Impact of KRASG12 mutations on survival with trifluridine/tipiracil plus bevacizumab in patients with refractory metastatic colorectal cancer: post hoc analysis of the phase III SUNLIGHT trial.

BACKGROUND: In metastatic colorectal cancer (mCRC), KRAS mutations are often associated with poorer survival; however, the prognostic impact of specific point mutations is unclear. In the phase III SUNLIGHT trial, trifluridine/tipiracil (FTD/TPI) plus bevacizumab significantly improved overall survival (OS) versus FTD/TPI alone. We assessed the impact of KRASG12 mutational status on OS in SUNLIGHT. PATIENTS AND METHODS: In the global, open-label, randomized, phase III SUNLIGHT trial, adults with mCRC who had received no more than two prior chemotherapy regimens were randomized 1 : 1 to receive FTD/TPI alone or FTD/TPI plus bevacizumab. In this post hoc analysis, OS was assessed according to the presence or absence of a KRASG12 mutation in the overall population and in patients with RAS-mutated tumors. RESULTS: Overall, 450 patients were analyzed, including 302 patients in the RAS mutation subgroup (214 with a KRASG12 mutation and 88 with a non-KRASG12RAS mutation). In the overall population, similar OS outcomes were observed in patients with and without a KRASG12 mutation [median 8.3 and 9.2 months, respectively; hazard ratio (HR) 1.09, 95% confidence interval (CI) 0.87-1.4]. Similar OS outcomes were also observed in the subgroup analysis of patients with a KRASG12 mutation versus those with a non-KRASG12RAS mutation (HR 1.03, 95% CI 0.76-1.4). FTD/TPI plus bevacizumab improved OS compared with FTD/TPI alone irrespective of KRASG12 mutational status. Among patients with a KRASG12 mutation, the median OS was 9.4 months with FTD/TPI plus bevacizumab versus 7.2 months with FTD/TPI alone (HR 0.67, 95% CI 0.48-0.93), and in patients without a KRASG12 mutation, the median OS was 11.3 versus 7.1 months, respectively (HR 0.59, 95% CI 0.43-0.81). CONCLUSIONS: The presence of a KRASG12 mutation had no detrimental effect on OS among patients treated in SUNLIGHT. The benefit of FTD/TPI plus bevacizumab over FTD/TPI alone was confirmed independently of KRASG12 status.

Effect of KRAS codon 12 or 13 mutations on survival with trifluridine/tipiracil in pretreated metastatic colorectal cancer: a meta-analysis.

BACKGROUND: KRAS gene mutations can predict prognosis and treatment response in patients with metastatic colorectal cancer (mCRC). METHODS: We undertook a meta-analysis of three randomized, placebo-controlled trials (RECOURSE, TERRA and J003) to investigate the impact of KRAS mutations in codons 12 or 13 on overall survival (OS) and progression-free survival in patients receiving trifluridine/tipiracil (FTD/TPI) for refractory mCRC. RESULTS: A total of 1375 patients were included, of whom 478 had a KRAS codon 12 mutation and 130 had a KRAS codon 13 mutation. In univariate analyses, the absence of a KRAS codon 12 mutation was found to significantly increase the OS benefit of FTD/TPI relative to placebo compared with the presence of the mutation {hazard ratio (HR), 0.62 [95% confidence interval (CI): 0.53-0.72] versus 0.86 (0.70-1.05), respectively; interaction P = 0.0206}. Multivariate analyses showed that taking confounding factors into account reduced the difference in treatment effect between the presence and the absence of KRAS codon 12 mutations, confirming that treatment benefit was maintained in patients with [HR, 0.73 (95% CI: 0.59-0.89)] and without [HR, 0.63 (95% CI: 0.54-0.74)] codon 12 mutations (interaction P = 0.2939). KRAS mutations in codon 13 did not reduce the OS benefit of FTD/TPI relative to placebo, and, furthermore, KRAS mutations at either codon 12 or codon 13 did not affect the progression-free survival benefit. CONCLUSIONS: Treatment with FTD/TPI produced a survival benefit, relative to placebo, regardless of KRAS codon 12 or 13 mutation status in patients with previously treated mCRC.

Neutropenia and survival outcomes in metastatic colorectal cancer patients treated with trifluridine/tipiracil in the RECOURSE and J003 trials.

BACKGROUND: The phase II J003 (N = 169) and phase III RECOURSE (N = 800) trials demonstrated a significant improvement in survival with trifluridine (FTD)/tipiracil (TPI) versus placebo in patients with refractory metastatic colorectal cancer. This post hoc analysis investigated pharmacokinetic data of FTD/TPI exposure and pharmacodynamic markers, such as chemotherapy-induced neutropenia (CIN) and clinical outcomes. PATIENTS AND METHODS: A total of 210 patients from RECOURSE were enrolled in this substudy. A limited sampling approach was used, with three pharmacokinetic samples drawn on day 12 of cycle 1. Patients were categorized as being above or below the median area under the plasma concentration-time curve (AUC) for FTD and TPI. We conducted a post hoc analysis using the entire RECOURSE population to determine the correlations between CIN and clinical outcome. We then carried out a similar analysis on the J003 trial to validate the results. RESULTS: In the RECOURSE subset, patients in the high FTD AUC group had a significantly increased CIN risk. Analyses of the entire population demonstrated that FTD/TPI-treated patients with CIN of any grade in cycles 1 and 2 had significantly longer median overall survival (OS) and progression-free survival (PFS) than patients who did not develop CIN and patients in the placebo group. Patients who required an FTD/TPI treatment delay had increased OS and PFS versus those in the placebo group and those who did not develop CIN. Similar results were obtained in the J003 cohort. CONCLUSIONS: In RECOURSE, patients with higher FTD drug exposure had an increased CIN risk. FTD/TPI-treated patients who developed CIN had improved OS and PFS versus those in the placebo group and those who did not develop CIN. Similar findings were reported in the J003 cohort, thus validating the RECOURSE results. The occurrence of CIN may be a useful predictor of treatment outcomes for FTD/TPI-treated patients. CLINICALTRIALS. GOV IDENTIFIER: NCT01607957 (RECOURSE). JAPAN PHARMACEUTICAL INFORMATION CENTER NUMBER: JapicCTI-090880 (J003).

Alternative rib bone biopsy measurements to estimate changes in skeletal mineral reserves in cattle.

Rib bone biopsy samples are often used to estimate changes in skeletal mineral reserves in cattle but differences in sampling procedures and the bone measurements reported often make interpretation and comparisons among experiments difficult. 'Full-core' rib bone biopsy samples, which included the external cortical bone, internal cortical bone and trabecular bone (CBext, CBint and Trab, respectively), were obtained from cattle known to be in phosphorus (P) adequate (Padeq) or severely P-deficient (Pdefic) status. Experiments 1 and 2 examined growing steers and Experiment 3 mature breeder cows. The thickness of cortical bone, specific gravity (SG), and the amount and concentration of ash and P per unit fresh bone volume, differed among CBext, CBint and Trab bone. P concentration (mg/cc) was closely correlated with both SG and ash concentrations (pooled data, r=0.99). Thickness of external cortical bone (CBText) was correlated with full-core P concentration (FC-Pconc) (pooled data, r=0.87). However, an index, the amount of P in CBext per unit surface area of CBext (PSACB; mg P/mm2), was more closely correlated with the FC-Pconc (pooled data, FC-Pconc=37.0+146×PSACB; n=42, r=0.94, RSD=7.7). Results for measured or estimated FC-Pconc in 10 published studies with cattle in various physiological states and expected to be Padeq or in various degrees of Pdefic status were collated and the ranges of FC-Pconc indicative of P adequacy and P deficiency for various classes of cattle were evaluated. FC-Pconc was generally in the range 130 to 170 and 100 to 120 mg/cc fresh bone in Padeq mature cows and young growing cattle, respectively. In conclusion, the FC-Pconc could be estimated accurately from biopsy samples of CBext. This allows comparisons between studies where full-core or only CBext biopsy samples of rib bone have been obtained to estimate changes in the skeletal P status of cattle and facilitates evaluation of the P status of cattle.

Predicted vitamin D status and colon cancer recurrence and mortality in CALGB 89803 (Alliance).

BACKGROUND: Observational studies suggest that higher levels of 25-hydroxyvitamin D3 (25(OH)D) are associated with a reduced risk of colorectal cancer and improved survival of colorectal cancer patients. However, the influence of vitamin D status on cancer recurrence and survival of patients with stage III colon cancer is unknown. PATIENTS AND METHODS: We prospectively examined the influence of post-diagnosis predicted plasma 25(OH)D on outcome among 1016 patients with stage III colon cancer who were enrolled in a National Cancer Institute-sponsored adjuvant therapy trial (CALGB 89803). Predicted 25(OH)D scores were computed using validated regression models. We examined the influence of predicted 25(OH)D scores on cancer recurrence and mortality (disease-free survival; DFS) using Cox proportional hazards. RESULTS: Patients in the highest quintile of predicted 25(OH)D score had an adjusted hazard ratio (HR) for colon cancer recurrence or mortality (DFS) of 0.62 (95% confidence interval [CI], 0.44-0.86), compared with those in the lowest quintile (Ptrend = 0.005). Higher predicted 25(OH)D score was also associated with a significant improvement in recurrence-free survival and overall survival (Ptrend = 0.01 and 0.0004, respectively). The benefit associated with higher predicted 25(OH)D score appeared consistent across predictors of cancer outcome and strata of molecular tumor characteristics, including microsatellite instability and KRAS, BRAF, PIK3CA, and TP53 mutation status. CONCLUSION: Higher predicted 25(OH)D levels after a diagnosis of stage III colon cancer may be associated with decreased recurrence and improved survival. Clinical trials assessing the benefit of vitamin D supplementation in the adjuvant setting are warranted. CLINICALTRIALS.GOV IDENTIFIER: NCT00003835.

Weekly docetaxel, cisplatin, and irinotecan (TPC): results of a multicenter phase II trial in patients with metastatic esophagogastric cancer.

BACKGROUND: Recent studies have examined the addition of docetaxel to fluorouracil and cisplatin in advanced esophagogastric cancer. PATIENTS AND METHODS: We carried out a phase I dose-escalation study of weekly docetaxel, cisplatin, and irinotecan (TPC), given on days 1 and 8 every 3 weeks, in patients with chemonaive solid tumors. Subsequently, we completed a multiinstitutional phase II study of TPC in patients with previously untreated, metastatic esophagogastric cancer. RESULTS: Thirty-nine patients were enrolled in the phase I trial; a weekly schedule of TPC was well tolerated. On that basis, docetaxel 30 mg/m(2), cisplatin 25 mg/m(2), and irinotecan 65 mg/m(2) were selected for the phase II trial, where in the first 18 patients irinotecan 65 mg/m(2) caused too much diarrhea and was reduced to 50 mg/m(2). Among 56 eligible patients with previously untreated, metastatic esophagogastric cancer enrolled in the phase II trial, three complete and 27 partial responses were observed (overall response rate=54%), and 15 patients (30%) had stable disease. Median progression-free survival was 7.1 months, and median survival was 11.9 months. At the final irinotecan dose of 50 mg/m(2), grade 3 or higher toxicity included diarrhea (26%), neutropenia (21%), nausea (18%), fatigue (16%), anorexia (13%), and thrombosis/embolism (13%). CONCLUSIONS: Weekly TPC is an active and well-tolerated regimen for patients with esophagogastric cancer.

Phase II study of FOLFOX, bevacizumab and erlotinib as first-line therapy for patients with metastatic colorectal cancer.

BACKGROUND: Targeting the epidermal growth factor receptor and angiogenesis have proven useful strategies against metastatic colorectal cancer. The benefit of combining inhibitors of both pathways is unknown. PATIENTS AND METHODS: Patients with previously untreated metastatic colorectal cancer were enrolled in a phase II trial of infusional 5-fluorouracil, leucovorin, oxaliplatin (FOLFOX), bevacizumab and erlotinib. The primary end point was progression-free survival. RESULTS: Thirty-five patients were enrolled and all came off trial for reasons other than progression; 18 (51%) had protocol-defined adverse events requiring removal, nine (26%) withdrew consent due to toxicity, six pursued surgery or localized therapies and two requested a treatment holiday. Principal toxic effects included rash, neuropathy and diarrhea. Seven patients came off trial before first restaging. By intention-to-treat analysis, one patient had a confirmed complete response, 10 had confirmed partial responses and one had an unconfirmed partial response (response rate = 34%). One patient had progressive disease at time of withdrawal from the trial, thus progression-free survival could not be calculated. CONCLUSION: The combination of FOLFOX, bevacizumab and erlotinib led to higher than expected early withdrawal due to toxicity, limiting conclusions regarding efficacy. These findings raise concern regarding the tolerability of adding more agents to already complex combination regimens for metastatic colorectal cancer.

Gankyrin, the 26 S proteasome, the cell cycle and cancer.

The known molecular players in cell-cycle control are much studied, not only to learn more about this intricate system, but also to understand the molecular features of oncogenic transformation. Infrequently, new players are discovered that change the interpretation of cell-cycle control. Gankyrin is one such player and was discovered in yeast two-hybrid screens as a new proteasomal subunit that interacts specifically with the S6b (rpt3) AAA (ATPase associated with various cellular activities) ATPase, which, with five other AAAs, are present in the so-called base of the 19 S regulator of the 26 S proteasome. Gankyrin is also the first liver oncogene. Gankyrin is found in other complexes that contain Rb (retinoblastoma protein) and the ubiquitin protein ligase Mdm2 (murine double minute 2). Gankyrin increases the hyperphosphorylation of Rb and therefore activates E2F-dependent transcription of DNA synthesis genes. Additionally, gankyrin, by binding to Mdm2, increases the ubiquitylation and degradation of p53 and prevents apoptosis. Gankyrin controls the functions of two major tumour suppressors and, when overexpressed, causes hepatocellular carcinoma.

Analysis of surgical salvage after failure of primary therapy in rectal cancer: results from Intergroup Study 0114.

PURPOSE: Intergroup Study 0114 was designed to study the effect of various chemotherapy regimens delivered after potentially curative surgical resection of T3, T4, and/or node-positive rectal cancer. A subset analysis was undertaken to investigate the prevalence and influence of salvage therapy among patients with recurrent disease. PATIENTS AND METHODS: Adjuvant therapy consisted of two cycles of fluorouracil (FU)-based chemotherapy followed by pelvic irradiation with chemotherapy and two more cycles of chemotherapy after radiation therapy. A total of 1,792 patients were entered onto the study and 1,696 were assessable. After a median of 8.9 years of follow-up, 715 patients (42%) had disease recurrence, and an additional 10% died without evidence of disease. Five hundred patients with follow-up information available had a single organ or single site of first recurrence (73.5% of all recurrences). RESULTS: A total of 171 patients (34% of those with a single organ or single site of recurrence) had a potentially curative resection of the metastatic or locally recurrent disease. Single-site first recurrences in the liver, lung, or pelvis occurred in 448 patients (90% of the single-site recurrences), with 159 (35%) of these undergoing surgical resection for attempted cure. Overall survival differed significantly between the resected and nonresected groups (P <.0001), with overall 5-year probabilities of.27 and.06, respectively. Controlling for worst performance status at the time of recurrence does not alter this relationship. Patients who underwent salvage surgery had significantly increased survival (P <.001) for each site. CONCLUSION: Attempted surgical salvage of rectal cancer recurrence is performed commonly in the United States. The chance of a long-term cure with such intervention is approximately 27%.

Colon cancer survival is associated with increasing number of lymph nodes analyzed: a secondary survey of intergroup trial INT-0089.

PURPOSE: To determine the relationship, in patients with adenocarcinoma of the colon, between survival and the number of lymph nodes analyzed from surgical specimens. PATIENTS AND METHODS: Intergroup Trial INT-0089 is a mature trial of adjuvant chemotherapy for high-risk patients with stage II and stage III colon cancer. We performed a secondary analysis of this group with overall survival (OS) as the main end point. Cause-specific survival (CSS) and disease-free survival were secondary end points. Rates for these outcome measures were estimated using Kaplan-Meier methodology. Log-rank test was used to compare overall curves, and Cox proportional hazards regression was used to multivariately assess predictors of outcome. RESULTS: The median number of lymph nodes removed at colectomy was 11 (range, one to 87). Of the 3411 assessable patients, 648 had no evidence of lymph node metastasis. Multivariate analyses were performed on the node-positive and node-negative groups separately to ascertain the effect of lymph node removal. Survival decreased with increasing number of lymph node involvement (P =.0001 for all three survival end points). After controlling for the number of nodes involved, survival increased as more nodes were analyzed (P =.0001 for all three end points). Even when no nodes were involved, OS and CSS improved as more lymph nodes were analyzed (P =.0005 and P =.007, respectively). CONCLUSION: The number of lymph nodes analyzed for staging colon cancers is, itself, a prognostic variable on outcome. The impact of this variable is such that it may be an important variable to include in evaluating future trials.

Proteasomal interactors control activities as diverse as the cell cycle and glutaminergic neurotransmission.

The six regulatory non-redundant ATPases in the base of the 19 S regulator of the 26 S proteasome belong to the AAA superfamily of ATPases. Yeast two-hybrid genetic screens, biochemical analyses and cell biological studies have identified and characterized new interactors of the human S6 (rpt3) and S8 (rpt6) ATPases of the 19 S regulator of the 26 S proteasome. The S6 ATPase interacts with gankyrin. This protein is found in purified human 26 S proteasomes and in a smaller complex(es) containing CDK4 and free S6 ATPase. Gankyrin overexpression causes the phosphorylation of the retinoblastoma protein (pRb) and the release of E2F transcription factor to trigger the expression of DNA synthesis genes. Gankyrin is oncogenic in nude mice and is overexpressed in hepatocellular carcinoma cells (HCCs). The S8 ATPase interacts with members of the large Homer-3 protein family. There are three Homer genes; the Homer 1 and 2 gene products control trafficking and calcium-store-related functions of metabotropic glutamate receptors (e.g. mGluR1alpha). Homer-3A11 by binding to the S8 ATPase brings mGluR1alpha to the 26 S proteasome for degradation. The degradation of mGluR1alpha is blocked by proteasomal inhibitors and by overexpression of the N-terminus of Homer which binds to the receptor. The S8 ATPase and mGluR1alpha are co-localized in Purkinje dendrites in rat cerebellum. The data are discussed in terms of the regulation of the cell cycle and glutaminergic receptor functions by the 26 S proteasome.

CD23 shedding: requirements for substrate recognition and inhibition by dipeptide hydroxamic acids.

CD23 (low affinity IgE receptor, FcepsilonRII) is expressed as a Type II extracellular protein on a variety of cells such as B cells, monocytes and macrophages and is cleaved from the cell surface to generate several distinct fragments. The expression of CD23 on the cell surface as well as the generation of soluble fragments of CD23 has been shown to be involved in regulation of IgE synthesis. CD23 is released from the cell surface by a metalloprotease, analogous to the cleavage of other cell surface molecules such as TNF-alpha. This activity has been extensively studied with respect to biochemical characterization and ability to cleave specific mutants of CD23. Both local sequence and distal domains have been shown to affect cleavage of CD23. Selective dipeptide hydroxamic acid inhibitors of CD23 processing have been identified and demonstrated to very potently and selectively inhibit CD23 processing.

Adjuvant therapy in rectal cancer: analysis of stage, sex, and local control--final report of intergroup 0114.

PURPOSE: The gastrointestinal Intergroup studied postoperative adjuvant chemotherapy and radiation therapy in patients with T3/4 and N+ rectal cancer after potentially curative surgery to try to improve chemotherapy and to determine the risk of systemic and local failure. PATIENTS AND METHODS: All patients had a potentially curative surgical resection and were treated with two cycles of chemotherapy followed by chemoradiation therapy and two additional cycles of chemotherapy. Chemotherapy regimens were bolus fluorouracil (5-FU), 5-FU and leucovorin, 5-FU and levamisole, and 5-FU, leucovorin, and levamisole. Pelvic irradiation was given to a dose of 45 Gy to the whole pelvis and a boost to 50.4 to 54 Gy. RESULTS: One thousand six hundred ninety-five patients were entered and fully assessable, with a median follow-up of 7.4 years. There was no difference in overall survival (OS) or disease-free survival (DFS) by drug regimen. DFS and OS decreased between years 5 and 7 (from 54% to 50% and 64% to 56%, respectively), although recurrence-free rates had only a small decrease. The local recurrence rate was 14% (9% in low-risk [T1 to N2+] and 18% in high-risk patients [T3N+, T4N]). Overall, 7-year survival rates were 70% and 45% for the low-risk and high-risk groups, respectively. Males had a poorer overall survival rate than females. CONCLUSION: There is no advantage to leucovorin- or levamisole-containing regimens over bolus 5-FU alone in the adjuvant treatment of rectal cancer when combined with irradiation. Local and distant recurrence rates are still high, especially in T3N+ and T4 patients, even with full adjuvant chemoradiation therapy.

Prominent stress response of Purkinje cells in Creutzfeldt-Jakob disease.

To examine the role of stress-related 70-kDa heat shock proteins (Hsp-s) in Creutzfeldt-Jakob disease (CJD), we performed immunocytochemistry to detect Hsp-72 and Hsp-73, together with the abnormal (PrP(Sc)) and the presumed cellular form (PrP(C)) of the prion protein, and TUNEL method to measure cellular vulnerability in different brain regions in CJD and control cases. While Hsp-73 showed uniform distribution in all the examined samples, an increase in the number of Purkinje cells with prominent accumulation of Hsp-72 in the CJD group was observed. These neurons also showed intense PrP(C) staining, but TUNEL-positive nuclei were only detected in the granular (Hsp-72-negative) cell layer. Fewer cells of the inferior olivary nucleus were immunoreactive for Hsp-72 in CJD than in control cases, and regions showing severe spongiform change and gliosis exhibited fewer Hsp-72-immunoreactive neurons. Our results indicate that accumulation of the inducible Hsp-72 in certain cell types may be part of a cytoprotective mechanism, which includes preservation of proteins like PrP(C).

The ubiquitin protein catabolic disorders.

The ubiquitin-proteasome system of intracellular proteolysis is essential for cell viability. We propose the concept that neurodegenerative diseases such as Alzheimer's and Parkinson's, as well as other conditions including some types of cancer, collectively represent a raft of 'ubiquitin protein catabolic disorders' in which altered function of the ubiquitin-proteasome system can cause or directly contribute to disease pathogenesis. Genetic abnormalities within the ubiquitin pathway, either in ubiquitin-ligase (E3) enzymes or in deubiquitinating enzymes, cause disease because of problems associated with substrate recognition or supply of free ubiquitin, respectively. In some cases, mutations in protein substrates of the ubiquitin-proteasome system may directly contribute to disease progression because of inefficient substrate recognition. Mutations in transcripts for the ubiquitin protein itself (as a result of 'molecular misreading') also affect ubiquitin-dependent proteolysis with catastrophic consequences. This has been shown in Alzheimer's disease and could apply to other age-associated neurodegenerative conditions. Within the nervous system, accumulation of unwanted proteins as a result of defective ubiquitin-dependent proteolysis may contribute to aggregation events, which underlie the pathogenesis of several major human neurodegenerative diseases.

Expression and purification of stable 33-kDa soluble human CD23 using the Drosophila S2 expression system.

CD23, a 45-kDa type II membrane glycoprotein present on B cells, monocytes, and other human immune cells, is a low-affinity receptor for IgE. The extracellular region of the membrane-bound human CD23 is processed into at least four soluble (s) CD23 forms, with apparent molecular masses of 37, 33, 29, and 25 kDa. High levels of sCD23 are found in patients with allergy, certain autoimmune diseases, or chronic lymphocytic leukemia. Therefore, inhibition of the processing of membrane-bound CD23 to control the cytokine-like effects of sCD23 offers a novel therapeutic opportunity. While the 37-, 29-, and 25-kDa forms of sCD23 have been expressed previously as recombinant proteins, the 33-kDa form has not been purified and characterized. To further investigate the multiple roles of sCD23 fragments and to devise assays to identify potent small-molecule inhibitors of CD23 processing, we have produced the 33-kDa form of sCD23 using Chinese hamster ovary (CHO) and Drosophila S2 cells. The CHO-expressed 33-kDa protein was found to undergo proteolytic degradation during cell growth and during storage of purified protein, resulting in accumulation of a 25-kDa form. The Drosophila system expressed the 33-kDa sCD23 in a stable form that was purified and demonstrated to be more active than the CHO-derived 25-kDa form in a monocyte TNFalpha release assay.

The ubiquitin-proteasome 26s pathway in liver cell protein turnover: effect of ethanol and drugs.

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Samuel W. French and R. J. Mayer. The presentations were (1) The ubiquitin-proteasome 26s pathway in liver cell protein turnover: Effect of alcohol and drugs, by Samuel W. French and F. Bardag-Gorce; (2) The role of CYP2E1 phosphorylation and degradation pathway in the induction of the enzyme, by Magnus Ingelman-Sundberg; (3) Role of proteasome in the proteolysis of oxidized proteins in experimental chronic alcoholism, by Helen Rouach; (4) Alcohol, proteolysis and liver cancer, by R. J. Mayer; (5) Effect of ethanol feeding on the ATP-ubiquitin-proteasome pathway in the liver cell, by F. Bardag-Gorce; (6) Novel mechanisms and targets for intracellular transport of CYP2E1, by E. Neve; and (7) Gankyrin, an oncoprotein commonly over expressed in hepatoma, by H. Higashitsuji.

Fluorouracil modulation in colorectal cancer: lack of improvement with N -phosphonoacetyl- l -aspartic acid or oral leucovorin or interferon, but enhanced therapeutic index with weekly 24-hour infusion schedule--an Eastern Cooperative Oncology Group/Cancer and Leukemia Group B Study.

PURPOSE: To investigate mechanism-directed regimens in maximizing the efficacy of fluorouracil (5-FU) in advanced colorected cancer. PATIENTS AND METHODS: Based on promising phase II data, a randomized comparison of various methods for the biochemical modulation of 5-FU was undertaken in patients with advanced colorectal cancer. The control group received single-agent 5-FU as a 24-hour infusion weekly. Patients (N = 1,120) with no prior chemotherapy for metastatic disease were randomized to one of the following arms: arm A, 5-FU 2,600 mg/m2 by 24-hour infusion, weekly; arm B, N-phosphonoacetyl-l-aspartic acid 250 mg/m2 day l, 5-FU 2,600 mg/m2 by 24-hour infusion day 2, weekly; arm C, 5-FU 600 mg/m2 with oral leucovorin (LV) 125 mg/m2 hourly for the preceding 4 hours, weekly; arm D, 5-FU 600 mg/m2 with intravenous (IV) LV 600 mg/m2, weekly; arm E, 5-FU 750 mg/m2/d IV by continuous infusion for 5 days, then 750 mg/m2 weekly, and recombinant interferon alfa-2a 9 million units subcutaneously three times weekly. Median follow-up was 4.8 years. RESULTS: Of the 1,098 assessable patients, 57% had measurable disease. The toxicity of all the regimens was tolerable. Grade 4 or worse toxicity occurred in 11%, 11%, 30%, 24%, and 22% on each arm, respectively; diarrhea was the most common adverse effect. These toxicity patterns favored significantly (P <.001) the 24-hour infusion arms. Median survival (months) by arm was A, 14.8; B, 11.9; C, 13.5; D, 13.6; and E, 15.2. These survival durations did not differ significantly. CONCLUSION: We conclude that a weekly infusion regimen of 5-FU is significantly less toxic than and as effective as 5-FU bolus regimens modulated by either LV or interferon in patients with metastatic colorectal cancer.