Randomized phase II trial of the multi-kinase inhibitor sorafenib versus interferon (IFN) in treatment-naïve patients with metastatic renal cell carcinoma (mRCC)

4501

Background: Sorafenib, an oral multi-kinase inhibitor that targets tumor growth and vascularization, significantly prolonged PFS in a Phase III trial with previously treated mRCC patients. This randomized Phase II trial investigated the efficacy and tolerability of sorafenib compared with IFN in first-line therapy of patients with clear-cell RCC. Methods: Untreated patients with mRCC were stratified by MSKCC prognostic score and randomized to receive continuous oral sorafenib 400 mg bid or IFN 9 million units tiw, with an option of dose escalation (600 mg bid sorafenib) or crossover from IFN to sorafenib upon disease progression. The study assessed PFS at 99 events as primary objective, best response (RECIST), overall survival, health-related quality of life, and adverse events (AEs). Results: Baseline characteristics of 188 patients (sorafenib n=97; IFN n = 91) were: median age 62.0 years; MSKCC score: 57% low, 41% intermediate, 1% high; prior nephrectomy: 82%; ECOG 0:1, 55.3%:44.7%. As of January 6, 2006, PFS events have been reported for 64 (34%) patients. Preliminary data showed drug-related AEs of any severity (sorafenib vs IFN) in 50.5% vs 51.6% of patients (≥grade 3: 8.2% vs 11.0%), including diarrhea (24.7% vs 5.5%), fatigue (14.4% vs 20.9%), fever (2.1% vs 18.7%), hypertension (13.4% vs 0%), nausea (5.2% vs 13.2%), flu-like syndrome (1.0% vs 6.6%), hand-foot skin reaction (6.2% vs 0%), and rash/desquamation (4.1% vs 0%). Drug-related metabolic/laboratory abnormalities at grade 3 (no grade 4) comprised hypophosphatemia (21.7% vs. 0%), lipase elevation (5.6% vs. 11.1%), anemia (0% vs. 5.3%) and hypoalbuminemia (0% vs. 3.6%). Five patients receiving IFN withdrew from treatment due to AEs, whereas only one patient withdrew from sorafenib. Conclusions: Sorafenib was generally well tolerated in RCC patients in the first-line setting, with relatively infrequent drug-related AEs ≥grade 3. Full PFS data will be presented at the meeting.

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Bevacizumab with or without erlotinib in metastatic renal cell carcinoma (RCC)

4523

Background: Bevacizumab (B) has clinical efficacy in metastatic RCC following cytokine treatment. A single-arm Phase II trial suggested potential clinical benefit of adding erlotinib (E) to B. To further assess this combination in RCC, we conducted a multicenter, randomized, double-blind Phase 2 trial comparing B+E vs B + placebo. Methods: Eligibility criteria included: previously untreated metastatic RCC with >50% clear cell histology; previous nephrectomy; ECOG PS 0 or 1; measurable disease; serum Ca++ ≤ 10 mg/dL; LDH ≤ 1.5 ULN; Hgb ≥ 9 g/dL; and standard exclusion criteria for B. All pts received B 10 mg/kg IV q 2 wk with either E 150 mg po daily or placebo until disease progression or unacceptable toxicity. Tumors were assessed using RECIST every 8 wks. A landmark analysis was performed 9 mo after accrual of the last pt. Objective response rate (ORR) and progression-free survival (PFS) were co-primary endpoints. Secondary endpoints included response duration, overall survival, and safety. Results: 104 pts (53 B, 51 B+E) were enrolled at 20 sites from Mar 2004–Oct 2004. 65 pts have discontinued therapy. 55 have progressed (PFS HR = 0.86, CI 0.5, 1.49). Median follow-up was 9.8 mo. Median survival duration was not reached. Only 1 treatment-related death due to GI perforation occurred (on B+E). Updated safety and survival data will be presented. Conclusions: B+E and B were well tolerated. Adding E does not appear to improve efficacy from B. PFS of 8.5 months with B compares favorably with the historical PFS of ∼ 4.7 mo with interferon alpha (IFN). Results of phase III trials comparing IFN ± B are pending.

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Phase II study of lenalidomide in patients (pts.) with metastatic renal cell carcinoma (MRCC)

4539

Background: MRCC is a disease with susceptibility to immunomodulatory and anti-angiogenic approaches. Lenalidomide (LEN) is a structural and functional analogue of thalidomide with enhanced immunomodulatory properties and unique activity and toxicity profiles. A phase II study of LEN in MRCC was conducted to determine efficacy and safety. Methods: Eligibility included histologically confirmed MRCC, measurable disease, ≤ 1 prior systemic therapy, ECOG PS 0–1, adequate organ function, and no brain metastases. LEN was administered orally at 25 mg daily for the first 21 days of a 28-day cycle. The primary endpoint was objective response rate as determined by RECIST criteria. Patients received treatment until disease progression or unacceptable toxicity. A two-stage design was employed to test the null hypothesis that the true response rate is ≤ 5% versus the alternative hypothesis that the true response rate is ≥ 20% (alpha = 0.05, power = 90%). Results: 28 pts. were enrolled. Median age was 67 years (range, 42–76). All patients had prior nephrectomy and 57% (16/28) received prior therapy. 21 pts. (75%) had clear cell histology. Pts. received a median of 4 cycles of therapy (range, 1–12+) with 21 pts. (75%) completing at least 2 cycles. Three pts. (10.7%; 95% CI = 2.3–28.2 %) demonstrated a partial response (PR) and 8 pts (28.5%) had stable disease (SD). A total of 11 pts. (39%) experienced median tumor shrinkage of 5% (range, 1–72%). Median time to progression (TTP) for the entire cohort was 4 months (m) (range, 0.67–14+). Ten pts (36%) were progression-free for ≥ 6 m and five pts (18%) were progression-free for ≥ 12 m. Previously treated pts had a TTP of 3 m compared to 5 m for pts with no prior therapy (p = .19). 6 pts (21%) continue on-study with a median follow up of 12.6 m (range, 7.3–14.2 m). Toxicities (all grades) included fatigue (93%), skin toxicity (rash, dry skin and pruritus; 68%) and leukopenia/neutropenia (65%). Grade 3/4 toxicities included fatigue/constitutional symptoms (11%), skin toxicity (7%) and leukopenia/neutropenia (29%). Conclusions: LEN demonstrated an anti-tumor effect in MRCC as evidenced by partial responses and additional pts. with tumor shrinkage. LEN was well tolerated with manageable toxicity. Further studies are warranted.

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Phase II study of volociximab (M200), an α5β1 anti-integrin antibody in refractory metastatic clear cell renal cell cancer (RCC)

4535

Background: Blocking angiogenesis has been shown to be an effective strategy for controlling tumor growth in RCC. Tumor angiogenesis occurs when pro-angiogenic growth factors are released, stimulating endothelial cell proliferation and migration to form neovessels. M200 is an IgG4 chimeric monoclonal antibody that targets α5β1, thereby inducing apoptosis of proliferating endothelial cells. M200 activity is independent of growth factor stimulus, suggesting that binding of fibronectin to α5β1 occurs downstream of growth factor signalling, and is possibly a final common pathway for the development of neovasculature. Methods: This is a multicenter, open label, single cohort pilot phase II study of 40 patients (pts) with RCC. Pts received no more than 2 prior regimens. Pts received M200 10 mg/kg IV every 2 weeks until disease progression. Pts were evaluated for efficacy every 8 weeks by objective response using RECIST criteria. An independent data safety monitoring board was utilized to review safety data. Results: A total of 40 pts were enrolled. All pts were evaluable for safety and 37 pts for objective response (to date). Median age was 62.8 years. ECOG score was 0 in 27 (67.5%) and 1 in 13 (32.5%) pts. Prior nephrectomy occured in 39 (97%) pts. Other prior treatment included IL-2 in 15 (37.5%), interferon alpha in 6 (15%), IL-2 + interferon in 2 (5%) pts. Most frequent side effects were fatigue 37.5%, nausea 15% and hypertension 7.5%. Five pts died in the study, four with progressive disease (PD) and 1 with arrhythmia (unrelated to M200). SD was observed in 32/37 (87%) of pts. No changes in hematological, renal and hepatic parameters were noted. Median time to progression was 113+ days. The average peak and trough concentrations of circulating M200 following 6 weeks of treatment were 390 μg/mL and 140 μg/mL, respectively. There were no detectable immune responses to M200. Conclusions: M200 is well tolerated at 10 mg/kg Q2W. Stable disease is noted in 87% of pts. Follow-up continues. A higher dose level is being evaluated.

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Efficacy and safety of sunitinib malate (SU11248) in bevacizumab-refractory metastatic renal cell carcinoma (mRCC)

4522

Background: Sunitinib malate (SU11248) is an oral, multitargeted tyrosine kinase inhibitor of the vascular endothelial growth factor receptor (VEGFR) family, platelet-derived growth factor receptor (PDGFR) and other related receptors. It has demonstrated anti-tumor activity in cytokine-refractory mRCC patients (pts). The activity of sunitinib in pts refractory to VEGF binding agents such as bevacizumab, however, has not been evaluated. It was hypothesized that tumor resistance to bevacizumab may be driven, in part, through pathways sensitive to inhibition by sunitinib. A phase II study evaluating the activity of sunitinib in bevacizumab-refractory mRCC was thus conducted. Methods: Pts with mRCC who demonstrated RECIST-defined disease progression within 3 months after bevacizumab-based therapy were treated with sunitinib (50 mg daily, 4 weeks of a 6-week cycle). Additional eligibility included measurable disease, clear cell histology, ≤ 2 prior systemic regimens, prior nephrectomy, performance status 0 or 1 and adequate organ function. The primary endpoint was objective response by RECIST criteria. A single-stage design was employed to test the null hypothesis that the true response rate is ≤ 5% versus the alternative hypothesis that the true response rate is ≥ 15%. Results: Accrual of 60 patients has been completed. Baseline characteristics include a median age of 59 years; 92% of pts had ≥ 2 metastatic sites and 23% had prior radiotherapy. Thirty-two of 60 pts enrolled are evaluable for response; 28 pts are too early for assessment. Twenty-six pts (81%) demonstrated some degree of tumor shrinkage, including, 4 pts (13%; 95% CI 4%, 29%) demonstrating an objective partial response. The most common treatment-related adverse events (AEs) included fatigue, diarrhea, dysgeusia, and nausea. Serious treatment-related AEs included fatigue, diarrhea, nausea and one fatal cerebral hemorrhage; 3 pts withdrew due to an AE. Conclusions: Sunitinib has substantial antitumor activity in bevacizumab-refractory mRCC pts, suggesting that sunitinib may inhibit signaling pathways involved in bevacizumab resistance. The precise mechanisms of response to sunitinib in bevacizumab-refractory tumors will require additional studies.

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Phase I trial of phenoxodiol delivered by continuous intravenous infusion in patients with solid cancer

BACKGROUND

Phenoxodiol is a multi-pathway initiator of apoptosis with broad anti-tumor activity and high specificity for tumor cells. Its biochemical effects are particularly suited to reversal of chemo-resistance, and the drug is being developed as a chemo-sensitizer of standard chemotherapeutics in solid cancers. This phase I, single-center trial was conducted to test a continuous intravenous dosing regimen of phenoxodiol in patients with late-stage, solid tumors to determine toxicity, pharmacokinetics, and preliminary efficacy.

METHODS

Phenoxodiol given by intravenous infusion continuously for 7 days on 14-day cycles was dose-escalated on an inter-patient basis at dosages of 0.65,1.3, 3.3, 20.0, and 27.0 mg/kg/day (three to four patients per stratum). Treatment cycles continued until disease progression. Toxicity was based on standard criteria; efficacy was based on changes in tumor burden (WHO); pharmacokinetic analysis was conducted on plasma samples at specified time points during treatment cycles.

RESULTS

Nineteen heavily-pre-treated patients with solid tumors received a median of three cycles of treatment (range 1-13); two patients received >or= 12 cycles. No dose-limiting toxicities were encountered, with emesis and fatigue (one patient) and rash (one patient) the only significant toxicities. Stabilized disease was the best efficacy outcome, with one patient showing stable disease at 24 weeks. Pharmacokinetics suggested a linear relationship between dosage and mean steady-state plasma concentrations of phenoxodiol.

CONCLUSION

A 7-day continuous infusion of phenoxodiol given every 2 weeks is well tolerated up to a dose of 27.0 mg/kg/day.

Synergistic growth inhibition by Iressa and Rapamycin is modulated by VHL mutations in renal cell carcinoma

Epidermal growth factor receptor (EGFR) and tumour growth factor alpha (TGFα) are frequently overexpressed in renal cell carcinoma (RCC) yet responses to single-agent EGFR inhibitors are uncommon. Although von Hippel–Lindau (VHL) mutations are predominant, RCC also develops in individuals with tuberous sclerosis (TSC). Tuberous sclerosis mutations activate mammalian target of rapamycin (mTOR) and biochemically resemble VHL alterations. We found that RCC cell lines expressed EGFR mRNA in the near-absence of other ErbB family members. Combined EGFR and mTOR inhibition synergistically impaired growth in a VHL-dependent manner. Iressa blocked ERK1/2 phosphorylation specifically in wt-VHL cells, whereas rapamycin inhibited phospho-RPS6 and 4E-BP1 irrespective of VHL. In contrast, phospho-AKT was resistant to these agents and MYC translation initiation (polysome binding) was similarly unaffected unless AKT was inhibited. Primary RCCs vs cell lines contained similar amounts of phospho-ERK1/2, much higher levels of ErbB-3, less phospho-AKT, and no evidence of phospho-RPS6, suggesting that mTOR activity was reduced. A subset of tumours and cell lines expressed elevated eIF4E in the absence of upstream activation. Despite similar amounts of EGFR mRNA, cell lines (vs tumours) overexpressed EGFR protein. In the paired cell lines, PRC3 and WT8, EGFR protein was elevated post-transcriptionally in the VHL mutant and EGF-stimulated phosphorylation was prolonged. We propose that combined EGFR and mTOR inhibitors may be useful in the subset of RCCs with wt-VHL. However, apparent differences between primary tumours and cell lines require further investigation.

Oral capecitabine vs intravenous 5-fluorouracil and leucovorin: integrated efficacy data and novel analyses from two large, randomised, phase III trials

This study evaluates the efficacy of capecitabine using data from a large, well-characterised population of patients with metastatic colorectal cancer (mCRC) treated in two identically designed phase III studies. A total of 1207 patients with previously untreated mCRC were randomised to either oral capecitabine (1250 mg m⁻² twice daily, days 1−14 every 21 days; n=603) or intravenous (i.v.) bolus 5-fluorouracil/leucovorin (5-FU/LV; Mayo Clinic regimen; n=604). Capecitabine demonstrated a statistically significant superior response rate compared with 5-FU/LV (26 vs 17%; P<0.0002). Subgroup analysis demonstrated that capecitabine consistently resulted in superior response rates (P<0.05), even in patient subgroups with poor prognostic indicators. The median time to response and duration of response were similar and time to progression (TTP) was equivalent in the two arms (hazard ratio (HR) 0.997, 95% confidence interval (CI) 0.885–1.123, P=0.95; median 4.6 vs 4.7 months with capecitabine and 5-FU/LV, respectively). Multivariate Cox regression analysis identified younger age, liver metastases, multiple metastases and poor Karnofsky Performance Status as independent prognostic indicators for poor TTP. Overall survival was equivalent in the two arms (HR 0.95, 95% CI 0.84–1.06, P=0.48; median 12.9 vs 12.8 months, respectively). Capecitabine results in superior response rate, equivalent TTP and overall survival, an improved safety profile and improved convenience compared with i.v. 5-FU/LV as first-line treatment for MCRC. For patients in whom fluoropyrimidine monotherapy is indicated, capecitabine should be strongly considered. Following encouraging results from phase I and II trials, randomised trials are evaluating capecitabine in combination with irinotecan, oxaliplatin and radiotherapy. Capecitabine is a suitable replacement for i.v. 5-FU as the backbone of colorectal cancer therapy.

A phase I trial of weekly gemcitabine and subcutaneous interferon alpha in patients with refractory renal cell carcinoma

INTRODUCTION

Recombinant human interferon-a2b (rHuIFN-alpha2b) and Interleukin-2 have limited effectiveness in the treatment of metastatic renal cell carcinoma (MRCC). Gemcitabine (Gemzar) is also reported to have activity against MRCC, and recent in vitro, in nude mice xenografts, and human data suggests increased activity of gemcitabine (Gemzar) when combined with IFN-alpha2b.

PURPOSE

A phase I clinical trial utilizing gemcitabine (Gemzar and rHuIFN-alpha2b was conducted in patients with metastatic renal cell carcinoma.

METHODS

Treatment consisted of: gemcitabine (Gemzar) 600 mg/m2 I.V. weekly and rHuIFN-alpha2b 1.0 MU/m2 (dose level A) or 3.0MU/m2 S.C. (dose level B) three times a week for 6 weeks with a 2 weeks rest period.

RESULTS

Thirteen patients were entered into the trial and were evaluated. Dose limiting toxicity was predominantly hematologic, and was seen at dose level B. This included grade 3 anemia (1 patient), neutropenia (1 patient), and nausea (1 patient) and grade 4 neutropenia (1 patient). The maximal tolerated dose was gemcitabine (Gemzar) 600 mg/m2 I.V. weekly and rHuIFN-alpha2b 1.0 MU/m2 three times a week.

CONCLUSION

This combination of gemcitabine (Gemzar) and rHuIFN-alpha2b has significant hematologic toxicity despite low doses of each agent. Further investigation of this combination using this schedule is not recommended.

Phase I trial of simultaneously administered GM-CSF and IL-6 in patients with renal-cell carcinoma: clinical and laboratory effects

BACKGROUND

Metastatic renal-cell carcinoma is a neoplasm that is minimally responsive to cytotoxic chemotherapy. Tumor regression following therapy with cytokines such as interferon alpha and or interleukin-2 is seen in selected subsets of patients. Investigations with other immunomodulatory cytokines, such as GM-CSF and IL-6 are therefore of interest.

PATIENTS AND METHODS

A phase I trial of concomitantly administered granulocyte macrophage-colony stimulating factor (3.0 mcg/kg/day s.c. d1-14) and escalating doses of interleukin-6 (1.0, 5.0 or 10.0 microg/kg/day d1-14) was conducted in patients with metastatic renal-cell carcinoma to explore the toxicity of the combination and its hematologic effects.

RESULTS

The most common side effects seen were fever, fatigue and arthralgias. Dose limiting toxicity included thrombocytosis and hyperbilirubinemia in patients receiving 10 microg/kg/day of IL-6. The hematologic effects of IL-6 and GM-CSF included leukocytoses and thrombocytosis, with increases in peripheral blood progenitors (BFU-E, CFU-GM, and CFU-GEMM). Evidence of platelet activation demonstrated by increased platelet expression of CD62 was found. No clinical responses were observed.

CONCLUSIONS

The combination of IL-6 and GM-CSF has pleotropic hematologic effects. Further studies with this combination for the treatment of renal-cell carcinoma are not recommended.

Cytokine therapy for metastatic renal cell carcinoma

Cytokine therapy for patients with metastatic renal cancer is based on observations suggesting this neoplasm may be responsive to immunotherapy. Two cytokines, interferon-alpha (IFN-alpha) and interleukin 2 (IL-2) produce tumor regressions in 10% to 15% of patients with metastatic disease. Randomized trials demonstrate a modest survival advantage for patients treated with IFN-alpha. Combinations of IL-2 and IFN-alpha appear to be associated with improved response rates, but no demonstrable effect on survival. Additions of other cytokines (eg, GM-CSF) or chemotherapy to this combination has been investigated, but results do not suggest they enhance the outcome. Patient selection remains an important issue in this patient population. Individuals who are asymptomatic and have limited pulmonary or soft-tissue disease are most likely to benefit. The roles of immune dysregulation and the addition of novel cytostatic agents to these regimens are under investigation.

Phase I and II trials of subcutaneously administered rIL-2, interferon alfa-2a, and fluorouracil in patients with metastatic renal carcinoma

PURPOSE

A phase I followed by a phase II trial utilizing rIL-2, IFN alpha, and 5-FU were conducted in patients with unresectable and/or metastatic renal cell carcinoma.

METHODS

Treatment consisted of: rIL-2 at 5.0 x 10(6) IU/m2 SQ on days 1-5 for 4 weeks, rHUIFN alpha-2a at 5.0 x 10(6) U/m2 SQ on days 1, 3, and 5 for 4 weeks, and 5-FU by IV bolus on days 1-5 during week 1. In the phase I study, patients were treated at varying doses of 5-FU: I-none, II-250 mg/m2, III-300, and IV 375. A phase II trial was then conducted utilizing the same schedule and maximum tolerated dose (MTD) for 5-FU.

RESULTS

Twenty patients were entered into the phase I trial. Dose-limiting toxicity included grade III nausea and vomiting, and one sudden cardiac death. The MTD for 5-FU was determined to be 300 mg/m2. In the phase II trial, a median of two cycles of therapy was administered to 25 evaluable patients. Toxicity was moderate and consisted primarily of fevers, chills, fatigue, nausea/vomiting, and anorexia. Grade IV thrombocytopenia, consistent with ITP, developed in one patient each on the phase I and phase II trial. Seven partial responses were seen among 25 patients treated in the phase II trial for a 28% (CI 12-49%) response rate.

CONCLUSIONS

The addition of 5-FU to rIL-2 and rHuIFN alpha-2a appears to increase the toxicity of this therapy. Randomized trials will be required to determine if efficacy is enhanced.

Randomized Multicenter Phase II Trial of Subcutaneous Recombinant Human Interleukin-12 Versus Interferon-α2a for Patients with Advanced Renal Cell Carcinoma

Recombinant human interleukin-12 (rHuIL-12) is a pleiotropic cytokine with anticancer activity against renal cell carcinoma (RCC) in preclinical models and in a phase I trial. A randomized phase II study of rHuIL-12 compared with interferon-alpha (IFN-alpha) evaluated clinical response for patients with previously untreated, advanced RCC. Patients were randomly assigned 2:1 to receive either rHuIL-12 or IFN-alpha2a. rHuIL-12 was administered by subcutaneous (s.c.) injection on days 1, 8, and 15 of each 28-day cycle. The dose of IL-12 was escalated during cycle 1 to a maintenance dose of 1.25 microg/kg. IFN was administered at 9 million units by s.c. injection three times per week. Serum concentrations of IL-12, IFN-gamma, IL-10, and neopterin were obtained in 10 patients treated with rHuIL-12 after the first full dose of 1.25 microg/kg given on day 15 (dose 3) of cycle 1 and again after multiple doses on day 15 (dose 6) of cycle 2. Thirty patients were treated with rHuIL-12, and 16 patients were treated with IFN-alpha. Two (7%) of 30 patients treated with rHuIL-12 achieved a partial response, and the trial was closed to accrual based on the low response proportion. IL-12 was absorbed rapidly after s.c. drug administration, with the peak serum concentration appearing at approximately 12 h in both cycles. Serum IL-12 concentrations remained stable on multiple dosing. Levels of IFN-gamma, IL-10, and neopterin increased with rHuIL-12 and were maintained in cycle 2. rHuIL-12 is a novel cytokine with unique pharmacologic and pharmacodynamic features under study for the treatment of malignancy and other medical conditions. The low response proportion associated with rHuIL-12 single-agent therapy against metastatic RCC was disappointing, given the preclinical data. Further study of rHuIL-12 for other medical conditions is underway. For RCC, the study of new cytokines is of the highest priority.

Roles of NF-kappaB and 26 S proteasome in apoptotic cell death induced by topoisomerase I and II poisons in human nonsmall cell lung carcinoma

Activation of signaling pathways after DNA damage induced by topoisomerase (topo) poisons can lead to cell death by apoptosis. Treatment of human nonsmall cell lung carcinoma (NSCLC-3 or NSCLC-5) cells with the topo I poison SN-38 or the topo II poison etoposide (VP-16) leads to activation of NF-kappaB before induction of apoptosis. Inhibiting the degradation of IkappaBalpha by pretreatment with the proteasome inhibitor MG-132 significantly inhibited NF-kappaB activation and apoptosis but not DNA damage induced by SN-38 or VP-16. Transfection of NSCLC-3 or NSCLC-5 cells with dominant negative mutant IkappaBalpha (mIkappaBalpha) inhibited SN-38 or VP-16 induced transcription and DNA binding activity of NF-kappaB without altering drug-induced apoptosis. Regulation of apoptosis by mitochondrial release of cytochrome c and activation of pro-caspase 9 followed by cleavage of poly(ADP-ribose) polymerase by effector caspases 3 and 7 was similar in neo and mIkappaBalpha cells treated with SN-38 or VP-16. In contrast to pretreatment with MG-132, exposure to MG-132 after SN-38 or VP-16 treatment of neo or mIkappaBalpha cells decreased cell cycle arrest in the S/G2 + M fraction and enhanced apoptosis compared with drug alone. In summary, apoptosis induced by topoisomerase poisons in NSCLC cells is not mediated by NF-kappaB but can be manipulated by proteasome inhibitors.

Tumor-induced sensitivity to apoptosis in T cells from patients with renal cell carcinoma: role of nuclear factor-kappaB suppression

Antitumor immunity fails to adequately develop in many cancer patients, including those with renal cell carcinoma (RCC). A number of different mechanisms have been proposed to explain the immune dysfunction observed in cancer patient T cells. Here we show that T cells from RCC patients display increased sensitivity to apoptosis. Tumor-infiltrating lymphocytes (TILs) display the most profound sensitivity, because 10-15% of those cells are apoptotic when assessed by terminal deoxynucleotidyltransferase-mediated nick end labeling in situ, and the number of apoptotic TILs further increases after 24 h of culture. Peripheral blood T cells from RCC patients are not directly apoptotic, although T lymphocytes derived from 40% of those individuals undergo activation-induced cell death (AICD) upon in vitro stimulation with phorbol myristate acetate and ionomycin. This is in contrast to T cells from normal individuals, which are resistant to AICD. TILs and peripheral blood T cells from RCC patients also exhibit impaired activation of the transcription factor, nuclear factor (NF)-kappaB. Additional findings presented here indicate that the heightened sensitivity of patient T cells to apoptosis may be tumor induced, because supernatants from RCC explants sensitize, and in some instances directly induce, normal T cells to apoptosis. These same supernatants also inhibit NF-kappaB activation. RCC-derived gangliosides may represent one soluble tumor product capable of sensitizing T cells to apoptosis. Pretreatment with neuraminidase, but not proteinase K, abrogated the suppressive effects of tumor supernatants on both NF-kappaB activation and apoptosis. Additionally, gangliosides isolated from tumor supernatants not only inhibited NF-kappaB activation but also sensitized T cells to AICD. These findings demonstrate that tumor-derived soluble products, including gangliosides, may contribute to the immune dysfunction of T cells by altering their sensitivity to apoptosis.

Cell cycle phase specificity in the potentiation of etoposide-induced DNA damage and apoptosis by KN-62, an inhibitor of calcium-calmodulin-dependent enzymes

The cell cycle phase-dependent induction of DNA damage and apoptosis by etoposide (VP-16) and its modulation by 1-[N,O-bis(1, 5-isoquinolinesulfonyl)-N-methyl-l-tyrosyl]-4-piperazine (KN-62), an inhibitor of calcium-calmodulin-dependent enzymes, were examined in sensitive (HL-60/S) and VP-16-resistant (HL-60/DOX0.05) HL-60 cells. Cells from exponential-phase cultures were enriched by centrifugal elutriation into G(1), S, and G(2)+M fractions. Modulation of VP-16-induced apoptosis by KN-62 in HL-60/S cells was apparent only in the S phase at the IC(50) concentration. However, in the HL-60/DOX0.05 cells, significant (P < 0.001) potentiation of VP-16-induced apoptosis by a non-cytotoxic concentration of 2 microM KN-62 was apparent in cells in the G(1), S, and G(2)+M phases, as well as over the entire concentration range tested. VP-16-induced apoptosis and its potentiation by a non-cytotoxic concentration of 2 microM KN-62 were correlative with drug-stabilized DNA cleavable complex formation based on a band depletion assay. In agreement with the results on apoptosis in the resistant HL-60/DOX0.05 cells, the enhanced depletion of the alpha and beta isoforms of topoisomerase II by VP-16 + KN-62 was observed in G(1), S, and G(2)+M cells. Results suggest that the effects of KN-62 in reversing resistance are based on its role as a potent sensitizer of VP-16-induced DNA damage and apoptosis in a cell cycle phase-independent manner.

A phase II pharmacodynamic study of pyrazoloacridine in patients with metastatic colorectal cancer

PURPOSE

To perform a phase II trial of pyrazoloacridine (PZA), a novel DNA intercalator, in patients with metastatic colorectal carcinoma and no previous therapy.

METHODS

PZA was administered at a dose of 750 mg/m2 intravenously over 3 h every 21 days. Pharmacokinetic studies to determine PZA plasma concentrations were performed.

RESULTS

No responses were seen in 14 response-evaluable patients. Patients received a median of two cycles of PZA (range 1-6). Toxicity included neutropenia and neurologic side-effects, which were > or = grade III in 73% and 14%, respectively. High plasma concentrations of PZA (Cmax) correlated with low neutrophil counts (P = 0.04).

CONCLUSIONS

PZA is inactive at this dose and schedule in colorectal cancer, and produces moderately severe toxicity.

Phase 1 trial of subcutaneous IL-6 in patients with refractory cancer: clinical and biologic effects

The authors evaluated the clinical and biologic effects of human recombinant interleukin-6 (rhIL-6) in patients with refractory cancer. A phase 1 trial using escalating doses of rhIL-6 (1-50 microg x kg(-1) x d(-1), Monday through Friday for 4 weeks) was performed in 30 patients. Toxicity was moderate and the maximum tolerated dose was determined to be 25 microg x kg(-1)x d(-1) based on cardiac and neurocortical toxicity in one patient each and thrombocytosis (platelets > 800,000/microL) in three patients. One patient with non-small-cell lung cancer had a partial response after three cycles of therapy. The biologic effects of rhIL-6 included anemia and dose-related thrombocytosis. Various proinflammatory activities were induced and included dose-related cyclical increases in peripheral blood monocytes and the CD14+/CD45RB+ +/- CD16C+ mononuclear cell populations. These increases were accompanied by increased levels of C-reactive protein, serum neopterin, and type I soluble tumor necrosis factor receptor. In contrast, rhIL-6 did not affect lymphocyte numbers or function (cytotoxicity, cytokine levels, immunoglobulin levels), with the possible exception of IL-2Ralpha mRNA induction in peripheral blood lymphocytes. rhIL-6 has pleiotropic proinflammatory actions in vivo and moderate toxicity when administered as long-term therapy.

Cytokine combinations: therapeutic use in patients with advanced renal cell carcinoma

Treatment of metastatic renal cell carcinoma (RCC) remains unsatisfactory. To enhance the antitumor effects of various cytokines, combinations of these agents have been investigated. Interleukin-2 (IL-2) and interferon-alfa (IFN-alpha) have been combined based on data from preclinical studies suggesting synergism. A review of available phase I and II trials in more than 1,400 patients indicates that response rates are approximately 20%. Complete regressions are seen in 3% to 5% of patients. To demonstrate that this combination increases overall response rates, randomized trials were required. The results of a phase III study demonstrate a significantly improved response rate (18.6%) and 1-year event-free survival (20.9%) for patients treated with continuous infusion recombinant (r) IL-2 and subcutaneous IFN-alpha compared with either cytokine alone. The toxicity of rlL-2 and IFN-alpha is related to cytokine dose and schedule, but appears less than that reported with high-dose rIL-2. Analysis of prognostic factors and surrogate marker changes have been conducted. Performance status and number of disease sites predict response. rIL-2 and IFNalpha were then combined with fluorouracil, with initial reports suggesting response rates greater than 40%. Recent reports indicate 1% to 39% of patients responding. In a group of 836 patients with metastatic RCC receiving this therapy, 25.3% responded. Randomized trials comparing chemoimmunotherapy to rIL-2 and/or IFN-alpha are now required. The biologic basis and rationale for utilization of cytokines are strong. Clinical results are consistent with improved response rates in patients receiving rIL-2 and IFN-alpha. Continued investigation of novel and new treatment approaches remains a priority.