Treatment-refractory Solid Tumors Research Articles

A pilot study of vinorelbine safety and pharmacokinetics (PKs) in patients (pts) with varying degrees of liver dysfunction (LD).

432 Background: Prospective data to support dosing guidelines for intravenous (IV) vinorelbine in pts with LD are limited. One study recommends standard 30 mg/m2 weekly for total bilirubin ≤2 mg/dL and a 50% dose reduction for bilirubin > 2 mg/dL. Another study recommends no dose modifications for bilirubin up to 3X the upper limit of normal (ULN). This phase I study describes the safety and PKs of vinorelbine in pts with varying degrees of hepatic impairment. Methods: Pts with treatment-refractory solid tumors received weekly IV 30 mg/m2 vinorelbine for normal liver function, 20 mg/m2 for mild LD defined as bilirubin < 1.5 mg/dL but aspartate aminotransferase (AST)/alanine aminotransferase (ALT) 1.5-2.5X ULN or alkaline phosphatase (ALK) 1.5-3X ULN, 15 mg/m2 or 30 mg/m2 for moderate LD defined as bilirubin 1.5-3.0 mg/dL and/or AST/ALT > 2.5 or ALK > 3X ULN, and 7.5 mg/m2 or 20 mg/m2 for severe LD defined as bilirubin > 3.0 mg/dL. Vinorelbine PKs were evaluated to describe its relationship with liver function. Results: 47 patients were enrolled (61.7% gastrointestinal and hepatobiliary cancers) and a total of 248 treatment-related adverse events (AEs) occurred. All-grade myelosuppression was the most common AE overall (41.1%). Out of 71 grade ≥3 AEs, 17 (23.9%) were grade 4 in severity with the majority (15/17) being myelosuppression. Rates of grade 4 hematologic AEs in the normal liver function and the 7.5 mg/m2 severe LD group were low ( < 10%). 4/17 grade 4 hematologic AEs were observed in the mild LD group while the remainder and majority occurred in the moderate-severe LD groups. Vinorelbine PKs were not correlated with the degree of LD, however free drug levels or levels of the active metabolite 4-O-deacetylvinorelbine were not measured. Conclusions: Weekly vinorelbine at 30 mg/m2 and 7.5 mg/m2 appears safe with normal liver function and severe LD, respectively. High rates of grade 4 myelosuppression with 15-30 mg/m2 vinorelbine in moderate-severe LD raise concerns for its safety in this population. Vinorelbine PKs are not affected by LD. However, it is possible that levels of the active metabolite could be higher in pts with LD if its elimination is impacted by LD to a greater extent than the parent drug. Clinical trial information: NCT00540982.

Activity and Immune Correlates of a Programmed Death-1 Blockade Antibody in the treatment of Refractory Solid Tumors.

Background: Blockade of programmed death 1 (PD-1), an inhibitory T lymphocyte receptor, is associated with immune system enhancement and tumor remission in various tumors. We assessed the anti-tumor activity and immune correlates of cancer patients treated with an anti-PD-1 antibody.Patients and Methods: Twelve patients with advanced metastatic tumors were treated with anti-PD-1 antibody. Responses were assessed after a 12-week treatment regimen. Biochemical and immunological indexes were measured before each cycle.Results: Among the 12 patients, 3 patients showed partial response while 6 patients had stable disease (objective response rate: 3/12, 25%; disease control rate: 9/12, 75%). During immunotherapy, the proportion of circulating CD3+ T lymphocytes remained stable, with decreasing trends of CD3+CD4+ T helper cell and increase in CD3+CD8+ T memory cells, in patients with stable disease. Additionally, an increase in serum lactate dehydrogenase levels seemed to correlate with tumor progression.Conclusions: An anti-PD-1 antibody produced objective responses in approximately 25% patients with various solid tumors, demonstrating that it could improve the immune system in vivo.

A study of vistusertib in combination with selumetinib in patients with advanced cancers: TORCMEK phase Ib results.

2548 Background: PI3K/mTOR and MAPK pathways are aberrantly activated in many tumours and interact to promote tumour growth and therapeutic resistance. Activity of single pathway inhibition is limited due to compensatory activation of alternative signalling pathways. Dual pathway inhibition has demonstrated synergistic activity in preclinical models, with broad activity across a range of molecular backgrounds. This study was designed to evaluate the optimal doses and schedule of vistusertib (dual mTOR1/2 inhibitor) and selumetinib (MEK1/2 inhibitor) when given in combination. Methods: Thisphase Ib/IIa trial with a dose escalation part (Ib) in treatment refractory advanced solid tumours and expansion cohorts in TNBC, squamous and non-squamous NSCLC (KRASmt & WT) (IIa). Both, continuous daily (CC) (25, 35, 50mg BD) and intermittent (IC) schedules (50, 100, 125mg BD 2ds on, 5 ds off) of vistusertib were investigated. Selumetinib dose was given at a dose of 75mg BD daily. Treatment was given until PD (RECIST 1.1) or intolerable toxicity. The primary endpoint was DLTs. Secondary endpoints included response, clinical benefit, PFS and PK. Results: 23 evaluable patients were enrolled in the PhaseIb part. For the intermittent schedule, no DLTs were reported at any of the dose levels IC1-3. For the continuous schedule, 2 out of 9 patients treated at dose level C2C developed DLTs (G3 mucositis, dizziness and rash). Dose level C3C was not tolerated with DLTs observed in 2 out of 3 patients (G3 mucositis and G3 LFTs). Separate MDTs were determined for intermittent (I3C) and continuous schedules (C2C). Adverse events were in keeping with established single agent safety profiles. Anti-tumour efficacy was demonstrated at various dose levels and across tumour types including uveal melanoma, breast, cervical, uterine, skin or colorectal cancers. There were no objective responses but confirmed stable disease for > 16 weeks were observed in 7 patients with a duration of response ranging up to 55+ weeks. Conclusions: Based on DLTs, dose intensity and cumulative toxicity, the intermittent schedule I3C was selected as RP2D for expansion cohorts. Preliminary anti-tumour activity was observed. Clinical trial information: NCT02583542.

Abstract 3209: CRLX101, an investigational nanoparticle-drug conjugate of camptothecin, demonstrates synergy with immunotherapy agents in preclinical models

Abstract CRLX101, an investigational nanoparticle-drug conjugate (NDC) containing the payload camptothecin, is currently being clinically evaluated in multiple treatment-refractory solid tumors. CRLX101 has been shown preclinically to be active in many different tumor types as a dual inhibitor of topoisomerase 1 and hypoxia-inducible factor 1α (HIF-1α). It has a long circulation half-life and has been shown pre-clinically to release camptothecin in a slow and prolonged manner in tumors. Camptothecin itself was identified as an active anti-tumor agent preclinically but was not developed clinically due to its poor tolerability in patients. The development of CRLX101, which has not shown significant toxicity in over 300 patients to date, offers a unique opportunity to improve cancer treatment in a meaningful way. Recent publications have suggested that tumor expression of the immune-suppressive molecule PD-L1 is controlled by HIF-1α. Since CRLX101 is a potent inhibitor of HIF-1α, it is possible that CRLX101 behaves as an inhibitor of the PD-1/PD-L1 axis in vivo. We therefore hypothesized that a combination of CRLX101 with agents that are being investigated in combination with the anti PD-1 antibody would lead to increased efficacy. Indole diamine oxygenase (IDO) inhibitors are a new class of drugs that decrease tumor-induced immune suppression and are currently being evaluated in the clinic with anti-PD-1 antibodies. Using syngeneic tumor models, we tested the combination of CRLX101 with three different IDO inhibitors. Treatment of the B16.F10 melanoma model with IDO inhibitors NLG919, INCB024360 or indoximod had no effect on tumor growth while CRLX101 as monotherapy showed moderate anti-tumor activity. When CRLX101 was combined with any of the three IDO inhibitors, the anti-tumor activity was greatly improved compared to monotherapy. Similar results were noted in other syngeneic tumor models. This improved combination response was not observed in IDO inhibitor combinations with the clinically approved topoisomerase inhibitor irinotecan, suggesting that CRLX101 provides a unique advantage in this context. Interestingly, CRLX101/IDO inhibitor combination was also superior to the combination of anti-PD-1 antibody and IDO inhibitor. These data suggest that CRLX101 in combination with IDO inhibitors can successfully block host-mediated immune-suppression to enhance anti-tumor immunity, and this combination may therefore show improved therapeutic activity in the clinic. We therefore plan to explore the immune-specific effects of CRLX101 as well as the mechanistic basis for the observed combination response, and use that information to guide CRLX101 clinical strategy in the setting of chemo-immunotherapy regimens. Citation Format: Douglas Lazarus, Christian Peters, Adam Stockmann, Scott Eliasof, Lata Jayaraman. CRLX101, an investigational nanoparticle-drug conjugate of camptothecin, demonstrates synergy with immunotherapy agents in preclinical models. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3209.

Abstract 1345: Tumor selective localization of CRLX101, an investigational nanoparticle-drug conjugate of camptothecin

Abstract CRLX101, an investigational nanoparticle-drug conjugate (NDC) containing the payload camptothecin, is currently being clinically evaluated in multiple treatment-refractory solid tumors. In preclinical models, CRLX101 is believed to release camptothecin in the tumor in a slow and prolonged manner due to its long circulation half-life. CRLX101 has been shown preclinically to be a dual inhibitor of topoisomerase 1 and hypoxia-inducible factor 1α. It has demonstrated striking anti-tumor activity in several different tumor models. Camptothecin itself was identified as an active anti-tumor agent preclinically but was not developed clinically due to its poor tolerability in patients. The development of CRLX101, which has not shown significant toxicity in over 300 patients to date, offers a unique opportunity to improve cancer treatment in a meaningful way. We hypothesized that CRLX101 utilizes the enhanced permeability and retention (EPR) effect to accumulate selectively in tumors. In this study, we sought to mechanistically dissect the process of CRLX101 entry and accumulation into tumor cells using multiple methods, both in vitro and in xenograft tumors in vivo. Using confocal microscopy, we detected camptothecin fluorescence in CRLX101-treated tumor cells in culture as well as in tumor tissue from mice treated with CRLX101. We can co-localize this camptothecin with intact nanoparticles using an anti-PEG antibody that specifically detects the PEG loops in the NDCs. More recently, we have shown that camptothecin and anti-PEG co-localize specifically in tumors of patients treated with CRLX101 but not in adjoining normal tissue. We can also demonstrate that macropinocytosis and activation of actin polymerization play a role in the process by which tumor cells take up CRLX101. Using an anti-CD31 antibody, we can visualize the distance traversed by CRLX101 from the tumor vasculature over time. We have developed novel analytical methods to precisely quantify both released and CRLX101-conjugated camptothecin over time in CRLX101 treated tumor cells in vitro, as well as in tumor tissue from mice treated with CRLX101 in vivo. Using cell viability assays, we can correlate the kinetics of camptothecin released inside tumor cells to the degree of tumor cell kill. We believe that these data are an important step forward in understanding the precise mechanism(s) underlying selective delivery of CRLX101 into tumor tissue. Citation Format: Christian G. Peters, Douglas Lazarus, Donna Brown, Ningning Zhang, Adam P. Stockmann, Roy Case, Ellen Rohde, Scott Eliasof, Lata Jayaraman. Tumor selective localization of CRLX101, an investigational nanoparticle-drug conjugate of camptothecin. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1345.

Abstract B37: Selective tumor localization of CRLX101, a novel nanoparticle-drug conjugate

Abstract CRLX101, an investigational nanoparticle-drug conjugate (NDC) containing the payload camptothecin conjugated to a biocompatible copolymer of cyclodextrin and polyethylene glycol (PEG), is currently being evaluated clinically in multiple treatment-refractory solid tumors. CRLX101 is a dual inhibitor of topoisomerase 1 (TOPO 1) and hypoxia-inducible factor 1α (HIF-1α) and has been shown pre-clinically to be active in many different tumor types. It has a long circulation half-life and is believed to release camptothecin in a slow and prolonged fashion in the tumor. Camptothecin is an active anti-tumor agent preclinically but was not developed clinically due to its poor tolerability in patients. The development of CRLX101, which has not demonstrated significant toxicity in over 250 patients dosed to date, offers a unique opportunity to improve cancer treatment in a meaningful way. We have previously published that in gastric cancer patients treated with CRLX101, camptothecin fluorescence can be visualized in tumor tissue but not adjoining normal tissue. Based on these data we hypothesized that CRLX101 utilizes the enhanced permeability and retention (EPR) effect to accumulate selectively in tumors. In this study, we sought to mechanistically dissect the process of CRLX101 entry and accumulation into tumor cells using multiple methods, both in vitro and in xenograft tumors in vivo. Using confocal microscopy, we can detect camptothecin fluorescence in CRLX101- treated tumor cells in culture as well as in tumor tissue from mice treated with CRLX101. We can co-localize this camptothecin with intact nanoparticles using an anti-PEG antibody that specifically detects the PEG loops in the NDCs. We can also demonstrate that macropinocytosis plays a role in the manner by which tumor cells take up CRLX101. Using an anti-CD31 antibody, we can visualize the distance traversed by CRLX101 from the tumor vasculature over time. We have developed novel analytical methods to precisely quantify both released and CRLX101-conjugated camptothecin over time in CRLX101 treated tumor cells in vitro, as well as in tumor tissue from mice treated with CRLX101 in vivo. Using cell viability assays, we can correlate the kinetics of camptothecin released inside tumor cells to the degree of tumor cell kill. We believe that these data are an important step forward in understanding the precise mechanism(s) underlying selective delivery of CRLX101 into tumor tissue. Citation Format: Christian G. Peters, Douglas Lazarus, Donna Brown, Ningning Zhang, Roy Case, Ellen Rohde, Scott Eliasof, Lata Jayaraman. Selective tumor localization of CRLX101, a novel nanoparticle-drug conjugate. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B37.

Phase I clinical trial of the intraperitoneal (IP) administration of a novel nanoparticle formulation of paclitaxel (NTX).

2558 Background: IP therapy is an attractive option for patients with IP carcinomatosis as many of these malignancies remain confined IP. Agents whose plasma clearance rates substantially exceed their rates of uptake from the peritoneal cavity are especially suited for IP administration. Pre-clinical studies of a novel formulation of nanoparticulate paclitaxel in animal tumor models demonstrated superior activity and substantially reduced systemic toxicity. This allowed for significant IP doses and concentrations, yet yielded very low systemic concentrations of paclitaxel. We report here the results of a Phase I trial of IP administered NTX. Methods: Patients (ECOG≤2) had relapsed, treatment refractory solid IP tumors and adequate organ function. NTX was administered IP as a bolus injection after 500 ml saline followed by IP administration of up to 2 L of saline. We utilized an accelerated dose escalation scheme until one DLT occurred during cycle 1, followed by a standard dose escalation (3+3 design) based on CTCAE V3 toxicities. The pharmacokinetics of IP administered NTX were characterized in plasma and ascites fluid. Secondary objectives were to define the recommended phase 2 dose of NTX, and characterize preliminary activity and toxicity. Results: 20 patients were treated at dose levels from 50 – 275 mg/M2 q 28 days. Primary malignancy was ovarian cancer (74%). Treatment was well tolerated at all dose levels. Common toxicities potentially related to NTX were: gastrointestinal (68%), constitutional (42%), and pain (42%). Average number of cycles received was 2 (range 1 to 6). Best response was stable disease (4 patients, 21%). Median length of disease stability was 99 days (range 85 to 151 days); median time on study patients with stable disease was 313 days (range 142 to 740 days). All Cmax in plasma were less than 35 ng/mL, with ascites fluid Cmax generally greater than 1000 ng/mL. Conclusions: IP NTX is well tolerated. MTD has not yet been reached. Pharmacokinetic data demonstrate significant, persistent IP exposure to paclitaxel with minimal systemic exposure. Accrual at the 275 mg/M2 dose level continues; updated results will be presented. Further clinical development of NTX is indicated. Clinical trial information: NCT00666991.

A phase I study of ombrabulin (O) combined with bevacizumab (B) in patients with advanced solid tumors.

2535 Background: O, a vascular-disrupting agent derived from combretastatin A4-phosphate, induces rapid tumor vascular shutdown via endothelial cell damage. Resistance to O may occur by surges in circulating endothelial progenitors (CEP) that repopulate the tumor vasculature. Experimental models suggest prolonged and synergistic antitumor activity when O is combined with VEGF-blockade, with reduction in CEP surge. This phase I study was performed to determine the maximum tolerated dose, safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD) and preliminary antitumor activity of O combined with B. Methods: Patients (pts) with advanced treatment-refractory solid tumors, ECOG PS ≤1, and adequate organ function were eligible. O (mg/m²) was administered intravenously (IV) on day (d)1 with B (mg/kg) IV on d2 in 21d cycles (C). A Bayesian model informed dose escalation steps. PK sampling, dynamic contrast-enhanced ultrasound (DCE-US) for tumor perfusion, and CEP samples were collected. Results: 39 pts (M:F 10:29; median age 51 years [range 25-75]) were treated at 12 dose levels combining O [8 to 50mg/m2] with B [5, 10, or 15mg/kg]. Ovary (16/39, 41%) and colon (4/39, 10%) were the most common primary sites. No C1 dose-limiting toxicities occurred in 37 evaluable pts. Drug-related grade 3-4 treatment emergent adverse events (AE) were hypertension (6/39, 15%), intestinal perforation (2/39, 5%), headache (1/39, 3%), myocardial infarction (1/39, 3%), and pulmonary embolism (1/39, 3%). 36 pts (14 ovarian) were evaluable for response by RECIST 1.1. Antitumor activity was observed at O 20mg/m2+ B 10mg/kg and above, with confirmed partial responses in 2/14 pts with ovarian primary (14%), CA125 responses in 2 further ovary/endometrial cancers lasting ≥ 6 months, and stable disease in 15/36 pts (42%) lasting ≥ 6 months in 3 pts. PK indicated no interactions of O+B. Analyses of CEP levels post O and paired DCE-US data are ongoing. Conclusions: The maximum administered dose (MAD) was O 50mg/m2 with B 15mg/kg, with no dose-limiting toxicities and vascular toxicity that was manageable. Promising antitumor activity was observed at doses below the MAD and warrants further evaluation. Clinical trial information: NCT01193595.

Abstract 3529: Effect of PNT2258, an anti-BCL2 DNA-interference drug, on tumor growth and immunological markers in mice and humans.

Abstract Background: The dysregulation of apoptosis is a defining characteristic of malignant cells where excessive concentration of BCL2 protein contributes to the anti-apoptotic phenotype, driving development and subsequent resistance to therapy. Chromosomal translocations, including the t(14;18) rearrangement, up-regulate BCL2 transcription, preventing tumor cell death in B-cell lymphomas. A new class of therapeutic agents, called DNA interference (DNAi) drugs, exert their therapeutic effect by selectively blocking the transcription of oncogenes. PNT2258 is the lead DNAi drug currently undergoing clinical evaluation in patients with hematological malignancies. PNT2258 contains PNT100, a single stranded, native sequence oligonucleotide targeted against BCL2, which is delivered to cancer cells in a protective liposomal transport system. We present data on the anti-tumor and immunomodulatory effects of PNT228 in mice compared with that observed in patients with advanced solid tumors treated with escalating doses of PNT2258. Material and Methods: Twenty-two patients received PNT2258 doses ranging from 1 to 150 mg/mˆ2 as part of a Phase I dose-escalation study in patients with advanced, treatment refractory solid tumors. Patient plasma specimens were analyzed using a 61-marker multiplex immunoassay. Balb/c and WSU-DLCL2 xenograft mice received PNT2258 or an encapsulated scrambled control (oligonucleotide) sequence at a dose of 20 mg/kg by intravenous infusion. Murine plasma was analyzed with a 37-marker multiplex immunoassay. Results: In the murine xenograft model, PNT2258 demonstrated sequence-specific anti-tumor and anti-BCL2 activity not observed with the scrambled control. Xenograft mice demonstrated a strong innate immune response that was very similar in magnitude for both PNT2258 and scrambled control. Balb/c mice exhibited a broad and relatively weak immune response to PNT2258 and a stronger response to the scrambled control suggesting activation of both adaptive and innate immune responses. In patients, PNT2258 did not produce clinical signs of immune stimulation. Multiplex immunoassay revealed a lack of significant drug-induced modulation of inflammatory biomarkers following treatment. PNT2258 did induce statistically significant dose-dependent changes in IP-10, leptin, MIP-1β, MCP-1, IL-17F, and IL-1RA consistent with a mechanistic response to BCL2 suppression. Conclusions: Biomarker response profiles of encapsulated human sequence-specific oligonucleotide therapeutics in mice are not predictive of responses in humans. PNT2258 is safe and well tolerated in patients with no evidence of an innate (TLR) response. The observed biomarker profile provides mechanistic confirmation of drug-induced BCL2 suppression at all doses tested. Leptin represents a unique biomarker that may be used to monitor PNT2258 anti-BCL2 activity in the clinic. Citation Format: Elzbieta Izbicka, Robert Streeper, Michael J. Wick, Drew Rasco, Amita Patnaik, Kyriakos P. Papadopoulos, Anthony W. Tolcher, Shari Gaylor, Michael J. Woolliscroft, Richard A. Messmann, Wendi V. Rodrigueza. Effect of PNT2258, an anti-BCL2 DNA-interference drug, on tumor growth and immunological markers in mice and humans. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3529. doi:10.1158/1538-7445.AM2013-3529

Abstract 446: Differential expression of immuno-regulatory genes associated with PD-L1 display: Implications for clinical blockade of the PD-1/PD-L1 pathway in melanoma.

Abstract Background: Blockade of the immunosuppressive PD-1/PD-L1 pathway has shown promising clinical results in patients with treatment-refractory solid tumors including melanoma. PD-L1, a protein displayed by many tumors, ligates the PD-1 co-inhibitory receptor on activated T cells. We previously found that IFN-γ, a potent inducer of PD-L1, was expressed by TILs in PD-L1(+) but not PD-L1(-) melanomas, creating an immunosuppressive microenvironment by a mechanism that we term “adaptive immune resistance” (Taube et al., Science Transl Med 2012). In the current study, we assessed other factors associated with PD-L1 expression in melanoma through differential gene expression analysis, in order to better understand the biology of this pathway and identify potential targets for combination immunotherapies. Methods: PD-L1(+) vs. (-) melanomas including immune cell infiltrates (n=11) were laser-capture microdissected (LCM) from formalin-fixed paraffin embedded (FFPE) specimens and analyzed by whole genome array analysis with cDNA-mediated Annealing, Selection, extension and Ligation (DASL), a novel technology that allows for gene expression analysis with partially degraded mRNAs obtained from FFPE specimens. Differentially expressed genes were submitted to the NIH functional analysis tool DAVID to search for enrichment in biologically related groups. Multiplex quantitative (q)RT-PCR was used to validate differential expression of genes of interest and to examine other candidate genes in new set of PD-L1(+) vs.(-) melanomas (n=11). Results: DASL/DAVID analysis of PD-L1(+) vs. PD-L1(-) melanomas uncovered genes of interest in several immunologically relevant pathways, including “Defense Response” (p<1.5E-9) and “T-cell activation” (p<2.2E-5). Multiplex qRT-PCR to examine genes of interest from the DAVID analysis along with other potentially relevant candidate genes was normalized to the GUSB housekeeping gene or to CD45 (pan-leukocyte marker), revealing over-expression of genes associated with immunosuppression (PD-1, PD-L1, LAG-3, IL-10), activated CD8 T cells (CD8A, IFN-γ, lysozyme, perforin, CCL5/RANTES), and antigen presenting cells (CD163, TLR3, CXCL1) in PD-L1(+) melanomas (p<0.10). Conclusions: These experiments identified groups of functionally related, differentially expressed immuno-regulatory genes in PD-L1(+) melanomas. These factors may coordinately create an immunosuppressive tumor microenvironment, by synergizing to enhance PD-L1 expression on tumor cells and to inhibit T cell function. Immunohistochemical and in vitro functional validation assays of candidate gene products are currently underway in order to identify new ways to overcome adaptive immune resistance in synergistic treatment combinations with PD-1/PD-L1 blockade. Citation Format: Geoffrey D. Young, Tracee L. McMiller, Haiying Xu, Shuming Chen, Alan E. Berger, Jinshui Fan, Robert A. Anders, Christopher Cheadle, Drew M. Pardoll, Suzanne L. Topalian, Janis M. Taube. Differential expression of immuno-regulatory genes associated with PD-L1 display: Implications for clinical blockade of the PD-1/PD-L1 pathway in melanoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 446. doi:10.1158/1538-7445.AM2013-446

Regorafenib in the treatment of malignant tumor

Regorafenib,an oral multi-kinase inhibitor,can inhabit a class of receptor tyrosine kinase,such as angiogenic,stromal,oncogenic and so on.Studies in vitro and clinical trials indicate that Regorafenib has significant antitumor activity.The results of clinical trials are encouraging for the treatment of Refractory solid tumors,especially for colorectal carcinoma. Key words: Receptor protein-tyrosine kinases; Enzyme inhibitors; Neoplasms

Durable Cancer Regression Off-Treatment and Effective Reinduction Therapy with an Anti-PD-1 Antibody

Results from the first-in-human phase I trial of the anti-programmed death-1 (PD-1) antibody BMS-936558 in patients with treatment-refractory solid tumors, including safety, tolerability, pharmacodynamics, and immunologic correlates, have been previously reported. Here, we provide long-term follow-up on three patients from that trial who sustained objective tumor regressions off therapy, and test the hypothesis that reinduction therapy for late tumor recurrence can be effective. Three patients with colorectal cancer, renal cell cancer, and melanoma achieved objective responses on an intermittent dosing regimen of BMS-936558. Following cessation of therapy, patients were followed for more than 3 years. A patient with melanoma who experienced a prolonged partial regression followed by tumor recurrence received reinduction therapy. A patient with colorectal cancer experienced a complete response, which is ongoing after 3 years. A patient with renal cell cancer experienced a partial response lasting 3 years off therapy, which converted to a complete response, which is ongoing at 12 months. A patient with melanoma achieved a partial response that was stable for 16 months off therapy; recurrent disease was successfully treated with reinduction anti-PD-1 therapy. These data represent the most prolonged observation to date of patients with solid tumors responding to anti-PD-1 immunotherapy and the first report of successful reinduction therapy following delayed tumor progression. They underscore the potential for immune checkpoint blockade with anti-PD-1 to reset the equilibrium between tumor and the host immune system.

Targeting hyaluronan (HA) in tumor stroma: A phase I study to evaluate the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of pegylated hyaluronidase (PEGPH20) in patients with solid tumors.

2579 Background: HA, a glycosaminoglycan, accumulates in ~25% of solid tumors and is associated with poor prognosis. Tumors that accumulate HA develop high interstitial fluid pressure (IFP) and become resistant to chemotherapy. In animal models, PEGPH20 reduced tumor-associated HA and increased efficacy of chemotherapy. Methods: This ongoing phase 1 study was designed to assess safety, tolerability, PK, PD, and the maximum tolerated dose (MTD) of PEGPH20 as a single agent in patients with treatment-refractory solid tumors. IV PEGPH20 was administered in a twice weekly or a once weekly dosing schedule with oral dexamethasone (dex) pre-and post dose. Biomarkers included tumor histochemistry to detect HA depletion, plasma HA catabolites, and DCE-MRI or FDG-PET. Results: Fifteen patients have been enrolled into the study. Dose administration ranged from 0.5 µg/kg to 5 µg/kg. Musculoskeletal events (MSEs) were the most common and dose limiting toxicities. To date, up to 3 µg/kg twice weekly IV infusions of PEGPH20 were well tolerated with manageable Grade 1 MSEs in most patients. MTD has not been reached. Plasma concentrations of PEGPH20 showed dose proportional exposure with a terminal half life of ~2 days. Enzymatic activity of PEGPH20 was reflected by dose-dependent HA catabolites in plasma. Pre- and post-dose tumor biopsies from 2 colon patients demonstrated 23-60% reduction in tumor HA after 4 weeks of dosing. Serial DCE-MRI and FDG-PET demonstrated increased tumor perfusion (Ktrans) and decreased metabolic activity 8 and 24hrs post-PEGPH20 in one patient each. Doses of ≤3 µg/kg were tolerated with intermittent Grade 1-2 MSE. Enrollment at dose levels > 3 µg/kg is ongoing. Conclusions: Repeated IV PEGPH20 infusion resulted in dose-dependent systemic exposure and is tolerated with concomitant dex treatment. HA catabolites in plasma demonstrated the in vivo enzymatic activity of PEGPH20. Reduced HA in tumor biopsies and serial DCE-MRI and FDG-PET images confirmed PD activity. Increased tumor perfusion by PEGPH20 may enhance drug delivery to tumor. Combination studies of PEGPH20 with cytotoxic chemotherapy are planned.

Abstract 1308: A phase I clinical study investigating disulfiram and copper gluconate in patients with advanced treatment-refractory solid tumors involving the liver

Abstract Background: Disulfiram inhibits hepatic aldehyde dehydrogenase causing accumulation of acetaldehyde when alcohol is ingested and is used to treat alcohol addiction. When metal ions such as copper are combined with disulfiram, key oncoproteins are bound, and inactivated. Disulfiram and copper can inhibit tumor cell growth in cell culture, and xenograft models, and induce cell killing via apoptosis. Here we determined the safety and tolerability of disulfiram when administered together with copper gluconate in patients with advanced treatment-refractory solid tumors involving the liver. Methods: Four preselected oral doses of copper gluconate were tested (2, 4, 6, and 8 mg tid) in a standard “3+3” design. Disulfiram 250 mg was administered once daily. Patients were observed for DLTs, and pharmacodynamic studies were performed. Patients were required to refrain from alcohol consumption during the study. Results: As of November 15, 2010, 15 patients with treatment refractory solid tumors metastatic to the liver have been enrolled. The average number of prior treatments was 7 (range 1-16). Malignancies represented included pancreatic (2), breast (4), colon (1), prostate (1), lung (1), cutaneous melanoma (2), and ocular melanoma (2). Grade 3 toxicities included dehydration (1), hyperglycemia (1), constipation (1), LFT elevations (2) and troponin elevation (1) but these were felt to be more likely related to advanced malignancy or to causes other than the study drugs. Although hepatic toxicity is a potential side effect of disulfiram, the only Grade 3 LFT elevations that occurred on treatment were in patients with disease progression in the liver suggesting that these events were not drug related. There was one reported Grade 2 disulfiram reaction due to exposure to alcohol. Other Grade 1 and 2 toxicities included changes in mental status (6), headaches (2), and dizziness (3) though many of these events corresponded to progression of the underlying malignancy. No radiographic responses to treatment have been observed. Six patients progressed within 28 days of starting treatment. One patient with advanced colon cancer achieved disease stability for 125 days. The average duration on treatment was 37 days (range 1 – 125 days). Reasons for discontinuing treatment included functional decline (4), disease progression (10), and death (1). Two remaining slots are open on the 8 mg dose cohort. Analysis of S-glutathionylation of proteins in response to treatment is ongoing. Conclusions: Disulfiram dosed at 250 mg daily together with copper gluconate at doses of 6 mg three times daily is well tolerated in patients with advanced solid tumors involving the liver. No DLT has yet been observed. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1308. doi:10.1158/1538-7445.AM2011-1308

Abstract LB-283: JX-594, a targeted multi-mechanistic oncolytic poxvirus, selectively infects tumor vasculature and causes acute tumor vascular disruption and necrosis in advanced cancer patients

Abstract JX-594 is a first-in-class targeted oncolytic poxvirus designed to selectively replicate in and destroy cancer cells with cell cycle abnormalities and epidermal growth factor receptor (EGFR)/ras pathway activation. Direct oncolysis plus granulocyte macrophage -colony stimulating factor (GM-CSF) expression also stimulates anti-tumoral immunity. JX-594 infection was evaluated in vitro on human umbilical vein endothelial cells (HUVECs) and by immunohistochemical analysis in tumor biopsies from JX-594 treated (intravenous administration) patients with advanced, treatment-refractory solid tumors. JX-594 associated changes in tumor perfusion were also assessed in patients by dynamic contrast-enhanced magnetic resonance imaging (dce-MRI; at baseline and Day 5 after intratumoral JX-594 administration). In vitro susceptibility of HUVECs to JX-594 infection was shown to be dependent on vascular endothelial growth factor (VEGF) stimulation. Furthermore, JX-594 was capable of infecting tumor-associated endothelial cells after intravenous infusion in patients with advanced solid tumors. No clinical evidence of normal vasculature infection or toxicity was noted. Tumor perfusion was significantly decreased within 5 days post JX-594 treatment, including in hepatocellular carcinoma and colorectal cancer metastases. Perfusion was markedly reduced in both directly injected and distant non-injected tumors. Choi (necrotic) responses at later timepoints were demonstrated. In addition to targeting cancers by direct infection and lysis of tumor cells, JX-594 is capable of directly infecting VEGF-stimulated/tumor-associated endothelial cells. By targeting tumor-associated vasculature, JX-594 acutely disrupts the tumor's blood supply leading to tumor destruction. Targeted oncolytic poxviruses such as JX-594 represent a novel and highly selective class of vascular disrupting agents. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-283. doi:10.1158/1538-7445.AM2011-LB-283

394 A phase I dose escalation and pharmacological study of the novel class I selective histone deacetylase inhibitor CHR-3996, in patients with advanced or treatment refractory solid tumours

The low success rate of animal cloning by somatic cell nuclear transfer (SCNT) associates with epigenetic aberrancy, including the abnormal acetylation of histones. Altering the epigenetic status by histone deacetylase inhibitors (HDACi) enhances the developmental potential of SCNT embryos. In the current study, we examined the effects of LBH589 (panobinostat), a novel broad-spectrum HDACi, on the nuclear reprogramming and development of pig SCNT embryos in vitro. In experiment 1, we compared the in vitro developmental competence of nuclear transfer embryos treated with different concentrations of LBH589. Embryos treated with 50 nM LBH589 for 24 hours showed a significant increase in the rate of blastocyst formation compared with the control or embryos treated with 5 or 500 nM LBH589 (32.4% vs. 11.8%, 12.1%, and 10.0%, respectively, P < 0.05). In experiment 2, we examined the in vitro developmental competence of nuclear transfer embryos treated with 50 nM LBH589 for various intervals after activation and 6-dimethylaminopurine. Embryos treated for 24 hours had higher rates of blastocyst formation than the other groups. In experiment 3, when the acetylation of H4K12 was examined in SCNT embryos treated for 6 hours with 50 nM LBH589 by immunohistochemistry, the staining intensities of these proteins in LBH589-treated SCNT embryos were significantly higher than in the control. In experiment 4, LBH589-treated nuclear transfer and control embryos were transferred into surrogate mothers, resulting in three (100%) and two (66.7%) pregnancies, respectively. In conclusion, LBH589 enhances the nuclear reprogramming and developmental potential of SCNT embryos by altering the epigenetic status and expression, and increasing blastocyst quality.

Abstract 2775: A phase I study of LCL161, an oral IAP inhibitor, in patients with advanced cancer

Abstract Introduction: LCL161 is a potent small molecule mimetic of the Smac mitochondrial protein. Like Smac, it binds to inhibitor of apoptosis proteins (IAPs) and prevents their interaction with active caspases. In addition, LCL161's binding to cIAP1 and cIAP2 leads to their proteasomal degradation, with subsequent NFκB activation and induction of IL-8 and MCP-1. LCL161 has single agent activity in tumor models with high basal TNF-α levels and broad synergistic anti-tumor activity in combination with taxanes. This first-in-human study of single agent LCL161 assesses its safety, pharmacokinetics (PK), pharmacodynamics (PD) and evidence of anti-tumor activity. Methods: Patients with advanced treatment-refractory solid tumors receive LCL161 as an oral solution once weekly. The dose of LCL161 is increased in successive cohorts of patients, with dose escalation guided by a Bayesian logistic regression model. PK and PD are assessed primarily during the first cycle (3 weeks) of treatment and disease status is assessed after the completion of every 2 cycles. Therapy continues until disease progression or unacceptable toxicity occurs. PK parameters are derived from non-compartmental analysis of plasma concentration versus time profiles. cIAP1 is detected in tissue by immunohistochemistry (IHC) and in peripheral blood mononuclear cells (PMBCs) by western blot. Circulating markers of cell death (e.g., M65) and a panel of cytokines are measured in plasma by ELISA. Results: As of November 1, 2009, 27 patients with an ECOG PS 0-1 have been enrolled and treated with LCL161 doses ranging from 10-1800 mg/week. In patients receiving doses ≤ 900 mg the median number of cycles is 2 (range 1-5). There have been no dose-limiting toxicities, although grade 1/2 nausea and vomiting have occurred at the 1800 mg dose. LCL161 exhibits dose-proportional PK through 1800 mg, demonstrates rapid absorption with a median Tmax of 1 h (range 0.5-2 h), and has a median half-life of 7 h (range 3-11 h). Doses &amp;gt;500 mg achieve an AUC0–24 equal to or greater than those needed for either single agent or combination activity in preclinical models. At LCL161 doses ≥ 320 mg cIAP1 levels are reduced consistently in skin punch biopsies 8 h after the first dose, and in a tumor biopsy at 24 h. cIAP1 levels in PMBCs are decreased 2 h post-dose and recover by the following week. Circulating markers of cell death peak on day 2 following doses ≥ 320 mg, and circulating cytokines, including MCP-1 and IL-8, increase 4 h post-doses ≥ 900 mg. No objective responses have been observed. At the 900 mg dose one patient (with rectal cancer) remains on study with stable disease for &amp;gt; 5 cycles. Conclusions: Oral LCL161 is well tolerated, has dose-proportional PK, and demonstrates target inhibition in patients, as demonstrated by cIAP degradation and cytokine induction. A solid oral formulation of LCL161 is being evaluated in this study, with plans to continue dose escalation and evaluate consecutive days of treatment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2775.

Promoting Healthy Skepticism in the News: Helping Journalists Get It Right

Promoting Healthy Skepticism in the News: Helping Journalists Get It Right

Anticancer Agents from the Australian Tropical Rainforest: Spiroacetals EBC‐23, 24, 25, 72, 73, 75 and 76

EBC-23, 24, 25, 72, 73, 75 and 76 were isolated from the fruit of Cinnamomum laubatii (family Lauraceae) in the Australian tropical rainforests. EBC-23 (1) was synthesized stereoselectively, in nine linear steps in 8 % overall yield, to confirm the reported relative stereochemistry and determine the absolute stereochemistry. Key to the total synthesis was a series of Tietze-Smith linchpin reactions. The novel spiroacetal structural motif, exemplified by EBC-23 (1), was found to inhibit the growth of the androgen-independent prostate tumor cell line DU145 in the mouse model, indicating potential for the treatment of refractory solid tumors in adults.

Internal radiotherapy using 32P colloid or microsphere for refractory solid tumors

The aim of this work was to study the effectiveness of 32P colloids or microspheres, by arterial interventional administration or stromal injection in the treatment of refractory solid tumors. By arterial intervention, under the guidance of computerized tomography, X-ray, ultrasonogram, or under direct vision of the surgical field, 32P microspheres (259-685 MBq) or radioactive colloid (281-666 MBq) was administered to 60 cases with refractory solid tumors. Tumor inhibition rate, side effects, survival period, and so on were observed. The tumor growth was obviously inhibited after the intratumoral injection of 32P colloid. The average survival time in the 60 cases was 35 months with a high tumor inhibition rate (93.4%). Thirty-one cases were completely relieved (51.7%), and 25 cases achieved partial remission (PR, 41.7%). One case with right lobe hepatocellular carcinoma has survived 90 months. The drug was ineffective only in four cases, including one patient who died of gastrointestinal hemorrhage and three of hepatic failure. No other obvious side effects were observed. Intratumoral necrosis, intense fibrosis in the tumor mass, and an integrated capsule encompassing the tumor were revealed by histological examination. Arterial interventional administration or stromal injection with 32P microspheres or colloid revealed a very fair clinical effectiveness in the treatment of refractory solid tumors. The range of safe effective dosage for 32P glass microspheres and 32P chromic phosphate in one treatment course is 555-740 MBq and 185-370 MBq, respectively.