Phase I trial of vorinostat and doxorubicin in solid tumours: histone deacetylase 2 expression as a predictive marker

Background:

Histone deacetylase inhibitors (HDACi) can sensitise cancer cells to topoisomerase inhibitors by increasing their access and binding to DNA.

Methods:

This phase I trial was designed to determine the toxicity profile, tolerability, and recommended phase II dose of escalating doses of the HDACi vorinostat, with weekly doxorubicin.

Results:

In total, 32 patients were treated; vorinostat was dosed at 400, 600, 800, or 1000 mg day⁻¹ on days 1–3, followed by doxorubicin (20 mg m⁻²) on day 3 for 3 of 4 weeks. Maximal tolerated dose was determined to be 800 mg day⁻¹ of vorinostat. Dose-limiting toxicities were grade 3 nausea/vomiting (two out of six) and fatigue (one out of six) at 1000 mg day⁻¹. Non-dose-limiting grade 3/4 toxicities included haematological toxicity and venous thromboembolism. Antitumor activity in 24 evaluable patients included two partial responses (breast and prostate cancer). Two patients with melanoma had stable disease for ⩾8 months. Histone hyperacetylation changes in peripheral blood mononuclear and tumour cells were comparable. Histone hyperacetylation seemed to correlate with pre-treatment HDAC2 expression.

Conclusion:

These findings suggest that vorinostat can be combined with weekly doxorubicin in this schedule at a dose of 800 mg day⁻¹. The HDAC2 expression may be a marker predictive of HDAC inhibition. Antitumor activity of this regimen in breast cancer, prostate cancer, and melanoma seems interesting.

A phase Ib trial of IPI-504 (retaspimycin hydrochloride), a novel Hsp90 inhibitor, in combination with docetaxel

3547

Background: IPI-504 is a water-soluble heat shock protein 90 (Hsp90) inhibitor. IPI-504 causes the degradation of a variety of mutated or amplified oncoproteins, including epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2). The combination of IPI-504 and docetaxel demonstrates additive efficacy in murine xenograft models. This Phase 1b trial was undertaken to identify the maximum tolerated dose (MTD) of IPI-504 in combination with docetaxel. Methods: Eligible patients (pts) had advanced solid tumors that were either refractory to available therapies or for which docetaxel alone was an appropriate therapy. Intravenous (IV) 75 mg/m2 docetaxel was given once every three weeks (q 3- weekly). IPI-504 was administered IV q 3-weekly, with 3 pts per cohort and inter-cohort dose escalation. All pts were evaluated for safety, pharmacokinetics (PK), and tumor response. Results: 16 pts have been enrolled at 3 dose levels of IPI-504 (7 at 300 mg/m2, 6 at 450 mg/m2, and 3 at 550 mg/m2). 6 pts had non-small cell lung cancer (NSCLC). Median age was 59 yrs (range 33–77). Median number of cycles received was 3 (1–11), with 5 pts currently on study. There have been 4 dose-limiting toxicities (DLTs): 1 at 300 mg/m2 (Grade 3 febrile neutropenia); 1 at 450 mg/m2 (Grade 3 fatigue); and 2 at 550 mg/m2 (Grade 1 asymptomatic sinus bradycardia requiring hospitalization for observation, and Grade 3 elevated AST with Grade 3 acute respiratory distress syndrome). All DLTs resolved on trial. No PK interactions between docetaxel and IPI-504 have been observed. The regimen of IPI-504 450 mg/m2 with docetaxel 75 mg/m2 has been identified as the recommended phase 2 dose on a q 3-weekly schedule. Conclusions: In this Phase 1b trial, the MTD of IPI-504 plus docetaxel q 3-weekly was identified. Toxicities were reversible and similar to those seen with docetaxel or IPI-504 alone in this patient population. Given the activity of single-agent IPI-504 against NSCLC and the standard use of docetaxel in that disease, an expanded evaluation of this regimen in pts with previously treated NSCLC is on-going. The combination of IPI-504 and docetaxel on a weekly schedule is also being explored.

[Table: see text]

Phase I study of vorinostat plus docetaxel in patients with solid tumor malignancies

2528

Background: Vorinostat is an inhibitor of histone deacetylase 6, which results in the acetylation of tubulin and the stabilization of microtubules. Since taxanes bind to stabilized microtubules, the administration of vorinostat followed by docetaxel, we hypothesized, should result in synergistic cytotoxicity. A phase I trial was conducted to determine the dose level of vorinostat plus docetaxel that would result in dose-limiting toxicity (DLT) in ≤ 30% of patients (pts). Methods: Eligible pts had castration-resistant prostate cancer (CRPC) or relapsed urothelial or non-small-cell lung cancer (NSCLC) after ≥1 prior chemotherapy regimen not containing docetaxel, a performance status of 0–2 and adequate organ function. Vorinostat was given orally for 14 days beginning on day 1 of a 21-day cycle. Docetaxel was given intravenously over 1 hour on day 4. The time-to-event continuous reassessment method guided dose escalation. Dose levels (DL) -1, 0, 1 and 2 corresponded to vorinostat 100, 100, 200 and 200 mg plus docetaxel 50, 60, 60, and 75 mg/m2, respectively. Blood was collected on days 1 and 4 of cycle 1 to measure drug levels by HPLC. Results: 12 pts were enrolled: median age 65 yrs (49–74); gender 9M:3F; 4 CRPC, 5 urothelial, 3 NSCLC. The median number of cycles was 2. 2 pts were treated at DL -1, 4 pts at DL 0, 5 pts at DL 1 and 1 pt at DL 2. 5 DLTs occurred in 5 pts: grade 4 neutropenic fever/sepsis (n = 2), anaphylactic reaction (n = 1), myocardial infarction (n = 1) and GI bleed (n = 1). Other toxicities included grade 4 neutropenia (n = 2), pulmonary embolus (n = 1) and GI bleed (n = 1). The estimated probability of DLT for DL -1 was .32 (90% posterior probability interval [PI], .11 to .53) for DL 0, .38 (90% PI, .16 to .58) and for DL 1, .43 (90% PI, .23 to .64). The trial was stopped due to excessive toxicity. No responses were noted. Conclusions: Combination vorinostat plus docetaxel was poorly tolerated with excessive DLTs requiring study termination. PK analysis will be presented. Supported in part by a grant from Merck & Co., Inc.

[Table: see text]

Phase 1 dose-escalation study of 17-allylamino-17-demethoxygeldanamycin (17AAG) in combination with irinotecan in patients with solid tumors

3533

Background: 17AAG is an inhibitor of the molecular chaperone Hsp90. Pre-clinical studies from our laboratory showed that treatment of cancer cells with 17AAG caused depletion of two critical checkpoint kinases, Chk1 and Wee1, resulting in abrogation of the G2/M checkpoint triggered by topoisomerase I poison, and selective induction of apoptosis in p53-defective cells. Methods: We initiated a phase 1 study of irinotecan (CPT) and 17AAG to determine the maximally tolerated doses (MTD) and tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of the combination. During the dose-escalating phase, patients (Pts) received CPT over 30 min followed by 17AAG over 2 hrs once weekly for two weeks in a 21-day cycle. At the MTD, Pts underwent post-treatment tumor biopsy for PD biomarker analysis after CPT only during week 1 and after the combination during week 2. Results: 22 Pts (median age 53; range 32–73; median KPS 80) with a wide spectrum of solid tumor types were enrolled. Four Pts developed dose-limiting toxicity in cohort 4 (100 mg/m2 CPT and 375 mg/m2 17AAG) including nausea, vomiting, diarrhea, and pulmonary embolism. The PKs of 17AAG and its metabolite 17AG were not affected by the co-administration of CPT. Although no CR/PR’s by RECIST criteria have been seen, minor responses were observed in CPT-naive Pts with pancreas (2), breast (1), and high grade neuroendocrine tumor (1). Pts are currently enrolled to the MTD expanded cohort for further assessment of tolerability and PD analysis. So far, paired tumor biopsies have been successfully obtained in 8/8 Pts and samples will be analyzed for p53 status, Hsp90 client protein depletion, G2/M checkpoint abrogation, and apoptosis. Conclusions: The combination of 17AAG and CPT can be given to Pts with acceptable toxicity. The recommended phase II dose of the combination is 100 mg/m2 CPT and 300 mg/m2 17AAG. (Supported by ASCO CDA and NCI K08 awards)

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 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.

An update on phase I study of dose-escalating imatinib mesylate plus standard-dosed temozolomide for the treatment of patients with malignant glioma

1560

Background: Imatinib mesylate, a kinase inhibitor of the PDGF receptor has been shown to decrease tumor interstitial pressure resulting in enhanced delivery of cytotoxic therapy. Recent phase II trial demonstrated promising anti-glioma activity of imatinib mesylate in combination with chemotherapy, hydroxyurea. Methods: The current phase I study is designed to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of imatinib mesylate when combined with temozolomide, a DNA methylator with established efficacy against gliomas. Eligibility criteria include: histologically confirmed malignant glioma; age of at least 18 years; KPS of at least 60%; less than grade 2 intratumoral hemorrhage; adequate hepatic, renal, and bone marrow function and lack of prior failure or significant toxicity following treatment with either imatinib mesylate or temozolomide. Temozolomide is dosed at 200 mg/m2 on days 4–8 of each 28-day cycle. Imatinib mesylate is administered on days 1–8 of each cycle and the dose is escalated in successive cohorts of 3–6 patients via a standard “3+3” dose escalation design. Patients are stratified based on concurrent use of enzyme-inducing anticonvulsants (EIAC) and both strata are independently escalated. Results: To date 47 patients have been enrolled including 40 with GBM and 7 with anaplastic gliomas. Median age is 53.9 years (range 28 to 72); 66% are male and 51% are on EIAC. The MTD has yet to be defined for either stratum. To date DLT of ALT elevation has been observed in one patient from non-EIAC stratum. Two patients discontinued therapy due to toxicities with one asymptomatic intracerebral hemorrhage and one severe hematologic toxicity. Pharmacokinetic sampling has been performed in approximately half of the patients. One patient completed the study (12 cycles) with stable disease. Eleven patients remain on study with one partial response and three patients have undergone more than 10 cycles of therapy with stable disease. Twenty-eight patients (59%) have developed progressive disease and discontinued therapy. Conclusions: Combination of imatinib mesylate and temozolomide is safe and well tolerated. Further accrual and dose escalation are ongoing.

[Table: see text]

Phase I pharmacokinetic (PK) and pharmacodynamic (PD) study of 17-Allylamino-17-demethoxygeldanamycin (17AAG) in children with solid tumors

9022

Background: 17AAG is a benzoquinone ansamycin that binds to heat shock protein 90 (Hsp90) and alters levels of cancer-associated proteins that are regulated by Hsp90. 17AAG has been well-tolerated in adults, but has not previously been administered to children. Methods: A Phase I study of 17AAG was initiated to define the maximally tolerated dose and toxicity profile of this drug in children. PK and PD were also studied. Cohorts of 3–6 patients with recurrent or refractory solid tumors were treated every 21 days with escalating doses of 17AAG twice weekly for two weeks. Plasma PK of 17AAG and its major metabolite, 17AG, were measured on day 1 by HPLC. Changes in levels of the inducible isoform of Hsp70 were assessed by Western blot using peripheral blood mononuclear cells (PBMCs) obtained 24 h after the 17AAG infusion. Actin was measured for comparison. Because 17AAG is a substrate for CYP3A4/5 and MDR1, pharmacogenetic analyses have been undertaken to determine if genotypes including CYP3A4*1B, CYP3A5*3, and MDR1 G2677T/A and C3435T influence 17AAG disposition. Results: 12 pts (median age 11 years, range 5–18) with neuroblastoma (5), osteosarcoma (4), Ewing’s family tumors (2), and desmoplastic small round cell tumor (1) have been treated with 17AAG. An MTD has yet to be defined though one dose limiting toxicity (Grade 3 hypoxia) was observed at Dose Level 4 (360 mg/m2). The AUC of 17AAG increased with dose, with a linear relationship between end of infusion 17AAG plasma concentration and AUC. The AUC of 17AAG increased with dose, with a linear relationship between end of infusion 17AAG plasma concentration and AUC. Clearance ranged between 12.5 and 29.6 l/hr/m2 (median, 21.6 l/h/m2) and did not change with increasing doses. Post-treatment increases in Hsp70 in PBMCs have been observed in pts treated with 17AAG doses at or above 150 mg/m2. Declines in Akt and IGF1R in PBMCs have been seen in some but not all pts following treatment. Conclusions: 17AAG is well tolerated in children at dose levels studied to date. 17AAG dose escalation continues and at the time of the meeting, updated data will be reported.

No significant financial relationships to disclose.

Phase I clinical study of infusional 5-fluorouracil with oxaliplatin and gemcitabine (FOG regimen) in patients with solid tumors

BACKGROUND

The aim of this study was to determine the maximum tolerated dose, recommended phase II dose (RPTD) and toxicities of the FOG regimen (infusional 5-fluorouracil, oxaliplatin, gemcitabine).

PATIENTS AND METHODS

Patients with advanced solid tumors were treated in an accelerated titration scheme. 5-Fluorouracil was administered intravenously at 200 mg/m(2)/day for 14 days and repeated every 21 days (one cycle). Gemcitabine was administered on days 1 and 8 over 30 min at 450-650 mg/m(2). Oxaliplatin was administered on day 1 over 2 h at 85-130 mg/m(2). For cycles 1, 3 and beyond, gemcitabine followed oxaliplatin; for cycle 2, gemcitabine preceded oxaliplatin.

RESULTS

Forty-five and 39 patients were assessable for toxicity and response, respectively. Cycle 1 dose-limiting toxicities (DLT) included neutropenia, thrombocytopenia and diarrhea. No DLT was observed in cycle 1 at the first four dose levels (DL). At DL-5, two of four (50%) patients experienced DLT in cycle 1. Expanding DL-4, nine of 26 (35%) patients experienced DLT in cycle 1. Because recurrent grade 3 toxicities were observed in three of six (50%) patients at DL-3, DL-2 was considered the RPTD. At the RPTD, three patients had a partial response (response rate 23%).

CONCLUSIONS

The RPTD for the 5-fluorouracil-oxaliplatin-gemcitabine combination is 200/100/450 mg/m(2). This novel regimen has demonstrated activity in advanced solid tumors and merits further investigation.

A phase I study of paclitaxel and altretamine as second-line therapy to cisplatin regimens for ovarian cancer

PURPOSE

The efficacy and pharmacokinetics of paclitaxel when combined with altretamine for ovarian cancer were studied.

METHODS

A group of 30 patients, whose only chemotherapy was one or more cisplatin-based non-paclitaxel-containing regimens and whose ovarian cancer failed to respond or had relapsed within 6 months of their last platinum regimen, received paclitaxel as a 3-h intravenous infusion and altretamine given orally in four divided doses daily for 14 days repeated every 28 days. Doses were escalated from paclitaxel/altretamine 135/150 mg/m2 to 250/300 mg/m2 in cohorts of three patients.

RESULTS

The dose-limiting toxicities at 250/300 mg/m2 were WHO grade 3 myalgias and arthralgias in two patients and grade 3 lethargy, stomach cramps, peripheral neuropathy and vomiting in single patients. Considering all dose levels in cycle 1, 16 patients had grade 3 or 4 neutropenia but there was only one episode of febrile neutropenia. Other grade 3 toxicities were vomiting in four patients, myalgias in three, peripheral neuropathy in two and lethargy in two. Grade 3 alopecia occurred in 23 patients. Three patients achieved a complete response and 12 achieved a partial response for an overall objective response rate of 50%. Responses occurred at all dose levels of 175/150 mg/m2 and higher. The median freedom from progression was 35 weeks, with a median survival of 55 weeks. Altretamine did not alter the pharmacokinetics of paclitaxel and there were no consistent differences in paclitaxel pharmacokinetic parameters or toxicities between course 1 and 2. No dose-response relationships were evident above paclitaxel/altretamine 175/150 mg/m2.

CONCLUSION

Paclitaxel and altretamine can be safely combined and with a high response rate in relapsed ovarian cancer, justifying further studies with this combination.

Use of preventive services by managed care enrollees: an updated perspective

We examined whether enrollees in managed care plans received more preventive services than enrollees in non-managed care plans did, by conducting an updated literature synthesis of studies published between 1990 and 1998. We found that 37 percent of comparisons indicated that managed care enrollees were significantly more likely to obtain preventive services; 3 percent indicated that they were significantly less likely to do so; and 60 percent found no difference. Enrollees in group/staff-model health maintenance organizations (HMOs) were more likely to receive preventive services, but there was little evidence, outside of Medicaid managed care, that managed care plans are worse at providing preventive services. However, most of the evidence is equivocal: Provision of preventive services was neither better nor worse in managed versus non-managed care plans. Because of the blurred distinctions among types of health plans, more research is needed to identify which plan characteristics are most likely to encourage appropriate utilization.