Jenny Wu

First-in-Human Phase I Study of Pictilisib (GDC-0941), a Potent Pan–Class I Phosphatidylinositol-3-Kinase (PI3K) Inhibitor, in Patients with Advanced Solid Tumors

Purpose: This first-in-human dose-escalation trial evaluated the safety, tolerability, maximal-tolerated dose (MTD), dose-limiting toxicities (DLT), pharmacokinetics, pharmacodynamics, and preliminary clinical activity of pictilisib (GDC-0941), an oral, potent, and selective inhibitor of the class I phosphatidylinositol-3-kinases (PI3K). Patients and Methods: Sixty patients with solid tumors received pictilisib at 14 dose levels from 15 to 450 mg once-daily, initially on days 1 to 21 every 28 days and later, using continuous dosing for selected dose levels. Pharmacodynamic studies incorporated 18F-FDG-PET, and assessment of phosphorylated AKT and S6 ribosomal protein in platelet-rich plasma (PRP) and tumor tissue. Results: Pictilisib was well tolerated. The most common toxicities were grade 1–2 nausea, rash, and fatigue, whereas the DLT was grade 3 maculopapular rash (450 mg, 2 of 3 patients; 330 mg, 1 of 7 patients). The pharmacokinetic profile was dose-proportional and supported once-daily dosing. Levels of phosphorylated serine-473 AKT were suppressed >90% in PRP at 3 hours after dose at the MTD and in tumor at pictilisib doses associated with AUC >20 h·μmol/L. Significant increase in plasma insulin and glucose levels, and >25% decrease in 18F-FDG uptake by PET in 7 of 32 evaluable patients confirmed target modulation. A patient with V600E BRAF–mutant melanoma and another with platinum-refractory epithelial ovarian cancer exhibiting PTEN loss and PIK3CA amplification demonstrated partial response by RECIST and GCIG-CA125 criteria, respectively. Conclusion: Pictilisib was safely administered with a dose-proportional pharmacokinetic profile, on-target pharmacodynamic activity at dose levels ≥100 mg and signs of antitumor activity. The recommended phase II dose was continuous dosing at 330 mg once-daily. Clin Cancer Res; 21(1); 77–86. ©2014 AACR.

Phase I study of sequence-selective minor groove DNA binding agent SJG-136 in patients with advanced solid tumors.

Purpose: This phase I dose-escalation study was undertaken to establish the maximum tolerated dose of the sequence-selective minor groove DNA binding agent SJG-136 in patients with advanced solid tumors. The study also investigated antitumor activity and provided pharmacokinetic and pharmacodynamic data. Experimental Design: Sixteen patients were assigned sequentially to escalating doses of SJG-136 (15-240 μg/m2) given as a 10-minute i.v. infusion every 21 days. The dose was subsequently reduced in incremental steps to 45 μg/m2 due to unexpected toxicity. Results: The maximum tolerated dose of SJG-136 was 45 μg/m2. The main drug-related adverse event was vascular leak syndrome (VLS) characterized by hypoalbuminemia, pleural effusions, ascites, and peripheral edema. Other unexpected adverse events included elevated liver function tests and fatigue. The VLS and liver toxicity had delayed onset and increased in severity with subsequent cycles. Disease stabilization was achieved for >6 weeks in 10 patients; in 2 patients this was maintained for >12 weeks. There was no evidence of DNA interstrand cross-linking in human blood lymphocytes with the use of the comet assay. Evidence of DNA interaction in lymphocytes and tumor cells was shown through a sensitive γ-H2AX assay. SJG-136 had linear pharmacokinetics across the dose range tested. Conclusions: SJG-136 was associated with dose-limiting VLS and hepatotoxicity when administered by short injection every 21 days. DNA damage was noted, at all dose levels studied, in circulating lymphocytes. The etiology of the observed toxicities is unclear and is the subject of further preclinical research. Alternative clinical dosing strategies are being evaluated.

γ-H2AX Foci Formation as a Pharmacodynamic Marker of DNA Damage Produced by DNA Cross-Linking Agents: Results from 2 Phase I Clinical Trials of SJG-136 (SG2000)

Purpose: To evaluate γ-H2AX foci as a pharmacodynamic marker for DNA damage induced by DNA interstrand cross-linking drugs. Experimental Design: γ-H2AX foci formation was validated preclinically in comparison with the Comet assay, and evaluated pharmacodynamically in two phase I studies of different dosing schedules of the novel cross-linking agent SJG-136 (SG2000). Results: The measurement of γ-H2AX foci in human fibroblasts and lymphocytes in vitro was more than 10-fold more sensitive than Comet assay measurement of cross-linking, with peak γ-H2AX response 24 hours after the peak of cross-linking. In lymphocytes from a phase I study (every three week schedule), γ-H2AX foci were detectable 1 hour following the end of administration, and in all patients, maximum response was observed at 24 hours. Significant levels of foci were still evident at days 8 and 15 consistent with the known persistence of the DNA damage produced by this agent. In two tumor biopsy samples, foci were detected 4 hours postinfusion with levels higher than in lymphocytes. Extensive foci formation was also observed before the third dose in cycle 1 in lymphocytes from a second phase I study (daily × 3 schedule). These foci also persisted with a significant level evident before the second cycle (day 21). An increased γ-H2AX response was observed during the second cycle consistent with a cumulative pharmacodynamic effect. No clear relationship between foci formation and administered drug dose was observed. Conclusion: This is the first use of γ-H2AX as a pharmacodynamic response to a DNA cross-linking agent in a clinical trial setting. Clin Cancer Res; 19(3); 721–30. ©2012 AACR.

Evaluation and Clinical Analyses of Downstream Targets of the Akt Inhibitor GDC-0068

Purpose: The oncogenic PI3K/Akt/mTOR pathway is an attractive therapeutic target in cancer. However, it is unknown whether the pathway blockade required for tumor growth inhibition is clinically achievable. Therefore, we conducted pharmacodynamic studies with GDC-0068, an ATP competitive, selective Akt1/2/3 inhibitor, in preclinical models and in patients treated with this compound. Experimental Design: We used a reverse phase protein array (RPPA) platform to identify a biomarker set indicative of Akt inhibition in cell lines and human-tumor xenografts, and correlated the degree of pathway inhibition with antitumor activity. Akt pathway activity was measured using this biomarker set in pre- and post-dose tumor biopsies from patients treated with GDC-0068 in the dose escalation clinical trial. Results: The set of biomarkers of Akt inhibition is composed of 10 phosphoproteins, including Akt and PRAS40, and is modulated in a dose-dependent fashion, both in vitro and in vivo. In human-tumor xenografts, this dose dependency significantly correlated with tumor growth inhibition. Tumor biopsies from patients treated with GDC-0068 at clinically achievable doses attained a degree of biomarker inhibition that correlated with tumor growth inhibition in preclinical models. In these clinical samples, compensatory feedback activation of ERK and HER3 was observed, consistent with preclinical observations. Conclusion: This study identified a set of biomarkers of Akt inhibition that can be used in the clinical setting to assess target engagement. Here, it was used to show that robust Akt inhibition in tumors from patients treated with GDC-0068 is achievable, supporting the clinical development of this compound in defined patient populations. Clin Cancer Res; 19(24); 6976–86. ©2013 AACR.

Pharmacokinetic and Pharmacodynamic Analysis of Circulating Biomarkers of Anti-NRP1, a Novel Antiangiogenesis Agent, in Two Phase I Trials in Patients with Advanced Solid Tumors

Purpose: MNRP1685A is a monoclonal antibody to neuropilin-1 (NRP1). We evaluated blood-based pharmacodynamic biomarkers of MNRP1685A in two phase I studies to assess exposure/response relationships to inform target dose and regimen selection. Experimental Design: The phase I studies evaluated escalating doses of MNRP1685A as a single agent or in combination with bevacizumab. Plasma placental growth factor (PlGF), VEGF, and circulating NRP1 (cNRP1) were evaluated at multiple time points using meso-scale discovery (MSD) assays and ELISA, respectively. Plasma PlGF was also measured in a phase I/II trial of bevacizumab in metastatic breast cancer (AVF0776). The association between PlGF and MNRP1685A dose was described by a sigmoid Emax model. cNRP1 and MNRP1685A PK profiles were described using a two-target quasi-steady state (QSS) model. Results: A dose- and time-dependent increase in plasma PlGF and cNRP1 was observed in all patients treated with MNRP1685A. PK/PD analysis showed that bevacizumab and MNRP1685A had an additive effect in elevating PlGF. Predictions based on the two-target QSS model showed that the free drug concentration to maintain greater than 90% saturation of membrane NRP1 (mNRP1) and cNRP1 is about 8 μg/mL. Conclusion: These data show that MNRP1685A inhibits the VEGF pathway in humans as assessed by an increase in plasma PlGF. MNRP1685A seems to enhance bevacizumab-mediated VEGF pathway blockade, as showed by an increase in the magnitude of PlGF elevation when combined with bevacizumab. PK/PD analysis of biomarkers in the phase I population allowed identification of doses at which apparent maximal pathway modulation was observed. Clin Cancer Res; 18(21); 6040–8. ©2012 AACR.

Abstract B153: A phase I study evaluating the pharmacokinetics (PK) and pharmacodynamic (PD) activity of the dual PI3K/mTOR inhibitor GDC-0980 administered once weekly (QW).

Background: The PI3K-AKT-mTOR signaling pathway is deregulated in a wide variety of cancers. GDC-0980 is a potent, selective, oral inhibitor of class I PI3K and mTOR kinase demonstrating broad activity in xenograft cancer models (breast, ovarian, lung, and prostate). Methods: A Phase I dose escalation study using a 3+3 design has been initiated in patients (pts) with advanced solid tumors or non-Hodgkin9s lymphoma. GDC-0980 is administered QW. The objectives are to determine the dose-limiting toxicities (DLTs) and maximum tolerated dose (MTD), evaluate PK and PD effects, and describe observed anti-tumor activity of GDC-0980 on this schedule. PD assessments include evaluating pAKT levels in platelet-rich plasma (PRP), biomarker pS6 in paired pre- and on-treatment tumor biopsies, tumor FDG avidity via PET imaging (FDG-PET), and tumor vasculature changes via DCE-MRI. Archival tumor tissue is evaluated for PTEN expression and PIK3CA mutations. Results: Thirty-two pts have been enrolled in 7 successive cohorts evaluating 6 to 200 mg of GDC-0980 QW. Drug-related adverse events (AEs) reported in ≥10% of pts were nausea, diarrhea, hyperglycemia, vomiting, and fatigue. The only Grade (g) ≥3 drug-related AEs have been g3 hyperglycemia at ≥150 mg GDC-0980. Hyperglycemic events have been asymptomatic and generally well managed after initiation of an oral diabetic agent. One patient each at 150 and 200 mg GDC-0980 experienced the DLT of a repeat fasting g3 hyperglycemia following a subsequent dose of GDC-0980 during the DLT assessment period despite initiation of oral diabetic therapy. The patient with the DLT at 150 mg has continued on-treatment for more than 8 months with isolated g3 events. Analyses of PK data suggest dose-proportional increases in fasting mean Cmax and AUC. Levels of pAKT in PRP were inversely correlated with GDC-0980 plasma concentrations. All patients treated at ≥25 mg with evaluable-paired tumor biopsies demonstrated significant decreases in pS6 IHC staining of up to 100%. Signs of clinical activity include 3 pts [gastrointestinal stromal tumor (GIST), solitary fibrous tumor, and ovarian cancer] treated at 150 mg QW who are all currently on study after 7 months. Clinical and PD activity was also observed in a pt with epithelioid sarcoma who was treated at 25 mg QW for 11 mo with a 22% decrease in tumor FDG avidity and a pt with ovarian cancer who was treated at 100 mg for 6.2 months and demonstrated a 22% decrease in tumor lesions by RECIST and 48% decrease in serum CA-125. By DCE-MRI, the pt with GIST on 150 mg QW demonstrated a 60% decrease in the blood-normalized area under the signal intensity-time curve (AUC BN ) in liver lesions as assessed by DCE-MRI after 2 doses of GDC-0980 suggesting a potential anti-angiogenic effect. Conclusions: GDC-0980 is generally well tolerated when administered QW up to 200 mg with signs of anti-tumor activity. Decreases in the PD markers pAKT and pS6 are consistent with downstream modulation of the PI3K pathway. Dose-escalation continues and updated PK/PD data will be presented. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B153.

Abstract 2017: Development of ultrasensitive Singulex immunoassays for CCL3 and CCL4, important biomarkers for the BTK inhibitor studies

Disregulation of B-Cell Receptor (BCR) leading to activation has been associated with a number of B-cell malignancies including Chronic Lymphocytic Leukemia (CLL) [1]. In response to BCR activation, B-cells secrete chemokines CCL3 and CCL4 that foster interactions between CLL cells and the leukemia microenvironment and to recruit T-cells. High levels of CCL3 have also been correlated with poor prognosis in CLL [2]. Bruton tyrosine kinase (BTK) has long been known to be a key component of B cell receptor (BCR) signaling that regulates B cell proliferation and survival. BTK inhibitors such as lbrutinib have been shown to disrupt secretion of BCR-dependent chemokines (CCL3/CCL4) and thereby reduce plasma concentrations in patients [3]. Consequently, these chemokines have been measured as pharmacodynamic biomarkers in a number of studies of molecules that inhibit BCR signaling [3]. However, baseline CCL3/CCL4 levels in CLL patients vary widely and are less than 10 pg/ml in a large proportion of patient samples, making detection of these cytokines in clinical samples challenging using existing immunoassays. In an effort to improve sensitivity of CCL3/CCL4 measurements in plasma samples, we developed ultrasensitive assays for CCL3 and CCL4 using the Singulex immunoassay platform. A direct comparison of multiple, commercially available immunoassays technologies and our optimized CCL3/CCL4 Singulex assay were performed using plasma samples from both healthy donors and CLL patients. Singulex proprietary Single Molecule Counting (SMCTM) technology combining digital counting enables the quantification of CCL3 and CCL4 with sensitivity of 0.37pg/ml and 0.15pg/ml respectively in plasma. This ultrasensitive assay has the potential to enable more robust and quantifiable measurements of CCL3 and CCL4 in the context of clinical studies testing BTK inhibitors. Citation Format: Jenny Q. Wu, Luciana Burton, Rajiv Raja, Ian McCaffery, Elicia Penuel, Walter Darbonne. Development of ultrasensitive Singulex immunoassays for CCL3 and CCL4, important biomarkers for the BTK inhibitor studies. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2017. doi:10.1158/1538-7445.AM2015-2017

P13. Intra-tumoral and surrogate immune responses in patients treated with the engineered anti-PD-L1 antibody (MPDL3280A)

Background PD-L1 regulates CD8 T cell/Th1 immune responses. PD-L1 expressed in the tumor microenvironment can bind to PD-1 or B7.1 on activated T cells and mediate cancer immune evasion. MPDL3280A is a human mAb containing an engineered Fc-domain designed to optimize efficacy and safety that targets PD-L1 and blocks it from binding to its receptors. Methods Immunologic pharmacodynamics effects were evaluated in tumors and bloods from patients treated with MPDL3280A. MPDL3280A was administered IV q3w in >300 pts with locally advanced or metastatic solid tumors. PD-L1 and CD8 were measured by IHC. PD-L1 expression was evaluated in tumor and intra-tumoral immune cells. CD8 was assessed in the tumor center, periphery and invasive margin. The expression of ≈90 immune-related markers was evaluated at baseline (BL) and on-treatment using a custom-designed immunochip. BL tumor samples were available for 125 pts, and matched on-treatment samples were available for 31 pts. Further, blood-based biomarkers and circulating immune subsets were serially measured in 114 patients by modified ELISA and FACS, respectively. Results

Abstract 555: DNA methylation patterns are associated with subpopulations of diffuse large B-cell lymphoma

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Diffuse large B-cell lymphoma (DLBCL) comprises two predominant molecular subtypes: germinal-center B-cell-like (GCB) and activated B-cell-like (ABC). These subtypes were initially identified by their gene expression profiles, which are reminiscent of the cell of origin of the lymphoma. Though histologically indistinguishable, these subtypes are associated with distinct clinical outcomes and may be predictive for response to novel therapies. The development of improved diagnostic biomarkers for these DLBCL subtypes could therefore inform clinical decision-making by enabling selection of patients likely to respond to such novel therapies. To investigate regulatory mechanisms potentially responsible for the differential gene expression patterns seen in the DLBCL subtypes and to identify potential biomarkers for these subtypes, we performed whole genome methylation profiling of 15 DLBCL cell lines and 21 DLBCL patient tissues and identified distinct DNA methylation patterns associated with the two DLBCL molecular subtypes. Analysis of the methylation patterns of several DLBCL classifier genes known to be differentially expressed in ABC compared to GCB revealed the classic DNA methylation correlation pattern: high mRNA expression was associated with low methylation in the vicinity of the transcriptional start site (TSS), and vice versa. Furthermore, comparison of differential methylation profiles with corresponding RNA-seq data further supports the notion that DNA methylation profiles underlie the gene expression patterns that are currently used to classify ABC and GCB DLBCL subtypes. Collectively, these data suggest that DNA methylation may contribute to the regulation of expression of key ABC and GCB DLBCL classifier genes and further, that the DNA methylation state at these loci could potentially serve as useful diagnostic biomarkers for the DLBCL subtypes. Citation Format: Jenny Wu, Ron McCord, Thomas Sandmann, Kim Walter, Richard Bourgon, Robert Soriano, Zora Modrusan, Walter Darbonne, Kirsten E. Mundt. DNA methylation patterns are associated with subpopulations of diffuse large B-cell lymphoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 555. doi:10.1158/1538-7445.AM2014-555

Phase I study of the DNA minor groove binding pyrrolobenzodiazepine dimer (SJG 136) administered every 21 days in patients with advanced solid tumours

2566 Background: This phase I study was undertaken to define dose-limiting toxicity (DLT) and maximum tolerated dose (MTD) of the pyrrolobenzodiazepine dimer SJG-136 in patients with advanced solid tumors. Methods: Good performance patients (PS ≤1) with refractory advanced solid tumors were assigned sequentially to escalating doses of SJG-136 (15 to 240 μg/m2) given as a 10-minute intravenous infusion once every 21 days. An accelerated dose-escalation strategy based on the Simon design was used. Results: 16 patients (11M, 5F) median age 70 years for M (range 41–79) and 56 for F (range 54–58) recruited. Cancer sites included biliary (2), colorectal (5), lung (1), oesophagogastric (2), pancreas (2), sarcoma (1), melanoma (3). Dose levels μg/m2) were 15 (1 pt), 30 (1 pt), 45 (7 pt), 60 (4 pt) 120 (2 pt), 240 (1 pt). 10 pts had grade 1–3 VLS (30–240 μg/m2) with Gr 3 occurring at the top doses at 120 and 240 in 2 pts. DLT were a delayed vascular leak syndrome (DVLS) seen in 4 of 5 pts treated at doses between ...