Disruption of parallel and converging signaling pathways contributes to the synergistic antitumor effects of simultaneous mTOR and EGFR inhibition in GBM cells

Elevated epidermal growth factor receptor (EGFR) and mammalian target of rapamycin (mTOR) signaling are known to contribute to the malignant properties of glioblastoma multiforme (GBM), which include uncontrolled cell proliferation and evasion of apoptosis. Small molecule inhibitors that target these protein kinases have been evaluated in multiple clinical trials for cancer patients, including those with GBM. Here we have examined the cellular and molecular effects of a combined kinase inhibition of mTOR (rapamycin) and EGFR (EKI-785) in U87 and U251 GBM cells. Simultaneous treatment with rapamycin and EKI-785 results in synergistic antiproliferative as well as proapoptotic effects. At a molecular level, rapamycin alone significantly decreases S6 phosphorylation, whereas EKI-785 alone promotes substantially reduced signal transducer and activator of transcription (STAT3) phosphorylation. Treatment with rapamycin alone also increases Akt phosphorylation on Ser-473, but this effect is blocked by a simultaneous administration of EKI-785. Individually, EKI-785 diminishes while rapamycin promotes the binding of the translation inhibitor eukaryotic initiation factor 4E binding protein (4EBP1) to the eukaryotic translation initiation factor 4E (eIF4E). In spite of these opposing effects, the highest level of 4EBP1-eIF4E binding occurs with the combination of the two inhibitors. These results indicate that the inhibition of EGFR and mTOR has distinct as well as common signaling consequences and provides a molecular rationale for the synergistic antitumor effects of EKI-785 and rapamycin administration.

In vitro and In vivo Antitumor Effects of the Dual Insulin-Like Growth Factor-I/Insulin Receptor Inhibitor, BMS-554417

The insulin-like growth factor receptor (IGF-IR) and insulin receptor are either overactivated and/or overexpressed in a wide range of tumor types and contribute to tumorigenicity, proliferation, metastasis, and drug resistance. Here, we show that BMS-554417, a novel small molecule developed as an inhibitor of IGF-IR, inhibits IGF-IR and insulin receptor kinase activity and proliferation in vitro, and reduces tumor xenograft size in vivo. In a series of carcinoma cell lines, the IC50 for proliferation ranged from 120 nmol/L (Colo205) to >8.5 micromol/L (OV202). The addition of stimulatory ligands was unnecessary for the antiproliferative effect in MCF-7 and OV202 cells. BMS-554417 treatment inhibited IGF-IR and insulin receptor signaling through extracellular signal-related kinase as well as the phosphoinositide 3-kinase/Akt pathway, as evidenced by decreased Akt phosphorylation at Ser473. At doses that inhibited proliferation, the compound also caused a G0-G1 arrest and prevented nuclear accumulation of cyclin D1 in response to LR3 IGF-I. In Jurkat T-cell leukemia cells, this agent triggered apoptotic cell death via the mitochondrial pathway. BMS-554417 was orally bioavailable and significantly inhibited the growth of IGF1R-Sal tumor xenografts in vivo. BMS-554417 is a member of a novel class of IGF-IR/insulin receptor inhibitors that have potential clinical applications because of their antiproliferative and proapoptotic activity in vitro and in vivo.

Phase II study of daily oral perifosine in patients with advanced soft tissue sarcoma

BACKGROUND

A multicenter Phase II study was performed to evaluate the clinical activity of an initial loading (150 mg every 6 hours x 4 doses) dose followed by continuous daily oral dosing (100 mg/day) of perifosine in patients with advanced soft tissue sarcomas (STSs).

METHODS

Patients with measurable metastatic STS received perifosine as first-, second-, or third-line treatment and underwent disease assessment every 8 weeks until disease progression, excessive toxicity, or patient refusal.

RESULTS

Twenty-three patients received 66 cycles (1 cycle = 4 weeks) of perifosine. One partial response of 9 months duration was observed. The overall 3 and 6 month progression-free survival was 22% and 9%. NCI CTC (v2.0) Grade 1 to 2 gastrointestinal toxicity or fatigue were the most common (>50% of subjects) toxicities observed. The steady-state plasma perifosine levels (Css) were similar to prior experience (mean 6 microg/mL). Patients with Css levels >6 microg/mL appeared more likely to remain on study past 2 months than those with levels <6 microg/mL.

CONCLUSIONS

Despite not achieving the primary objective of > or =40% 6-month progression-free survival rate, optimism remains for this agent in STS patients. Prolonged responses in heavily pretreated STS patients continue to be observed with perifosine treatment. Continued assessment of perifosine in STS appears warranted, with special attention to specific histologies or tumor characteristics that might identify a more sensitive population and achieving perifosine Css levels >6 microg/mL.

A phase I and pharmacokinetic study of a powder-filled capsule formulation of oral irinotecan (CPT-11) given daily for 5 days every 3 weeks in patients with advanced solid tumors

PURPOSE

Intravenous (i.v.) irinotecan is a cytotoxic topoisomerase I inhibitor with broad clinical activity in metastatic colorectal cancer and other tumors. The development of an oral formulation of irinotecan could enhance convenience and lessen the expense of palliative irinotecan delivery. This phase I study evaluated the dose-limiting toxicities (DLT), maximum tolerated dose (MTD), and pharmacokinetics (PK) of irinotecan given as a powder-filled capsule (PFC) daily for 5 days every 3 weeks.

PATIENTS AND METHODS

Patients with advanced solid tumors received escalating doses of oral irinotecan daily for 5 days every 3 weeks. Plasma samples were collected following the first and fifth doses of irinotecan during Cycle 1 to determine the PK of irinotecan and its major circulating metabolites: SN-38, SN-38G, and APC.

RESULTS

20 patients (median age 61.5 years, range 40-75; M/F 12/8; ECOG PS 0=5, 1=11, 2=4) received oral irinotecan at dose levels of 30 (n=3), 40 (n=3), 50 (n=6), and 60 (n=8) mg/m(2)/day. Of the eight patients enrolled at 60 mg/m(2), three patients experienced DLT (> or = grade 3) consisting of nausea (three patients), vomiting (three patients), diarrhea (two patients), and febrile neutropenia (two patients) for which all the three patients required hospitalization. Treatment of six patients at the 50-mg/m(2) dose level resulted in no DLT. Other toxicities observed include abdominal pain, alopecia, anorexia, and asthenia. After oral administration, irinotecan was rapidly absorbed into systemic circulation and converted to the active metabolite SN-38. Increasing dose levels resulted in a dose-dependent increase in mean exposure parameters (Cmax and AUC) of irinotecan and metabolites. Systemic exposure parameters (Cmax and AUC(0-24)) of irinotecan and SN-38 were comparable between days 1 and 5. The extent of conversion from irinotecan to SN-38 was approximately threefold higher after the oral administration compared to that previously observed after i.v. administration. The exposure parameters of irinotecan or SN-38 are of limited value in predicting severity of Cycle 1 toxicities in the twofold dose range evaluated.

CONCLUSION

Daily oral administration of irinotecan as the PFC formulation for 5 days every 3 weeks can safely deliver protracted exposure to SN-38, with the MTD of 50 mg/m(2)/d.

Phase II study of Erlotinib (OSI-774) in patients with advanced hepatocellular cancer

PURPOSE

Epidermal growth factor receptor/human epidermal growth factor receptor 1 (EGFR/HER1) and ligand expression is frequently seen in hepatocellular cancers (HCCs). Erlotinib (Tarceva, OSI-774; OSI Pharmaceuticals, Melville, NY) is a receptor tyrosine kinase inhibitor with specificity for the EGFR/HER1.

METHODS

The primary objective of this study was to determine the proportion of patients with advanced HCC who were progression-free at 6 months. Patients with either unresectable or metastatic disease were studied. Only one prior systemic or locoregional therapy was allowed. Erlotinib was given continuously at a dose of 150 mg per day orally.

RESULTS

Thirty-eight patients with HCC were enrolled. Median age of the patients was 69 years (range, 27 to 83 years). A majority of patients (63%) had an Eastern Cooperative Oncology Group performance status of 1. Forty-seven percent of patients had received prior chemotherapy for advanced HCC. EGFR/HER1 expression was detected in 88% of the patients. Median number of cycles per patient was two (range, 1 to 26). Twelve (32%; CI 95%, 18 to 49) of the 38 patients with HCC were progression-free at 6 months. Three patients had partial radiologic responses of duration of 2, 10, and 11 months, respectively. Disease control was seen in 59% of the patients. Median overall survival time was 13 months. Ten patients (26%) had toxicity-related dose reductions of erlotinib. Grade 3/4 skin toxicity or diarrhea was encountered in five and three patients, respectively.

CONCLUSION

Results of this trial suggest a benefit for EGFR/HER1 blockade with erlotinib in patients with HCC manifested by disease control. Additional studies with erlotinib as a single agent or in combination with other agents are warranted.

Epidermal growth factor receptor and activated epidermal growth factor receptor expression in gastrointestinal carcinoids and pancreatic endocrine carcinomas

The epidermal growth factor receptor (EGFR) plays an important role in the pathogenesis of many tumors. To analyze the expression of EGFR and activated EGFR in well-differentiated neuroendocrine carcinomas including primary and metastatic gastrointestinal carcinoid tumors and pancreatic endocrine tumors (PET), we examined 58 gastrointestinal carcinoid tumors and 48 PET using immunohistochemistry, Western blotting, and RT-PCR. EGFR and activated EGFR (P-EGFR) were expressed by both gastrointestinal carcinoids and PET in primary and metastatic tumors, although a higher percentage of gastrointestinal carcinoid tumors expressed EGFR and activated EGFR. Western blotting detected a 170 kDa band for both EGFR and activated EGFR in three primary carcinoid tumors and two metastatic carcinoid tumors to the liver. RT-PCR analysis confirmed the expression of EGFR mRNA in both primary and metastatic carcinoid tumors. Patients with activated EGFR expression in their primary PET had a significantly worse prognosis compared to those who did not express activated-EGFR (P = 0.043). These results indicate that gastrointestinal carcinoid tumors as well as PET express EGFR and activated EGFR, and that expression is more common in gastrointestinal carcinoid tumors compared to pancreatic endocrine tumors. These findings implicate the EGFR and P-EGFR signal transduction pathway in the pathogenesis of these neuroendocrine tumors and suggest that targeted therapy directed against the EGFR tyrosine kinase domain may be a useful therapeutic approach in patients with unresectable metastatic gastrointestinal carcinoid tumors and pancreatic endocrine tumors.

A phase I and pharmacokinetic study of the selective, non-peptidic inhibitor of matrix metalloproteinase BAY 12-9566 in combination with etoposide and carboplatin

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that degrade the extracellular matrix during the processes of invasion, metastasis and angiogenesis. BAY 12-9566 (BAY) is a selective, non-peptidic biphenyl inhibitor of MMPs, with nanomolar inhibitory activity against MMP-2, -3 and -9, and anti-invasive, anti-metastatic and anti-angiogenic activity in a variety of tumor models. This phase I study of oral BAY was conducted to evaluate the safety and pharmacokinetics of BAY when administered in combination with etoposide (VP-16) or in combination with VP-16 and carboplatin (CBDCA) in subjects with advanced cancer. The first cohort of patients (n=8) received a cycle of VP-16, 60 mg/m, followed 1 week later by a fixed daily oral dose of BAY, 800 mg b.i.d., to which three potential possible doses of VP-16 (low dose: 60 mg/m; mid dose: 90 mg/m; high dose: 120 mg/m) were added every 3 weeks as tolerated. The second cohort (n=5) received VP-16 (120 mg/m) and CBDCA (AUC=5) followed 1 week later by a fixed daily oral dose of BAY (800 mg) b.i.d., to which VP-16 (120 mg/m) and CBDCA (AUC=5) were added. Dose-limiting toxicity (DLT) was defined as toxicity grade 3 or above. Maximum tolerated dose was declared if two or more patients experienced DLT. A performance status of 0-2 and acceptable organ function were required for eligibility. Plasma concentrations of BAY and VP-16 were measured to investigate pharmacokinetic interactions. Eight eligible patients with a variety of tumor types (median age 64 years, range 44-76) were enrolled in the first cohort, six of who whom completed all three levels of VP-16. Progressive disease occurred in five of the eight patients; three patients continued on study with treatment. Drug level and pharmacokinetics analysis of BAY and VP-16 were also determined. The combination of BAY and VP-16 was tolerable in the first cohort, permitting enrollment of the second cohort. In the second cohort (n=5), the combination of BAY, VP-16 and CDBCA was intolerable at the doses used due to excessive hematologic toxicity in the first five patients enrolled. Pharmacokinetics and toxicity analysis was performed for this group of patients. Only Level 1 of treatment was completed for Cohort II. At this point the study was halted due to toxicity and the results of an interim analysis that failed to demonstrate sufficient clinical activity of this compound in other clinical trials. We conclude that the combination of BAY and VP-16 was well tolerated. However, the combination of BAY, VP-16 and CDBCA produces significant hematologic toxicity. Findings from this study may help to direct further studies with other inhibitors of MMPs.

Phase I and Pharmacologic Study of Infusional Topotecan and Carboplatin in Relapsed and Refractory Acute Leukemia

PURPOSE

To assess the maximum tolerated dose, toxicities, pharmacokinetics, and antileukemic activity of topotecan and carboplatin in adults with recurrent or refractory acute leukemias.

EXPERIMENTAL DESIGN

Patients received topotecan and carboplatin by 5-day continuous infusion at nine dose levels. Patients achieving a complete remission received up to two additional courses for consolidation. Plasma topotecan and ultrafilterable platinum were assayed on days 1 to 5. In addition, pretreatment levels of various polypeptides in leukemic cells were examined by immunoblotting to assess possible correlations with response.

RESULTS

Fifty-one patients received a total of 69 courses of therapy. Dose-limiting toxicity consisted of grade 4/5 typhlitis and grade 3/4 mucositis after one course of therapy or grade 4 neutropenia and thrombocytopenia lasting >50 days when a second course was administered on day 21. Among 45 evaluable patients, there were 7 complete remissions, 2 partial remissions, 1 incomplete complete remission, and 1 reversion to chronic-phase chronic myelogenous leukemia. Topotecan steady-state plasma concentrations increased with dose. No accumulation of topotecan or ultrafilterable platinum occurred between days 1 and 5 of therapy. Leukemic cell levels of topoisomerase I, checkpoint kinase 1, checkpoint kinase 2, and Mcl-1 correlated with proliferating cell nuclear antigen but not with response. In contrast, low Bcl-2 expression correlated with response (P = 0.014, Mann-Whitney U test).

CONCLUSIONS

The maximum tolerated dose was 1.6 mg/m(2)/d topotecan plus 150 mg/m(2)/d carboplatin. The complete remission rate in a heavily pretreated population was 16% (33% at the highest three dose levels). Responses seem to correlate with low pretreatment blast cell Bcl-2 expression.

Phase 1 Trial of Flavopiridol Combined with Cisplatin or Carboplatin in Patients with Advanced Malignancies with the Assessment of Pharmacokinetic and Pharmacodynamic End Points

PURPOSE

Flavopiridol, a cyclin-dependent kinase inhibitor, transcription inhibitor, and DNA-interacting agent, was combined with cisplatin or carboplatin to establish toxicities, evaluate pharmacokinetics, and examine its effects on patient cancers and levels of selected polypeptides in patient peripheral blood mononuclear cells (PBMC).

EXPERIMENTAL DESIGN

Therapy was given every 3 weeks. Stage I: cisplatin was fixed at 30 mg/m2 with escalating flavopiridol. Stage II: flavopiridol was fixed at the stage I maximum tolerated dose (MTD) with escalation of cisplatin. Stage III: flavopiridol was fixed at the stage I MTD with escalation of carboplatin.

RESULTS

Thirty-nine patients were treated with 136 cycles of chemotherapy. Neutropenia was seen in only 11% of patients. Grade 3 flavopiridol/CDDP toxicities were nausea (30%), vomiting (19%), diarrhea (15%), dehydration (15%), and neutropenia (10%). Flavopiridol combined with carboplatin resulted in unexpectedly high toxicities and one treatment-related death. Stable disease (>3 months) was seen in 34% of treated patients, but there were no objective responses. The stage II MTD was 60 mg/m2 cisplatin and 100 mg/m2/24 hours flavopiridol. As given, CDDP did not alter flavopiridol pharmacokinetics. Flavopiridol induced increased p53 and pSTAT3 levels in patient PBMCs but had no effects on cyclin D1, phosphoRNA polymerase II, or Mcl-1.

CONCLUSIONS

Flavopiridol and cisplatin can be safely combined in the treatment of cancer patients. Unexpected toxicity in flavopiridol/carboplatin-treated patients attenuates enthusiasm for this alternative combination. Analysis of polypeptide levels in patient PBMCs suggests that flavopiridol may be affecting some, but not all, of its known in vitro molecular targets in vivo.

Novel therapeutics in colorectal cancer

Colorectal cancer is an excellent tumor model for evaluating novel therapeutic strategies. Development of a mechanistic understanding of how this cancer develops, spreads, and grows allows a tailored approach to all stages of treatment: prevention, adjuvant treatment, and therapy of advanced disease. We focus on therapy in the advanced disease setting, although progress in this area could lend itself to treatment of early or premalignant disease. In the last 20 years, information has been generated about the intracellular pathways of tumor formation, invasion, and metastasis. As a result, specific molecular processes have been targeted for therapeutic intervention, including cell surface growth factor receptors, proliferation signaling, cell cycling, apo-ptosis, angiogenesis, and matrix metalloproteinases. We review the scientific rationale for recently developed novel therapeutics in colorectal cancer, and the results of clinical trials to date. We also suggest appropriate clinical settings for specific targets and outline future directions of research.

Early results of a phase I trial of oblimersen sodium for relapsed or refractory Waldenstrom's macroglobulinemia

Oblimersen sodium is an antisense oligonucleotide to the first 6 codons of the B-cell leukemia gene 2 (bcl-2) open reading frame. It prevents the expression of the bcl-2 gene product and leads to apoptosis in cells that express Bcl-2. bcl-2 is one of the major apoptosis regulatory gene families and is found in a variety of low-grade B-cell non-Hodgkin's lymphomas. The in vitro use of oblimersen in Waldenstrom's macroglobulinemia (WM) cell line results in enhanced toxicity when exposed to fludarabine, dexamethasone, or rituximab. Oblimersen should also enhance the cytotoxic effect of chemotherapy in WM. Presented herein are early data on the phase I portion of a phase I/II study of oblimersen in WM to identify the maximum tolerated dose and to evaluate response in patients with symptomatic WM.

Phase I-II trial of ONYX-015 in combination with MAP chemotherapy in patients with advanced sarcomas

ONYX-015 is a provisionally replication competent adenovirus with oncolytic activity in cells with malfunctioning p53. Sarcomas represent a rational target for this approach given the high frequency of p53 mutations (40-75%) and MDM-2 amplification (10-30%). We, therefore, undertook a phase I/II study of ONYX-015, days 1-5 every month administered intratumorally under radiographic guidance, in combination with MAP (mitomycin-C, doxorubicin, cisplatin) chemotherapy in patients with advanced sarcoma. Six patients were treated. Injected lesions included liver metastases in four patients and chest wall metastases in two patients. Sarcoma histologies were gastrointestinal stromal tumors (GIST, two patients), leiomyosarcoma (two patients), liposarcoma (one patient), and malignant peripheral nerve sheath tumor (1 patient). Dose escalation was performed from 10(9) plaque forming units (PFU)/dose (total dose of 5 x 10(9) PFU/cycle) to 10(10) PFU/dose (total dose of 5 x 10(10) PFU/cycle) without dose-limiting toxicity being encountered. Immunohistochemistry of the metastatic lesions prior to treatment showed that five out of six patients were positive for p53, while two patients also had mdm-2 overexpression. Adenoviral replication was detected in two out of six patient biopsies on day 5 of the first cycle, by in situ hybridization (ISH). Both patients were treated at the highest dose level. ONYX-015 viral DNA was detected by quantitative PCR in the plasma of 5/6 patients on day 5 of the first cycle, and up to day 12 (7 days after the last viral dose) in one patient who had extended sampling for viral kinetics performed, suggesting viral replication in sarcoma tissue. One patient with p53 mutation and MDM-2 amplification achieved a partial response to treatment that lasted 11 months. In conclusion, intratumoral administration of ONYX-015 in combination with MAP chemotherapy is well tolerated with no significant toxicity due to ONYX-015 being encountered. Detection of viral DNA in post treatment tumor specimens by ISH and detection of the ONYX-015 genome in the peripheral blood by quantitative PCR, up to 7 days after the last viral dose provide evidence for adenoviral replication. There was evidence of antitumor activity in one out of six patients. Further investigation of this approach in patients with recurrent sarcomas is warranted.

A Phase I and Pharmacologic Trial of Two Schedules of the Proteasome Inhibitor, PS-341 (Bortezomib, Velcade), in Patients with Advanced Cancer

PURPOSE

To define the toxicities, pharmacodynamics, and clinical activity of the proteasome inhibitor, PS-341 (bortezomib), in patients with advanced malignancies.

PATIENTS AND METHODS

Twenty-eight patients (14 male and 14 female) received PS-341 twice weekly for 4 of 6 weeks (schedule I). Because toxicity necessitated dose omissions on this schedule, 16 additional patients (12 male and 4 female) received PS-341 twice weekly for 2 of every 3 weeks (schedule II). A total of 73 courses of treatment was given (median, 2; range, 1-4). Inhibition of 20S proteasome activity in peripheral blood mononuclear cells (PBMC) and accumulation of proteasome-targeted polypeptides in tumor tissue were evaluated as pharmacodynamic markers of PS-341 activity.

RESULTS

The most common toxicity was thrombocytopenia, which was dose limiting at 1.7 mg/m2 (schedule I) and 1.6 mg/m2 (schedule II), respectively. Sensory neuropathy was dose-limiting in a patient in schedule I. Grade > or =3 toxicities for schedule I were constipation, fatigue, myalgia, and sensory neuropathy. Grade > or =3 toxicities for schedule II were dehydration resulting from diarrhea, nausea and vomiting, fatigue, hypoglycemia, and hypotension. The maximum tolerated dose was 1.5 mg/m2 for both schedules. Reversible dose-dependent decreases in 20S proteasome activity in PBMCs were observed, with 36% inhibition at 0.5 mg/m2, 52% at 0.9 mg/m2, and 75% at 1.25 mg/m2. Accumulation of proteasome-targeted polypeptides was detected in tumor samples after treatment with PS-341. A patient with multiple myeloma had a partial response.

CONCLUSION

PS-341 given 1.5 mg/m2 twice weekly for 2 of every 3 weeks is well tolerated and should be further studied.

Evaluation of Epothilone B Analog in Advanced Soft Tissue Sarcoma: A Phase II Study of the Phase II Consortium

Purpose

Epothilones are a new class of nontaxane tubulin polymerization agents that have activity in taxane-resistant tumors. Epothilone B (BMS-247550) is a semisynthetic analog of the natural product epothilone B. This study was performed to determine the activity of BMS-247550 in patients with soft tissue sarcomas (STSs) who had not received prior chemotherapy for metastatic disease.

Patients and Methods

Patients with measurable, advanced, or metastatic STS with no prior chemotherapy for metastatic disease were treated with BMS-2457550 50 mg/m2 intravenously during 1 hour every 21 days. All responses were confirmed 4 weeks later.

Results

Thirty-one patients (median age, 54 years; range, 19 to 78 years; 48% female) were entered onto the trial and were assessable for response. All but one patient had an Eastern Cooperative Oncology Group performance score of 0% or 1%, and 39% had received prior adjuvant chemotherapy. Mean follow-up was 22 months, with a confirmed response rate of 6% (95% CI, 0% to 17%). Median time to progression was 4.5 months (95% CI, 1.9 to 8.3 months), and 1 year progression-free survival was 17% (95% CI, 8% to 38%). Median survival was 16.4 months, with a 1-year survival of 61% (95% CI, 46% to 81%). Toxicity was mainly hematologic, with eight of 31 (26%) patients experiencing grade 3 to 4 leukopenia; 15 of 31 patients (48%) experienced grade 3 to 4 neutropenia. The grade 3 to 4 nonhematologic toxicities included neuropathies (26%), myalgia (13%), and fatigue (10%).

Conclusion

BMS-247550 has limited activity against STSs when given in this dose and schedule. The clinical toxicity is similar to that of taxanes.

Somatostatin analogues in the treatment of gastroenteropancreatic neuroendocrine tumors

Gastroenteropancreatic neuroendocrine tumors constitute a heterogeneous group of neoplasms that are often associated with typical symptoms due to excessive and uncontrolled release of diverse hormones. Because these tumors are usually slow growing, surgery is the cornerstone of treatment. However, these rare tumors can present with rapid progression that requires aggressive systemic therapy or diffuse metastatic disease not amenable to surgical palliation. For most patients, medical approaches are necessary at some point in the course of their disease, especially since most tumors are at an advanced stage at the time of diagnosis. Most gastroenteropancreatic neuroendocrine tumors express high levels of somatostatin receptors, which are bound by somatostatin or its synthetic analogues. These agents, alone or combined with other therapies, such as Interferon or radioisotopes, are therefore used frequently to control hormone-related symptoms and, for some patients, the growth of the disease Itself. This article reviews the evidence for the use of somatostatin analogues in the treatment of gastroenteropancreatic neuroendocrine tumors based on a MEDLINE search of literature published from January 1970 to July 2003.

Heat shock protein 90 inhibition sensitizes acute myelogenous leukemia cells to cytarabine

Previous studies demonstrated that ataxia telangiectasia mutated- and Rad3-related (ATR) kinase and its downstream target checkpoint kinase 1 (Chk1) facilitate survival of cells treated with nucleoside analogs and other replication inhibitors. Recent results also demonstrated that Chk1 is depleted when cells are treated with heat shock protein 90 (Hsp90) inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG). The present study examined the effects of 17-AAG and its major metabolite, 17-aminogeldanamycin (17-AG), on Chk1 levels and cellular responses to cytarabine in human acute myelogenous leukemia (AML) cell lines and clinical isolates. Cytarabine, at concentrations as low as 30 nM, caused activating phosphorylation of Chk1, loss of the phosphatase Cdc25A, and S-phase slowing. Conversely, treatment with 100 to 300 nM 17-AAG for 24 hours caused Chk1 depletion that was accompanied by diminished cytarabine-induced S-phase accumulation, decreased Cdc25A degradation, and enhanced cytotoxicity as measured by inhibition of colony formation and induction of apoptosis. Additional studies demonstrated that small inhibitory RNA (siRNA) depletion of Chk1 also sensitized cells to cytarabine, whereas disruption of the phosphatidylinositol 3-kinase (PI3k) signaling pathway, which is also blocked by Hsp90 inhibition, did not. Collectively, these results suggest that treatment with 17-AAG might represent a means of reversing checkpoint-mediated cytarabine resistance in AML.

Phase I trial of 17-allylamino-17-demethoxygeldanamycin in patients with advanced cancer

PURPOSE

We determined the maximum-tolerated dose (MTD) and the dose-limiting toxicities (DLT) of 17-allylamino-17-demethoxygeldanamycin (17-AAG) when infused on days 1, 8, and 15 of a 28-day cycle in advanced solid tumor patients. We also characterized the pharmacokinetics of 17-AAG, its effect on chaperone and client proteins, and whether cytochrome P450 (CYP) 3A5 and NAD(P)H:quinone oxidoreductase 1 (NQO1) polymorphisms affected 17-AAG disposition or toxicity.

PATIENTS AND METHODS

An accelerated titration design was used. Biomarkers were measured in peripheral-blood mononuclear cells (PBMCs) at baseline and on days 1 and 15, and pharmacokinetic analysis was performed on day 1 of cycle 1. CYP3A5*3 and NQO1*2 genotypes were determined and correlated with pharmacokinetics and toxicity.

RESULTS

Twenty-one patients received 52 courses at 11 dose levels. DLTs at 431 mg/m(2) were grade 3 bilirubin (n = 1), AST (n = 1), anemia (n = 1), nausea (n = 1), vomiting (n = 1), and myalgias (n = 1). No tumor responses were seen. 17-AAG consistently increased heat shock protein (Hsp) 70 levels in PBMCs. At the MTD, the clearance and half-life (t(1/2)) of 17-AAG were 11.6 L/h/m(2) and 4.15 hours, respectively; whereas the active metabolite 17-aminogeldanamycin had a t(1/2) of 7.63 hours. The CYP3A5*3 and NQO1*2 polymorphisms were not associated with 17-AAG toxicity. The CYP3A5*3 polymorphism was associated with higher 17-AAG clearance.

CONCLUSION

The MTD of weekly 17-AAG is 308 mg/m(2). 17-AAG induced Hsp70 in PBMCs, indicating that Hsp90 has been affected. Further evaluation of 17-AAG is ongoing using a twice-weekly regimen, and this schedule of 17-AAG is being tested in combination with chemotherapy.

A Phase I Trial of the Novel Farnesyl Protein Transferase Inhibitor, BMS-214662, in Combination with Paclitaxel and Carboplatin in Patients with Advanced Cancer

PURPOSE

This phase I study was conducted to determine the toxicities, pharmacokinetics, and pharmacodynamics of BMS-214662, a farnesyl transferase inhibitor, in combination with paclitaxel and carboplatin, in patients with advanced solid tumors.

EXPERIMENTAL DESIGN

Patients with solid tumors received one of six escalating dose levels of BMS-214662 infused over 1 hour given following paclitaxel and carboplatin on the first day of a 21-day cycle. Toxicities were graded by the National Cancer Institute common toxicity criteria and recorded as maximum grade per patient for each treatment cycle. Inhibition of farnesyl transferase activity in peripheral blood mononuclear cells (PBMCs) was evaluated. Accumulation of unfarnesylated HDJ-2 in PBMCs of patients was evaluated as a marker of farnesyl transferase inhibition by BMS-214662.

RESULTS

Thirty patients received 141 cycles of treatment through six dose levels. Dose-limiting toxicities were neutropenia, thrombocytopenia, nausea, and vomiting. There was no pharmacokinetic interaction between BMS-214662 and paclitaxel. The maximum tolerated dose was established as BMS-214662 (160 mg/m(2)), paclitaxel (225 mg/m(2)) and carboplatin (area under the curve = 6 on day 1), every 21 days. Inhibition of HDJ-2 farnesylation in PBMCs of patients was shown. One measurable partial response was observed in a patient with taxane-resistant esophageal cancer. There was partial regression of evaluable disease in two other patients (endometrial and ovarian cancer). Stable disease (> 4 cycles) occurred in eight other patients.

CONCLUSIONS

The combination of BMS-214662 with paclitaxel and carboplatin was well tolerated, with broad activity in solid tumors. There was no correlation between dose level and accumulation of unfarnesylated HDJ-2 in PBMCs nor tumor response.

A phase IB study of the pharmacokinetics of gemcitabine and pemetrexed, when administered in rapid sequence to patients with advanced solid tumors

BACKGROUND

We have previously demonstrated that pemetrexed is clinically active when administered 90 min after gemcitabine in a phase I study. The present study was undertaken to evaluate the efficacy, toxicity, and pharmacokinetics of gemcitabine and pemetrexed when pemetrexed is administered immediately after gemcitabine.

PATIENTS AND METHODS

A total of 14 patients received 84 cycles of treatment. Gemcitabine 1250 mg/m(2) was administered on days 1 and 8 of each 21-day cycle, and pemetrexed 500 mg/m(2) on day 8 immediately following gemcitabine administration. Toxicities were graded according to the National Cancer Institute Common Toxicity Criteria and recorded as maximum grade per patient for all treatment cycles. Pharmacokinetic analyses of plasma gemcitabine and pemetrexed concentrations were performed.

RESULTS

Neutropenia was the most common severe toxicity. Non-hematologic toxicities, which included nausea, vomiting, fatigue, diarrhea, rash, and elevated transaminases were of mild-to-moderate severity. No increased toxicity was observed with this schedule in comparison to the previous phase I schedule. There was no pharmacokinetic interaction between the two drugs. One partial response was documented in a patient with non-small-cell lung cancer. Eight patients had disease stabilization for five or more cycles.

CONCLUSION

Gemcitabine immediately followed by pemetrexed is well tolerated and clinically active, and deserves further evaluation in phase II trials.

Pathogenesis and risk factors of small bowel adenocarcinoma: a colorectal cancer sibling?

Small bowel adenocarcinoma (SBA) is a very rare entity accounting for one-fourth of the small intestine neoplasms. Usually accompanied by nonspecific symptoms occurring late in the course of the disease, they are associated with a dismal prognosis. It appears that SBA shares several genetic characteristics with large bowel tumors, but also has unique features. The purpose of this article is to review pathogenesis and risks factors of SBA to better understand its molecular features as well as its resemblances and dissimilarities with colorectal cancer (CRC). Better understanding of sporadic and hereditary genetic pathways potentially involved will undoubtedly lead to better prevention and therapeutic management of this rare but aggressive disease.

The role of checkpoint kinase 1 in sensitivity to topoisomerase I poisons

Agents that target topoisomerase I are widely utilized to treat human cancer. Previous studies have indicated that both the ataxia telangiectasia mutated (ATM)/checkpoint kinase (Chk) 2 and ATM- and Rad 3-related (ATR)/Chk1 checkpoint pathways are activated after treatment with these agents. The relative contributions of these two pathways to survival of cells after treatment with topoisomerase I poisons are currently unknown. To address this issue, we assessed the roles of ATR, Chk1, ATM, and Chk2 in cells treated with the topoisomerase I poisons camptothecin and 7-ethyl-10-hydroxycamptothecin (SN-38), the active metabolite of irinotecan. Colony forming assays demonstrated that down-regulation of ATR or Chk1 sensitized cells to SN-38 and camptothecin. In contrast, ATM and Chk2 had minimal effect of sensitivity to SN-38 or camptothecin. Additional experiments demonstrated that the Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin, which down-regulates Chk1, also sensitized a variety of human carcinoma cell lines to SN-38. Collectively, these results show that the ATR/Chk1 pathway plays a predominant role in the response to topoisomerase I inhibitors in carcinoma cells and identify a potential approach for enhancing the efficacy of these drugs.

Gemcitabine and ISIS-2503 for patients with locally advanced or metastatic pancreatic adenocarcinoma: a North Central Cancer Treatment Group phase II trial

PURPOSE

Gemcitabine remains the standard therapy for metastatic pancreatic adenocarcinoma (ACA), but has limited activity. ISIS-2503 is an antisense compound directed against H-ras with preclinical activity against pancreatic ACA in tumor models. The combination of ISIS-2503 and gemcitabine has been evaluated in a prior phase I study.

METHODS

Patients with metastatic or locally advanced pancreatic ACA not amenable to surgery or local radiation received gemcitabine 1,000 mg/m(2) intravenously over 30 minutes on days 1 and 8 and ISIS-2503 6 mg/kg/d as a continuous intravenous infusion over 14 days of an every-3-weeks cycle. Responses were monitored by radiologic imaging every 6 weeks.

RESULTS

Forty-eight eligible patients were enrolled, 43 with metastatic disease. Median follow-up was 12.6 months (range, 2.2 to 16.8 months) for living patients. A median of four cycles of treatment was given (range, 1 to 18 cycles). All patients were assessable for response and toxicity. The 6-month survival percentage was 57.5% (95% CI, 44.9% to 73.5%) and the median survival was 6.6 months. The response rate was 10.4% (one complete response, four partial responses). Clinically significant toxicity was limited except for one fatal pulmonary embolism.

CONCLUSION

This study shows a promising response rate to the combination of gemcitabine and ISIS-2503 in patients with pancreatic ACA. The observed 6-month survival rate in these patients met our protocol-defined criteria for success. This regimen is tolerable, but is of unclear benefit. Additional studies evaluating the role of gemcitabine and ISIS-2503 in the treatment of pancreatic ACA should be considered.

Large cell carcinoma with calcitonin and vasoactive intestinal polypeptide-associated Verner-Morrison syndrome

Verner-Morrison syndrome, characterized by diarrhea, hypokalemia, and hypochlorhydria, is caused most commonly by vasoactive intestinal polypeptide-secreting islet cell tumors of the pancreas. Verner-Morrison syndrome has not been described as a paraneoplastic syndrome in non-small cell lung cancer. We describe a 38-year-old man with metastatic non-small cell lung cancer of large cell carcinoma with neuroendocrine differentiation who presented with bone metastasis and intractable secretory diarrhea that was unresponsive to pharmacological treatment, including octreotide. Laboratory evaluation indicated elevated serum calcitonin and vasoactive intestinal polypeptide levels. Chemotherapy resulted in a transient response in the patient's diarrhea and neuroendocrine markers. The patient did not respond to further therapy and died 5 months after onset of back pain. To our knowledge, this is the first published case of large cell carcinoma with neuroendocrine differentiation associated with treatment-responsive paraneoplastic Verner-Morrison syndrome.

A phase II study of bortezomib in the treatment of metastatic malignant melanoma

BACKGROUND

Bortezomib is a proteasome inhibitor with manageable clinical toxicity and laboratory evidence of anti-melanoma activity. Therefore, it was considered for clinical testing in patients with metastatic melanoma.

METHODS

Patients with metastatic melanoma and adequate hematologic, renal, and hepatic function were treated with bortezomib (a 1.5-mg/m2 intravenous bolus twice weekly for 2 of every 3 weeks). Eligible patients were age > or = 18 years with an Eastern Cooperative Oncology Group performance status of 0-1. The primary goal of the current study was to evaluate the 18-week disease progression-free survival rate and tolerability of bortezomib in these patients.

RESULTS

The current study was intended to treat 45 patients. It was closed at the planned interim analysis due to early evidence of insufficient clinical efficacy. Twenty-seven patients with a median age of 56 years (range, 32-77 years)were accrued. There were no major clinical responses to treatment. Only 6 patients (22%) achieved stable disease. Of these 6 patients, 4 were still stable after 4 cycles of treatment, but were removed from the study due to toxicity. The median time to disease progression was 1.5 months (95% confidence interval [95% CI], 1.4-1.6) with a median overall survival of 14.5 months (95% CI, 9-22). Having failed bortezomib, most patients proceeded to other clinical trials. Twenty-six patients were evaluable for toxicity. One patient was removed from the study for other reasons and could not return for the cycle evaluation and thus was never evaluated. Of the 26 patients, no Grade 4/5 treatment-related toxicities (using the National Cancer Institute Common Toxicity Criteria [version 2.0]) were reported. Eleven patients (42%) had Grade 3 toxicities (believed to be at least possibly related to treatment), including sensory neuropathy, thrombocytopenia, constipation, fatigue, ileus, abdominal pain, and infection without neutropenia. The median number of treatment cycles patients received was two (range, one to six treatment cycles). Two patients (7%) had 1 dose delay and 6 patients (22%) had dose reductions during 1 treatment cycle due to adverse events.

CONCLUSIONS

Single-agent bortezomib, administered twice weekly x 2 weeks, every 3 weeks at a dose of 1.5 mg/m2, was not found to be effective in the treatment of patients with metastatic melanoma.

A phase I study of 153Sm-EDTMP with fixed high-dose melphalan as a peripheral blood stem cell conditioning regimen in patients with multiple myeloma

Despite response rates of 30% after high-dose chemotherapy with autologous hematopoietic stem cell transplant, patients with multiple myeloma are not cured. 153Samarium ethylenediaminetetramethylenephosphonate (153Sm-EDTMP; Quadramet) is a short-range, beta-emitting therapeutic radiopharmaceutical with avid skeletal uptake. In total, 12 patients were treated with escalating doses of 153Sm-EDTMP (N=3/group; 6, 12, 19.8, and 30 mCi/kg) and a fixed dose of melphalan (200 mg/m(2)). No dose limiting toxicity was seen. To better standardize the marrow compartment radiation dose, the study was modified such that an additional six patients were treated at a targeted absorbed radiation dose to the red marrow of 40 Gy based on a trace labeled infusion 1 week prior to the therapy. Despite rapid elimination of unbound radiopharmaceutical via kidneys and bladder, no episodes of nephrotoxicity, hemorrhagic cystitis, or delayed radiation nephritis were observed with a median follow-up of 31 months (range 8.5-44). Median times to ANC>0.5 and platelet >20 x 10(6)/l were 12 and 11 days, respectively, with no graft failures. Overall response rate was 94% including seven very good partial responses and five complete responses. Addition of 153Sm EDTMP to melphalan conditioning appears to be safe, well-tolerated and worthy of further study.

Small Bowel Adenocarcinoma: A Rare but Aggressive Disease

Unlike the colon and rectum, the small intestine is associated with a very low rate of tumor occurrence. Adenocarcinomas represent the most frequent of these rare digestive tumors and are often fatal as a result of tardy diagnosis. Regardless of the stage, surgery usually remains the cornerstone of small bowel adenocarcinoma therapy. Because of the rarity of the disease, very few significant clinical trials have identified any efficient nonsurgical treatment; however, recent data indicate these tumors might be sensitive to chemotherapy alone or in association with radiation therapy. Conversely, a great deal of progress has been achieved in diagnosis of the tumor, whether by adaptation of existing techniques or development of new ones. We reviewed the clinical aspects of this rare but aggressive disease, focusing on new diagnostic procedures as well as on recent advances in their therapeutic management.

Phase I and pharmacokinetic study of fostriecin given as an intravenous bolus daily for five consecutive days

Fostriecin (CI-920) is a potent inhibitor of protein phosphatase 2A (PP2A) and protein phosphatase 4(PP4) found to have anticancer activity in preclinical testing. A phase I study was conducted to evaluate the maximum-tolerated dose (MTD), toxicity profile, and pharmacokinetics (PK) of this drug. Forty-six patients were treated with escalating doses of fostriecin (2-47 mg/m2) administered as a daily bolus infusion for five consecutive days. PK studies were performed at different time points following administration of fostriecin. Dose-limiting toxicities included: elevation of creatinine, bilirubin, and hepatic transaminases; nausea, anorexia, lethargy, and hypotension. PK studies were compatible with a two-compartment model. Regression analysis revealed a significant relationship between dose and clearance; however, the r2 value was only 0.168 indicating a low predictive value for the model. No significant difference was seen in PK parameters with repeated dosing during the same cycle. Although no tumor responses were seen, 16 patients had stable disease with a median duration response of 2.6 months. The study was closed before reaching MTD due to problems with the supply of fostriecin from the National Cancer Institute of the United States (NCI US). New methods for synthesizing fostriecin have recently been described and therefore further development of this unique anticancer agent may be warranted.

Heterogeneous role of caspase-8 in fenretinide-induced apoptosis in epithelial ovarian carcinoma cell lines

The mechanism of action of fenretinide, a synthetic retinoid currently undergoing testing as a chemopreventive and chemotherapeutic agent, is incompletely understood. In the present study, fenretinide caused apoptotic changes, including DNA fragmentation and cleavage of caspase substrates, in six low-passage ovarian cancer cell lines. However, the caspase activation pathway used by this agent varied. Transient transfection of cDNA-encoding cytokine response modifier A (CrmA), a caspase-8 inhibitor, diminished fenretinide-induced death in OV177 cells. Likewise, IETD(OMe)-fluoromethylketone (fmk) inhibited fenretinide-induced apoptosis by >80% in OV177 or OV266 cells and by approximately 50% in OV17, OV167, or OV207 cells. Further analysis demonstrated that inhibition of Fas ligand, tumor necrosis factor-alpha, or TRAIL signaling with blocking reagents did not affect fenretinide-induced apoptosis, raising the possibility that fenretinide activates caspase-8 in a death receptor-independent manner. In contrast, CrmA transfection or IETD(OMe)-fmk treatment did not inhibit fenretinide-induced apoptosis in OV202 cells. These divergent behaviors did not correlate with increased levels of procaspase-10, which is relatively resistant to CrmA and IETD(OMe)-fmk, nor with the expression of procaspase-8 and -9, apoptotic protease activating factor-1, or cellular FLICE-like inhibitory protein. Similarly, fenretinide treatment increased ceramide levels equally in cells that do (OV177) and do not (OV202) rely on caspase-8 to initiate apoptosis. These results indicate that synthetic retinoids can use caspase-8 as an initiating caspase, but they also indicate unexpected heterogeneity in caspase activation pathways among closely related cell lines.

Phase I and pharmacokinetic study of two different schedules of oxaliplatin, irinotecan, Fluorouracil, and leucovorin in patients with solid tumors

PURPOSE

We sought to determine the maximum-tolerated dose (MTD) and evaluate the toxicities and clinical activity of two irinotecan (CPT-11), fluorouracil (FU), leucovorin (LV), and oxaliplatin schedules in patients with advanced solid tumors. Additionally, we investigated the effect of CPT-11 on oxaliplatin pharmacokinetics.

PATIENTS AND METHODS

Thirteen patients (cohort 1) received intravenous CPT-11 (infusion) and FU/LV (bolus) on days 1, 8, 15, and 22 and oxaliplatin (infusion) on days 1 and 15 every 6 weeks for a total 37 courses (median, three courses) at three dose levels. Twenty-two cohort 2 patients received intravenous CPT-11/oxaliplatin (infusion, day 1) and FU/LV (90-minute bolus infusion, days 2 to 5) every 3 weeks for a total of 122 courses (median, four courses) at three dose levels. Pharmacokinetic and neurotoxicity assessments were performed at the cohort 2 MTD.

RESULTS

Dose-limiting toxicity (DLT) seen in both cohorts at the starting dose required dose de-escalation. Cohort 1 DLT included diarrhea and neutropenia. In cohort 2, diarrhea, vomiting, dehydration, neutropenia, febrile neutropenia, and paresthesias were DLTs. Antitumor activity was seen in both cohorts. In cohort 2, the total platinum area under the curve of patients increased 17% in cycle 2 (P =.048), but objective neurotoxicity was not seen.

CONCLUSION

The toxicities resulting from the addition of oxaliplatin to CPT-11/FU/LV are significant but manageable. The MTDs for the weekly schedule are CPT-11 (75 mg/m2), oxaliplatin (50 mg/m2), FU (320 mg/m2), and LV (20 mg/m2); and, for the 3-weekly schedule, the MTDs are CPT-11 (175 mg/m2), oxaliplatin (85 mg/m2), FU (240 mg/m2), and LV (20 mg/m2). Second-cycle platinum accumulation raises the possibility for enhanced cumulative neurotoxicity with CPT-11/oxaliplatin combinations.

The Hsp90 chaperone complex as a novel target for cancer therapy

BACKGROUND

Heat shock protein 90 (Hsp90) is responsible for chaperoning proteins involved in cell signaling, proliferation and survival. 17-allylamino-17-demethoxygeldanamycin (17-AAG) is an anticancer agent currently in phase I trials in the USA and UK. It represents a class of drugs, the benzoquinone ansamycin antibiotics, capable of binding and disrupting the function of Hsp90, leading to the depletion of multiple oncogenic client proteins.

MATERIALS AND METHODS

Studies were identified through a PubMed search, review of bibliographies of relevant articles and review of abstracts from national meetings.

RESULTS

Preclinical studies have demonstrated that disruption of many client proteins chaperoned by Hsp90 is achievable and associated with significant growth inhibition, both in vitro and in tumor xenografts. Following an overview of the mechanism of action of ansamycin antibiotics and the pathways they disrupt, we review the current clinical status of 17-AAG, and discuss future directions for combinations of traditional antineoplastics with 17-AAG.

CONCLUSIONS

17-AAG represents a class of drugs capable of affecting multiple targets in the signal transduction pathway involved in tumor cell proliferation and survival. Early results from phase I studies indicate that 17-AAG administration results in an acceptable toxicity profile while achieving in vivo disruption of client proteins.

A Phase I trial of the farnesyl protein transferase inhibitor R115777 in combination with gemcitabine and cisplatin in patients with advanced cancer

PURPOSE

This Phase I study was undertaken to define the toxicity, pharmacodynamics, and maximum tolerated dose of the combination of R115777, a farnesyl transferase inhibitor, with gemcitabine and cisplatin in patients with advanced solid tumors.

PATIENTS AND METHODS

Thirty patients with solid tumors received a median of 2.5 cycles (range 1-30+) through five dose levels. R115777 was administered p.o. twice daily for 14 days. Gemcitabine was infused 15 min after the ingestion of R115777 on days 1 and 8. Cisplatin was administered starting 30 min after completion of the gemcitabine infusion on day 1. Cycles were repeated every 21 days. Toxicities were graded by the National Cancer Institute Common Toxicity Criteria and recorded as maximum grade per patient for each treatment cycle. At the maximum tolerated dose, accumulation of prelamin A in buccal mucosa cells of patients was evaluated as a marker of farnesyl transferase inhibition by R115777.

RESULTS

Neutropenia and thrombocytopenia were the most common toxicities. Dose-limiting toxicity in cycle 1 was myelosuppression with thrombocytopenia alone (4 patients), neutropenia alone (1 patient), or a combination of both (3 patients). Common nonhematologic toxicities were anorexia, rash, nausea, vomiting, and fatigue, none of which was dose limiting in the first cycle. At the maximum tolerated dose, defined as R115777 300 mg twice daily p.o., 1000 mg/m(2) gemcitabine, and 75 mg/m(2) cisplatin, inhibition of prelamin A farnesylation in buccal mucosa cells of patients was demonstrated, confirming that R115777 inhibits protein farnesylation in vivo. Nine objective responses (one complete response and eight partial responses) were documented in 27 evaluable patients.

CONCLUSION

The combination of R115777 with gemcitabine and cisplatin was well tolerated and showed evidence of antitumor activity. The maximum tolerated dose of R115777 successfully inhibits farnesyltransferase in patients in vivo. This combination warrants further evaluation in a number of tumor types.

Irinotecan in the treatment of glioma patients: current and future studies of the North Central Cancer Treatment Group

Other than nitrosoureas (carmustine and lomustine) and temozolomide, no agents have consistently demonstrated clinically meaningful benefits for patients with gliomas. The active metabolite of irinotecan, 7-ethyl-10-hydroxy camptothecin (SN-38), exhibited promising antitumor effects in preclinical glioma models. Clinical trials using weekly or every 3 weeks dosing of irinotecan have been completed. Toxicity consisted primarily of mild to moderate neutropenia and diarrhea with both schedules, with occasional severe toxicity including one death from neutropenia and infection. Preliminary analyses have suggested imaging responses in 10-15% of patients. Preclinical models and our understanding of the mechanism of action suggest that irinotecan may sensitize glioma cells to the cytotoxic actions of radiation therapy and alkylating agents; clinical trials designed to assess the therapeutic benefit of combination therapy currently are in progress. There is substantial clinical evidence that the concurrent administration of irinotecan with certain anticonvulsants produces reduced exposure to SN-38. In the absence of anticonvulsants, there is also substantial interpatient variability in drug exposure, perhaps reflecting inherited differences in drug metabolism. Finally several mechanisms of tumor cell resistance to irinotecan have been hypothesized, but the clinical significance of these observations has not been confirmed. Correlative studies to address these pharmacokinetic, pharmacogenetic, and drug resistance questions are ongoing.

Phase II study of the farnesyl transferase inhibitor R115777 in patients with advanced non-small-cell lung cancer

PURPOSE

This phase II study was undertaken to define the efficacy and pharmacodynamics of R115777, a farnesyl transferase inhibitor, in the first-line treatment of patients with advanced non-small-cell lung cancer.

PATIENTS AND METHODS

Forty-four patients with measurable stage IIIB (pleural effusion) or stage IV disease received 193 courses of treatment (median, 2.0; range, 1 to 22) with R115777 300 mg administered orally twice daily for 21 of every 28 days. Buccal mucosa samples and peripheral blood mononuclear cells (PBMCs) were collected before and after 8 days of treatment to evaluate inhibition of farnesyl transferase in vivo.

RESULTS

No objective complete or partial responses were documented. Seven patients (16%; 95% confidence interval [CI], 8% to 31%) had disease stabilization for greater than 6 months. Median survival was 7.7 months (95% CI, 6.5 to 10.5) and time to progression was 2.7 months (95% CI, 1.9 to 3.1). The most severe toxicity was neutropenia (9% grade 3, 7% grade 4) and the most common toxicities were anemia (50% grade 1 or 2, 5% grade 3) and anorexia (50% grade 1 or 2, 2% grade 3). Mild peripheral neuropathy occurred in 25% of patients. Evidence of farnesyl transferase inhibition was documented in 83% of patients.

CONCLUSION

Single-agent R115777 was well tolerated in patients with advanced NSCLC, but demonstrated minimal clinical activity. Inhibition of farnesylation in vivo was consistently documented. On the basis of promising results of farnesyl transferase inhibitor combinations with standard chemotherapy agents, future studies of this agent in NSCLC should be in combination with systemic chemotherapy.

A phase I trial of ISIS 2503, an antisense inhibitor of H-ras, in combination with gemcitabine in patients with advanced cancer

PURPOSE

The purpose of this study was to define the toxicity, pharmacokinetics, and clinical activity of the combination of ISIS 2503, an oligodeoxynucleotide antisense inhibitor of H-ras, and gemcitabine in patients with advanced solid tumors.

EXPERIMENTAL DESIGN

The target dose of ISIS 2503 on this study was 6 mg/kg/day. Twenty-seven patients (16 male, 11 female) received 97 treatment courses (median, 2; range, 1-13). Nineteen patients were treated with a fixed gemcitabine dose of 1000 mg/m(2) on days 1 and 8 and two escalating doses of ISIS 2503 (4 and 6 mg/kg/day) as a 14-day continuous infusion starting on day 1. In addition, 8 patients (5 male, 3 female) received a flat dose of ISIS 2503 based on ideal body weight. Cycles were repeated every 3 weeks. Toxicities, graded according to the National Cancer Institute Common Toxicity Criteria, were recorded as maximum grade/patient for all treatment cycles. Pharmacokinetic analyses were performed to evaluate any interaction between these two agents.

RESULTS

The most common nondose-limiting toxicity was hematological, manifested as neutropenia (5 grade 2, 7 grade 3, and 1 grade 4) and thrombocytopenia (10 grade 1, 5 grade 2, 5 grade 3, and 1 grade 4). Nonhematological toxicities included anorexia (7 grade 1, 3 grade 2, and 1 grade 3), nausea (10 grade 1 and 1 grade 3), fatigue (6 grade 1, 5 grade 2, and 3 grade 3), fever (6 grade 1, 2 grade 2, 1 and grade 3), and thrombosis associated with central lines (5). The plasma concentration of gemcitabine at the end of infusion was altered in the presence of ISIS 2503, leading to alterations on other pharmacokinetic parameters, but the observed differences were not clinically relevant. The plasma disposition of ISIS 2503 was not altered by gemcitabine coadministration. One partial response was documented in a heavily pretreated patient with metastatic breast cancer. Disease stabilization for greater than six cycles of treatment was observed in 5 patients.

CONCLUSIONS

The combination of gemcitabine and ISIS 2503 was well tolerated and clinically active in this group of heavily pretreated patients. The recommended Phase II dose of gemcitabine (1000 mg/m(2)) and ISIS 2503 (6 mg/kg/day) warrants additional evaluation.

A phase I study of sequential irinotecan and 5-fluorouracil/leucovorin

BACKGROUND

Irinotecan (CPT-11) and 5-fluorouracil (5-FU)/leucovorin are active agents in colorectal cancer. A sequence-dependent synergism of SN-38 followed by 5-FU/leucovorin in vitro led us to conduct a phase I trial of CPT-11 followed by 5-FU/leucovorin to determine the maximum tolerated dose (MTD) and toxicities of this regimen and to obtain preliminary indications of its activity in patients with advanced solid tumors.

PATIENTS AND METHODS

Fifty-six patients were enrolled in sequential cohorts to receive escalating doses of CPT-11 (90 min infusion) on day 1, followed by leucovorin 20 mg/m(2) (intravenous push) and 5-FU (90 min infusion) on days 2-5 of each 21-day cycle.

RESULTS

A total of 347 treatment cycles (median 4, range 1-25) were administered. Dose-limiting toxicities were diarrhea, neutropenia and fatigue. Nine patients with colorectal cancer and one with gastric cancer had partial or minor responses. Eight of the 10 had prior chemotherapy.

CONCLUSIONS

CPT-11 and 5-FU/leucovorin, as constituents of this novel mechanism-based schedule, have promising activity in patients who have received prior chemotherapy. The recommended phase II/III starting doses are CPT-11 275 mg/m(2) over 90 min on day 1, and 5-FU 400 mg/m(2) plus leucovorin 20 mg/m(2) on days 2-5 every 21 days. This combination can be administered safely to this schedule if there is strict adherence to the 90 min infusion time for both CPT-11 and 5-FU.

A phase I and pharmacologic study of pyrazoloacridine (NSC 366140) and carboplatin in patients with advanced cancer

BACKGROUND

Pyrazoloacridine (PZA) is the first of a new class of rationally synthesized acridine derivatives to undergo clinical testing as an anticancer agent. We previously demonstrated cytotoxic synergy between combinations of PZA and platinum compounds. Subsequent studies revealed that PZA inhibits removal of platinum-DNA adducts in cultured A549 cells. Based on these results, we undertook a phase I study of the combination of PZA and carboplatin (CBDCA).

PATIENTS AND METHODS

Twenty-eight patients received 76 28-day courses (median 2.5, range 1-6) of CBDCA (30-minute infusion) followed by PZA (3-hour infusion), through six dose levels [PZA/CBDCA] (200/AUC 3, 400/AUC 3, 400/AUC 4, 400/AUC 5, 500/AUC 5, 600/AUC 5 mg/m2/AUC). Pharmacokinetic analyses were performed to evaluate the disposition of PZA. Retention of platinum-DNA adducts in peripheral blood mononuclear cells of patients was also evaluated.

RESULTS

The most common and dose-limiting toxicity was myelosuppression, consisting of neutropenia and leukopenia. Non-hematologic toxicities of anorexia, nausea and stomatitis were mild to moderate. In six patients evaluated at the MTD, CBDCA did not appear to affect the pharmacokinetics of PZA. One patient with malignant melanoma had a partial response. Disease stabilization for greater than 4 courses of treatment occurred in 4 patients.

CONCLUSION

The combination of PZA and CBDCA was well tolerated and may have utility in some tumor types.