Phase II Study of Palbociclib (PD-0332991) in CCND1, 2, or 3 Amplification: Results from the NCI-MATCH ECOG-ACRIN Trial (EAY131) Subprotocol Z1B

PURPOSE

Cyclin D/CDK4/6 is critical in controlling the G1 to S checkpoint. CCND, the gene encoding cyclin D, is known to be amplified in a variety of solid tumors. Palbociclib is an oral CDK4/6 inhibitor, approved in advanced breast cancer in combination with endocrine therapy. We explored the efficacy of palbociclib in patients with nonbreast solid tumors containing an amplification in CCND1, 2, or 3.

PATIENTS AND METHODS

Patients with tumors containing a CCND1, 2, or 3 amplification and expression of the retinoblastoma protein were assigned to subprotocol Z1B and received palbociclib 125 mg once daily for 21 days of a 28-day cycle. Tumor response was assessed every two cycles.

RESULTS

Forty patients were assigned to subprotocol Z1B; 4 patients had outside assays identifying the CCND1, 2, or 3 amplification and were not confirmed centrally; 3 were ineligible and 2 were not treated (1 untreated patient was also ineligible), leaving 32 evaluable patients for this analysis. There were no partial responses; 12 patients (37.5%) had stable disease as best response. There were seven deaths on study, all during cycle 1 and attributable to disease progression. Median progression-free survival was 1.8 months. The most common toxicities were leukopenia (n = 21, 55%) and neutropenia (n = 19, 50%); neutropenia was the most common grade 3/4 event (n = 12, 32%).

CONCLUSIONS

Palbociclib was not effective at treating nonbreast solid tumors with a CCND1, 2, or 3 amplification in this cohort. These data do not support further investigation of single-agent palbociclib in tumors with CCND1, 2, or 3 amplification.

A phase 2 study of defactinib (VS-6063) in patients with NF2 altered tumors: Results from NCI-match (EAY131) subprotocol U

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Background: The NCI-MATCH trial assigns patients (pts) with solid tumors, lymphomas, or multiple myeloma to targeted therapies based on genetic alterations identified in tumor biopsies. Neurofibromatosis 2 (NF2)-inactivated tumors demonstrate increased sensitivity to FAK inhibition in preclinical models. Arm U evaluated the FAK inhibitor defactinib in pts with NF2 altered tumors. Methods: Patients found to harbor an inactivating NF2 mutation on NGS were assigned to the ARM U substudy MATCH. Defactinib 400 mg was given by mouth twice daily until progression or intolerable toxicity. The primary endpoint was objective response rate (ORR). Secondary endpoints included toxicity, progression-free survival (PFS), and 6-month PFS. Results: Of 5,548 cases with sufficient tissue for genomic analysis, 51 pts were found to have NF2 alterations (< 1% of the total analyzed). While NF2 alterations are known to occur more commonly in meningiomas and mesotheliomas, alterations were also detected in an array of other tumor types, including renal cell carcinomas and ovarian cancers. Thirty-five pts were ultimately enrolled; 33 patients were started on therapy, with 2 of those determined to be ineligible for outcome analysis. All pts had received at least one prior therapy, with 52% (16/31) having received 3 or more prior lines of therapy. Median follow-up was 35.9 months. ORR [90% CI] was 3% (1/31, [0.16, 14.86]), with the one partial response in a pt with choroid meningioma. Of the twelve pts whose best response was stable disease (39%, 12/31), 8 demonstrated some degree of tumor shrinkage (Table) with a disease control rate of 42% (13/31). Median PFS was 1.9 months for the 31 eligible pts who received study treatment, with median PFS of 9.3 months for the 9 patients who had a best response of stable disease or better. Six pts achieved a PFS of greater than 5.5 months. Among all treated pts (n=33), the most common treatment-related toxicities were fatigue (36%), nausea (33%), and hyperbilirubinemia (27%). There were no grade 4 or 5 toxicities; 27% of pts had grade 3 toxicities. No correlation could be made between clinical outcomes and tumor histology or specific NF2 genotype. Conclusions: Defactinib monotherapy had limited clinical activity in this cohort of previously treated patients with solid tumors exhibiting NF2 loss. Clinical trial information: NCT04439331. [Table: see text]

Abstract CT061: Binimetinib in patients with tumors with NRAS mutations: NCI-MATCH ECOG-ACRIN Cancer Research Group subprotocol EAY131-Z1A

Background: NRAS-mutations are established oncologic drivers in many malignancies with no effective targeted therapy options. Preclinical and clinical data have suggested that downstream inhibition with a MEK inhibitor, such as binimetinib, might be efficacious for NRAS-mutated cancers. Methods: Patients who enrolled in the multicenter NCI-MATCH trial master protocol underwent tumor biopsy and molecular profiling by targeted next generation sequencing with a custom Oncomine AmpliSeq™ panel. Patients with refractory solid tumors harboring codon 12, 13, or 61 NRAS-mutations were enrolled in subprotocol Z1A, a single arm study of binimetinib 45 mg twice daily. Patients with melanoma were excluded. The primary endpoint was objective response rate (ORR). Secondary endpoints included progression-free survival (PFS) and overall survival (OS). A post-hoc analysis examined association of NRAS-mutation allele with outcome and histology. Results: 47 eligible patients with refractory solid tumors harboring codon 12, 13, or 61 NRAS-mutations were treated on this trial. The most common cancer types enrolled on this subprotocol were colorectal adenocarcinoma (24/47, 51%), cholangiocarcinoma (7/47, 15%), low-grade papillary serous carcinoma of the ovary (3/47, 6%), and endometrioid endometrial adenocarcinoma patients (3/47, 6%). Observed toxicity was moderate, similar to previous reports, and 27.7% (13 of 47) of eligible patients discontinued binimetinib because of adverse events. The ORR was 2.1% (1 of 47 patients), and the median PFS was 3.5 months. The sole confirmed partial response (PR) was observed in a codon 61 NRAS-mutated indolent malignant ameloblastoma. One patient with a colorectal cancer harboring a NRAS codon 61 mutation had an unconfirmed PR, and two others with NRAS codon 61 mutated colorectal cancer had stable disease for at least 12 months. In a post-hoc analysis, patients with cancers bearing a codon 61 NRAS-mutation (n=22) had a significantly longer OS (p=0.04) and PFS (p=0.006) than those with tumors harboring codon 12 or 13 NRAS-mutations (n=25). Similarly, colorectal cancer patients with NRAS codon 61 mutations treated with binimetinib (n=8) had a significantly longer OS (p=0.03) and PFS (p=0.007) than those with NRAS codon 12 or 13 mutated (n=16) tumors. Conclusions: Single-agent binimetinib did not demonstrate promising efficacy in NRAS-mutated solid tumors. Further studies are needed to clarify whether the increased OS and PFS observed in codon 61 NRAS-mutated cancers reflects a more favorable prognosis for this subtype.

Citation Format: James M. Cleary, Victoria Wang, Rebecca Heist, Scott Kopetz, Edith P. Mitchell, James Zwiebel, Helen X. Chen, Shuli Li, Robert Gray, Lisa McShane, Larry Rubinstein, David Patton, Funda Meric-Bernstam, Melissa Dillmon, Mickey Williams, Stanley Hamilton, Barbara Conley, Peter O'Dwyer, Lyndsay Harris, Carlos Arteaga, Alice Chen, Keith Flaherty. Binimetinib in patients with tumors with NRAS mutations: NCI-MATCH ECOG-ACRIN Cancer Research Group subprotocol EAY131-Z1A [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT061.

Transforming the Early Drug Development Paradigm at the National Cancer Institute: The Formation of NCI's Experimental Therapeutics Clinical Trials Network (ETCTN)

Early drug development for cancer requires broad collaboration and skilled clinical investigators to enable enrollment of patients whose tumors have defined molecular profiles. To respond to these challenges, the National Cancer Institute (NCI) transformed its 60-year-old early-phase drug development program in 2014 into the Experimental Therapeutics Clinical Trials Network (ETCTN). The ETCTN is a consolidated, national network of 40+ academic institutions responsible for conducting more than 100 early-phase clinical trials. It promotes team science coordinated among basic, translational, and clinical investigators, emphasizing the inclusion of early career trialists. This perspective provides a brief overview of the ETCTN, summarizes its successes and challenges over its first grant funding cycle, and discusses the program's future directions. Measures indicated strong connectivity across the institutions, significant increases in investigator approval of the ETCTN scientific portfolio from years 1 to 4, and substantial research activity over 5 years, with 334 letters of intent submitted, 102 trials activated, and 3,570 patients accrued. The ETCTN's successful adoption relied heavily on the inclusion of senior investigators who have long-standing interactions with the NCI and a willingness to participate in a team science approach and to mentor early career investigators. In addition, NCI invested substantial resources in a centralized infrastructure to conduct trials and to support the inclusion of biomarkers in its studies. The ETCTN provides evidence that a collaborative national clinical trial network for early drug development is feasible and can address the demands of precision medicine approaches to oncologic clinical trials.

Combination of the histone deacetylase inhibitor vorinostat with bevacizumab in patients with clear-cell renal cell carcinoma: a multicentre, single-arm phase I/II clinical trial

BACKGROUND

Class II histone deacetylase (HDAC) inhibitors induce hypoxia-inducible factor-1 and -2α degradation and have antitumour effects in combination with vascular endothelial growth factor (VEGF) inhibitors. In this study, we tested the safety and efficacy of the HDAC inhibitor vorinostat and the VEGF blocker bevacizumab in metastatic clear-cell renal cell carcinoma (ccRCC) patients previously treated with different drugs including sunitinib, sorafenib, axitinib, interleukin-2, interferon, and temsirolimus.

METHODS

Patients with up to two prior regimens were eligible for treatment, consisting of vorinostat 200 mg orally two times daily × 2 weeks, and bevacizumab 15 mg kg-1 intravenously every 3 weeks. The primary end points were safety and tolerability, and the proportion of patients with 6 months of progression-free survival (PFS). Correlative studies included immunohistochemistry, FDG PET/CT scans, and serum analyses for chemokines and microRNAs.

RESULTS

Thirty-six patients were enrolled, with 33 evaluable for toxicity and efficacy. Eighteen patients had 1 prior treatment, 13 patients had 2 prior treatments, and 2 patients were treatment naïve. Two patients experienced grade 4 thrombocytopenia and three patients had grade 3 thromboembolic events during the course of exposure. We observed six objective responses (18%), including one complete response and five partial responses. The proportion of patients with PFS at 6 months was 48%. The median PFS and overall survival were 5.7 months (confidence interval (CI): 4.1-11.0) and 13.9 months (CI: 9.8-20.7), respectively. Correlative studies showed that modulation of specific chemokines and microRNAs were associated with clinical benefit.

CONCLUSIONS

The combination of vorinostat with bevacizumab as described is relatively well tolerated. Response rate and median PFS suggest clinical activity for this combination strategy in previously treated ccRCC.

Radiation-Therapeutic Agent Clinical Trials: Leveraging Advantages of a National Cancer Institute Programmatic Collaboration

A number of oncology phase II radiochemotherapy trials with promising results have been conducted late in the overall experimental therapeutic agent development process. Accelerated development and approval of experimental therapeutic agents have stimulated further interest in much earlier radiation-agent studies to increase the likelihood of success in phase III trials. To sustain this interest, more forward-thinking preclinical radiobiology experimental designs are needed to improve discovery of promising radiochemotherapy plus agent combinations for clinical trial testing. These experimental designs should better inform next-step radiation-agent clinical trial dose, schedule, exposure, and therapeutic effect. Recognizing the need for a better strategy to develop preclinical data supporting radiation-agent phase I or II trials, the National Cancer Institute (NCI)-Cancer Therapy Evaluation Program (CTEP) and the NCI-Molecular Radiation Therapeutics Branch of the Radiation Research Program have partnered to promote earlier radiobiology studies of CTEP portfolio agents. In this Seminars in Radiation Oncology article, four key components of this effort are discussed. First, we outline steps for accessing CTEP agents for preclinical testing. Second, we propose radiobiology studies that facilitate transition from preclinical testing to early phase trial activation. Third, we navigate steps that walk through CTEP agent strategic development paths available for radiation-agent testing. Fourth, we highlight a new NCI-sponsored cooperative agreement grant supporting in vitro and in vivo radiation-CTEP agent testing that informs early phase trial designs. Throughout the article, we include contemporary examples of successful radiation-agent development initiatives.

National Cancer Institute's Precision Medicine Initiatives for the new National Clinical Trials Network

The promise of precision medicine will only be fully realized if the research community can adapt its clinical trials methodology to study molecularly characterized tumors instead of the traditional histologic classification. Such trials will depend on adequate tissue collection, availability of quality controlled, high throughput molecular assays, and the ability to screen large numbers of tumors to find those with the desired molecular alterations. The National Cancer Institute's (NCI) new National Clinical Trials Network (NCTN) is well positioned to conduct such trials. The NCTN has the ability to seamlessly perform ethics review, register patients, manage data, and deliver investigational drugs across its many sites including both in cities and rural communities, academic centers, and private practices. The initial set of trials will focus on different questions: (1) Exceptional Responders Initiative-why do a minority of patients with solid tumors or lymphoma respond very well to some drugs even if the majority do not?; (2) NCI MATCH trial-can molecular markers predict response to targeted therapies in patients with advanced cancer resistant to standard treatment?; (3) ALCHEMIST trial-will targeted epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) inhibitors improve survival for adenocarcinoma of the lung in the adjuvant setting?; and (4) Lung Cancer Master Protocol trial for advanced squamous cell lung cancer-is there an advantage to developing drugs for small subsets of molecularly characterized tumors in a single, multiarm trial design? These studies will hopefully spawn a new era of treatment trials that will carefully select the tumors that may respond best to investigational therapy.

A phase I trial and viral clearance study of reovirus (Reolysin) in children with relapsed or refractory extra-cranial solid tumors: a Children's Oncology Group Phase I Consortium report

BACKGROUND

Reovirus is a naturally occurring human virus that is cytopathic to malignant cells possessing an activated Ras signaling pathway. We conducted a phase I trial of Reolysin, a manufactured, proprietary isolate of purified reovirus, in children with relapsed/refractory extracranial solid tumors to define the recommended phase 2 dose (RP2D), toxicities, and pharmacokinetic properties when administered as a single agent or in combination with cyclophosphamide.

PROCEDURES

Reolysin was administered intravenously for 5 consecutive days, every 28 days. Using a 3 + 3 design, the following dose levels were evaluated: 3 × 10(8) Tissue Culture Inhibitory Dose 50% (TCID50 )/kg; 5 × 10(8) TCID50 /kg (maximum dose was 3 × 10(10) TCID50 ); and 5 × 10(8) TCID50 /kg plus oral cyclophosphamide (50 mg/m(2) /day × 21 days).

RESULTS

Twenty-nine patients were enrolled; 28 were eligible and 24 were evaluable for toxicity and response. There were no hematologic dose-limiting toxicities. Grade 5 respiratory failure and a Grade 5 thromboembolic event were reported, both in the setting of progressive disease. The median time to clear the reovirus viremia was 6.5 days. Eight of 24 patients were viremic beyond the 5 days of therapy, all were negative by day 17. No patient had detectable viral RNA in saliva or stool. There were no objective responses.

CONCLUSIONS

Reolysin at a dose of 5 × 10(8) TCID50 /kg daily for 5 days was well tolerated in children alone and in combination with oral cyclophosphamide. Virus was cleared rapidly from the serum and shedding in stool and saliva was not detectable.

Phase I study of the histone deacetylase inhibitor entinostat in combination with 13-cis retinoic acid in patients with solid tumours

BACKGROUND

Preclinical studies suggest that histone deacetylase (HDAC) inhibitors may restore tumour sensitivity to retinoids. The objective of this study was to determine the safety, tolerability, and the pharmacokinetic (PK)/pharmacodynamic (PD) profiles of the HDAC inhibitor entinostat in combination with 13-cis retinoic acid (CRA) in patients with solid tumours.

METHODS

Patients with advanced solid tumours were treated with entinostat orally once weekly and with CRA orally twice daily × 3 weeks every 4 weeks. The starting dose for entinostat was 4 mg m(-2) with a fixed dose of CRA at 1 mg kg(-1) per day. Entinostat dose was escalated by 1 mg m(-2) increments. Pharmacokinetic concentrations of entinostat and CRA were determined by LC/MS/MS. Western blot analysis of peripheral blood mononuclear cells and tumour samples were performed to evaluate target inhibition.

RESULTS

A total of 19 patients were enroled. The maximum tolerated dose (MTD) was exceeded at the entinostat 5 mg m(-2) dose level (G3 hyponatremia, neutropenia, and anaemia). Fatigue (G1 or G2) was a common side effect. Entinostat exhibited substantial variability in clearance (147%) and exposure. CRA trough concentrations were consistent with prior reports. No objective responses were observed, however, prolonged stable disease occurred in patients with prostate, pancreatic, and kidney cancer. Data further showed increased tumour histone acetylation and decreased phosphorylated ERK protein expression.

CONCLUSION

The combination of entinostat with CRA was reasonably well tolerated. The recommended phase II doses are entinostat 4 mg m(-2) once weekly and CRA 1 mg kg(-1) per day. Although no tumour responses were seen, further evaluation of this combination is warranted.

Pediatric phase I trial and pharmacokinetic study of vorinostat: a Children's Oncology Group phase I consortium report

PURPOSE

The purpose of this study was to determine the maximum-tolerated dose (MTD), dose-limiting toxicities (DLT), and pharmacokinetics of vorinostat administered as a single agent and in combination 13-cis retinoic acid (13cRA) in children with refractory solid tumors; to evaluate the tolerability of the solid tumor MTD in children with refractory leukemias; and to characterize the pharmacokinetics of a vorinostat suspension in children.

PATIENTS AND METHODS

Vorinostat was administered orally daily starting at 180 mg/m(2)/d with escalations planned in 30% increments. Pharmacokinetic studies were performed with the initial dose. Acetyl-histone (H3) accumulation was assessed by Western blotting of peripheral blood mononuclear cells (PBMC).

RESULTS

Sixty-four patients were enrolled on this multipart trial. In patients with solid tumors, the MTD was 230 mg/m(2)/d with dose-limiting neutropenia, thrombocytopenia, and hypokalemia at 300 mg/m(2)/d. DLTs observed with the combination of 13cRA and vorinostat included thrombocytopenia, neutropenia, anorexia, and hypertriglyceridemia, resulting in a MTD of vorinostat 180 mg/m(2)/d 4 times per week and 13cRA 80 mg/m(2)/dose twice per day, days 1 through 14 every 28 days. Wide interpatient variability was noted in vorinostat disposition, with area under the concentration-time curves at 230 mg/m(2)/d for the capsule (range, 1,415 to 9,291 ng/mL x hr) and oral suspension (range, 1,186 to 4,780 ng/mL x hr). Significant accumulation of acetylated H3 histone in PBMC was observed after administration of vorinostat, particularly at higher doses. One patient with neuroblastoma experienced a complete response to the combination.

CONCLUSION

In children with recurrent solid tumors, vorinostat is well-tolerated at 230 mg/m(2)/d, with a modest dose reduction being required when combining vorinostat with 13cRA. Drug disposition is similar to that observed in adults.

Phase II trial of the histone deacetylase inhibitor belinostat in women with platinum resistant epithelial ovarian cancer and micropapillary (LMP) ovarian tumours

AIM

Micropapillary/borderline (LMP) ovarian tumours are rarely included in clinical trials and are intrinsically resistant to radiation and chemotherapy. Platinum resistant epithelial ovarian cancer (EOC) has a poor prognosis. The histone deacetylase inhibitor belinostat demonstrated antitumour activity in pre-clinical ovarian cancer models.

METHODS

A phase II study was performed to evaluate the activity of belinostat in two patient populations: women with metastatic or recurrent platinum resistant (progression within 6 months) EOC and LMP ovarian tumours, both groups had received no more than 3 prior lines of chemotherapy. Belinostat 1000 mg/m(2)/d was administered iv days 1-5 of a 21 d cycle. Peripheral blood mononuclear cells (PBMCs) and tumour biopsies, where possible, for correlative studies were obtained prior to and following treatment.

RESULTS

Eighteen patients with EOC and 14 patients with LMP tumours were enrolled on study. Belinostat was well tolerated with no grade four toxicity (179 cycles). Grade 3 toxicity consisted of thrombosis (3 patients), hypersensitivity (1) and elevated ALP (1). One patient with LMP tumour had a partial response (unconfirmed) and 10 had stable disease (SD), 3 were non-evaluable. Median progression-free survival (PFS) was 13.4 months (95% confidence interval (CI), 5.6--not reached). Best response in patients with EOC was SD (nine patients) and median PFS was 2.3 months (95% CI, 1.2-5.7 months). An accumulation of acetylated histones H3 and H4 was noted in PBMCs and in tumour tissue.

CONCLUSIONS

Belinostat is well tolerated in both patient groups and shows some activity in patients with micropapillary (LMP) disease.

Vorinostat in advanced prostate cancer patients progressing on prior chemotherapy (National Cancer Institute Trial 6862): trial results and interleukin-6 analysis: a study by the Department of Defense Prostate Cancer Clinical Trial Consortium and University of Chicago Phase 2 Consortium

BACKGROUND

This phase 2 trial was designed to evaluate the efficacy of vorinostat in chemotherapy-pretreated patients with metastatic castration-resistant prostate cancer.

METHODS

Patients with disease progression on 1 prior chemotherapy, a prostate-specific antigen (PSA) >or=5 ng/mL, and adequate organ function were treated with 400 mg vorinostat orally daily. The primary endpoint was the 6-month progression rate. Secondary endpoints included safety, rate of PSA decline, objective response, overall survival, and effects of vorinostat on serum interleukin-6 (IL-6) levels.

RESULTS

Twenty-seven eligible patients were accrued. The median number of cycles delivered was 2 (range, 1-7). All patients were taken off therapy before 6 months. The best objective response in the eligible patient was stable disease in 2 (7%) patients. No PSA decline of >or=50% was observed. There was 1 grade 4 adverse event (AE), and 44% of patients experienced grade 3 adverse events. The most common adverse events were fatigue (81%), nausea (74%), anorexia (59%), vomiting (33%), diarrhea (33%), and weight loss (26%). Median time to progression and overall survival were 2.8 and 11.7 months, respectively. Median IL-6 levels (pg/mL) were higher in patients removed from the protocol for toxicity compared with progression at all time points, including baseline (5.2 vs 2.1, P = .02), Day 15 Cycle 1 (9.5 vs 2.2, P = .01), Day 1 Cycle 2 (9.8 vs 2.2, P = .01), and end of study (11.0 vs 2.9, P = .09).

CONCLUSIONS

Vorinostat at this dose was associated with significant toxicities limiting efficacy assessment in this patient population. The significant association between IL-6 levels and removal from the study for toxicities warrants further investigation.

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.

Phase I study of vorinostat in combination with bortezomib for relapsed and refractory multiple myeloma

PURPOSE

Vorinostat, a histone deacetylase inhibitor, enhances cell death by the proteasome inhibitor bortezomib in vitro. We sought to test the combination clinically.

EXPERIMENTAL DESIGN

A phase I trial evaluated sequential dose escalation of bortezomib at 1 to 1.3 mg/m2 i.v. on days 1, 4, 8, and 11 and vorinostat at 100 to 500 mg orally daily for 8 days of each 21-day cycle in relapsed/refractory multiple myeloma patients. Vorinostat pharmacokinetics and dynamics were assessed.

RESULTS

Twenty-three patients were treated. Patients had received a median of 7 prior regimens (range, 3-13), including autologous transplantation in 20, thalidomide in all 23, lenalidomide in 17, and bortezomib in 19, 9 of whom were bortezomib-refractory. Two patients receiving 500 mg vorinostat had prolonged QT interval and fatigue as dose-limiting toxicities. The most common grade >3 toxicities were myelo-suppression (n = 13), fatigue (n = 11), and diarrhea (n = 5). There were no drug-related deaths. Overall response rate was 42%, including three partial responses among nine bortezomib refractory patients. Vorinostat pharmacokinetics were nonlinear. Serum Cmax reached a plateau above 400 mg. Pharmacodynamic changes in CD-138+ bone marrow cells before and on day 11 showed no correlation between protein levels of NF-kappaB, IkappaB, acetylated tubulin, and p21CIP1 and clinical response.

CONCLUSIONS

The maximum tolerated dose of vorinostat in our study was 400 mg daily for 8 days every 21 days, with bortezomib administered at a dose of 1.3 mg/m2 on days 1, 4, 8, and 11. The promising antimyeloma activity of the regimen in refractory patients merits further evaluation.

Phase II trial of vorinostat in recurrent glioblastoma multiforme: a north central cancer treatment group study

PURPOSE

Vorinostat, a histone deacetylase inhibitor, represents a rational therapeutic target in glioblastoma multiforme (GBM).

PATIENTS AND METHODS

Patients with recurrent GBM who had received one or fewer chemotherapy regimens for progressive disease were eligible. Vorinostat was administered at a dose of 200 mg orally twice a day for 14 days, followed by a 7-day rest period.

RESULTS

A total of 66 patients were treated. Grade 3 or worse nonhematologic toxicity occurred in 26% of patients and consisted mainly of fatigue (17%), dehydration (6%), and hypernatremia (5%); grade 3 or worse hematologic toxicity occurred in 26% of patients and consisted mainly of thrombocytopenia (22%). Pharmacokinetic analysis showed lower vorinostat maximum concentration and area under the curve (0 to 24 hours) values in patients treated with enzyme-inducing anticonvulsants, although this did not reach statistical significance. The trial met the prospectively defined primary efficacy end point, with nine of the first 52 patients being progression-free at 6 months. Median overall survival from study entry was 5.7 months (range, 0.7 to 28+ months). Immunohistochemical analysis performed in paired baseline and post-vorinostat treatment samples in a separate surgical subgroup of five patients with recurrent GBM showed post treatment increase in acetylation of histones H2B and H4 (four of five patients) and of histone H3 (three of five patients). Microarray RNA analysis in the same samples showed changes in genes regulated by vorinostat, such as upregulation of E-cadherin (P = .02).

CONCLUSION

Vorinostat monotherapy is well tolerated in patients with recurrent GBM and has modest single-agent activity. Histone acetylation analysis and RNA expression profiling indicate that vorinostat in this dose and schedule affects target pathways in GBM. Additional testing of vorinostat in combination regimens is warranted.

Phase I/II study of G3139 (Bcl-2 antisense oligonucleotide) in combination with doxorubicin and docetaxel in breast cancer

PURPOSE

Preclinical data showed enhancement of breast cancer cell death when G3139 was combined with anthracyclines and taxanes. We evaluated the efficacy and safety of a Bcl-2 antisense oligonucleotide, G3139, in combination with doxorubicin (A) and docetaxel (T) in patients with locally advanced breast cancer (LABC).

EXPERIMENTAL DESIGN

Following a brief phase I to determine the phase II dose, patients with locally advanced breast cancer received G3139 administered by continuous i.v. infusion for 5 to 7 days with bolus A (50 mg/m2) and T (75 mg/m2) administered on either day 3 or 6 of therapy with G3139. Cycles were repeated every 21 days x 6 in the neoadjuvant setting. Serial plasma samples were obtained for pharmacokinetic analysis. Tissue samples were obtained before and after therapy for pharmacodynamic analysis of Bcl-2 expression.

RESULTS

Thirty patients (median age, 49 years; range, 24-71 years) received 160 cycles. During the phase I portion of the trial, the dose of G3139 was escalated from 3 to 7 mg/kg/d (i.v. for 5 days) in combination with AT. During the phase II portion of the trial, several doses and schedules of G3139 were evaluated. There were no pathologic complete responses. Pharmacodynamic studies showed limited Bcl-2 down-regulation in the primary tumors.

CONCLUSIONS

G3139 in combination with doxorubicin and docetaxel is well tolerated. No pathologic complete response was seen and pharmacodynamic studies showed very little down-regulation of Bcl-2 in primary tumors, perhaps related to issues with insufficient drug delivery to the intact tumor.

A phase I pharmacokinetic and pharmacodynamic correlative study of the antisense Bcl-2 oligonucleotide g3139, in combination with carboplatin and paclitaxel, in patients with advanced solid tumors

PURPOSE

This phase I trial assessed the safety and tolerability of G3139 when given in combination with carboplatin and paclitaxel chemotherapy. The effect of G3139 treatment on Bcl-2 expression in peripheral blood mononuclear cells (PBMC) and paired tumor biopsies was also determined.

EXPERIMENTAL DESIGN

Patients with advanced solid malignancies received various doses of G3139 (continuous i.v. infusion days 1-7), carboplatin (day 4), and paclitaxel (day 4), repeated in 3-week cycles, in a standard cohort-of-three dose-escalation schema. Changes in Bcl-2/Bax transcription/expression were assessed at baseline and day 4 (prechemotherapy) in both PBMCs and paired tumor biopsies. The pharmacokinetic interactions between G3139 and carboplatin/paclitaxel were measured.

RESULTS

Forty-two patients were evaluable for safety analysis. Primary toxicities were hematologic (myelosuppression and thrombocytopenia). Dose escalation was stopped with G3139 at 7 mg/kg/d, carboplatin at area under the curve of 6, and paclitaxel at 175 mg/m(2) due to significant neutropenia seen in cycle 1 and safety concerns in further escalating chemotherapy in this phase I population. With G3139 at 7 mg/kg/d, 13 patients underwent planned tumor biopsies, of which 12 matched pairs were obtained. Quantitative increases in intratumoral G3139 with decreases in intratumoral Bcl-2 gene expression were seen. This paralleled a decrease in Bcl-2 protein expression observed in PBMCs.

CONCLUSIONS

Although the maximal tolerated dose was not reached, the observed toxicities were consistent with what one would expect from carboplatin and paclitaxel alone. In addition, we show that achievable intratumoral G3139 concentrations can result in Bcl-2 down-regulation in solid tumors and PBMCs.

Phase II multicenter study of oblimersen sodium, a Bcl-2 antisense oligonucleotide, in combination with rituximab in patients with recurrent B-cell non-Hodgkin lymphoma

Oblimersen sodium plus rituximab was evaluated in relapsed/refractory B-cell non-Hodgkin lymphoma (NHL) patients. Oblimersen was administered as a continuous intravenous infusion at a daily dose of 3 mg/kg/d for 7 d on alternate weeks for 3 weeks. Rituximab was given at a weekly dose of 375 mg/m(2) for six doses. Patients with stable disease or objective response were allowed to receive a second course of treatment. The overall response rate (ORR) was 42% with 10 complete responses (CR) and eight partial responses (PR). Twelve (28%) patients achieved a minimal response or stable disease. Among the 20 patients with follicular lymphoma the ORR was 60% (eight CR, four PR). Three of the responders were refractory to prior treatment with rituximab, and two of the responses occurred in patients who had failed an autologous stem cell transplant. Median duration of response was 12 months. Most toxicities were low grade and reversible. In conclusion, oblimersen sodium can be safely combined with rituximab. The combination appears to be most beneficial in patients with indolent NHL and warrants further investigation in a large randomized trial.

A phase II study of vorinostat (NSC 701852 ) in patients (pts) with relapsed non-small cell lung cancer (NSCLC)

18044

Background: Vorinostat is a small molecule inhibitor of histone deacetylase (HDAC). HDAC inhibitors have shown preclinical activity in lung cancer and are postulated to have an antitumor effect by alteration in acetylation status of histone and non-histone proteins. Methods: Pts with relapsed NSCLC who failed no more than 1 prior cytotoxic therapy were eligible. Treatment: vorinostat, 400 mg po daily in a 21 day cycle. Primary objective: response rate (RR), with goal of at least one responder in first 14 evaluable pts. Secondary objectives: time to progression (TTP), overall survival (OS), safety, and correlative assays. Results: 14 pts enrolled from 12/05- 12/06. Median age 59.5 yrs (range 47–79). 11 females. PS 0:1, 10 pts:4 pts. Thirteen of 14 pts had only 1 prior cytotoxic regimen; 1 pt had only prior erlotinib. Best response to prior treatment: stable disease (SD; 11 pts), progressive disease (PD; 3 pts). Median time since last prior therapy: 2.1 mo (range 0.2–78.5). Vorinostat treatment compliance: 95.8 %. Two pts were not evaluable for response due to not completing Cycle 1 of treatment due to PD. No objective antitumor responses have been seen in the first 12 evaluable pts. Seven pts experienced SD (median 4.2 mo, range 2–10.7). Median TTP: 2.8 mo (range 1–10.7+); median OS 6.5 mo (range 1.4–10.7+); estimated 6 mo OS rate 50% (SE 16%). Grade (Gr) 5 toxicity: CVA (1 pt). Gr 3/4 toxicities: neutropenia (Gr 4–1 pt), lymphopenia (Gr 3–2 pts), fatigue (Gr 3–1 pt), elevated alk phos (Gr 3–1 pt), memory impairment (Gr 3–1 pt), PE/DVT (Gr 3–1 pt; Gr 4–2 pts), dehydration (Gr 3–1 pt). Data from the following correlative studies will be updated: p53 status, gene expression, H3 acetylation, transcription of p21, Nur77, Hsp70, erbB1 and 2, and Akt, cell cycle arrest, and assay of isoprostanes generated by treatment with vorinostat. Conclusions: Vorinostat 400 mg daily is tolerable with more than 80% of patients completing Cycle 1. Vorinostat yields TTP in relapsed NSCLC similar to that of other targeted agents. Although 4 of 14 pts experienced vascular events on treatment, these occurrences are common in this disease setting. At least two additional pts are still to be accrued. Further studies in NSCLC should focus on combining vorinostat with other antitumor agents.

No significant financial relationships to disclose.

A phase I study of vorinostat (suberoylanilide hydroxamic acid) in combination with 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) in patients with advanced colorectal cancer (CRC)

4088

Background: At 5μM, vorinostat decreases thymidilate synthase (TS) expression by ∼ 40 fold, which translates into synergistic antitumor activity when added to 5-FU. We conducted a phase I study of vorinostat plus FOLFOX in patients with CRC to determine the recommended dose of this combination. Methods: Vorinostat was escalated in a standard 3+3 design with a planned expansion of the maximum tolerated dose (MTD) cohort to 10 patients (pts). Vorinostat (100mg, 200mg, 300mg, 400 mg dose levels) was given twice daily for 1 week followed by 1 week break. FOLFOX was administered at a fixed standard dose every 2 weeks on the 4th day of vorinostat. Tumor biopsies were obtained from liver metastases before and on the 4th day of vorinostat (prior to FOLFOX) to assess TS expression. Results: 19 pts were treated on study (M/F: 12/7; median age: 58; ECOG 0/1: 6/13). All pts had failed prior FOLFOX therapy. Dose-limiting toxicities (DLT) were noted in 3 pts: 2/4 pts at dose level (DL)4 (vorinostat 400mg BID) consisting of grade (G) 3 fatigue, & diarrhea in 1 pt and G3 fatigue in the other; 1/8 pts at DL3 (MTD, vorinostat 300mg BID) consisting of G3 fatigue, anorexia, nausea, and dehydration. 8 pts have been treated at the MTD for a total of 38 cycles. “All Cycles” G3–4 toxicities at the MTD consisted of 2 pts with G3 neutropenia and 2 pts with G3 thrombocytopenia along with the above described DLT. Responses were evaluable in 17 pts: 0 Objective Response, 8 Stable Disease (4 confirmed). TS expression by IHC and by RT-PCR showed modest decreases in 2/6 patients after vorinostat treatment. Cmax of SAHA was < 2μM at all investigated DL, which could explain the lack of adequate TS down-regulation. Conclusions: vorinostat 300mg PO BID × 1 week every 2 weeks in combination with FOLFOX is the established recommended dose. The lack of significant TS down-regulation may be due to the suboptimal serum vorinostat concentrations. Alternate shorter vorinostat schedules may allow for further daily dose escalations and hence for better likelihood of TS down-regulation. This study was partly supported by CTEP, NCI.

No significant financial relationships to disclose.

Phase 2 study of suberoylanilide hydroxamic acid (SAHA) in relapsed or refractory indolent non-Hodgkin lymphoma: A California Cancer Consortium study

18515

Background: The indolent (follicular, marginal zone and mantle cell) lymphomas tend to recur with decreasing intervals of remission post standard chemotherapy. Vorinostat (SAHA, Zolinza), an orally administered hydroxamic acid histone deacetylase inhibitor with activity against class I and II deactylases, with preclinical and clinical activity against various forms of lymphoma, is being studied in patients with relapsed or refractory indolent lymphoma. Methods: Patients with relapsed or refractory follicular, marginal zone, or mantle cell lymphoma are eligible. Vorinostat is dosed at 200 mg po twice daily for 14 consecutive days on a 21 day cycle. CT scanning and marrow biopsy is performed after every three cycles. Patients may have received up to four prior chemotherapy regimens including Zevalin or Bexxar; previous transplant is allowed. Results: 15 patients (9 female, 6 male) have been enrolled thus far. Median age is 64 (40- 78) years One patient was found to have coexisting DLBCL and was removed from study. Four patients were taken off study due to progression, three stopped due to toxicity (fatigue in a 73 yo woman who had stable to improved marginal zone lymphoma after 10 cycles, fatigue and atrial fibrillation in a 65 yo man after 7 cycles, diarrhea in a 78 year old woman after 2 cycles). Complete Response (CR) in a patient with follicular lymphoma was attained after 9 cycles, this CR persists now for eight months at the time of abstract submission off therapy. A partial response (PR) was seen in a 40 yo man with lymphoma progression despite multiple rounds of therapy, with rapidly expanding masses just prior to starting vorinostat, the largest of which was 16x12.3 cm. This lesion currently measures 7.2x4.6 cm, with disappearance of many other sites; patient continues on vorinostat. Three of the patients with continued stable disease beyond 9 cycles have marginal zone lymphoma, while the two responders (CR or PR) have follicular lymphoma. A patient with PET resolution and decreases in two of the involved sites stopping after 10 cycles due to fatigue, developed rapid progression three months after stopping vorinostat. Conclusions: Vorinostat demonstrates preliminary activity against follicular and marginal zone lymphoma.

No significant financial relationships to disclose.

A phase I study of vorinostat (VOR) in combination with capecitabine (CAP) in patients (pts) with advanced solid tumors

3576

Background: VOR (suberoylanilide hydroxamic acid; SAHA) is a small molecule inhibitor of histone deacetylase (HDAC) that binds directly to the enzyme’s active site in the presence of a zinc ion. Aberrant HDAC activity has been implicated in a variety of cancers. The combination of 5-fluorouracil and VOR is synergistic in preclinical tumor models. Methods: This phase I study evaluated safety, tolerability, and the recommended phase II dose (RPTD) of VOR and CAP in pts with advanced solid tumors. VOR was administered orally daily while CAP was administered orally bid on days 1–14 of a 21 d cycle. Results: Three dose levels have been evaluated (VOR (mg/d)/CAP (mg/bid)): 300/750, 300/1,000 and 400/1,000. Twenty-three pts have been treated: 6M/17F, median age 59 (range 41–73), ECOG 0:1:2 = 9:13:1, prior therapy 1:2:3 or more = 3:7:13. Pts had colorectal cancer (n=6), nasopharyngeal (n=3) and various other tumors. A total of 104 cycles have been administered, with median = 2 (range 1–15). One dose limiting toxicity (DLT) (grade 3 diarrhea) occurred in 6 patients at dose level 1. No DLT were observed at dose level 2, and 2 DLTs (grade 3 fatigue and grade 3 nausea/vomiting) occurred at dose level 3. RPTD was determined to be VOR 300 mg/d and CAP 1,000 mg/bid. Most common toxicities of any grade and at least possibly attributable (n=22) are: thrombocytopenia (59% of pts), fatigue (55%), nausea (55%), vomiting (50%), hypoalbuminemia (45%), anemia (41%), diarrhea (41%), anorexia (41%), elevated creatinine (36%), lymphopenia (36%), hyponatremia (36%), and hyperglycemia (36%). Common grade 3 toxicities included: hand-foot syndrome (23% of pts), diarrhea (14%), fatigue (14%), and lymphopenia (14%). One pt died on study from ventricular fibrillation due to sotalol and hypocalcemia from pre-existing hypoparathyroidism. Five patients with various tumor types had PR (2 confirmed, 3 unconfirmed) (2 nasopharyngeal, 1 each of ovarian, endometrial and squamous cell carcinoma of head and neck). In addition, disease stabilization was seen in 12 patients. Conclusions: VOR and CAP are well tolerated, and this combination is active in several tumor types. Further evaluations of VOR and CAP are warranted.

No significant financial relationships to disclose.

A phase I study of bevacizumab in combination with sunitinib in advanced solid tumors

15532

Background: Bevacizumab is a humanized monoclonal antibody that binds to all biologically active isoforms of human vascular endothelial growth factor (VEGF). Sunitinib is a potent tyrosine kinase inhibitor of VEGFR-2, PDGFR, KIT, and FLT3. This phase I trial of bevacizumab and sunitinib was undertaken to determine the maximal tolerated dose (MTD), dose-limiting toxicity (DLT), and to evaluate for any tumor response for this novel combination. Methods: Patients (pts) with advanced solid tumors, ECOG performance status 0 or 1, and having adequate organ function were eligible. Patients received bevacizumab IV on days 1, 15, and 29 of a 42 day cycle. Sunitinib was given for 28 days with a 14 day rest. DLT was defined as any grade 4 toxicity, grade 3 cardiac event, hypertension not controlled to < 160/90 mmHg with medication, or proteinuria > 3.5 gm/24 hours. Results: Nine patients, 6 male and 3 female, with tumor types including renal carcinoma (2), bladder (2), pancreatic, testicular, melanoma, gastric, and neuroendocrine were enrolled. The median patient age was 55 years (range 37 to 83). Median number of prior systemic therapies was 2 (range 0 to 3). A total of 15 cycles have been administered (cycles range 1 to 4). Grade 1 or 2 toxicities that occurred with a > 20% incidence included anorexia, bleeding, diarrhea, dyspnea, fatigue, fever, hypomagnesemia, nausea, pain, vomiting, and weight loss. Grade 3 toxicities included hypertension (3 pts), fatigue and hypokalemia (2 pts) and one episode each of hand-foot syndrome, and hypophosphatemia. At the dose level bevacizumab 3 mg/kg and sunitnib 25 mg/day no DLTs were observed. One patient experienced DLTs of grade 4 hypertension and headache at the dose level of bevacizumab 5 mg/kg and sunitinib 37.5 mg/day. This dose level has expanded to six patients and toxicity assessment is continuing. One patient with papillary renal carcinoma has an unconfirmed partial response and three patients have experienced stable disease. Conclusions: Enrollment and toxicity evaluations are ongoing. DLTs of headache and hypertension have occurred. This trial will determine the maximal tolerated dose of this novel anti-angiogenic combination for future renal cell carcinoma studies. Supported by the NCI/Clinical Therapeutic Evaluation Program Grant U01 CA62502.

No significant financial relationships to disclose.

Phase I trial of a sequence-specific combination of the HDAC inhibitor, vorinostat (SAHA) followed by doxorubicin in advanced solid tumor malignancies

3502

Background: Preclinical cell culture and xenograft studies suggest that pre-exposure of cancer cells to a histone deacetylase inhibitor (HDACi) may potentiate topoisomerase (topo) inhibitors. The HDACi-induced histone acetylation and chromatin modulation facilitates DNA access and target recruitment for topo II inhibitors. Methods: This Phase I trial explores the safety, tolerability and maximum tolerated dose (MTD) of a weekly schedule of escalating vorinostat doses (twice daily days 1–3) followed by doxorubicin (20 mg/m2) on day 3 (3 out of 4 weeks). Histone acetylation and topo II expression are evaluated in pre-and post-vorinostat peripheral blood mononuclear cells and in tumor cells of the 30 patients treated at the MTD. Results: To date, 15 patients [median age 54 (38–73)] have been treated in 4 vorinostat cohorts: 200, 300, 400, 500 mg bid. Tumor types included: breast (3), melanoma (3), pancreatic (2) and one each of SCLC, sarcoma, endometrial, colon, prostate, renal cell and bladder cancer. Dose-limiting toxicities included a grade 3 thrombocytopenia (1/6) at the 400 mg bid dose. Non-dose limiting Grade 3 and 4 toxicities include neutropenia, thrombocytopenia, fatigue, pulmonary embolus, and anemia (1 pt each). Currently, vorinostat doses of 500 mg bid are being evaluated. One confirmed partial response in a breast cancer patient, as well as minor responses in a melanoma and a prostate cancer patient were seen in 10 evaluable patients. Patients received a median number of 2 (1–9+) treatment cycles. Doxorubicin is stopped after 6 cycles and patients continue on vorinostat alone. H3 and H4 histone acetylation and topo II expression will be correlated with vorinostat dose, plasma concentration and response. Conclusion: A sequence-specific combination of vorinostat and doxorubicin is active without exacerbation of doxorubicin toxicity. The tolerated vorinostat dose exceeds the proposed single agent dose for vorinostat derived from patients with hematological malignancies. Histone hyperacetylation occurs in peripheral blood mononuclear cells at all levels. The anti-tumor activity in breast cancer and melanoma will be further explored.

No significant financial relationships to disclose.

A phase I study of the combination of a DNA topoisomerase inhibitor, idarubicin, with the histone deacetylase inhibitor vorinostat, in advanced acute leukemia

7066

Background: Vorinostat (suberoylanilide hydroxamic acid, SAHA) is a histone deacetylase inhibitor (HDACi) with single agent activity in patients with advanced leukemia. HDACi lead to the acetylation of histones and facilitate an open chromatin configuration. Idarubicin potently inhibits DNA topoisomerase (topo) II by forming stable complexes with it, and eventually leading to ds-DNA breaks and apoptosis. Because of their effect on the chromatin of dividing cells, we postulated that the pairing of an HDACi with a topo II inhibitor, would have antileukemia activity. We tested this in vitro in leukemia cell lines and have shown that the combination of idarubicin and SAHA is synergistic. Methods: To test this clinically, we developed a phase I trial of the combination of idarubicin and SAHA, given in 2 different schedules, in advanced leukemia. In schedule A, idarubicin 12 mg/m2 daily for 3 days is given concurrently with SAHA, orally TID for 14 days (starting at 100 mg). In schedule B, SAHA is only given for 3 days. Only SAHA was dose-escalated, following a classic 3+3 schema, with the plan to treat 10 patients at the MTD. If both schedules were open at any given time, patients were randomized among them. Results: So far, 20 patients have been treated: 8 in schedule A and 12 in B. Median age of the patients is 56 (21–80). Of the patients enrolled thus far, 19 (95%) had relapsed, refractory AML, 1 had MDS, and 8 out of the 20 (40%) had diploid cytogenetics. In schedule A, a dose of idarubicin at 12 mg/m2 and SAHA at 100 mg was found to be above the MTD, with the DLT's being myelosuppression, encephalopathy, and dysphagia. Dose escalation of schedule B continues currently at a dose of SAHA at 400 mg. No severe grade 3 or 4 toxicities have been observed on this schedule. No cardiac toxicity has been observed. So far, 2 CR and 2 complete marrow responses have been observed. All of these patients had failed previous anthracycline-based chemotherapy. Induction of γ-H2AX, histone acetylation, and induction of topo II and p21CIP1 mRNA expression are being evaluated, as well as pharmacokinetic characteristics of both agents. Conclusion: The combination of idarubicin with SAHA is safe and active, and SAHA could be incorporated in the treatment of front-line AML.

No significant financial relationships to disclose.

Phase 1 and pharmacologic study of MS-275, a histone deacetylase inhibitor, in adults with refractory and relapsed acute leukemias

MS-275 is a benzamide derivative with potent histone deacetylase (HDAC) inhibitory and antitumor activity in preclinical models. We conducted a phase 1 trial of orally administered MS-275 in 38 adults with advanced acute leukemias. Cohorts of patients were treated with MS-275 initially once weekly x 2, repeated every 4 weeks from 4 to 8 mg/m2, and after 13 patients were treated, once weekly x 4, repeated every 6 weeks from 8 to 10 mg/m2. The maximum-tolerated dose was 8 mg/m2 weekly for 4 weeks every 6 weeks. Dose-limiting toxicities (DLTs) included infections and neurologic toxicity manifesting as unsteady gait and somnolence. Other frequent non-DLTs were fatigue, anorexia, nausea, vomiting, hypoalbuminemia, and hypocalcemia. Treatment with MS-275 induced increase in protein and histone H3/H4 acetylation, p21 expression, and caspase-3 activation in bone marrow mononuclear cells. No responses by classical criteria were seen. Our results show that MS-275 effectively inhibits HDAC in vivo in patients with advanced myeloid leukemias and should be further tested, preferably in patients with less-advanced disease.

Combined DNA methyltransferase and histone deacetylase inhibition in the treatment of myeloid neoplasms

Optimal reexpression of most genes silenced through promoter methylation requires the sequential application of DNA methyltransferase inhibitors followed by histone deacetylase inhibitors in tumor cell cultures. Patients with myelodysplastic syndrome or acute myeloid leukemia (AML) were treated with the methyltransferase inhibitor 5-azacitidine (aza-CR) followed by the histone deacetylase inhibitor sodium phenylbutyrate. Major responses associated with cytogenetic complete response developed in patients receiving prolonged dosing schedules of aza-CR. Bisulfite sequencing of the p15 promoter in marrow DNA during the first cycle of treatment showed heterogeneous allelic demethylation in three responding patients, suggesting ongoing demethylation within the tumor clone, but no demethylation in two nonresponders. Six of six responding patients with pretreatment methylation of p15 or CDH-1 promoters reversed methylation during the first cycle of therapy (methylation-specific PCR), whereas none of six nonresponders showed any demethylation. Gene demethylation correlated with the area under the aza-CR plasma concentration-time curve. Administration of both drugs was associated with induction of acetylation of histones H3 and H4. This study provides the first demonstration that molecular mechanisms responsible for responses to DNA methyltransferase/histone deacetylase inhibitor combinations may include reversal of aberrant epigenetic gene silencing. The promising percentage of major hematologic responses justifies the testing of such combinations in prospective randomized trials.

Phase II multicenter trial of bevacizumab plus fluorouracil and leucovorin in patients with advanced refractory colorectal cancer: an NCI Treatment Referral Center Trial TRC-0301

PURPOSE

To provide bevacizumab (BV) -based therapy to patients with advanced colorectal cancers (CRC) who had exhausted standard chemotherapy options, and to evaluate the response to BV combined with fluorouracil (FU) and leucovorin (LV) in this patient population.

PATIENTS AND METHODS

This was a multicenter, single-arm treatment trial conducted under the National Cancer Institute Treatment Referral Center network nationwide. Patients were treated with BV 5 mg/kg every 2 weeks combined with FU/LV; FU was administered by bolus or continuous infusion. Eligibility criteria included advanced CRC that had progressed after irinotecan- and oxaliplatin-based chemotherapy, Eastern Cooperative Oncology Group performance status 0 to 2, and absence of thromboembolism. The primary end point was objective response rate (RR) in the first 100 assessable patients. All patients received follow-up for toxicity and survival.

RESULTS

Due to rapid accrual, a total of 350 patients were enrolled at 32 participating sites nationwide by October 2003. In the initially planned cohort of 100 assessable patients, the objective RR was 4% (95% CI, 1.1% to 9.9%) by investigators' assessment and 1% (95% CI, 0% to 5.5%) based on independent review; median progression-free survival was 3.5 months and median overall survival was 9.0 months. The safety profile was similar to prior BV trials in CRC. Grade 3 to 4 hemorrhage occurred in 5% of patients, including 3.8% with bleeding in the GI tract. Other adverse events such as hypertension, thrombosis, and bowel perforation were also observed at rates consistent with other studies.

CONCLUSION

For patients with advanced CRC that had progressed after both irinotecan-based and oxaliplatin-based chemotherapy regimens, the combination of BV and FU/LV was associated with rare objective responses.

A phase II trial of oblimersen sodium (G3139) in combination with doxorubicin (DOX) in advanced hepatocellular carcinoma (HCC). NCI protocol # 5798

14072

Background: Advanced HCC is refractory to most standard forms of chemotherapy, however responses to DOX are seen. The bcl-2 protein confers resistance to apoptosis in cancer cells and is important in tumor progression and resistance to chemotherapy. The bcl-2 antisense oligonucleotide, G3139 (G), has been shown to enhance the activity of DOX in tumor models by blocking bcl-2 synthesis. This argues for evaluating G + DOX in combination in HCC. By decreasing tumor bcl-2 protein levels, HCC may be sensitized to the apoptotic effects of DOX. Methods: We completed a phase II trial evaluating treatment with G at 7 mg/ kg for 7 days cont. i.v. infusion (d1–8) plus DOX at 45 mg/m2 i.v. bolus d5, every 28 d (as determined from our phase I HCC study). Eligible patients (pts) had path-confirmed, measurable, advanced HCC. Minimal eligibility included Childs-Pugh A cirrhosis, adequate hematological (hem) parameters and ECOG PS <2. Tumor biopsies for correlative studies were obtained at baseline and cycle 1 d 4 in consenting pts. Results: 19 patients were accrued, 1 was ineligible, 18 evaluable for toxicity, 17 evaluable for response; receiving a median (med) of 2 cycles (range 1,10). Risk for HCC was 39% HBV, 22% HCV, 17% alcohol, 22% other. Most common toxicities were hem and could be attributed to both G+DOX and to G alone. Overall grade 3–4 toxicities seen were: ANC- 67% (med nadir d 24–25), lymphopenia - 44%, thrombocytopenia - 6%, transaminitis - 33% and grade 1–2 G-fever - 67%. No responses were seen and the trial was stopped at stage 1. Six patients (35%) had stable disease, with one pt completing 10 cycles as per protocol (pt # 22). Med TTP is 1.8 months (1.7-NA) and 6-month PFS is 17.2% (5.3–56.4). 18 of 19 pts have died with med OS of only 5.4 months (2.7–11.6). Correlative studies on 3 available pts’ paired tumor biopsies showed absent baseline bcl-2 expression but moderate expression of both bcl-xl and BAX protein and with no change after exposure to G (includes pt #22). Conclusions: G + DOX is inactive in HCC at this dose and schedule. The overlap of hem toxicity may have resulted in suboptimal DOX dosing in HCC. Low baseline bcl-2 tumor expression relative to bcl-xl seen may suggest a relative insensitivity to the effects of bcl-2 inhibition in these HCC tumors.

[Table: see text]

A phase I study of G3139 in combination with RICE chemotherapy in relapsed non-Hodgkin’s lymphoma (NHL)

17529

Background: Aggressive lymphomas are chemosensitive, but frequently relapse. Bcl-2 protein overexpression promotes tumor cell survival via anti-apoptosis, and is clinically correlated with shortened remission duration and decreased survival. The antisense oligonucleotide oblimersen sodium (G3139) downregulates bcl-2, has activity in NHL, and may be synergistic with chemotherapy. Methods: Pts had histologically confirmed aggressive NHL that relapsed after one prior anthracycline-based regimen. G3139 was given as a continuous infusion on Days 1–8 (168 hours) every 14 days, with stem cell collection following cycle 3. Standard RICE chemotherapy was given on Days 4–6, allowing 72 hrs pre- and 48 hrs post-chemo G3139. Dose-limiting toxicity (DLT) was defined as grade 3 or greater non-hematologic toxicity, grade 4 thrombocytopenia, duration of neutropenia <500/mL greater than 7 days despite growth factors, grade 3 hemolytic anemia, or prolonged severe anemia. Pharmacodynamic endpoints included measurement of bcl-2 protein in peripheral blood (FACS analysis) and tumor (IHC), and bcl-2 RT-PCR in blood and tumor. Results: 8 pts were enrolled. At dose level 1 (G3139 3 mg/kg/day), both enrolled pts had grade 4 thrombocytopenia. The next 6 patients were treated with G3139 2.5 mg/kg/day (Dose Level -1) without any DLT’s. There were no grade 3 or 4 non-hematologic toxicities. 7 evaluable pts had successful stem cell collections: median CD34+ 4.2 × 106/kg (range, 1.3–8.72 × 106/kg). Responses: 4 CR/CRu, 2 PR, 1 SD, 1 too early. There was no detectable decrease in bcl-2 protein in the blood using flow cytometry or RT-PCR. Conclusion: The maximum tolerated dose of G3139 given over 8 days in combination with RICE chemotherapy is 2.5 mg/kg/day. It is unlikely that this dose sufficiently suppresses bcl-2 levels. The protocol will thus be amended to shorten the G3139 infusion to 5 days with renewed efforts to escalate the dose.

No significant financial relationships to disclose.

Phase 1 pharmacokinetic and pharmacodynamic study of the histone deacetylase inhibitor MS-275 in combination with 13-cis retinoic acid in patients with advanced solid tumors

3055

Background: Preclinical studies suggest that histone deacetylase (HDAC) inhibitors may restore tumor sensitivity to retinoids. The objective of this study was to determine the maximum-tolerated dose (MTD), the dose-limiting toxicity (DLT), and the pharmacokinetic (PK)/pharmacodynamic (PD) profiles of the HDAC inhibitor MS-275 in combination with 13-cis retinoic acid (CRA). Methods: Patients (pts) with advanced solid tumors were treated with MS-275 orally once weekly and CRA orally twice daily x 3 weeks every 4 weeks. The starting dose for MS-275 was 4 mg/m2 and the dose was escalated based on toxicity assessments. The fixed dose for CRA was 1 mg/kg/day. PK concentrations of MS-275 and CRA were determined by LC/MS/MS. Western Blot analysis on peripheral-blood mononuclear cells (PBMCs) and tumor samples (when feasible) were performed to evaluate target inhibition. Results: To date thirteen pts have been enrolled. Tumor types include prostate (4 pts), bladder and renal cell (2 pts), and others. The MTD was exceeded at the 5 mg/m2 dose level (G3 hyponatremia, neutropenia and anemia). Fatigue (G1 or G2) is a common side effect. MS-275 peak concentrations were 141.6±75.7ng/mL at 4mg/m2 and 139.5±30.9 ng/mL at 5mg/m2. MS-275 half-life and clearance were 108.2±47.9h and 9.4±6.0L/h/m2, which is consistent with prior reports for MS-275 as single agent. Median CRA steady-state trough levels were 182.4 ng/mL. The MTD was 4 mg/m2 MS-275 and 1 mg/kg CRA. Five pts remained on treatment for ≥ 4 months including pts with prostate cancer (3), pancreatic cancer (6 months) and a pt with renal cell carcinoma (12 months) who presented a partial response in the lungs. Histones isolated from PBMCs showed transient but consistent protein acetylation post-therapy. Tumor biopsy of a liver lesion from prostate carcinoma revealed post-therapy induced histone acetylation and decreased phosphorylated ERK and STAT3 protein expression consistent with HDAC inhibitory activity. Conclusions: Combination of MS-275 with CRA is reasonably well tolerated and 4 mg/m2 is the Phase II recommended dose for MS-275 in combination with CRA. Tumor response and PD data suggest clinical and biological activity for this combination strategy.

[Table: see text]

Phase I study of vorinostat, a histone deacetylase (HDAC) inhibitor, in combination with carboplatin (Cb) and paclitaxel (P) for patients with advanced solid malignancies (NCI #6922)

2077

Background: Vorinostat (SAHA) induces differentiation & growth arrest in a variety of human carcinoma cell lines by inhibiting HDAC. It also enhances the efficacy of chemotherapy. We are conducting a phase I study to evaluate the combination of vorinostat, Cb & P for patients with advanced solid malignancies. Methods: Patients with advanced solid malignancies who were candidates for combination therapy with Cb & P were eligible. Vorinostat was given orally on d 1–14 of each 21-d-cycle, except in cycle 1 when begun on d -4 to facilitate PK studies. Cb & P were given on d 1 of each cycle. Plasma concentrations of vorinostat, & its 2 major metabolites were quantitated with a novel LC-MS/MS assay. Results: Dose level 4 has been determined as the recommended phase II dose (RP2D) for the combination, since the RP2D of single agent vorinostat is 400 mg on this schedule. Observed toxicities included nausea, vomiting, neutropenia & thrombocytopenia, none of which were dose-limiting. Of 9 patients evaluable for response, 4 had PR (1 head & neck cancer, 3 non-small cell lung cancer), & 2 had stable disease. Vorinostat was rapidly absorbed & AUC increased with dose. Vorinostat PK parameters included Tmax 0.5–2 h, t1/2 1.6 ± 0.5 h, & CL/F 5.8 ± 1.7 l/min. Cb & P did not alter vorinostat PK. 4-Anilino-4-oxobutanoic acid was the major, & long-lived, vorinostat metabolite, with Cmax 1.5–7 fold > vorinostat Cmax & t ½ ∼6h. Vorinostat glucuronide Cmax was 1–5 fold > vorinostat Cmax & glucuronide t ½ ∼2h. The RP2D cohort is being expanded to 12 patients to obtain additional clinical & PK data. Conclusions: Vorinostat can be safely administered in combination with Cb & P at their recommended doses. Vorinostat PK are not altered by Cb & P. Promising anti-cancer activity has been noted in patients with advanced NSCLC. Support: U01CA099168–01, U01CA62505, NIH/NCCR/GCRC grant 5M01RR 00056.

[Table: see text]

No significant financial relationships to disclose.

Phase I trial of the oral histone deacetylase inhibitor MS-275 administered with food

13036

Background: The histone deacetylase (HDAC) inhibitor MS-275, a synthetic benzamide derivative, has demonstrated antitumor activity in vitro & in vivo. After determining maximum tolerable dose (MTD = 2 mg/m2) & dose limiting toxicity (DLT) for MS-275 given to fasting patients (pts) weekly ×4 q6 weeks, we explored toxicity profile, MTD, & pharmacokinetics (PK) of MS-275 when given po on the same schedule with food. Methods: MS-275 at 2, 4, or 6 mg/m2 was administered to pts with advanced malignancy & PS ≤2, LFTs ≤2.5 × normal, adequate hematopoietic & renal function, & normal resting MUGA. PK samples were analyzed by LC-MS. Data for pts in the fed state were compared to data obtained in previous cohorts of pts treated in the fasting state. Protein acetylation assessed by a novel flow cytometric assay & HDAC enzymatic activity were measured in peripheral blood mononuclear cells (PBMC). Results: 16 pts received a median of 2 cycles (1–5) of MS-275 2–6 mg/m2 with food. No DLT occurred on 2 or 6 mg/m2 (n = 3 each), while 1 pt on 4 mg/m2 (n = 10) had a DLT: grade 3 hypophosphatemia. For 2–6 mg/m2 other grade 3 toxicities were neutropenia & lymphopenia. Grade 1–2 toxicities in >1 pt were leucopenia, anemia, thrombocytopenia, fatigue, nausea, vomiting, headache, hypoalbuminemia, hypophosphatemia, hyponatremia, & hypocalcemia. MTD has not been reached; current dose level is 8 mg/m2. Comparing PK for fasting & fed pts on 2–4 mg/m2, there was no difference in Tmax (0.5h); average Cmax & AUC were 35% & 25% lower, respectively, in fed pts; this difference is not statistically significant. Interindividual variability in exposure to MS-275 increased from 52% in fasting pts to 100% in fed pts. PBMC protein acetylation & HDAC inhibition were seen at all dose levels (2–6 mg/m2) in fed pts. Of 9 pts evaluable for response (2–4 mg/m2), 2 of 6 pts on 4 mg/m2 had stable disease. Conclusions: MTD has not yet been established for MS-275 given with food on this schedule but is ≥4 mg/m2 weekly x4 q6 weeks. Interindividual variability in exposure increases with food. Whether intestinal absorption is decreased when MS-275 is given with food requires further evaluation with additional patients. Drug-related protein hyperacetylation & HDAC inhibition were observed.

[Table: see text]

Phase II trial of fenretinide in advanced renal carcinoma

PURPOSE

Fenretinide, a synthetic form of retinoid, induced apoptosis even in chemotherapy resistant cell lines. A phase II study was hence conducted to evaluate toxicity and efficacy of fenretinide in metastatic renal cancer.

METHODS

Eligibility included unresectable or metastatic renal cell carcinoma (RCC), adequate organ function and Zubrod performance status < or =2. Prior immunotherapy and a maximum of one prior chemotherapy regimen were allowed. Fenretinide was administered at a dose of 900 mg/m(2) twice daily orally for 7 days in a 21-day cycle. Toxicity was assessed at the start of each cycle, and response every 2 cycles.

RESULTS

Nineteen eligible patients enrolled of which fifteen had visceral/bone metastases. Seventeen patients had prior nephrectomy and 11 had prior immunotherapy. 76 cycles of therapy were delivered. Therapy was very well tolerated with few severe toxicities consisting of thrombosis in 1 individual and grade 3 fatigue, nausea and diarrhea in 1 patient. 5 patients had grade 2 nyctalopia and 3 patients had transient grade 2 visual toxicity. No objective responses were noted. Stable disease was seen in seven of nineteen cases (37%, 90% C.I. 0.21-0.59). Median time to progression was 1.5 months and median duration of stable disease was 5.8 months (90% C.I. 3.0-8.4). Median survival was 10 months. Tumor fenretinide levels were obtained in three patients and were in the lower end of the therapeutic range.

CONCLUSION

Fenretinide was well tolerated but demonstrated minimal activity that was consistent with results of intratumoral drug measurements. Strategies are needed that will increase systemic and tumor levels of fenretinide.

Phase I and Pharmacokinetic Study of MS-275, a Histone Deacetylase Inhibitor, in Patients With Advanced and Refractory Solid Tumors or Lymphoma

Purpose

The objective of this study was to define the maximum-tolerated dose (MTD), the recommended phase II dose, the dose-limiting toxicity, and determine the pharmacokinetic (PK) and pharmacodynamic profiles of MS-275.

Patients and Methods

Patients with advanced solid tumors or lymphoma were treated with MS-275 orally initially on a once daily × 28 every 6 weeks (daily) and later on once every-14-days (q14-day) schedules. The starting dose was 2 mg/m2and the dose was escalated in three- to six-patient cohorts based on toxicity assessments.

Results

With the daily schedule, the MTD was exceeded at the first dose level. Preliminary PK analysis suggested the half-life of MS-275 in humans was 39 to 80 hours, substantially longer than predicted by preclinical studies. With the q14-day schedule, 28 patients were treated. The MTD was 10 mg/m2and dose-limiting toxicities were nausea, vomiting, anorexia, and fatigue. Exposure to MS-275 was dose dependent, suggesting linear PK. Increased histone H3 acetylation in peripheral-blood mononuclear-cells was apparent at all dose levels by immunofluorescence analysis. Ten of 29 patients remained on treatment for ≥ 3 months.

Conclusion

The MS-275 oral formulation on the daily schedule was intolerable at a dose and schedule explored. The q14-day schedule is reasonably well tolerated. Histone deacetylase inhibition was observed in peripheral-blood mononuclear-cells. Based on PK data from the q14-day schedule, a more frequent dosing schedule, weekly × 4, repeated every 6 weeks is presently being evaluated.

Phase II study of G3139, a Bcl-2 antisense oligonucleotide, in combination with dexamethasone and thalidomide in relapsed multiple myeloma patients

PURPOSE

Bcl-2 regulates the mitochondrial apoptosis pathway that promotes chemotherapy resistance. Bcl-2 antisense oligonucleotide, G3139, targets Bcl-2 mRNA.

PATIENTS AND METHODS

G3139 was administered (3 to 7 mg/kg/d for 7 days) by continuous intravenous infusion. On day 4, patients started thalidomide (100 to 400 mg as tolerated) and dexamethasone (40 mg daily for 4 days) on 21-day cycles for three cycles. Stable and responding patients continued on 35-day cycles for 2 years.

RESULTS

Thirty-three patients (median age, 60 years; range, 28 to 76 years) received 220 cycles. Patients received a median of three prior regimens including thalidomide (n = 15) and stem-cell transplantation (n = 31). The regimen was well tolerated; the median number of cycles per patient was eight (range, one to 16+ cycles). Toxicities included reversible increase in creatinine, thrombocytopenia, neutropenia, fatigue, anorexia, constipation, fever, neuropathy, edema, electrolyte disturbances, and hyperglycemia. Fifty-five percent of patients had objective responses, including two complete responses (CRs), four near CRs (positive immunofixation), and 12 partial responses; six patients had minimal responses (MRs). Of patients who received prior thalidomide, seven had objective responses, and three had MRs. The median duration of response was 13 months, and estimated progression-free and overall survival times were 12 and 17.4 months, respectively. Responding patients had significant increase in polyclonal immunoglobulin M (P = .005), indicating innate immune system activation. Western blot analysis of Bcl-2 protein isolated from myeloma cells before and after G3139 demonstrated a decrease of Bcl-2 levels in three of seven patients compared with six of nine patients using reverse transcriptase polymerase chain reaction.

CONCLUSION

G3139, dexamethasone, and thalidomide are well tolerated and result in encouraging clinical responses in relapsed multiple myeloma patients.

A phase I open-label, dose-escalation, multi-institutional trial of injection with an E1B-Attenuated adenovirus, ONYX-015, into the peritumoral region of recurrent malignant gliomas, in the adjuvant setting

ONYX-015 is an oncolytic virus untested as a treatment for malignant glioma. The NABTT CNS Consortium conducted a dose-escalation trial of intracerebral injections of ONYX-015. Cohorts of six patients at each dose level received doses of vector from 10(7) plaque-forming units (pfu) to 10(10) pfu into a total of 10 sites within the resected glioma cavity. Adverse events were identified on physical exams and testing of hematologic, renal, and liver functions. Efficacy data were obtained from serial MRI scans. None of the 24 patients experienced serious adverse events related to ONYX-015. The maximum tolerated dose was not reached at 10(10) pfu. The median time to progression after treatment with ONYX-015 was 46 days (range 13 to 452 + days). The median survival time was 6.2 months (range 1.3 to 28.0 + months). One patient has not progressed and 1 patient showed regression of interval-increased enhancement. With more than 19 months of follow-up, 1/6 recipients at a dose of 10(9) and 2/6 at a dose of 10(10) pfu remain alive. In 2 patients who underwent a second resection 3 months after ONYX-015 injection, a lymphocytic and plasmacytoid cell infiltrate was observed. Injection of ONYX-015 into glioma cavities is well tolerated at doses up to 10(10) pfu.

Phase II study of fenretinide (NSC 374551) in adults with recurrent malignant gliomas: A North American Brain Tumor Consortium study

PURPOSE

Fenretinide induces apoptosis in malignant gliomas in vitro. This two-stage phase II trial was conducted to determine the efficacy of fenretinide in adults with recurrent malignant gliomas.

PATIENTS AND METHODS

Twenty-two patients with anaplastic gliomas (AG) and 23 patients with glioblastoma (GBM) whose tumors had recurred after radiotherapy and no more than two chemotherapy regimens were enrolled. Fenretinide was given orally on days 1 to 7 and 22 to 28 in 6-week cycles in doses of 600 or 900 mg/m(2) bid.

RESULTS

Six of 21 (29%) patients in the AG arm and two of 23 (9%) patients in the GBM arm had stable disease at 6 months. One patient with AG treated at 900 mg/m(2) bid dosage had a partial radiologic response. Median progression-free survival (PFS) was 6 weeks for the AG arm and 6 weeks for the GBM arm. PFS at 6 months was 10% for the AG arm and 0% for the GBM arm. Grade 1 or 2 fatigue, dryness of skin, anemia, and hypoalbuminemia were the most frequent toxicities reported. The trial was closed after the first stage because of the inadequate activity at the fenretinide doses used. The first-administration mean plasma C(max) for fenretinide was 832 +/- 360 ng/mL at the 600 mg/m(2) bid dosage and 1,213 +/- 261 ng/mL at the 900 mg/m(2) bid dosage.

CONCLUSION

Fenretinide was inactive against recurrent malignant gliomas at the dosage used in this trial. However, additional studies using higher doses of the agent are warranted based on the tolerability of the agent and the potential for activity of a higher fenretinide dosage, as suggested in this trial.

Targeting Vascular Endothelial Growth Factor for Relapsed and Refractory Adult Acute Myelogenous Leukemias

PURPOSE

Vascular endothelial growth factor (VEGF) promotes acute myelogenous leukemia (AML) cell growth and survival and may contribute to drug resistance. bevacizumab, an anti-VEGF monoclonal antibody, exhibits clinical activity against diverse malignancies when administered with cytotoxic chemotherapy. We conducted a Phase II clinical trial of bevacizumab administered after chemotherapy to adults with refractory or relapsed AML, using a timed sequential therapy (TST) approach.

EXPERIMENTAL DESIGN

bevacizumab 10 mg/kg was administered on day 8 after 1-beta-d-arabinofuranosylcytosine 2 g/m(2)/72 h beginning day 1 and mitoxantrone 40 mg/m(2) beginning day 4. In vivo laboratory correlates included AML cell VEGF receptor-1 (FLT-1) expression, marrow microvessel density, and free serum VEGF before and during TST with bevacizumab.

RESULTS

Forty-eight adults received induction therapy. Myelosuppression occurred in all of the patients similar to other TST regimens. Toxicities were decreased ejection fraction (6%), cerebrovascular bleed (4%), and mortality of 15%. Overall response was 23 of 48 (48%), with complete response (CR) in 16 (33%). Eighteen (14 CR and 4 partial response) underwent one consolidation cycle and 5 (3 CR and 2 partial response) underwent allogeneic transplant. Median overall and disease-free survivals for CR patients were 16.2 months (64%, 1 year) and 7 months (35%, 1 year). Marrow blasts demonstrated FLT-1 staining before bevacizumab and marked decrease in microvessel density after bevacizumab. VEGF was detected in pretreatment serum in 67% of patients tested, increased by day 8 in 52%, and decreased in 93% (67% undetectable) 2 h after bevacizumab.

CONCLUSIONS

In this single arm study, cytotoxic chemotherapy followed by bevacizumab yields a favorable CR rate and duration in adults with AML that is resistant to traditional treatment approaches. The clearance of marrow blasts in some patients after bevacizumab suggests that VEGF neutralization might result directly in leukemic cell death. The potential biological and clinical activity of bevacizumab in AML warrants additional clinical and laboratory study.