Martin Gutierrez

Phase 0 Clinical Trial of the Poly (ADP-Ribose) Polymerase Inhibitor ABT-888 in Patients With Advanced Malignancies

PURPOSE We conducted the first phase 0 clinical trial in oncology of a therapeutic agent under the Exploratory Investigational New Drug Guidance of the US Food and Drug Administration. It was a first-in-human study of the poly (ADP-ribose) polymerase (PARP) inhibitor ABT-888 in patients with advanced malignancies. PATIENTS AND METHODS ABT-888 was administered as a single oral dose of 10, 25, or 50 mg to determine the dose range and time course over which ABT-888 inhibits PARP activity in tumor samples and peripheral blood mononuclear cells, and to evaluate ABT-888 pharmacokinetics. Blood samples and tumor biopsies were obtained pre- and postdrug administration for evaluation of PARP activity and pharmacokinetics. A novel statistical approach was developed and utilized to study pharmacodynamic modulation as the primary end point for trials of limited sample size. RESULTS Thirteen patients with advanced malignancies received the study drug; nine patients underwent paired tumor biopsies. ABT-888 demonstrated good oral bioavailability and was well tolerated. Statistically significant inhibition of poly (ADP-ribose) levels was observed in tumor biopsies and peripheral blood mononuclear cells at the 25-mg and 50-mg dose levels. CONCLUSION Within 5 months of study activation, we obtained pivotal biochemical and pharmacokinetic data that have guided the design of subsequent phase I trials of ABT-888 in combination with DNA-damaging agents. In addition to accelerating the development of ABT-888, the rapid conclusion of this trial demonstrates the feasibility of conducting proof-of-principle phase 0 trials as part of an alternative paradigm for early drug development in oncology.

Phase II Study of Dose-Adjusted EPOCH and Rituximab in Untreated Diffuse Large B-Cell Lymphoma With Analysis of Germinal Center and Post-Germinal Center Biomarkers

PURPOSE To assess the clinical outcome and the influence of biomarkers associated with apoptosis inhibition (Bcl-2), tumor proliferation (MIB-1), and cellular differentiation on the outcome with dose-adjusted (DA) EPOCH (etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin) plus rituximab (R) infusional therapy in diffuse large B-cell lymphoma (DLBCL) with analysis of germinal center B-cell (GCB) and post-GCB subtypes by immunohistochemistry. PATIENTS AND METHODS Phase II study of 72 patients with untreated de novo DLBCL who were at least 18 years of age and stage II or higher. Radiation consolidation was not permitted. RESULTS Patients had a median age of 50 years (range, 19 to 85) and 40% had a high-intermediate or high International Prognostic Index (IPI). At 5 years, progression-free survival (PFS) and overall survival (OS) were 79% and 80%, respectively, with a median potential follow-up of 54 months. PFS was 91%, 90%, 67%, and 47%, and OS was 100%, 90%, 74%, and 37%, for 0 to 1, 2, 3, and 4 to 5 IPI factors, respectively, at 5 years. The Bcl-2 and MIB-1 biomarkers were not associated with PFS or OS. Based on DA-EPOCH historical controls, rituximab only benefited Bcl-2 positive tumors. Bcl-6 expression was associated with higher PFS whereas GCB exhibited a marginally significant higher PFS compared with post-GCB DLBCL. CONCLUSION DA-EPOCH-R outcome was not affected by tumor proliferation and rituximab appeared to overcome the adverse effect of Bcl-2. Bcl-6 may identify a biologic program associated with a superior outcome. Overall, DA-EPOCH-R shows promising outcome in low and intermediate IPI groups. A molecular model of treatment outcome with rituximab and chemotherapy is presented.

A Phase I Combination Study of Olaparib with Cisplatin and Gemcitabine in Adults with Solid Tumors

Purpose: To determine the safety and tolerability of olaparib with cisplatin and gemcitabine, establish the maximum tolerated dose (MTD), and evaluate the pharmacodynamic and pharmacokinetic profile of the combination. Experimental Design: We conducted a phase I study of olaparib with cisplatin and gemcitabine in patients with advanced solid tumors. Treatment at dose level 1 (DL1) consisted of olaparib 100 mg orally every 12 hours on days 1 to 4, gemcitabine 500 mg/m2 on days 3 and 10, and cisplatin 60 mg/m2 on day 3. PAR levels were measured in peripheral blood mononuclear cells (PBMC). Results: Dose-limiting toxicities (DLT) in two of three patients at DL1 included thrombocytopenia and febrile neutropenia. The protocol was amended to enroll patients treated with ≤2 prior severely myelosuppressive chemotherapy regimens and treated with olaparib 100 mg once daily on days 1 to 4 (DL−1). No DLTs were seen in six patients at DL−1. Because of persistent thrombocytopenia and neutropenia following a return to DL1, patients received 100 mg olaparib every 12 hours on day 1 only. No hematologic DLTs were observed; nonhematologic DLTs included gastrointestinal bleed, syncope, and hypoxia. Of 21 patients evaluable for response, two had partial response. Olaparib inhibited PARP in PBMCs and tumor tissue, although PAR levels were less effectively inhibited when olaparib was used for a short duration. Conclusions: Olaparib in combination with cisplatin and gemcitabine is associated with myelosuppression even at relatively low doses. Modified schedules of olaparib in chemotherapy naive patients will have to be explored with standard doses of chemotherapy. Clin Cancer Res; 18(8); 2344–51. ©2012 AACR.

Hand-foot skin reaction increases with cumulative sorafenib dose and with combination anti-vascular endothelial growth factor therapy

Purpose: Sorafenib, a vascular endothelial growth factor (VEGF) receptor-2 and RAF kinase inhibitor, commonly causes skin toxicity. We retrospectively analyzed dermatologic toxicity in patients receiving combined antiangiogenic therapy involving sorafenib and bevacizumab. Experimental Design: Castration-resistant prostate cancer and metastatic non-small cell lung cancer patients were accrued to phase II studies, receiving sorafenib 400 mg twice daily. A phase I study explored sorafenib 200 to 400 mg twice daily with bevacizumab 5 to 10 mg/kg every 2 weeks in patients with advanced solid tumors. The probability of development of maximum grade of dermatologic toxicity as a function of the cumulative dose of sorafenib was determined. Additional analyses compared extent of toxicity, pharmacokinetics, and patient risk factors. Results: Ninety-six patients were enrolled: 54 received sorafenib and 42 received bevacizumab/sorafenib. Hand-foot skin reaction (HFSR) was observed in 50 of 96 (52%) patients. Grade 2 to 3 HFSR developed in 16 of 54 (30%) sorafenib patients and 24 of 42 (57%) bevacizumab/sorafenib patients (P = 0.012) and was associated with cumulative sorafenib exposure (P = 0.0008). Twenty-four of 42 phase I patients randomized to start with bevacizumab had increased risk of grade 2 to 3 HFSR than those starting with sorafenib (P = 0.013) after adjusting for association between HFSR risk and hypertension (P = 0.01), which was the only toxicity associated with HFSR. There was no association between HFSR and baseline history of neuropathy, prior taxane/platinum treatment, or systemic sorafenib levels. Conclusions: Sorafenib-related HFSR is associated with increasing cumulative sorafenib dose. HFSR is increased in patients treated with bevacizumab/sorafenib combination anti-VEGF therapy, and this finding is not explained by pharmacokinetic interaction between the two agents. Our results suggest that the pathophysiology of HFSR may be related to VEGF inhibition.

Role of a Doxorubicin-Containing Regimen in Relapsed and Resistant Lymphomas: An 8-Year Follow-Up Study of EPOCH

PURPOSE Curative up-front regimens for non-Hodgkins lymphomas contain doxorubicin, vincristine, and cyclophosphamide, whereas salvage regimens generally contain non-cross-resistant agents. We hypothesized that up-front agents may be highly effective for salvage and developed an infusional regimen based on in vitro evidence of increased efficacy. PATIENTS AND METHODS A prospective phase II study of etoposide, vincristine, and doxorubicin over 96 hours with bolus cyclophosphamide and oral prednisone (EPOCH) was performed in 131 patients with relapsed or resistant lymphoma. RESULTS Seventy-nine percent of patients had aggressive histologies, 46% were considered high risk by the International Prognostic Index, and 34% had resistant disease. Eighty-eight percent of patients had received at least four of the agents in EPOCH, and 94% had received doxorubicin. In 125 assessable patients, 29 (24%) achieved complete responses and 60 (50%) achieved partial responses. Among 42 patients with resistant disease, 57% responded, and in 28 patients with relapsed aggressive de novo lymphomas, 89% responded with 54% complete responses. With a median follow-up of 76 months, the overall and event-free survivals (EFS) were 17.5 and 7 months, respectively. In 33 patients with sensitive aggressive disease who did not receive stem-cell transplantation, EFS was 19% at 36 months. Toxicity was primarily hematologic, with an 18% incidence of febrile neutropenia. No clinically significant cardiac toxicity was observed, despite no maximum cumulative doxorubicin dose. CONCLUSION EPOCH is highly effective in patients who had previously received most/all of the same drugs and produces durable remissions in curable subtypes. Salvage regimens need not contain non-cross-resistant agents, and infusional schedules may partially reverse drug resistance and reduce toxicity.

Phase I Trial of MS-275, a Histone Deacetylase Inhibitor, Administered Weekly in Refractory Solid Tumors and Lymphoid Malignancies

Purpose: MS-275 is a histone deacetylase inhibitor that has shown potent and unique anticancer activity in preclinical models. The aims of this phase I trial were to determine the dose-limiting toxicities and maximum tolerated dose of oral MS-275 in humans administered with food on a once weekly schedule and to study the pharmacokinetics of oral MS-275. Experimental Design: Patients with refractory solid tumors and lymphoid malignancies were treated with oral MS-275 on a once weekly schedule for 4 weeks of a 6-week cycle. Samples for pharmacokinetic and pharmacodynamic analyses were collected during cycle 1. Protein acetylation in subpopulations of peripheral blood mononuclear cells was measured using a multivariable flow cytometry assay. Results: A total of 22 patients were enrolled, and 19 were considered evaluable for toxicity. The maximum tolerated dose was 6 mg/m2. No National Cancer Institute Common Toxicity Criteria grade 4 toxicities were observed. Dose-limiting grade 3 toxicities were reversible and consisted of hypophosphatemia, hyponatremia, and hypoalbuminemia. Non–dose-limiting grade 3 myelosuppression was also observed. The mean terminal half-life of MS-275 was 33.9 ± 26.2 and the Tmax ranged from 0.5 to 24 h. Although there was considerable interpatient variability in pharmacokinetics, the area under the plasma concentration versus time curve increased linearly with dose. Conclusions: MS-275 is well tolerated at a dose of 6 mg/m2 administered weekly with food for 4 weeks every 6 weeks. Drug exposure increases linearly with dose, and protein acetylation increased in all the subpopulations of peripheral blood mononuclear cells following MS-275 administration.

Designing Phase 0 Cancer Clinical Trials

Phase 0 trials are designed primarily to evaluate the pharmacodynamic and/or pharmacokinetic properties of selected investigational agents before initiating more traditional phase I testing. One of the major objectives of phase 0 trials is to interrogate and refine a target or biomarker assay for drug effect in human samples implementing procedures developed and validated in preclinical models. Thus, close collaboration between laboratory scientists and clinical investigators is essential to the design and conduct of phase 0 trials. Given the relatively small number of patients and tissue samples, showing a significant drug effect in phase 0 trials requires precise and reproducible assay procedures and innovative statistical methodology. Furthermore, phase 0 trials involving limited exposure of a study agent administered at low doses and/or for a short period allow them to be initiated under the Food and Drug Administration exploratory investigational new drug guidance with less preclinical toxicity data than usually required for traditional first-in-human studies. Because of the very limited drug exposure, phase 0 trials offer no chance of therapeutic benefit, which can impede patient enrollment, particularly if invasive tumor biopsies are required. The challenges to accrual are not insurmountable, however, and well-designed and executed phase 0 trials are feasible and have great potential for improving the efficiency and success of subsequent trials, particularly those evaluating molecularly targeted agents.

Phase I trial of 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), a heat shock protein inhibitor, administered twice weekly in patients with advanced malignancies

PURPOSE Phase I dose-escalation study to determine the toxicity and maximum tolerated dose (MTD) of 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), a heat shock protein 90 (Hsp90) inhibitor, administered on a twice weekly schedule in patients with advanced cancer. EXPERIMENTAL DESIGN 17-DMAG was administered as a 1- to 2-h infusion twice weekly in 4-week cycles. An accelerated titration design was followed until toxicity was observed, at which point standard dose-escalation proceeded. MTD was defined as the dose at which no more than one of the six patients experienced a dose-limiting toxicity (DLT). Pharmacokinetics were assessed, and Hsp70 mRNA, whose gene product is a chaperone previously shown to be upregulated following the inhibition of Hsp90, was measured in peripheral blood mononuclear cells (PBMCs). RESULTS A total of 31 patients received 92 courses of treatment. The MTD was 21mg/m(2)/d; 20 patients were enrolled at this dose level. Nine patients had stable disease for a median of 4 (range 2-22) months. Both C(max) and AUC increased proportionally with dose. The most common toxicities were grade 1 or 2 fatigue, anorexia, nausea, blurred vision and musculoskeletal pain. DLTs were peripheral neuropathy and renal dysfunction. Expression of Hsp70 mRNA in PBMCs was highly variable. CONCLUSION Twice-weekly i.v. infusion of 17-DMAG is well tolerated, and combination phase I studies are warranted.

A Phase I Study of PF-04929113 (SNX-5422), an Orally Bioavailable Heat Shock Protein 90 Inhibitor, in Patients with Refractory Solid Tumor Malignancies and Lymphomas

Purpose: To determine the maximum tolerated dose (MTD), toxicities, and pharmacokinetic/pharmacodynamic profile of the Hsp90 inhibitor PF-04929113 (SNX-5422) in patients with advanced solid tumors and lymphomas. Methods: This was a single-institution, phase I, dose-escalation study of PF-04929113 administered twice weekly. Endpoints included determination of dose-limiting toxicities (DLT), MTD, the safety profile of PF-04929113, pharmacodynamic assessment of PF-04929113 on Hsp70 induction, pharmacokinetic analysis of PF-04928473 (SNX-2112) and its prodrug PF-04929113, and assessment of response. Results: Thirty-three patients with advanced malignancies were treated. Dose escalation was continued up to 177 mg/m2 administered orally twice a week. One DLT (nonseptic arthritis) was noted. No grade 4 drug-related adverse events were seen; grade 3 adverse events included diarrhea (9%), nonseptic arthritis (3%), aspartate aminotransferase elevation (3%), and thrombocytopenia (3%). No objective responses were seen in 32 evaluable patients. Fifteen patients (47%) had stable disease; 17 patients (53%) had progressive disease. Pharmacokinetic data revealed rapid absorption, hepatic, and extrahepatic clearance, extensive tissue binding, and almost linear pharmacokinetics of the active drug PF-04928473. Pharmacodynamic studies confirmed inhibition of Hsp90 and a linear correlation between pharmacokinetic parameters and Hsp70 induction. Conclusions: PF-04929113 administered orally twice a week is well tolerated and inhibits its intended target Hsp90. No objective responses were seen, but long-lasting stabilizations were obtained. Although no clinically significant drug-related ocular toxicity was seen in this study, the development of PF-04929113 has been discontinued because of ocular toxicity seen in animal models and in a separate phase I study. Clin Cancer Res; 17(21); 6831–9. ©2011 AACR.

Monitoring drug-induced gammaH2AX as a pharmacodynamic biomarker in individual circulating tumor cells.

Purpose: Circulating tumor cells (CTC) in peripheral blood of patients potentially represent a fraction of solid tumor cells available for more frequent pharmacodynamic assessment of drug action than is possible using tumor biopsy. However, currently available CTC assays are limited to cell membrane antigens. Here, we describe an assay that directly examines changes in levels of the nuclear DNA damage marker γH2AX in individual CTCs of patients treated with chemotherapeutic agents. Experimental Design: An Alexa Fluor 488–conjugated monoclonal γH2AX antibody and epithelial cancer cell lines treated with topotecan and spiked into whole blood were used to measure DNA damage–dependent nuclear γH2AX signals in individual CTCs. Time-course changes in both CTC number and γH2AX levels in CTCs were also evaluated in blood samples from patients undergoing treatment. Results: The percentage of γH2AX-positive CTCs increased in a concentration-dependent manner in cells treated with therapeutically relevant concentrations of topotecan ex vivo. In samples from five patients, percent γH2AX-positive cells increased post-treatment from a mean of 2% at baseline (range, 0-6%) to a mean of 38% (range, 22-64%) after a single day of drug administration; this increase was irrespective of increases or decreases in the total CTC count. Conclusions: These data show promise for monitoring dynamic changes in nuclear biomarkers in CTCs (in addition to CTC count) for rapidly assessing drug activity in clinical trials of molecularly targeted anticancer therapeutics as well as for translational research. Clin Cancer Res; 16(3); 1073–84