Udai Banerji

Phase I Pharmacokinetic and Pharmacodynamic Study of 17-Allylamino, 17-Demethoxygeldanamycin in Patients With Advanced Malignancies

PURPOSE To study the toxicity and pharmacokinetic-pharmacodynamic profile of 17-allylamino, 17- demethoxygeldanamycin (17-AAG) and to recommend a dose for phase II trials. PATIENTS AND METHODS This was a phase I study examining a once-weekly dosing schedule of 17-AAG. Thirty patients with advanced malignancies were treated. RESULTS The highest dose level reached was 450 mg/m(2)/week. The dose-limiting toxicities (DLTs) encountered were grade 3 diarrhea in three patients (one at 320 mg/m(2)/week and two at 450 mg/m(2)/week) and grade 3 to 4 hepatotoxicity (AST/ALT) in one patient at 450 mg/m(2)/week. Two of nine DLTs were at the highest dose level. Two patients with metastatic melanoma had stable disease and were treated for 15 and 41 months, respectively. The dose versus area under the curve-relationship for 17-AAG was linear (r(2) = .71) over the dose range 10 to 450 mg/m(2)/week, with peak plasma concentrations of 8,998 mug/L (standard deviation, 2,881) at the highest dose level. After the demonstration of pharmacodynamic changes in peripheral blood leukocytes, pre- and 24 hours post-treatment, tumor biopsies were performed and demonstrated target inhibition (c-RAF-1 inhibition in four of six patients, CDK4 depletion in eight of nine patients and HSP70 induction in eight of nine patients) at the dose levels 320 and 450 mg/m(2)/week. It was not possible to reproducibly demonstrate these changes in biopsies taken 5 days after treatment. CONCLUSION It has been possible to demonstrate that 17-AAG exhibits a tolerable toxicity profile with therapeutic plasma concentrations and target inhibition for 24 hours after treatment and some indications of clinical activity at the dose level 450 mg/m(2)/week. We recommend this dose for phase II clinical trials.

Heat shock protein 90 as a drug target: some like it hot.

Heat shock protein 90 (HSP90) is a ubiquitously expressed chaperone that is involved in the posttranslational folding and stability of proteins. Inhibition at the NH2-terminal ATP-binding site leads to the degradation of client proteins by the ubiquitin proteasome pathway. Inhibition of HSP90 leads to the degradation of known oncogenes, such as ERB-B2, BRAF, and BCR-ABL, leading to the combinatorial blockade of multiple signal transduction pathways, such as the RAS-RAF-mitogen-activated protein/extracellular signal-regulated kinase kinase-extracellular signal-regulated kinase and phosphatidylinositol 3-kinase pathways. Multiple structurally diverse HSP90 inhibitors are undergoing early clinical evaluation. The clinical focus of these drugs should be solid tumors, such as breast, prostate, and lung cancers, along with malignant melanoma, in addition to hematologic malignancies, such as chronic myeloid leukemia and multiple myeloma. HSP90 inhibitors can be used as single agents or in combination with other targeted treatments or conventional forms of treatment such as chemotherapy and radiotherapy. Clinical trials evaluating efficacy of these agents should include innovative designs to capture cytostasis evidenced by clinical nonprogression and enrichment of patient populations by molecular characterization. The results of clinical trials evaluating the efficacy of drugs targeting this exciting target are awaited.

Gene expression profiling of human colon cancer cells following inhibition of signal transduction by 17-allylamino-17-demethoxygeldanamycin, an inhibitor of the hsp90 molecular chaperone.

A number of molecular therapeutic agents, derived from exploiting our knowledge of the oncogenic pathways that are frequently deregulated in cancer, are now entering clinical trials. One of these is the novel agent 17-allylamino-17-demethoxygeldanamycin that acts to inhibit the hsp90 molecular chaperone. Treatment of four human colon cancer cell lines with iso-effective concentrations of this agent resulted in depletion of c-raf-1 and akt and inhibition of signal transduction. We have used gene expression array analysis to identify genes responsive to treatment with this drug. The expression of hsp90 client protein genes was not affected, but hsc hsp70, hsp90β, keratin 8, keratin 18 and caveolin-1 were deregulated following treatment. These observations were consistent with inhibition of signal transduction and suggested a possible mechanism of resistance or recovery from 17-allylamino-17-demethoxygeldanamycin treatment. The results shed light on the molecular mode of action of the hsp90 inhibitors, and suggest possible molecular markers of drug action for use in hypothesis testing clinical trials.

The First-in-Human Study of the Hydrogen Sulfate (Hyd-Sulfate) Capsule of the MEK1/2 Inhibitor AZD6244 (ARRY-142886): A Phase I Open-Label Multicenter Trial in Patients with Advanced Cancer

Purpose: In part A, the aim was to define the maximum tolerated dose (MTD) of the hydrogen sulfate (Hyd-Sulfate) oral capsule formulation of the mitogen-activated protein kinase kinase inhibitor AZD6244 (ARRY-142886). In part B, the aim was to compare the pharmacokinetic profile of the new Hyd-Sulfate capsule with the initial AZD6244 free-base suspension and further characterize the pharmacodynamic profile and efficacy of the new formulation. Experimental Design: In part A, 30 patients received escalating doses of AZD6244 Hyd-Sulfate twice daily. In part B, 29 patients were randomized to a single dose of the Hyd-Sulfate capsule or free-base suspension, followed by a washout, then a single dose of the alternative formulation. Patients received the Hyd-Sulfate capsule twice daily at MTD of part A thereafter. Results: The MTD of the Hyd-Sulfate capsule was 75 mg twice daily. Dose limiting toxicities were Common Terminology Criteria for Adverse Events grade 3 acneiform rash and pleural effusion. Fatigue (65.7%) and acneiform dermatitis (60.0%) were the most frequent adverse events at the MTD. Based on area under curve0-24, exposure of the 75 mg Hyd-Sulfate capsule relative to the 100 mg free-base suspension was 197% (90% confidence interval, 161-242%). Pharmacodynamic analysis showed that inhibition of 12-O-tetradecanoylphorbol-13-acetate–induced extracellular signal-regulated kinase phosphorylation in peripheral blood lymphocytes was related to plasma concentrations of AZD6244, with an estimated IC50 of 352 ng/mL and maximum inhibition (Emax) of ∼91%, showing target inhibition. A patient with metastatic melanoma bearing a V600E BRAF mutation achieved a complete response persisting after 15 months of therapy. Conclusions: The AZD6244 Hyd-Sulfate capsule formulation has shown a favorable toxicity, pharmacokinetic, and pharmacodynamic profile, and is being taken forward in ongoing clinical trials. Clin Cancer Res; 16(5); 1613–23

Pharmacokinetic-pharmacodynamic relationships for the heat shock protein 90 molecular chaperone inhibitor 17-allylamino, 17-demethoxygeldanamycin in human ovarian cancer xenograft models.

Purpose: To establish the pharmacokinetic and pharmacodynamic profile of the heat shock protein 90 (HSP90) inhibitor 17-allylamino, 17-demethoxygeldanamycin (17-AAG) in ovarian cancer xenograft models. Experimental Design: The effects of 17-AAG on growth inhibition and the expression of pharmacodynamic biomarkers c-RAF-1, CDK4, and HSP70 were studied in human ovarian cancer cell lines A2780 and CH1. Corresponding experiments were conducted with established tumor xenografts. The variability and specificity of pharmacodynamic markers in human peripheral blood lymphocytes (PBL) were studied. Results: The IC50 values of 17-AAG in A2780 and CH1 cells were 18.3 nmol/L (SD, 2.3) and 410.1 nmol/L (SD, 9.4), respectively. Pharmacodynamic changes indicative of HSP90 inhibition were demonstrable at greater than or equal the IC50 concentration in both cell lines. Xenograft experiments confirmed tumor growth inhibition in vivo. Peak concentrations of 17-AAG achieved in A2780 and CH1 tumors were 15.6 and 16.5 μmol/L, respectively, and there was no significant difference between day 1 and 11 pharmacokinetic profiles. Reversible changes in pharmacodynamic biomarkers were shown in tumor and murine PBLs in both xenograft models. Expression of pharmacodynamic markers varied between human PBLs from different human volunteers but not within the same individual. Pharmacodynamic biomarker changes consistent with HSP90 inhibition were shown in human PBLs exposed ex vivo to 17-AAG but not to selected cytotoxic drugs. Conclusion: Pharmacokinetic-pharmacodynamic relationships were established for 17-AAG. This information formed the basis of a pharmacokinetic-pharmacodynamic-driven phase I trial.

Biomarker-driven Early Clinical Trials in Oncology: A Paradigm Shift in Drug Development

Early clinical trials represent a crucial bridge between preclinical drug discovery and the especially resource-intense randomized phase III trial—the definitive regulatory hurdle for drug approval. High attrition rates and rising costs, when coupled with the extraordinary opportunities opened up by cancer genomics and the promise of personalized medicine call for new approaches in the conduct and design of phase I/II trials. The key challenge lies in increasing the odds for successful and efficient transition of a compound through the drug development pipeline. The incorporation of scientifically and analytically validated biomarkers into rationally designed hypothesis-testing clinical trials offers a promising way forward to achieving this objective. In this article, we provide an overview of biomarkers in early clinical trials, including examples where they have been particularly successful, and the caveats and pitfalls associated with indiscriminate application. We describe the use of pharmacodynamic end points to demonstrate the proof of modulation of target, pathway, and biologic effect, as well as predictive biomarkers for patient selection and trial enrichment. Establishing the pharmacologic audit trail provides a means to assess and manage risk in a drug development program and thus increases the rationality of the decision-making process. Accurate preclinical models are important for pharmacokinetic-pharmacodynamic-efficacy modeling and biomarker validation. The degree of scientific and analytical validation should ensure that biomarkers are fit-for purpose, according to the stage of development and the impact on the trial; specifically they are either exploratory or used to make decisions within the trial. To be maximally useful at an early stage, these must be in place before the commencement of phase I trials. Validation and qualification of biomarkers then continues through clinical development. We highlight the impact of modern technology platforms, such as genomics, proteomics, circulating tumor cells, and minimally invasive functional and molecular imaging, with respect to their potential role in improving the success rate and speed of drug development and in interrogating the consequences of therapeutic intervention and providing a unique insight into human disease biology. With these technologies already having an impact in the clinic today, we predict that further future advances will come from the application of network analysis to clinical trials, leading to individualized systems-based medicine for cancer.

A Phase I Study of the Heat Shock Protein 90 Inhibitor Alvespimycin (17-DMAG) Given Intravenously to Patients with Advanced Solid Tumors

Purpose: A phase I study to define toxicity and recommend a phase II dose of the HSP90 inhibitor alvespimycin (17-DMAG; 17-dimethylaminoethylamino-17-demethoxygeldanamycin). Secondary endpoints included evaluation of pharmacokinetic profile, tumor response, and definition of a biologically effective dose (BED). Patients and Methods: Patients with advanced solid cancers were treated with weekly, intravenous (i.v.) 17-DMAG. An accelerated titration dose escalation design was used. The maximum tolerated dose (MTD) was the highest dose at which ≤1/6 patients experienced dose limiting toxicity (DLT). Dose de-escalation from the MTD was planned with mandatory, sequential tumor biopsies to determine a BED. Pharmacokinetic and pharmacodynamic assays were validated prior to patient accrual. Results: Twenty-five patients received 17-DMAG (range 2.5–106 mg/m2). At 106 mg/m2 of 17-DMAG 2/4 patients experienced DLT, including one treatment-related death. No DLT occurred at 80 mg/m2. Common adverse events were gastrointestinal, liver function changes, and ocular. Area under the curve and mean peak concentration increased proportionally with 17-DMAG doses 80 mg/m2 or less. In peripheral blood mononuclear cells significant (P < 0.05) HSP72 induction was detected (≥20 mg/m2) and sustained for 96 hours (≥40 mg/m2). Plasma HSP72 levels were greatest in the two patients who experienced DLT. At 80 mg/m2 client protein (CDK4, LCK) depletion was detected and tumor samples from 3 of 5 patients confirmed HSP90 inhibition. Clinical activity included complete response (castration refractory prostate cancer, CRPC 124 weeks), partial response (melanoma, 159 weeks), and stable disease (chondrosarcoma, CRPC, and renal cancer for 28, 59, and 76 weeks, respectively). Couclusions: The recommended phase II dose of 17-DMAG is 80 mg/m2 weekly i.v. Clin Cancer Res; 17(6); 1561–70. ©2011 AACR.

Gene and Protein Expression Profiling of Human Ovarian Cancer Cells Treated with the Heat Shock Protein 90 Inhibitor 17-Allylamino-17-Demethoxygeldanamycin

The promising antitumor activity of 17-allylamino-17-demethoxygeldanamycin (17AAG) results from inhibition of the molecular chaperone heat shock protein 90 (HSP90) and subsequent degradation of multiple oncogenic client proteins. Gene expression microarray and proteomic analysis were used to profile molecular changes in the A2780 human ovarian cancer cell line treated with 17AAG. Comparison of results with an inactive analogue and an alternative HSP90 inhibitor radicicol indicated that increased expression of HSP72, HSC70, HSP27, HSP47, and HSP90beta at the mRNA level were on-target effects of 17AAG. HSP27 protein levels were increased in tumor biopsies following treatment of patients with 17AAG. A group of MYC-regulated mRNAs was decreased by 17AAG. Of particular interest and novelty were changes in expression of chromatin-associated proteins. Expression of the heterochromatin protein 1 was increased, and expression of the histone acetyltransferase 1 and the histone arginine methyltransferase PRMT5 was decreased by 17AAG. PRMT5 was shown to be a novel HSP90-binding partner and potential client protein. Cellular protein acetylation was reduced by 17AAG, which was shown to have an antagonistic interaction on cell proliferation with the histone deacetylase inhibitor trichostatin A. This mRNA and protein expression analysis has provided new insights into the complex molecular pharmacology of 17AAG and suggested new genes and proteins that may be involved in response to the drug or be potential biomarkers of drug action.

Antibody-drug conjugates—an emerging class of cancer treatment

Antibody-drug conjugates (ADCs) are an emerging novel class of anticancer treatment agents that combines the selectivity of targeted treatment with the cytotoxic potency of chemotherapy drugs. New linker technology associated with novel highly potent cytotoxic payloads has permitted the development of more effective and safe ADCs. In recent years, two ADCs have been licensed, T-DM1 and brentuximab vedotin, and are already establishing their place in cancer treatment. A plethora of ADCs are being investigated in phases I and II trials, emerging data of which appears promising. As we deepen our understanding of what makes a successful ADC, an increasing number of ADCs will likely become viable treatment options as single agents or in combination with chemotherapy. This review will present the philosophy underlying ADCs, their main characteristics and current research developments with a focus on ADCs in solid tumours.

Serial Next-Generation Sequencing of Circulating Cell-Free DNA Evaluating Tumor Clone Response To Molecularly Targeted Drug Administration

Purpose: We evaluated whether next-generation sequencing (NGS) of circulating cell-free DNA (cfDNA) could be used for patient selection and as a tumor clone response biomarker in patients with advanced cancers participating in early-phase clinical trials of targeted drugs. Experimental Design: Plasma samples from patients with known tumor mutations who completed at least two courses of investigational targeted therapy were collected monthly, until disease progression. NGS was performed sequentially on the Ion Torrent PGM platform. Results: cfDNA was extracted from 39 patients with various tumor types. Treatments administered targeted mainly the PI3K–AKT–mTOR pathway (n = 28) or MEK (n = 7). Overall, 159 plasma samples were sequenced with a mean sequencing coverage achieved of 1,685X across experiments. At trial initiation (C1D1), 23 of 39 (59%) patients had at least one mutation identified in cfDNA (mean 2, range 1–5). Out of the 44 mutations identified at C1D1, TP53, PIK3CA and KRAS were the top 3 mutated genes identified, with 18 (41%), 9 (20%), 8 (18%) different mutations, respectively. Out of these 23 patients, 13 received a targeted drug matching their tumor profile. For the 23 patients with cfDNA mutation at C1D1, the monitoring of mutation allele frequency (AF) in consecutive plasma samples during treatment with targeted drugs demonstrated potential treatment associated clonal responses. Longitudinal monitoring of cfDNA samples with multiple mutations indicated the presence of separate clones behaving discordantly. Molecular changes at cfDNA mutation level were associated with time to disease progression by RECIST criteria. Conclusions: Targeted NGS of cfDNA has potential clinical utility to monitor the delivery of targeted therapies. Clin Cancer Res; 21(20); 4586–96. ©2015 AACR.