these cells to IL-2 was demonstrated by the need for concentrations of IL-2 higher than 44 pM to obtain a significant response and by the dramatic inhibition of this response by anti-p75 monoclonal antibody. Anti-TAC monoclonal antibody inhibited only the poor proliferation obtained at low doses of IL-2 suggesting a minor role for TAC and high affinity IL-2 receptors. This was in contrast to the partial inhibition of proliferation by anti-p75 or anti-TAC observed in unstimulated pretherapy peripheral blood lymphocytes suggesting that these cells respond to IL-2 through both high affinity receptors and intermediate affinity p75 receptors. The T-cells isolated from in vivo activated peripheral blood lymphocytes, despite expressing TAC, were not responsive to IL-2, suggesting that these cells express predominantly nonfunctional low affinity TAC receptors. NK cells activated by IL-2 in vivo represent a unique model system of IL-2 dependent cells that respond and proliferate to IL-2 essentially through the p75 IL-2 receptor.

Administration of interleukin-2 (IL-2) in vitro or in vivo can activate a variety of immune effector functions involving T lymphocytes and natural killer cells. These immune cells and their secreted cytokines can potentially play a central role in the host antitumor response. With the isolation and cloning of the IL-2 gene, purified recombinant IL-2 has become available to test for clinical, immunologic, and antitumor effects. Early clinical studies suggest that the IL-2 doses required to induce antitumor effects are accompanied by severe life-threatening toxicity. Therefore, sustained treatment with lower doses of IL-2 has been developed that has a milder, acceptable toxicity. Most importantly, a small percentage of cancer patients experience significant shrinkage of their tumor with this IL-2 regimen alone. Further modification of this regimen is necessary. Preclinical studies indicate that combinations of IL-2 with other modalities may increase the therapeutic potential of the in vivo lymphokine-activated killer activity; combination therapy with other cytokines and monoclonal antibodies show significant promise. Furthermore, new technologic advances with the ability to produce human chimeric antibodies and bispecific hybrid antibodies has the potential to make combined IL-2 and antibody therapy more successful. IL-2 has been associated with overly optimistic expectations and overly negative reactions from physicians and the public. However, the immune activation induced by IL-2, the small number of clinical responses, and the preclinical data suggesting synergism with other approaches indicate that further development may make IL-2 part of a regimen that will enable better cancer treatment.

Peripheral blood lymphocytes obtained from cancer patients receiving interleukin-2 (IL-2) on two separate clinical protocols were evaluated for their in vitro responses to IL-2, alloantigens, and PHA. IL-2 in vivo induced enhanced in vitro proliferative responses to IL-2 and diminished in vitro proliferative responses to phytohemagglutinin (PHA) and alloantigens. Alloinduced cytotoxic T cell responses were also depressed following in vivo IL-2. We examined the kinetics of the in vitro proliferative response to PHA and IL-2 and found that while the response of lymphocytes primed in vivo with IL-2 to PHA was depressed at all times during the 2 week in vitro exposure, the response to IL-2 peaked earlier and higher than did the response to IL-2 by lymphocytes obtained prior to IL-2 therapy. These contrasting effects on antigen-induced T cell responses vs. IL-2 induced nonspecific proliferative and cytotoxic responses suggest the importance of dose and timing of IL-2 administration when used to enhance antigen-specific T cell responses or as an immune enhancing agent combined with vaccines.

15524 Background: The rationale for combining HD IL-2 with B includes potential synergistic immune interactions, non-overlapping toxicities, and potential for added clinical benefit. We have initiated a multi-center phase II study designed to estimate the efficacy of combination therapy of standard HD IL-2 and B therapy in mRCC pts. Methods: Pts with histologically confirmed mRCC, predominantly clear cell histology, measurable or evaluable disease, KPS of =80%, adequate end organ function for HD IL-2, and no underlying coagulopathy or thrombotic event are eligible for this study. One cycle consists of 84 days. B (10 mg/kg) IV is given every 2 wks beginning 2 wks prior to the first dose of IL-2. B is dosed 1 hr prior to initiating IL-2 on days IL-2 is given. HD IL-2 (600,000 IU/kg) IV Q8 hours (maximum 28 doses) is given during two 5-day courses separated by 9 days (starting on day 15 and 29). Results: We report the results of the first 15 of a planned 60 pts. The median age is 54 (range 40–73) with 9 men and 6 women. 14 pts have a MSKCC intermediate prognostic score, one pt has a poor prognostic score. In the first cycle, the median number of B doses was 7 of a planned 7 (range 2–7) and the median number of IL-2 doses was 17 of a planned 28 (range 6–26). There has been one treatment related death from unresponsive hypotension which occurred during the second cycle. Typical IL-2 toxicities have been noted thus far. Among a variety of correlative studies, we evaluated the serum L- ornithine (L-O) level, a byproduct of arginase-mediated arginine metabolism that has been shown to inversely correlate with TCR? chain expression. L-O level are significantly elevated in RCC pts possibly due to VEGF stimulation of arginase production. In 4 patients tested to date, peripheral blood L-O levels have dramatically decreased over the course of therapy. Conclusions: HD IL-2 and B can be given safely and may impact on immune regulatory pathways. [Table: see text]

8511 Background: Sorafenib (SOR), a potent and selective multi-kinase inhibitor, exerts its anti-tumor and anti-angiogenic effects via inhibition of VEGFR-1, -2, -3, PDGFR-a, -β, and Raf. Dacarbazine (DTIC) is an FDA-approved cytotoxic agent for advanced melanoma. Phase I/II results of SOR + DTIC were encouraging and prompted this randomized phase II study. Methods: This was a multi- center, double-blinded, placebo-controlled study; eligibility criteria included measurable disease by RECIST, no prior cytotoxic chemotherapy, and no active brain metastases. Advanced melanoma patients (pts) stratified by stage (unresectable III vs IVM1a/M1b vs M1c) and ECOG PS (0 vs 1) were randomized to receive DTIC 1,000 mg/m2 q 21 days + oral placebo (PL) or oral SOR 400 mg bid continuously until the occurrence of progressive disease or intolerable toxicity. The primary endpoint was progression-free survival (PFS) of DTIC+SOR vs DTIC+PL. Using a two-sided test with a = 0.05, 77 PFS events were needed to detect a hazard ratio (HR) of 0.5 (SOR/PL) with 86 % power. The secondary endpoint was overall survival and tertiary endpoints were objective response rate (ORR), time to progression, and duration of response. Results: 101 pts were enrolled over 12 months (51 DTIC+SOR, 50 DTIC+PL). Treatment arms were balanced for age (median 58 yrs), gender (male 70%), PS (ECOG 1 39%), stage (Stage IV M1c 52%) and baseline LDH (>ULN 29%). At the time of analysis by independent assessment, the median PFS of DTIC+PL vs DTIC+SOR was 11.7 wks (95% CI 6.1, 17.9) vs 21.1 wks (95% CI: 16, 28); HR 0.67 [p=0.07]; PFS rate at Day 180 was 18% vs 41%; and ORR was 12% vs 24%. Survival data are immature. Toxicities of Grade 3 or higher (DTIC+PL vs DTIC+SOR) included neutropenia (12% vs 33%), leukopenia (6% vs 14%), thrombocytopenia (18% vs 35%), thrombosis/embolism (0% vs 6%), hypertension (0 vs 8%), hand-foot skin reaction (0 vs 4%), and CNS hemorrhage (0% vs 8%). 3 of the 4 pts with CNS hemorrhage had new brain metastases. No treatment-related deaths occurred in either arm. Conclusions: DTIC+SOR was well tolerated and showed a strong efficacy trend compared with DTIC+PL in median PFS, PFS rate at 6 months and ORR in chemotherapy-naïve pts with advanced melanoma. This regimen warrants further evaluation in larger clinical trial settings. No significant financial relationships to disclose.