A Phase 1 and Biodistribution Study of ABT-806i, an 111In-Radiolabeled Conjugate of the Tumor-Specific Anti-EGFR Antibody ABT-806.

ABT-806 is a tumor-specific antibody targeting the epidermal growth factor receptor (EGFR). This study assessed safety, biodistribution, and pharmacokinetics of 111In-radiolabeled ABT-806 (ABT-806i) and effects of repeated doses of ABT-806 on receptor occupancy. Methods: Eligible patients had advanced tumors likely to express EGFR/EGFRvIII; adequate performance status and organ function; and measurable disease by RECIST 1.1. In cohort 1, 6 patients received a bolus administration of ABT-806i and underwent SPECT followed by whole-body planar scans. In cohort 2, 12 patients were imaged similarly as in 1 initially; thereafter, they received 3 doses of unlabeled ABT-806, before another dose of ABT-806i with associated SPECT and whole-body planar scans. At the end of both cohorts, patients who had stable or responding disease were able to enroll into an extension study (M12-326) in which they received unlabeled ABT-806 every 2 wk until disease progression, withdrawal of consent, or intolerable toxicity. Results: No toxicity related to ABT-806i infusion was observed. ABT-806i showed minimal uptake in normal tissues and cleared gradually from blood with a half-life of 6.0 ± 1.5 d. The mean effective dose of ABT-806i was 0.137 mSv/MBq for males and 0.183 mSv/MBq for females. ABT-806i tumor uptake varied and did not correlate with archived tumor EGFR expression. No change in ABT-806i uptake was observed after interval ABT-806 treatment, indicating stable EGFR expression in tumor. The patient with highest tumor uptake of ABT-806i had advanced head and neck cancer and experienced a partial response. Conclusion: ABT-806i allows for real-time imaging of EGFR conformational expression in tumors, has an acceptable radiation dosimetry, and provides important additional information about antigen expression compared with standard approaches using archival tissue. Its role to assist in patient selection for EGFR-based therapeutics and investigate treatment resistance should be further investigated.

Comparison of Biomarker Assays for EGFR: Implications for Precision Medicine in Patients with Glioblastoma.

PURPOSE: Patients with glioblastoma (GBM) have a poor prognosis and are in desperate need of better therapies. As therapeutic decisions are increasingly guided by biomarkers, and EGFR abnormalities are common in GBM, thus representing a potential therapeutic target, we systematically evaluated methods of assessing EGFR amplification by multiple assays. Specifically, we evaluated correlation among fluorescence in situ hybridization (FISH), a standard assay for detecting EGFR amplification, with other methods.Experimental Design: Formalin-fixed, paraffin-embedded tumor samples were used for all assays. EGFR amplification was detected using FISH (N = 206) and whole-exome sequencing (WES, N = 74). EGFR mRNA expression was measured using reverse transcription-polymerase chain reaction (RT-PCR, N = 206) and transcriptome profiling (RNAseq, N = 64). EGFR protein expression was determined by immunohistochemistry (IHC, N = 34). Significant correlations among various methods were determined using Cohen's kappa (κ = 0.61-0.80 defines substantial agreement) or R 2 statistics. RESULTS: EGFR mRNA expression levels by RNA sequencing (RNAseq) and RT-PCR were highly correlated with EGFR amplification assessed by FISH (κ = 0.702). High concordance was also observed when comparing FISH to WES (κ = 0.739). RNA expression was superior to protein expression in delineating EGFR amplification. CONCLUSIONS: Methods for assessing EGFR mRNA expression (RT-PCR, RNAseq) and copy number (WES), but not protein expression (IHC), can be used as surrogates for EGFR amplification (FISH) in GBM. Collectively, our results provide enhanced understanding of available screening options for patients, which may help guide EGFR-targeted therapeutic approaches.

Safety and efficacy of depatuxizumab mafodotin + temozolomide in patients with EGFR-amplified, recurrent glioblastoma: results from an international phase I multicenter trial.

Background: Patients with glioblastoma (GBM) have a dismal prognosis. Nearly all will relapse with no clear standard of care for recurrent disease (rGBM). Approximately 50% of patients have tumors harboring epidermal growth factor receptor (EGFR) amplification. The antibody-drug conjugate depatuxizumab mafodotin (depatux-m) binds cells with EGFR amplification, is internalized, and releases a microtubule toxin, killing the cell. Here we report efficacy, safety and pharmacokinetics (PK) of depatux-m + temozolomide (TMZ) in patients with EGFR-amplified rGBM. Methods: M12-356 (NCT01800695) was an open-label study encompassing patients with newly diagnosed or rGBM across 3 treatment arms. Results are reported for adults with EGFR-amplified, measurable rGBM who received depatux-m (0.5-1.5 mg/kg) on days 1 and 15, and TMZ (150-200 mg/m2) on days 1-5 in a 28-day cycle. Patients were bevacizumab and nitrosourea naïve. Results: There were 60 patients, median age 56 years (range, 20-79). Fifty-nine patients previously received TMZ. Common adverse events (AEs) were blurred vision (63%), fatigue (38%), and photophobia (35%). Grades 3/4 AEs were split between ocular and non-ocular AEs, occurring in 22% of patients each. Systemic PK exposure of depatux-m was dose proportional. The objective response rate was 14.3%, the 6-month progression-free survival rate was 25.2%, and the 6-month overall survival rate was 69.1%. Conclusions: Depatux-m + TMZ displayed an AE profile similar to what was described previously. Antitumor activity in this TMZ-refractory population was encouraging. Continued study of depatux-m in patients with EGFR-amplified, newly diagnosed, or recurrent GBM is ongoing in 2 global, randomized trials (NCT02573324, NCT02343406).

Efficacy and safety results of depatuxizumab mafodotin (ABT-414) in patients with advanced solid tumors likely to overexpress epidermal growth factor receptor.

BACKGROUND: Epidermal growth factor receptor (EGFR) alterations are associated with multiple cancers. Current EGFR-directed therapies have led to increased efficacy but are associated with specific side effects. The antibody-drug conjugate depatuxizumab mafodotin (depatux-m) targets EGFR with a monoclonal antibody linked to a cytotoxin, and is highly tumor-specific. METHODS: This phase 1/2 study evaluated the safety, pharmacokinetics, and efficacy of depatux-m in patients who had advanced solid tumors with known wild-type EGFR overexpression, amplification, or mutated EGFR variant III. A 3 + 3 dose escalation was used, and 2 dosing schedules were evaluated. Depatux-m also was manufactured under an alternate process to reduce the drug load and improve the safety profile, and it was tested at the maximum tolerated dose (MTD). In another cohort, prolonged infusion time of depatux-m was evaluated; and a cohort with confirmed EGFR amplification also was evaluated at the MTD. RESULTS: Fifty-six patients were treated. The MTD and the recommended phase 2 dose for depatux-m was 3.0 mg/kg. Common adverse events (AEs) were blurred vision (48%) and fatigue (41%). A majority of patients (66%) experienced 1 or more ocular AEs. Grade 3 or 4 AEs were observed in 43% of patients. One patient with EGFR-amplified, triple-negative breast cancer had a partial response. Stable disease was observed in 23% of patients. Pharmacokinetics revealed that depatux-m exposures were approximately dose-proportional. CONCLUSIONS: Depatux-m resulted in infrequent nonocular AEs but increased ocular AEs. Patient follow-up confirmed that ocular AEs were reversible. Lowering the drug-antibody ratio did not decrease the number of ocular AEs. A partial response in 1 patient with EGFR-amplified disease provides the opportunity to study depatux-m in diseases with a high incidence of EGFR amplification. Cancer 2018;124:2174-83. © 2018 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Safety, pharmacokinetics, and antitumor response of depatuxizumab mafodotin as monotherapy or in combination with temozolomide in patients with glioblastoma.

Background: We recently reported an acceptable safety and pharmacokinetic profile of depatuxizumab mafodotin (depatux-m), formerly called ABT-414, plus radiation and temozolomide in newly diagnosed glioblastoma (arm A). The purpose of this study was to evaluate the safety and pharmacokinetics of depatux-m, either in combination with temozolomide in newly diagnosed or recurrent glioblastoma (arm B) or as monotherapy in recurrent glioblastoma (arm C). Methods: In this multicenter phase I dose escalation study, patients received depatux-m (0.5-1.5 mg/kg in arm B, 1.25 mg/kg in arm C) every 2 weeks by intravenous infusion. Maximum tolerated dose (MTD), recommended phase II dose (RP2D), and preliminary efficacy were also determined. Results: Thirty-eight patients were enrolled as of March 1, 2016. The most frequent toxicities were ocular, occurring in 35/38 (92%) patients. Keratitis was the most common grade 3 adverse event observed in 6/38 (16%) patients; thrombocytopenia was the most common grade 4 event seen in 5/38 (13%) patients. The MTD was set at 1.5 mg/kg in arm B and was not reached in arm C. RP2D was declared as 1.25 mg/kg for both arms. Depatux-m demonstrated a linear pharmacokinetic profile. In recurrent glioblastoma patients, the progression-free survival (PFS) rate at 6 months was 30.8% and the median overall survival was 10.7 months. Best Response Assessment in Neuro-Oncology responses were 1 complete and 2 partial responses. Conclusion: Depatux-m alone or in combination with temozolomide demonstrated an acceptable safety and pharmacokinetic profile in glioblastoma. Further studies are currently under way to evaluate its efficacy in newly diagnosed (NCT02573324) and recurrent glioblastoma (NCT02343406).

Phase I Study of Enavatuzumab, a First-in-Class Humanized Monoclonal Antibody Targeting the TWEAK Receptor, in Patients with Advanced Solid Tumors.

This phase I study evaluates the safety, MTD, pharmacokinetics (PK), pharmacodynamics, and preliminary anticancer activity of enavatuzumab, a humanized IgG1 antibody to the TWEAK receptor, in patients with advanced solid malignancies. Patients received escalating doses of enavatuzumab given intravenously over 60 minutes every 2 weeks. Blood was obtained for PK and biomarker assessment. Three patients were enrolled per dose level in a standard 3+3 design with response assessment by RECIST version 1.0, every 8 weeks. Thirty patients were enrolled at 6 dose levels ranging from 0.1 to 1.5 mg/kg. Dose-limiting toxicities included grade 4 (G4) lipase, G3 bilirubin, and G4 amylase elevations. There was no apparent correlation of liver or pancreatic enzyme elevation with drug exposure or the presence of liver metastases. Enavatuzumab exhibited a two-compartment linear PK model. Estimated systemic clearance was 23 to 33 mL/h with an elimination half-life of 7 to 18 days. The predicted target efficacious peak and trough concentrations occurred at 1.0 mg/kg following the second dose. There were no objective responses; 4 patients had stable disease. The MTD of enavatuzumab is 1.0 mg/kg i.v. every 2 weeks. Higher doses were not tolerated due to hepatopancreatic lab abnormalities. Further evaluation of the mechanisms of the liver and pancreatic enzyme toxicities is needed before embarking on further single-agent or combination strategies. Mol Cancer Ther; 17(1); 215-21. ©2017 AACR.

Efficacy of depatuxizumab mafodotin (ABT-414) monotherapy in patients with EGFR-amplified, recurrent glioblastoma: results from a multi-center, international study.

PURPOSE: Patients with recurrent glioblastoma (rGBM) have a poor prognosis. Epidermal growth factor receptor (EGFR) gene amplification is present in ~ 50% of glioblastomas (GBMs). Depatuxizumab mafodotin (depatux-m), formerly ABT-414, is an antibody-drug conjugate that preferentially binds cells with EGFR amplification, is internalized and releases a potent antimicrotubule agent, monomethyl auristatin F (MMAF). Here we report the safety, pharmacokinetics, and efficacy of depatux-m monotherapy at the recommended Phase 2 dose (RPTD) in patients with EGFR-amplified, rGBM. METHODS: M12-356 (NCT01800695) is an open-label study with three escalation and expansion cohorts. Sixty-six patients with EGFR-amplified, rGBM were treated with depatux-m monotherapy at 1.25 mg/kg intravenously every 2 weeks. Adults with measurable rGBM, who were bevacizumab-naïve, with EGFR amplification were eligible. RESULTS: Among 66 patients, median age was 58 years (range 35-80). All patients were previously treated with radiotherapy/temozolomide. The most common adverse events (AEs) were eye related (91%), including blurred vision (65%), dry eye (29%), keratitis, and photophobia (27% each). Grade 3/4 AEs occurred in 42% of all patients, and ocular Grade 3/4 AEs occurred in 33% of patients overall. One patient (2%) had a Grade 4 ocular AE. Ocular AEs were manageable and usually resolved once treatment with depatux-m ceased. The objective response rate was 6.8%, the 6-month progression-free survival rate was 28.8%, and the 6-month overall survival rate was 72.5%. CONCLUSION: Depatux-m monotherapy displayed frequent but mostly Grade 1/2 ocular toxicities. A PFS6 of 28.8% was observed in this rGBM population, warranting further study.

Safety and tolerability of veliparib combined with capecitabine plus radiotherapy in patients with locally advanced rectal cancer: a phase 1b study.

BACKGROUND: Further optimisation of present standard chemoradiation is needed in patients with locally advanced rectal cancer. Veliparib, an oral poly(ADP-ribose) polymerase inhibitor, has been shown to enhance the antitumour activity of chemotherapy and radiotherapy in preclinical models. We aimed to establish the maximum tolerated dose and establish the recommended phase 2 dose of veliparib combined with neoadjuvant capecitabine and radiotherapy. METHODS: This phase 1b, open-label, multicentre, dose-escalation study was done at six hospitals (one in Australia and five in the USA). Patients were eligible if they were aged 18 years or more and were newly diagnosed with stage II to III locally advanced, resectable adenocarcinoma of the rectum with a distal tumour border of less than 12 cm from anal verge. Patients were ineligible if they had received anticancer therapy or surgery (except colostomy or ileostomy) 28 days or less before the first dose of study drug, previous pelvic radiotherapy, or previous treatment with poly (ADP-ribose) polymerase inhibitors. Enrolled patients received capecitabine (825 mg/m2 orally twice daily) with radiotherapy (50·4 Gy in 1·8 Gy fractions daily, approximately 5 days consecutively per week for about 5·5 weeks). Veliparib (20-400 mg orally twice daily) was administered daily starting on day 2 of week 1 and continuing until 2 days after radiotherapy completion. Patients underwent total mesorectal excision 5-10 weeks after radiotherapy completion. The primary objectives were to establish the maximum tolerated dose and recommended phase 2 dose of veliparib plus capecitabine and radiotherapy, with an exposure-adjusted continual reassessment methodology. Efficacy and safety analyses were done per protocol. The reported study has completed accrual and all analyses are final. This trial is registered with ClinicalTrials.gov, number NCT01589419. FINDINGS: Between June 12, 2012, and Jan 13, 2015, 32 patients received veliparib (22 in the dose-escalation group; ten in the safety expansion group); 31 were assessable for efficacy (<400 mg, n=16; 400 mg, n=15). During dose escalation, grade 2 dose-limiting toxic effects occurred in two patients; no grade 3-4 dose-limiting toxic effects were noted. Therefore, the maximum tolerated dose was not reached; the recommended phase 2 dose was selected as 400 mg twice daily. The most common treatment-emergent adverse events in all 32 patients were nausea (17 [53%]), diarrhoea (16 [50%]), and fatigue (16 [50%]). Grade 3 diarrhoea was noted in three (9%) of 32 patients; no grade 4 events were reported. Veliparib pharmacokinetics were dose proportional, with no effect on capecitabine pharmacokinetics. Tumour downstaging after surgery was noted in 22 (71%) of 31 patients; nine (29%) of 31 patients achieved a pathological complete response. INTERPRETATION: Veliparib plus capecitabine and radiotherapy had an acceptable safety profile and showed a dose-proportional pharmacokinetic profile with no effect on the pharmacokinetics of capecitabine. Preliminary antitumour activity warrants further evaluation. FUNDING: AbbVie Inc.

Evaluation of the effect of the EGFR antibody-drug conjugate ABT-414 on QT interval prolongation in patients with advanced solid tumors likely to over-express EGFR.

PURPOSE: ABT-414 is an antibody-drug conjugate (ADC) being developed for the treatment of tumors harboring amplification of the epidermal growth factor receptor (EGFR). This study evaluated the potential of ABT-414 to prolong the QT interval as part of the initial phase 1 study (NCT01741727). METHODS: Data from patients who received ABT-414 monotherapy at a dose of 1-4 mg/kg once every 3 weeks or 1 or 1.5 mg/kg weekly for 2 out of every 3 weeks (alternate schedule) by intravenous infusion were included in the analysis of triplicate 12-lead ECGs obtained before dosing and through 168 h after dosing. Data from time-matched pharmacokinetic samples and QT interval assessments were evaluated using linear mixed-effects modeling to determine the effects of ABT-414, total ABT-806, and cysteine-maleimidocaproyl monomethyl auristatin F (Cys-mcMMAF) on the QT interval corrected using Fridericia's formula (QTcF). RESULTS: Fifty-one patients were included in the analyses. ABT-414 had no clinically meaningful effect on QTcF. Using pooled data from doses ≥2 mg/kg, the estimated mean ∆QTcF reached a maximum of 4.30 ms after dosing, with a one-sided 95% upper confidence bound of 8.32 ms. The exposure-response analysis showed no statistically significant relationship between ΔQTcF and the concentration of any analyte (P > 0.05). No patient had a QTcF value >480 ms or a ∆QTcF value >30 ms. CONCLUSIONS: ABT-414 had no clinically meaningful effect on the QTcF interval at doses being evaluated for treatment of patients with solid tumors.

Efficacy and safety results of ABT-414 in combination with radiation and temozolomide in newly diagnosed glioblastoma.

BACKGROUND: The purpose of this study was to determine the maximum tolerated dose (MTD), recommended phase II dose (RPTD), safety, and pharmacokinetics of ABT-414 plus radiation and temozolomide in newly diagnosed glioblastoma. ABT-414 is a first-in-class, tumor-specific antibody-drug conjugate that preferentially targets tumors expressing overactive epidermal growth factor receptor (EGFR). METHODS: In this multicenter phase I study, patients received 0.5-3.2 mg/kg ABT-414 every 2 weeks by intravenous infusion. EGFR alterations, O6-methylguanine-DNA methyltransferase (MGMT) promoter hypermethylation, and isocitrate dehydrogenase (IDH1) gene mutations were assessed in patient tumors. Distinct prognostic classes were assigned to patients based on a Molecular Classification Predictor model. RESULTS: As of January 7, 2016, forty-five patients were enrolled to receive ABT-414 plus radiation and temozolomide. The most common treatment emergent adverse events were ocular: blurred vision, dry eye, keratitis, photophobia, and eye pain. Ocular toxicity at any grade occurred in 40 patients and at grades 3/4 in 12 patients. RPTD and MTD were set at 2 mg/kg and 2.4 mg/kg, respectively. Among 38 patients with pretreatment tumor tested centrally, 39% harbored EGFR amplification, of which 73% had EGFRvIII mutation. Among patients with available tumor tissue (n = 30), 30% showed MGMT promoter methylation and none had IDH1 mutations. ABT-414 demonstrated an approximately dose proportional pharmacokinetic profile. The median duration of progression-free survival was 6.1 months; median overall survival has not been reached. CONCLUSION: ABT-414 plus chemoradiation demonstrated an acceptable safety and pharmacokinetic profile in newly diagnosed glioblastoma. Randomized studies are ongoing to determine efficacy in newly diagnosed (NCT02573324) and recurrent glioblastoma (NCT02343406).

Molecular imaging in oncology drug development.

Tremendous breakthroughs are being made in cancer drug discovery and development. However, such breakthroughs come at a high financial cost. At a time when there is increasing pressure on drug pricing, in part because of increased life expectancy, it is more important than ever to drive new therapeutics towards patients as efficiently as possible. In this review we discuss the applications of molecular imaging in oncology drug development, with a focus on its ability to enable better early decision making, to increase efficiency and thereby to lower costs.

Veliparib in combination with whole-brain radiation therapy for patients with brain metastases from non-small cell lung cancer: results of a randomized, global, placebo-controlled study.

Veliparib is a potent, orally bioavailable, poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitor that crosses the blood-brain barrier and has been shown to potentiate the effects of radiation in preclinical and early clinical studies. This phase 2, randomized, global study evaluated the efficacy and safety of veliparib in combination with whole-brain radiation therapy (WBRT) in patients with brain metastases from non-small cell lung cancer (NSCLC). Three-hundred and seven patients with brain metastases from NSCLC were randomized 1:1:1 to WBRT (30 Gy in 10 fractions) plus 50 mg veliparib twice daily (BID; n = 103), 200 mg veliparib BID (n = 102), or placebo BID (n = 102). Treatment began within 28 days of diagnosis. Tumor response and safety were assessed; the primary endpoint was overall survival (OS). Patients who received ≥1 dose of treatment were included in the safety analysis. All randomized patients were included in the efficacy endpoint analyses. Patient characteristics were well balanced between treatment arms. Median OS was 185 days for patients treated with WBRT plus placebo and 209 days for WBRT plus veliparib (50 or 200 mg). No statistically significant differences in OS, intracranial response rate, and time to clinical or radiographic progression between any of the treatment arms were noted. No differences were observed in adverse events (all grades) across treatment arms; nausea, fatigue, alopecia, and headache were the most commonly reported. No new safety signals were identified for veliparib. A significant unmet need for therapies that improve the outcomes of patients with brain metastases from NSCLC remains.

A Phase II Trial of a Histone Deacetylase Inhibitor Panobinostat in Patients With Low-Grade Neuroendocrine Tumors.

LESSONS LEARNED: Pancreatic neuroendocrine tumors versus carcinoid tumors should be examined separately in clinical trials.Progression-free survival is more clinically relevant as the primary endpoint (rather than response rate) in phase II trials for low-grade neuroendocrine tumors. BACKGROUND: The most common subtypes of neuroendocrine tumors (NETs) are pancreatic islet cell tumors and carcinoids, which represent only 2% of all gastrointestinal malignancies. Histone deacetylase (HDAC) inhibitors have already been shown to suppress tumor growth and induce apoptosis in various malignancies. In NET cells, HDAC inhibitors have resulted in increased Notch1 expression and subsequent inhibition of growth. We present here a phase II study of the novel HDAC inhibitor panobinostat in patients with low-grade NET. METHODS: Adult patients with histologically confirmed, metastatic, low-grade NETs and an Eastern Cooperative Oncology Group (ECOG) performance status of ≤2 were treated with oral panobinostat 20 mg once daily three times per week. Treatment was continued until patients experienced unacceptable toxicities or disease progression. The study was stopped at planned interim analysis based on a Simon two-stage design. RESULTS: Fifteen patients were accrued, and 13 were evaluable for response. No responses were seen, but the stable disease rate was 100%. The median progression-free survival (PFS) was 9.9 months, and the median overall survival was 47.3 months. Fatigue (27%), thrombocytopenia (20%), diarrhea (13%), and nausea (13%) were the most common related grade 3 toxicities. There was one grade 4 thrombocytopenia (7%). These results did not meet the prespecified criteria to open the study to full accrual. CONCLUSION: The HDAC inhibitor panobinostat has a high stable disease rate and reasonable PFS in low-grade NET, but has a low response rate.

Safety, efficacy, and pharmacokinetics of navitoclax (ABT-263) in combination with irinotecan: results of an open-label, phase 1 study.

PURPOSE: The oral Bcl-2 inhibitor navitoclax demonstrated activity in solid and hematologic malignancies as monotherapy and in combination with other cytotoxic agents in preclinical and early clinical studies. We evaluated the safety, pharmacokinetics (PK), and antitumor activity of navitoclax plus irinotecan. METHODS: In this multicenter, open-label, phase 1 dose escalation study, adults with advanced solid tumors received navitoclax (starting dose 150 mg/day) in combination with 1 of 2 irinotecan schedules during a 21-day cycle: a once-every-3-week regimen (Q3W 180, 250, or 350 mg/m(2)) or a once-weekly regimen (QW 75 or 100 mg/m(2)). Enrollment occurred until a maximum tolerated dose (MTD) and/or recommended phase 2 dose (RPTD) was reached. RESULTS: All patients (Q3W, n = 14; QW, n = 17) were evaluable for safety, PK, and efficacy. The most common adverse event in both groups was diarrhea (Q3W 92.9 %; QW 76.5 %), which was the most frequent grade 3/grade 4 adverse event (Q3W 42.9 %; QW 29.4 %). The study was amended to exclude 4 UGT1A1*28 7/7 homozygous patients due to frequent irinotecan-related grade 3/grade 4 diarrhea and/or febrile neutropenia. No apparent PK interactions between navitoclax and irinotecan were observed. The MTD of the combination was exceeded in the Q3W group at the lowest dose administered. In the QW group, the MTD and RPTD for navitoclax were 150 mg when combined with irinotecan 75 mg/m(2). One patient in each group achieved a partial response. CONCLUSION: The RPTD of navitoclax in combination with irinotecan 75 mg/m(2) QW during a 21-day cycle was 150 mg in these heavily pretreated patients.

Safety, efficacy, and pharmacokinetics of navitoclax (ABT-263) in combination with erlotinib in patients with advanced solid tumors.

PURPOSE: Navitoclax (ABT-263), a novel, oral Bcl-2 inhibitor, enhances the antitumor effects of chemotherapy in vitro by lowering the apoptotic threshold. This phase I study (NCT01009073) evaluated the safety, pharmacokinetics, and preliminary antitumor activity of navitoclax combined with erlotinib in patients with advanced solid tumors. PATIENTS AND METHODS: An open-label dose escalation study included an arm evaluating navitoclax combined with erlotinib, which included a dose escalation cohort and a planned safety expansion cohort. Patients with documented cancers for whom erlotinib therapy was appropriate received erlotinib 150 mg orally once daily plus navitoclax 150 mg orally once daily, with navitoclax dose escalation via a continuous reassessment method model. RESULTS: Eleven patients were enrolled, including six patients with nonsmall cell lung cancer. Dose-limiting toxicities, most commonly diarrhea, were observed in 4 patients. Navitoclax dosing remained at 150 mg/day because the maximum tolerated dose was exceeded at this starting dose. The planned dose escalation did not occur; no recommended phase II dose (RPTD) was identified, and there was no safety expansion cohort. The most common treatment-related adverse events were diarrhea, nausea, vomiting, and decreased appetite. Pharmacokinetic analysis showed no apparent interactions between co-administered navitoclax and erlotinib. No objective responses were observed; the disease control rate was 27 % (95 % CI, 6-61 %). CONCLUSION: At the erlotinib and navitoclax doses administered, RPTD was not reached, but the safety profile of the combination was consistent with data from monotherapy studies. There were no apparent pharmacokinetic interactions between erlotinib and navitoclax. Three patients had stable disease.

Population Pharmacokinetics of ABT-806, an Investigational Anti-Epidermal Growth Factor Receptor (EGFR) Monoclonal Antibody, in Advanced Solid Tumor Types Likely to Either Over-Express Wild-Type EGFR or Express Variant III Mutant EGFR.

BACKGROUND AND OBJECTIVES: ABT-806 is a veneered 'humanized' recombinant IgG1κ antibody that is specific for a unique epitope of human epidermal growth factor receptor (EGFR) expressed only on tumor cells with the EGFRde2-7 (EGFRvIII) deletion mutant as well as tumors with wild-type amplified receptors. We aimed to develop a population pharmacokinetic model of ABT-806 in cancer patients, and to evaluate fixed versus body weight-based dosing regimens. METHODS: The pharmacokinetics of ABT-806 were evaluated in a phase I, open-label study in cancer patients following intravenous infusion of ABT-806 every other week. A total of 587 serum concentrations of ABT-806 from 61 patients were analyzed using non-linear mixed-effects modeling. The impact of body weight-based and fixed dosing of ABT-806 was evaluated using a simulation approach. RESULTS: A two-compartment model with linear elimination was used to describe the serum concentration-time data of ABT-806. The population estimates of the apparent clearance from the central (CLc) and peripheral (CLp) compartments were 0.011 and 0.025 L/h, respectively. The apparent volume of distribution estimates of the central (V 1) and peripheral (V 2) compartments were 3.5 and 3.3 L, respectively. The estimates of inter-subject variability (percentage coefficient of variation) in CLc, CLp, V 1, and V 2 were 38, 37, 20, and 48 %, respectively. Albumin on CLc and body weight on V 1 were statistically significant covariates; however, they explained 18 and 30 % of the inter-individual variability of clearance and V 1, respectively. Simulation results indicated that fixed and body weight-based dosing regimens yield similar steady-state concentrations and overall variability. CONCLUSIONS: ABT-806 demonstrated a unique pharmacokinetic profile compared to the marketed monoclonal antibodies against EGFR. The analysis indicates it is feasible to switch to fixed doses in subsequent clinical trials of ABT-806.

A multicenter phase 1 study of γ -secretase inhibitor RO4929097 in combination with capecitabine in refractory solid tumors.

BACKGROUND: RO4929097 is an oral inhibitor of γ -secretase that results in Notch signaling inhibition. Prior work has demonstrated that Notch signaling inhibition enhances chemotherapy sensitivity of cancer cells. This phase I study was conducted to determine maximum tolerated dose (MTD), toxicities and efficacy of RO4929097 and capecitabine in advanced solid tumors. METHODS: Patients with refractory solid tumors received capecitabine at a fixed dose of 1,000 mg/m(2) twice daily with escalating doses of RO4929097 on a 21-day cycle in a 3 + 3 design. Capecitabine was administered for 14 days and the RO49029097 once daily, 3 days per week, both for a 21 day cycle. RESULTS: Thirty patients were treated on six dose levels (20 to 150 mg). The maximally tolerated dose was not reached. One dose limiting toxicity was observed at each level 3 through 6 (hypophosphatemia, fatigue, and nausea/vomiting). Three confirmed partial responses were observed: two patients with fluoropyrimide-refractory colon cancer and one patient with cervical cancer. Autoinduction of RO4929097 was demonstrated with increasing dose levels and duration. CONCLUSIONS: The recommended phase 2 dose is capecitabine 1,000 mg/m(2) orally twice daily on days 1 through 14 with RO4929097 20 mg orally once daily on days 1-3, 8-10 and 15-17 with a 21 day cycle. Clinical benefit was observed in cervical and colon cancer. Autoinduction of RO4929097 was seen both with increasing cycle number and increasing dose. Plasma concentrations of RO4929097 were above those needed for Notch inhibition.

Studying navitoclax, a targeted anticancer drug, in healthy volunteers--ethical considerations and risk/benefit assessments and management.

BACKGROUND: Biopharmaceutical studies for anti-cancer drugs are typically conducted in cancer patients due to unacceptable toxicities to healthy volunteers. Navitoclax is a first-in-class, orally bioavailable, targeted Bcl-2 family protein inhibitor that has been studied in cancer patients. METHODS: A strategy that integrated the evaluation of non-clinical toxicology data and clinical data in cancer patients was employed to assess the feasibility, determine doses and establish risk management plans for studying navitoclax in healthy volunteers. Two relative bioavailability/food effect studies with either a 25 mg dose or 50 and 100 mg doses of navitoclax were conducted sequentially in healthy female volunteers of non-childbearing potential. RESULTS/CONCLUSION: Navitoclax was well-tolerated in both studies in healthy volunteers, and did not impose risks beyond the minimal levels expected in healthy volunteer studies. Compared to a similar study in cancer patients, the studies in healthy volunteers generated higher quality data in a short period of time to support formulation selection.

A phase I study of vorinostat in combination with bortezomib in patients with advanced malignancies.

BACKGROUND: A phase I study to assess the maximum-tolerated dose (MTD), dose-limiting toxicity (DLT), pharmacokinetics (PK) and antitumor activity of vorinostat in combination with bortezomib in patients with advanced solid tumors. METHODS: Patients received vorinostat orally once daily on days 1-14 and bortezomib intravenously on days 1, 4, 8 and 11 of a 21-day cycle. Starting dose (level 1) was vorinostat (400 mg) and bortezomib (0.7 mg/m(2)). Bortezomib dosing was increased using a standard phase I dose-escalation schema. PKs were evaluated during cycle 1. RESULTS: Twenty-three patients received 57 cycles of treatment on four dose levels ranging from bortezomib 0.7 mg/m(2) to 1.5 mg/m(2). The MTD was established at vorinostat 400 mg daily and bortezomib 1.3 mg/m(2). DLTs consisted of grade 3 fatigue in three patients (1 mg/m(2),1.3 mg/m(2) and 1.5 mg/m(2)) and grade 3 hyponatremia in one patient (1.5 mg/m(2)). The most common grade 1/2 toxicities included nausea (60.9%), fatigue (34.8%), diaphoresis (34.8%), anorexia (30.4%) and constipation (26.1%). Objective partial responses were observed in one patient with NSCLC and in one patient with treatment-refractory soft tissue sarcoma. Bortezomib did not affect the PKs of vorinostat; however, the Cmax and AUC of the acid metabolite were significantly increased on day 2 compared with day 1. CONCLUSIONS: This combination was generally well-tolerated at doses that achieved clinical benefit. The MTD was established at vorinostat 400 mg daily × 14 days and bortezomib 1.3 mg/m(2) on days 1, 4, 8 and 11 of a 21-day cycle.

Vorinostat in combination with bortezomib in patients with advanced malignancies directly alters transcription of target genes.

INTRODUCTION: Vorinostat is a small molecule inhibitor of class I and II histone deacetylase enzymes which alters the expression of target genes including the cell cycle gene p21, leading to cell cycle arrest and apoptosis. METHODS: Patients enrolled in a phase I trial were treated with vorinostat alone on day 1 and vorinostat and bortezomib in combination on day 9. Paired biopsies were obtained in eleven subjects. Blood samples were obtained on days 1 and 9 of cycle 1 prior to dosing and 2 and 6 h post-dosing in all 60 subjects. Gene expression of p21, HSP70, AKT, Nur77, ERB1, and ERB2 was evaluated in peripheral blood mononuclear cells and tissue samples. Chromatin immunoprecipitation of p21, HSP70, and Nur77 was also performed in biopsy samples. RESULTS: In peripheral blood mononuclear cells, Nur77 was significantly and consistently decreased 2 h after vorinostat administration on both days 1 and 9, median ratio of gene expression relative to baseline of 0.69 with interquartile range 0.49-1.04 (p < 0.001); 0.28 (0.15-0.7) (p < 0.001), respectively, with more pronounced decrease on day 9, when patients received both vorinostat and bortezomib. p21, a downstream target of Nur77, was significantly decreased on day 9, 2 and 6 h after administration of vorinostat and bortezomib, 0.67 (0.41-1.03) (p < 0.01); 0.44 (0.25-1.3) (p < 0.01), respectively. The ChIP assay demonstrated a protein-DNA interaction, in this case interaction of Nur77, HSP70 and p21 with acetylated histone H3, at baseline and at day 9 after treatment with vorinostat in tissue biopsies in most patients. CONCLUSION: Vorinostat inhibits Nur77 expression, which in turn may decrease p21 and AKT expression in PBMCs. The influence of vorinostat on target gene expression in tumor tissue was variable; however, most patients demonstrated interaction of acetylated H3 with Nur77, HSP70, and p21 which provides evidence of interaction with the transcriptionally active acetylated H3.