Order of patient entry and outcomes in phase II clinical trials: A meta-analysis of individual patient data.

BACKGROUND: Prior meta-analysis of stem-cell transplantation trials for renal-cell carcinoma observed that clinical outcomes vary by subjects' order of entry, specifically their quartile of accrual. We test this hypothesis using meta-analysis of individual patient data from diverse Phase II trials conducted by an oncology consortium. METHODS: Eligible were all Phase II trials in hematologic or solid tumors opened and closed by California Cancer Consortium during 2005-2020. Excluded were trials closed in first quartile or currently embargoed pending publication and subjects ineligible per protocol or untreated on study. The primary risk factor was entry by quartile of planned sample size. As a cross-protocol endpoint, primary outcome was time to discontinuation of intervention. One-stage meta-analysis used a shared frailty model with trial as random effect. As covariates, stepwise selection retained tumor type, obesity, their interaction, calendar year, entry at least 3 years post-diagnosis, and performance status but rejected age, sex, randomized design, and class of drug. RESULTS: Twenty trials (including 8 terminated early, 2 not published) included n = 923 subjects. Most (90.6%) subjects discontinued intervention, usually for disease progression or toxicity. Independently of covariates, risk of discontinuation increased (p < 0.0001) with each quartile of entry (Hazards Ratio 1.13, 95% CI 1.06-1.22), culminating at Quartile 4 (HR 1.46, 1.36-1.57). The 95% prediction interval for the Hazards Ratio in future trials was (1.04-1.24). Progression-free survival similarly worsened by quartile of entry. CONCLUSION: In Phase II trials, clinical outcome worsens with quartile of entry. This finding merits independent replication, and the cause of this phenomenon merits investigation.

Erlotinib and Onalespib Lactate Focused on EGFR Exon 20 Insertion Non-Small Cell Lung Cancer (NSCLC): A California Cancer Consortium Phase I/II Trial (NCI 9878).

BACKGROUND: Onalespib is a novel heat shock protein 90 inhibitor (HSP90i). Previous preclinical and clinical studies with HSP90i have demonstrated activity in EGFR-mutant non-small cell lung cancer (NSCLC). This study sought to determine the safety and tolerability of onalespib plus erlotinib in EGFR-mutant NSCLC and to evaluate the preliminary efficacy of the combination in epidermal growth factor receptor exon 20 insertion (EGFRex20ins) NSCLC. PATIENTS AND METHODS: Standard 3+3 dose escalation was followed by a phase II expansion in EGFRex20ins. The phase II component targeted a response rate of 25% versus a background rate of 5%. Prospective next-generation sequencing (NGS) of 70 cancer-related genes, including EGFR, via plasma circulating tumor DNA (ctDNA) was performed. Toxicity was graded by Common Terminology Criteria for Adverse Events (CTCAE), version 4, and response was determined by Response Evaluation Criteria in Solid Tumours (RECIST) 1.1. RESULTS: Eleven patients were treated (nine dose escalation, two dose expansion). Two dose-limiting toxicities (DLTs) occurred in dose level (DL) 0 and zero in DL -1 (minus). In 10 EGFRex20ins patients, no responses were observed, median progression-free survival was 5.4 months (95% confidence interval, 0.9-5.7), and the disease control rate (DCR) was 40% (median, 3.5 months). EGFRex20ins was detected in nine of 10 ctDNA samples at baseline; on-treatment ctDNA clearance was not observed. Grade 3 diarrhea was the predominant toxicity in 45% of patients. The recommended phase II dose is DL -1 (minus): erlotinib 150 mg orally every morning and onalespib 120 mg/m2 intravenously on days 1, 8, and 15 every 28 days. CONCLUSION: Overlapping toxicities of erlotinib and onalespib, mainly diarrhea, limited the tolerability of this combination, and limited clinical activity was observed, so the trial was closed early. Plasma EGFRex20ins ctDNA was detected in the majority of patients; failure to clear ctDNA was consistent with lack of tumor response (NCT02535338).

A phase I study of intravenous fenretinide (4-HPR) for patients with malignant solid tumors.

BACKGROUND: Fenretinide is a synthetic retinoid that can induce cytotoxicity by several mechanisms. Achieving effective systemic exposure with oral formulations has been challenging. An intravenous lipid emulsion fenretinide formulation was developed to overcome this barrier. We conducted a study to establish the maximum tolerated dose (MTD), preliminary efficacy, and pharmacokinetics of intravenous lipid emulsion fenretinide in patients with advanced solid tumors. METHODS: Twenty-three patients with advanced solid tumors refractory to standard treatments received fenretinide as a continuous infusion for five consecutive days in 21-day cycles. Five different dose cohorts were evaluated between doses of 905 mg/m2 and 1414 mg/m2 per day using a 3 + 3 dose escalation design. A priming dose of 600 mg/m2 on day 1 was introduced in an attempt to address the asymptomatic serum triglyceride elevations related to the lipid emulsion. RESULTS: The treatment-related adverse events occurring in ≥ 20% of patients were anemia, hypertriglyceridemia, fatigue, aspartate aminotransferase (AST)/alanine aminotransferase (ALT) increase, thrombocytopenia, bilirubin increase, and dry skin. Five evaluable patients had stable disease as best response, and no patients had objective responses. Plasma steady-state concentrations of the active metabolite were significantly higher than with previous capsule formulations. CONCLUSION: Fenretinide emulsion intravenous infusion had a manageable safety profile and achieved higher plasma steady-state concentrations of the active metabolite compared to previous capsule formulations. Single-agent activity was minimal but combinatorial approaches are under evaluation.

Untenable dosing: A common pitfall of modern DLT-targeting Phase I designs in oncology.

BACKGROUND: There is increasing use of Phase I statistical designs to find a dose that causes rapidly emerging and particularly concerning severe or life-threatening toxicities (dose-limiting toxicities, DLTs) in a specified percent of patients most commonly 25%. While a convenient statistical framework, the foundation for selecting any specified target DLT rate, and its relevance to the recommended Phase II dose is generally lacking. METHOD: We surveyed 78 medical oncologists, most (69%) with experience as a principal investigator on a Phase I study, to ascertain their opinions related to this approach to Phase I studies and the targets often chosen. RESULTS: Eighty-seven percent of respondents preferred severe toxicities in only 5%-10% of patients, consistent with 58% of respondents noting that 10% or fewer patients experience severe toxicities in the first cycle with standard outpatient treatments. The survey also documented in an example that the majority (62%) of physicians modify their patient selection during the conduct of the study based on observed toxicity and 78% note that higher toxicity is acceptable in patients where a cure is more likely. CONCLUSION: DLT-target rate designs search for a single target that is rarely well-supported in a patient population that is not stable. The most common target used is inconsistent with the toxicity of most clinically used drugs and investigator preference and can lead to the pursuit of unacceptable doses. Use of Phase I trial designs with a target DLT rate should be limited to settings with a well-justified target and should specify how the target relates to the recommended Phase II dose.

Model of a Queuing Approach for Patient Accrual in Phase 1 Oncology Studies.

Importance: Phase 1 cancer studies, which guide dose selection for subsequent studies, are almost 3 times more prevalent than phase 3 studies and have a median study duration considerably longer than 2 years, which constitutes a major component of drug development time. Objective: To discern a method to reduce the duration of phase 1 studies in adult and pediatric cancer studies without violating risk limits by better accommodating the accrual and evaluation process (or queue). Design: The process modeled, the phase 1 queue (IQ), includes patient interarrival time, screening, and dose-limiting toxicity evaluation. For this proof of principle, the rules of the 3 + 3 and rolling 6 phase 1 designs were modified to improve patient flow through the queue without exceeding the maximum risk permitted in the parent designs. The resulting designs, the IQ 3 + 3 and the IQ rolling 6, were each compared with their parent design by simulations in 12 different scenarios. Main Outcomes and Measures: (1) The time from study opening to determination of the maximum tolerated dose (MTD), (2) the number of patients treated to determine the MTD, and (3) the association of the design with the dose selected as the MTD. Results: Based on 800 simulations, for all 12 scenarios considered, the IQ 3 + 3 and the IQ rolling 6 designs were associated with reduced expected study durations compared with the parent design. The expected IQ 3 + 3 reduction ranged from 1.6 to 10.4 months (with 3.7 months for the standard scenario), and the expected reduction associated with IQ rolling 6 ranged from 0.4 to 10.5 months (with 3.4 months for the standard scenario). The increase in the mean number of patients treated in the IQ 3 + 3 compared with the 3 + 3 ranged from 0.6 to 3.2 patients. No increase in the number of patients was associated with the IQ rolling 6 compared with the rolling 6 design. The probability of selecting a dose level as the MTD changed by less than 3% for all dose levels and scenarios in both parent designs. Conclusions and Relevance: This study found that IQ designs were associated with reduced mean duration of phase 1 studies compared with their parent designs without changing the risk limits or MTD selection operating characteristics. These approaches have been successfully implemented in both hematology and solid tumor phase 1 studies.

Phase 1 study of the Aurora kinase A inhibitor alisertib (MLN8237) combined with the histone deacetylase inhibitor vorinostat in lymphoid malignancies.

Alisertib, an Aurora kinase A inhibitor, was evaluated in a Phase 1 study in combination with the histone deacetylase inhibitor vorinostat, in patients with relapsed/refractory lymphoid malignancies (N = 34; NCT01567709). Patients received alisertib plus vorinostat in 21-day treatment cycles with escalating doses of alisertib following a continuous or an intermittent schedule. All dose-limiting toxicities (DLTs) were hematologic and there were no study-related deaths. The recommended phase 2 dose (RP2D) of the combination was 20 mg bid of alisertib and 200 mg bid of vorinostat on the intermittent schedule. A 13-patient expansion cohort was treated for a total of 18 patients at the RP2D. There were no DLTs at the RP2D, and toxicities were mainly hematologic. Two patients with DLBCL achieved a durable complete response, and two patients with HL achieved partial response. Alisertib plus vorinostat showed encouraging clinical activity with a manageable safety profile in heavily pretreated patients with advanced disease.

Inhibition of MDR1 Overcomes Resistance to Brentuximab Vedotin in Hodgkin Lymphoma.

PURPOSE: In classical Hodgkin lymphoma, the malignant Reed-Sternberg cells express the cell surface marker CD30. Brentuximab vedotin is an antibody-drug conjugate (ADC) that selectively delivers a potent cytotoxic agent, monomethyl auristatin E (MMAE), to CD30-positive cells. Although brentuximab vedotin elicits a high response rate (75%) in relapsed/refractory Hodgkin lymphoma, most patients who respond to brentuximab vedotin eventually develop resistance. PATIENTS AND METHODS: We developed two brentuximab vedotin-resistant Hodgkin lymphoma cell line models using a pulsatile approach and observed that resistance to brentuximab vedotin is associated with an upregulation of multidrug resistance-1 (MDR1). We then conducted a phase I trial combining brentuximab vedotin and cyclosporine A (CsA) in patients with relapsed/refractory Hodgkin lymphoma. RESULTS: Here, we show that competitive inhibition of MDR1 restored sensitivity to brentuximab vedotin in our brentuximab vedotin-resistant cell lines by increasing intracellular MMAE levels, and potentiated brentuximab vedotin activity in brentuximab vedotin-resistant Hodgkin lymphoma tumors in a human xenograft mouse model. In our phase I trial, the combination of brentuximab vedotin and CsA was tolerable and produced an overall and complete response rate of 75% and 42% in a population of patients who were nearly all refractory to brentuximab vedotin. CONCLUSIONS: This study may provide a new therapeutic strategy to combat brentuximab vedotin resistance in Hodgkin lymphoma. This is the first study reporting an effect of multidrug resistance modulation on the therapeutic activity of an ADC in humans. The expansion phase of the trial is ongoing and enrolling patients who are refractory to brentuximab vedotin to confirm clinical activity in this population with unmet need.

Intravenous 5-fluoro-2'-deoxycytidine administered with tetrahydrouridine increases the proportion of p16-expressing circulating tumor cells in patients with advanced solid tumors.

PURPOSE: Following promising responses to the DNA methyltransferase (DNMT) inhibitor 5-fluoro-2'-deoxycytidine (FdCyd) combined with tetrahydrouridine (THU) in phase 1 testing, we initiated a non-randomized phase 2 study to assess response to this combination in patients with advanced solid tumor types for which tumor suppressor gene methylation is potentially prognostic. To obtain pharmacodynamic evidence for DNMT inhibition by FdCyd, we developed a novel method for detecting expression of tumor suppressor protein p16/INK4A in circulating tumor cells (CTCs). METHODS: Patients in histology-specific strata (breast, head and neck [H&N], or non-small cell lung cancers [NSCLC] or urothelial transitional cell carcinoma) were administered FdCyd (100 mg/m2) and THU (350 mg/m2) intravenously 5 days/week for 2 weeks, in 28-day cycles, and progression-free survival (PFS) rate and objective response rate (ORR) were evaluated. Blood specimens were collected for CTC analysis. RESULTS: Ninety-three eligible patients were enrolled (29 breast, 21 H&N, 25 NSCLC, and 18 urothelial). There were three partial responses. All strata were terminated early due to insufficient responses (H&N, NSCLC) or slow accrual (breast, urothelial). However, the preliminary 4-month PFS rate (42%) in the urothelial stratum exceeded the predefined goal-though the ORR (5.6%) did not. An increase in the proportion of p16-expressing cytokeratin-positive CTCs was detected in 69% of patients evaluable for clinical and CTC response, but was not significantly associated with clinical response. CONCLUSION: Further study of FdCyd + THU is potentially warranted in urothelial carcinoma but not NSCLC or breast or H&N cancer. Increase in the proportion of p16-expressing cytokeratin-positive CTCs is a pharmacodynamic marker of FdCyd target engagement.

Phase I trial of belinostat in combination with 13-cis-retinoic acid in advanced solid tumor malignancies: a California Cancer Consortium NCI/CTEP sponsored trial.

PURPOSE: The reported maximum tolerated dose (MTD) of single-agent belinostat is 1000 mg/m2 given days 1-5, every 21 days. Pre-clinical evidence suggests histone deacetylase inhibitors enhance retinoic acid signaling in a variety of solid tumors. We conducted a phase I study of belinostat combined with 50-100 mg/m2/day 13-cis-retinoic acid (13-cRA) in patients with advanced solid tumors. METHODS: Belinostat was administered days 1-5 and 13-cRA days 1-14, every 21 days. Dose-limiting toxicity (DLT) was defined as cycle 1 hematologic toxicity grade ≥ 3 not resolving to grade ≤ 1 within 1 week or non-hematologic toxicity grade ≥ 3 (except controlled nausea and vomiting and transient liver function abnormalities) attributable to belinostat. RESULTS: Among 51 patients, two DLTs were observed: grade 3 hypersensitivity with dizziness and hypoxia at 1700 mg/m2/day belinostat with 100 mg/m2/day 13-cRA, and grade 3 allergic reaction at 2000 mg/m2/day belinostat with 100 mg/m2/day 13-cRA. The MTD was not reached. Pharmacokinetics of belinostat may be non-linear at high doses. Ten patients had stable disease, including one with neuroendocrine pancreatic cancer for 56 cycles, one with breast cancer for 12 cycles, and one with lung cancer for 8 cycles. Partial responses included a patient with keratinizing squamous cell carcinoma of the tonsils, and a patient with lung cancer. CONCLUSIONS: The combination of belinostat 2000 mg/m2 days 1-5 and 13-cRA 100 mg/m2 days 1-14, every 21 days, was well-tolerated and an MTD was not reached despite doubling the established single-agent MTD of belinostat.

Phase II Trial of Cabozantinib Plus Erlotinib in Patients With Advanced Epidermal Growth Factor Receptor (EGFR)-Mutant Non-small Cell Lung Cancer With Progressive Disease on Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Therapy: A California Cancer Consortium Phase II Trial (NCI 9303).

Introduction: Mesenchymal epidermal transition and vascular endothelial growth factor pathways are important in mediating non-small cell lung cancer (NSCLC) tumorigenesis and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) resistance. We hypothesized that treatment with cabozantinib plus erlotinib in EGFR mutation-positive NSCLC following progression on EGFR TKI therapy may allow tumors to overcome this resistance or restore sensitivity to therapy regardless of T790M status. Methods: Patients with advanced NSCLC, known EGFR mutation and progressive disease on an EGFR TKI immediately prior to enrollment without intervening therapy were enrolled. Patients received erlotinib 150 mg and cabozantinib 40 mg daily. The primary endpoint was evaluation of efficacy by objective response rate. Secondary endpoints included assessment of progression free survival (PFS), overall survival, change in tumor growth rate, safety and toxicity, and the evaluation of specific EGFR mutations and MET amplification in pre-treatment tissue and plasma. Results: Thirty-seven patients were enrolled at 4 centers. Four patients had partial response (10.8%) and 21 had stable disease (59.5%). A greater than 30% increase in tumor doubling time was observed in 79% of assessable patients (27/34). Median PFS was 3.6 months for all patients. Diarrhea (32%) was the most common grade 3 adverse event; 3 patients had asymptomatic grade 4 elevation of amylase and lipase. Conclusions: Combination erlotinib and cabozantinib demonstrates activity in a highly pretreated population of patients with EGFR mutation and progression on EGFR TKI. Further elucidation of beneficial patient subsets is warranted. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT01866410.

A Phase I Study of the Combination of Rituximab and Ipilimumab in Patients with Relapsed/Refractory B-Cell Lymphoma.

PURPOSE: Based on the potential for ipilimumab (I) to augment T-cell activation, we hypothesize that ipilimumab would augment the efficacy of rituximab (R) in patients with relapsed/refractory (R/R) CD20+non-Hodgkin's lymphoma (NHL). This phase I study aimed to identify a recommended phase 2 dose, document toxicities, and preliminarily assess efficacy and potential predictive biomarkers. PATIENTS AND METHODS: Thirty-three patients with R/R CD20+B-cell lymphoma received R at 375 mg/m2weekly for 4 weeks and I at 3 mg/kg on day 1 and every 3 weeks for four doses. Responding patients went on to maintenance with each agent given every 12 weeks. To facilitate correlative analysis, the expansion phase randomized patients to simultaneous R+I versus R with I delayed 2 weeks. RESULTS: Toxicity was manageable; no dose-limiting toxicity was observed at the doses studied. When considering the entire cohort, efficacy was modest, with an objective response rate (ORR) of 24% and median progression-free survival (PFS) of 2.6 months. However, in follicular lymphoma patients, the ORR was 58% with a median PFS of 5.6 months. The randomized comparison of R with R+I demonstrated that R+I resulted in more effective B-cell depletion (BCD). Both B-cell depletion and the ratio of CD45RA-regulatory T cell (Treg) to Treg were associated with response at all time points. CONCLUSIONS: The combination of R+I has manageable toxicity and encouraging efficacy in R/R follicular lymphoma. The ratio of CD45RA-Tregs to total Tregs, and peripheral BCD should be studied further as potential predictors of response.

Concentrations of the DNA methyltransferase inhibitor 5-fluoro-2'-deoxycytidine (FdCyd) and its cytotoxic metabolites in plasma of patients treated with FdCyd and tetrahydrouridine (THU).

PURPOSE: Although the DNA methyltransferase inhibitor 5-fluoro-2'-deoxycytidine (FdCyd), is being evaluated clinically, it must be combined with the cytidine deaminase inhibitor tetrahydrouridine (THU) to prevent rapid metabolism of FdCyd to the pharmacologically active, yet unwanted, metabolites 5-fluoro-2'-deoxyuridine (FdUrd), 5-fluorouracil (FU), and 5-fluorouridine (FUrd). We assessed plasma concentrations of FdCyd and metabolites in patients receiving FdCyd and THU. METHODS: We validated an LC-MS/MS assay, developed for a preclinical study, to quantitate FdCyd and metabolites in human plasma. Patients were treated with five daily, 3-h infusions of FdCyd at doses of 5-80 mg/m(2) with 350 mg/m(2) THU. Plasma was obtained during, and before the end of infusions on days 1 and 5. RESULTS: The lower limits of quantitation for FU, FdUrd, FUrd, FC and FdCyd were 1, 1.5, 10, 3, and 10 ng/ml, respectively. Plasma FdCyd increased with dose, from 19-96 ng/ml at 5 mg/m(2) to 1,600-1,728 ng/ml at 80 mg/m(2). FdUrd was undetectable in patients treated with FdCyd doses <20 mg/m(2), and increased from 2.3 ng/ml at 20 mg/m(2) to 3.5-5.7 ng/ml at 80 mg/m(2). FU increased from 1.2-5.5 ng/ml at 5 mg/m(2) to 6.0-12 ng/ml at 80 mg/m(2). CONCLUSIONS: By co-administering FdCyd with THU, FdCyd plasma concentrations were achieved that are known to inhibit DNA methylation in vitro. The accompanying plasma FU and FdUrd concentrations are <10% those observed after therapeutic infusions of FU or FdUrd, while FdCyd levels are well above those required to inhibit methylation in vitro. Therefore, inhibition of DNA methylation with FdCyd and THU appears feasible.

A phase I trial of topotecan plus tivantinib in patients with advanced solid tumors.

PURPOSE: Tyrosine kinase inhibitors (TKI) that target MET signaling have shown promise in various types of cancer, including lung cancer. Combination strategies have been proposed and developed to increase their therapeutic index. Based on preclinical synergy between inhibition of MET and topoisomerase I, a phase I study was designed to explore the combination of topotecan with the MET TKI tivantinib. METHODS: Eligible patients with advanced solid malignancies for which there was no known effective treatment received topotecan at doses of 1.0-1.5 mg/m2/day for five consecutive days in 21-day cycles with continuous, oral tivantinib given at escalating doses of 120-360 mg orally twice daily. Pharmacokinetic analyses of tivantinib were included. Circulating tumor cells (CTC) were collected serially to identify peripheral changes in MET phosphorylation. RESULTS: The trial included 18 patients, 17 of whom received treatment. At the planned doses, the combination of topotecan and tivantinib was not tolerable due to thrombocytopenia and neutropenia. The addition of G-CSF to attenuate neutropenia did not improve tolerability. Greater tivantinib exposure, assessed through pharmacokinetic analysis, was associated with greater toxicity. No responses were seen. MET phosphorylation was feasible in CTC, but no changes were seen with therapy. CONCLUSIONS: The combination of topotecan and oral tivantinib was not tolerable in this patient population.

Phase I Study of Fenretinide Delivered Intravenously in Patients with Relapsed or Refractory Hematologic Malignancies: A California Cancer Consortium Trial.

Purpose: A phase I study was conducted to determine the MTD, dose-limiting toxicities (DLT), and pharmacokinetics of fenretinide delivered as an intravenous emulsion in relapsed/refractory hematologic malignancies.Experimental Design: Fenretinide (80-1,810 mg/m2/day) was administered by continuous infusion on days 1 to 5, in 21-day cycles, using an accelerated titration design.Results: Twenty-nine patients, treated with a median of three prior regimens (range, 1-7), were enrolled and received the test drug. Ninety-seven courses were completed. An MTD was reached at 1,280 mg/m2/day for 5 days. Course 1 DLTs included 6 patients with hypertriglyceridemia, 4 of whom were asymptomatic; 2 patients experienced DLT thrombocytopenia (asymptomatic). Of 11 patients with response-evaluable peripheral T-cell lymphomas, two had complete responses [CR, progression-free survival (PFS) 68+ months; unconfirmed CR, PFS 14+ months], two had unconfirmed partial responses (unconfirmed PR, PFS 5 months; unconfirmed PR, PFS 6 months), and five had stable disease (2-12 cycles). One patient with mature B-cell lymphoma had an unconfirmed PR sustained for two cycles. Steady-state plasma levels were approximately 10 mcg/mL (mid-20s µmol/L) at 640 mg/m2/day, approximately 14 mcg/mL (mid-30s µmol/L) at 905 mg/m2/day, and approximately 22 mcg/mL (mid-50s µmol/L) at 1,280 mg/m2/day.Conclusions: Intravenous fenretinide obtained significantly higher plasma levels than a previous capsule formulation, had acceptable toxicities, and evidenced antitumor activity in peripheral T-cell lymphomas. A recommended phase II dosing is 600 mg/m2 on day 1, followed by 1,200 mg/m2 on days 2 to 5, every 21 days. A registration-enabling phase II study in relapsed/refractory PTCL (ClinicalTrials.gov identifier: NCT02495415) is ongoing. Clin Cancer Res; 23(16); 4550-5. ©2017 AACR.

Efficacy of the PARP Inhibitor Veliparib with Carboplatin or as a Single Agent in Patients with Germline BRCA1- or BRCA2-Associated Metastatic Breast Cancer: California Cancer Consortium Trial NCT01149083.

Purpose: We aimed to establish the MTD of the poly (ADP-ribose) (PAR) polymerase inhibitor, veliparib, in combination with carboplatin in germline BRCA1- and BRCA2- (BRCA)-associated metastatic breast cancer (MBC), to assess the efficacy of single-agent veliparib, and of the combination treatment after progression, and to correlate PAR levels with clinical outcome.Experimental Design: Phase I patients received carboplatin (AUC of 5-6, every 21 days), with escalating doses (50-20 mg) of oral twice-daily (BID) veliparib. In a companion phase II trial, patients received single-agent veliparib (400 mg BID), and upon progression, received the combination at MTD. Peripheral blood mononuclear cell PAR and serum veliparib levels were assessed and correlated with outcome.Results: Twenty-seven phase I trial patients were evaluable. Dose-limiting toxicities were nausea, dehydration, and thrombocytopenia [MTD: veliparib 150 mg po BID and carboplatin (AUC of 5)]. Response rate (RR) was 56%; 3 patients remain in complete response (CR) beyond 3 years. Progression-free survival (PFS) and overall survival (OS) were 8.7 and 18.8 months. The PFS and OS were 5.2 and 14.5 months in the 44 patients in the phase II trial, with a 14% RR in BRCA1 (n = 22) and 36% in BRCA2 (n = 22). One of 30 patients responded to the combination therapy after progression on veliparib. Higher baseline PAR was associated with clinical benefit.Conclusions: Safety and efficacy are encouraging with veliparib alone and in combination with carboplatin in BRCA-associated MBC. Lasting CRs were observed when the combination was administered first in the phase I trial. Further investigation of PAR level association with clinical outcomes is warranted. Clin Cancer Res; 23(15); 4066-76. ©2017 AACR.

BCL2 Inhibition by Venetoclax: Targeting the Achilles' Heel of the Acute Myeloid Leukemia Stem Cell?

Venetoclax is an oral drug with an excellent side-effect profile that has the potential to revolutionize acute myeloid leukemia (AML) therapy in two areas. Venetoclax-based combination therapies could be a bridge to hematopoietic cell transplant with curative intent for patients with refractory/relapsed AML, and venetoclax-based therapy could provide meaningful survival prolongation for older patients with AML who are not candidates for more aggressive therapies. Cancer Discov; 6(10); 1082-3. ©2016 AACR.See related article by Konopleva and colleagues, p. 1106.

A phase I pharmacodynamic study of GTI-2040, an antisense oligonucleotide against ribonuclotide reductase, in acute leukemias: a California Cancer Consortium study.

We performed a phase I study of GTI-2040, an antisense oligonucleotide against ribonucleotide reductase mRNA, on a novel dosing schedule of days 1-4 and 15-18 by continuous infusion to examine efficacy and tolerability in patients with leukemia. A dose of 11 mg/kg/d was safely reached. Dose-limiting toxicities (DLTs) at the higher levels included elevated troponin I and liver function enzymes. There were no objective responses to GTI-2040 in this study; 7/24 patients were able to complete the predetermined three infusion cycles. Pharmacokinetic and pharmacodynamic studies were performed, indicating a trend towards increasing intracellular drug levels and decreasing RRM2 gene expression with increasing doses. This dose schedule may be considered if appropriate combinations are identified in preclinical studies.

Oral and intravenous pharmacokinetics of 5-fluoro-2'-deoxycytidine and THU in cynomolgus monkeys and humans.

INTRODUCTION: 5-Fluoro-2'-deoxycytidine (FdCyd; NSC48006), a fluoropyrimidine nucleoside inhibitor of DNA methylation, is degraded by cytidine deaminase (CD). Pharmacokinetic evaluation was carried out in cynomolgus monkeys in support of an ongoing phase I study of the PO combination of FdCyd and the CD inhibitor tetrahydrouridine (THU; NSC112907). METHODS: Animals were dosed intravenously (IV) or per os (PO). Plasma samples were analyzed by LC-MS/MS for FdCyd, metabolites, and THU. Clinical chemistry and hematology were performed at various times after dosing. A pilot pharmacokinetic study was performed in humans to assess FdCyd bioavailability. RESULTS: After IV FdCyd and THU administration, FdCyd C(max) and AUC increased with dose. FdCyd half-life ranged between 22 and 56 min, and clearance was approximately 15 mL/min/kg. FdCyd PO bioavailability after THU ranged between 9 and 25 % and increased with increasing THU dose. PO bioavailability of THU was less than 5 %, but did result in plasma concentrations associated with inhibition of its target CD. Human pilot studies showed comparable bioavailability for FdCyd (10 %) and THU (4.1 %). CONCLUSION: Administration of THU with FdCyd increased the exposure to FdCyd and improved PO FdCyd bioavailability from <1 to 24 %. Concentrations of THU and FdCyd achieved after PO administration are associated with CD inhibition and hypomethylation, respectively. The schedule currently studied in phase I studies of PO FdCyd and THU is daily times three at the beginning of the first and second weeks of a 28-day cycle.

Pharmacodynamics (PD) and pharmacokinetics (PK) of E7389 (eribulin, halichondrin B analog) during a phase I trial in patients with advanced solid tumors: a California Cancer Consortium trial.

BACKGROUND: The California Cancer Consortium completed a phase I trial of E7389 (eribulin mesylate), an analog of the marine natural product halichondrin B. This trial was to determine the pharmacodynamics, pharmacokinetics, and MTD of E7389 administered by bolus injection weekly for 3 weeks out of four. METHODS: This trial included a rapid titration design. Real-time pharmacokinetics were utilized to guide dose escalation. Initially, single-patient cohorts were enrolled with intra- and inter-patient dose doubling. The second phase was a standard 3 + 3 dose escalation schedule. At the MTD, a cohort of patients was enrolled for target validation studies (separate manuscript). The starting dose was 0.125 mg/m(2), and doses were doubled within and between patients in the first phase. Blood and urine sampling for E7389 pharmacokinetics was performed on doses 1 and 3 of cycle 1. Levels were determined using a LC/MS/MS assay. RESULTS: Forty patients were entered. Thirty-eight were evaluable for toxicity and 35 for response. The rapid escalation ended with a grade 3 elevation of alkaline phosphatase at 0.5 mg/m(2)/week. The second phase ended at 2.0 mg/m(2)/week with dose-limiting toxicities of grades 3 and 4 febrile neutropenia. Other toxicities included hypoglycemia, hypophosphatemia, and fatigue. The MTD was 1.4 mg/m(2)/week. Responses included four partial responses (lung cancer [2], urothelial [1], and melanoma [1]). CONCLUSIONS: E7389 was well tolerated in this trial with the major toxicity being myelosuppression. PD shows that E7389 induces significant morphologic changes (bundle formation) in the microtubules of peripheral blood mononuclear cells and tumor cells in vivo. The data suggest that lower intra-tumoral levels of ß-tubulin III or higher intra-tumoral levels of MAP4 may correlate with response to E7389, while lower intra-tumoral levels of stathmin may be associated with progression. PK data reveal that E7389 exhibits a tri-exponential elimination from the plasma of patients receiving a rapid i.v. infusion. At sub-toxic doses, plasma concentrations of E7389 are maintained well above the levels required for activity in vitro for >72 h.