High activity and reduced neurotoxicity of bi-fractionated oxaliplatin plus 5-fluorouracil/leucovorin for elderly patients with advanced colorectal cancer.

BACKGROUND: The proportion of elderly within the general population is increasing and the incidence of colorectal cancer increases with age. Oxaliplatin and 5-fluorouracil (FU) combination is active in this disease. PATIENTS AND METHODS: This multicenter phase II study was designed to investigate feasibility, efficacy, activity of daily living (ADL) and instrumental activity of daily living (IADL) in elderly patients with metastatic colorectal cancer treated, as first-line chemotherapy, with a bi-fractionated oxaliplatin/5-FU based regimen. Treatment was oxaliplatin 45 mg/m2, leucovorin 200 mg/m2, 5-FU 400 mg/m2 and 22 h continuous infusion of 5-FU 600 mg/m2, all given intravenously on days 1 and 2, every 2 weeks. RESULTS: Seventy-eight patients were enrolled; median age was 75 years (range 70-85). Among 77 evaluable patients, we observed seven complete responses and 32 partial responses, for an overall response rate of 51% (95% confidence interval 40% to 62%). A stabilization of disease was observed in 25% of patients while 19 patients progressed. Canadian NCI grade 3/4 toxicities were: neutropenia in 32% of patients (febrile in two), diarrhea in 10%, mucositis in 4%, and fatigue in 4%. Sensory neuropathy was mild and occurred as grade 3 in 6% of patients. ADL and IADL scores did not change significantly during treatment. CONCLUSIONS: The bi-fractionated delivery of oxaliplatin plus 5-FU/leucovorin demonstrated high antitumor activity in elderly patients with advanced colorectal cancer. Splitting oxaliplatin administration might reduce incidence of severe neuropathy, although this has to be confirmed by further studies.

Long-survival in responding patients with metastatic breast cancer treated with doxorubicin-docetaxel combination. A multicentre phase II trial.

BACKGROUND: The doxorubicin-docetaxel combination is active in breast cancer; the aim of the present study was to evaluate the complete response rate and safety profile of the doxorubicin and docetaxel regimen as first-line chemotherapy in metastatic breast cancer patients. PATIENTS AND METHODS: Forty-three patients entered the study. Treatment plan was: doxorubicin (50 mg/m2, i.v. bolus) followed 1 hour later by docetaxel (75 mg/m2 i.v. infusion over 1 hour), q 3 weeks, for up to six courses. The patients achieving a response or a stabilisation of disease after 6 courses were allowed to intensify the treatment with docetaxel (100 mg/m2, q 3 weeks) for up to 2 courses. G-CSF (or GM-CSF) was administered if clinically indicated. RESULTS: Patients' median age was 57years (range 32-75) and 72% of them had visceral disease. A total of 217 doxorubicin-docetaxel courses were delivered, with 70% of patients receiving all the 6 planned cycles. Among the 40 patients assessable for response (WHO criteria), 7 (16%) achieved a complete remission and 22 (51%) a partial remission, for an overall response rate (intent-to-treat) of 67% (95% C.I. =53% to 81%). In 19 patients, the treatment was intensified with two more single-agent docetaxel cycles, without ameliorating the response. Twenty-seven patients with oestrogen receptor-positive received hormonal therapy as 'maintenance' after completing chemotherapy treatment. NCIC G3-G4 neutropenia was recorded in 58% of patients, with G/GM-CSF used in 23 (53%) patients and 91 (38%) cycles. No patients experienced severe cardiac or neurological toxicity. No toxic death occurred. With a median follow-up of 41 months among alive patients, we observed in responder patients an overall median time to progression and survival of 18 and 33 months respectively, with ten long-survivors still alive. CONCLUSION: This study confirmed the combination doxorubicin-docetaxel as a very active regimen for metastatic breast cancer. Remarkably long survival times were observed not only in complete responders, but also in those patients who responded partially. This might be equally attributed to first-line treatment and sequential maintenance hormonal therapy.

Advanced colorectal cancer in elderly patients: tolerance and efficacy of leucovorin and fluorouracil bolus plus continuous infusion.

BACKGROUND: Colorectal cancer (CRC) incidence increases sharply with age. In this study we assessed activity, toxicity and both the activity of daily living (ADL) and instrumental activity of daily living (IADL) of the De Gramont schedule in a series of advanced CRC patients aged > or = 70 years. PATIENTS AND METHODS: Sixty-two previously untreated advanced CRC patients entered the study. Median age was 75 (range 70-88). RESULTS: 447 courses were delivered. All of the 62 patients were evaluable for toxicity, 55 for response and ADL-IADL indexes. We recorded 2 complete and 9 partial responses, for an overall response rate of 20%. ADL and IADL indexes improved in 33%, remained stable in 49% and worsened in 18% of evaluable patients. Treatment was very well-tolerated with no serious hematological or non-hematological toxicities. CONCLUSIONS: The De Gramont schedule was very well tolerated in advanced CRC elderly patients, although our work could not confirm the original reported activity. ADL and IADL indexes improved or remained stable in 82% of evaluable patients.

Evaluation of the accuracy of gadobenate dimeglumine-enhanced MR imaging in the detection and characterization of focal liver lesions.

OBJECTIVE: We evaluated the extent to which hepatic lesion characterization and detection is improved by using gadobenate dimeglumine for enhancement of MR images. MATERIALS AND METHODS: Eighty-six patients were imaged before gadobenate dimeglumine administration, immediately after the 2 mL/sec bolus administration of a 0.05 mmol/kg dose (dynamic imaging), and at 60-120 min after the IV infusion at 10 mL/min of a further 0.05 nmol/kg dose (delayed imaging). The accuracy for lesion characterization was assessed for a total of 107 lesions. Sensitivity for lesion detection was assessed for a total of 149 lesions detected on either intra-operative sonography, iodized oil CT, CT during arterial portography, or follow-up contrast-enhanced CT as the gold standard. RESULTS: The accuracy in differentiating benign from malignant liver lesions increased from 75% and 82% (the findings of two observers) on unenhanced images alone, to 89% and 80% on dynamic images alone (p<0.001, p = 0.8), and to 90.7% when combining the unenhanced and dynamic image sets (p<0.001, p = 0.023). Delayed images did not further improve accuracy (90% and 91%; p = 0.002, p< 0.05). A similar trend was apparent in terms of accuracy for specific diagnosis: values ranged from 49% and 62% on unenhanced images alone, to 76% and 70% on combined unenhanced and dynamic images (p<0.001, p = 0.06), and to 75% and 70% on inclusion of delayed images (p<0.001, p = 0.12). The sensitivity for lesion detection increased from 77% and 81% on unenhanced images alone, to 87% and 85% on combined unenhanced and dynamic images (p = 0.001, p = 0.267), and to 92% and 89% when all images were considered (p<0.001, p = 0.01). CONCLUSION: Contrast-enhanced dynamic MR imaging with gadobenate dimeglumine significantly increases sensitivity and accuracy over unenhanced imaging for the characterization of focal hepatic lesions, and delayed MR imaging contributes to the improved detection of lesions.

Gadolinium chelates with weak binding to serum proteins. A new class of high-efficiency, general purpose contrast agents for magnetic resonance imaging.

RATIONALE AND OBJECTIVES: The authors assess the effect of weak protein binding on the efficacy of gadolinium chelates as contrast agents for magnetic resonance imaging (MRI). METHODS: Chelates with no (gadopentetate dimeglumine), weak (gadobenate dimeglumine), and strong (B-21326/7) protein binding were compared by in vitro MRI at 2T (spin echo [SE]: repetition time [TR]/echo time [TE] 350/8 mseconds) on solutions in 0.5 mM bovine serum albumin and in rat whole blood, and by in vivo MRI at 2T on rat models of brain tumors (SE TR/TE 350/10 mseconds) and of focal blood-brain barrier disruption (SE TR/TE 400/15 mseconds) after injection of MPP+. Relaxation rate enhancement in the blood of normal rabbits was measured in vivo after administration of contrast agents using IR-Snapshot FLASH. RESULTS: Signal intensity enhancement measured in vitro for whole rat blood 0.1 mM in gadobenate was 142% relative to the same concentration of gadopentetate. Peak signal intensity enhancement in brain tumors was 87% +/- 8% and 64% +/- 5% after 0.1 mmol/kg intravenous administration of gadobenate and gadopentetate, respectively; in MPP+ lesions, the peak signal intensity enhancement was 22% +/- 9%, 32% +/- 7%, and 64% +/- 14% after 0.2 mmol/kg intravenous of gadopentetate, gadobenate, and B-21326/7, respectively. In rabbits, the relaxation enhancement of blood 5 minutes after B-21326/7 and gadobenate administration was 323% and 182%, respectively, relative to the same dose (0.1 mmol/kg intravenous) of gadopentetate. CONCLUSIONS: Weak protein binding can substantially increase the efficacy of gadolinium chelates as general purpose contrast agents for MRI.

In vitro and in vivo characterisation of low-resistant mouse reticulosarcoma (M5076) sublines obtained after pulse and continuous exposure to cisplatin.

In order to simulate drug resistance observed in the clinic, two cisplatin-resistant cell lines were produced from a murine ovarian reticulosarcoma, M5076 (M5), by pulse (M5/CDDP) and continuous (M5/CDDPc) treatment with cis-diamminedichloroplatinum(II)(CDDP). These cell lines showed a similar stable low level of resistance (approximately 3-fold) to CDDP and cross-resistance to carboplatin, iproplatin and the new alkylating agent tallimustine, but not to L-PAM (L-phenylalanine mustard) and BCNU (1,3-bis(2-chloroethyl)-1-nitrosourea). Collateral sensitivity to two inhibitors of topoisomerase II, VP16 (etoposide) and doxorubicin (Dox), but cross-resistance to the topoisomerase I inhibitor, camptothecin, were observed. The two cell lines were also sensitive to 5-fluorouracil. No increase in the level of glutathione or activity of glutathione S-transferase could be observed in resistant cells compared with the parental M5 cells. Total DNA platination immediately after treatment was similar in the parental and resistant cell lines. Repair of total DNA platination, measured after 24 h of recovery, was undetectable in M5 and M5/CDDP cells, but was 33% in M5/ CDDPc cells. Initial DNA-interstrand cross-links (DNA-ISC) were six times higher in M5 than in M5/CDDP cells, but 24 h after treatment, both lines had completely repaired this damage. M5/ CDDPc cells did not show formation of DNA-ISC at any time after treatment. The two resistant cell lines were tumorigenic when implanted in mice and resistant to CDDP treatment in vivo. The CDDP resistant tumours were not cross-resistant in vivo to L-PAM, BCNU and Dox, which had been active in vitro, nor to tallimustine, which had been cross-resistant in vitro. Mechanisms of resistance in M5/CDDP and M5-CDDPc seem to be based on a lower formation of DNA-ISC combined, for the latter cell line, with a higher repair capacity for total DNA platination.

Sensitivity of CHO mutant cell lines with specific defects in nucleotide excision repair to different anti-cancer agents.

Nucleotide excision repair (NER) is one of the major DNA repair systems in mammalian cells, able to remove a broad spectrum of unrelated lesions. In this report the role of ERCC (excision repair cross-complementing) 1, ERCC2, ERCC3, ERCC4, and ERCC6 genes in removing the lesions caused by alkylating agents with different structures and mechanisms of action has been studied using UV-sensitive DNA repair-deficient mutant CHO cell lines. We confirmed that ERCC1 and ERCC4 play a role in the repair of cis-diamminedichloroplatinum (DDP)- and Melphalan (L-PAM)-induced DNA damage, while a marginal role of ERCC2 and ERCC3 in the cellular response to DDP and L-PAM treatment has been observed. Treatment with methylating agents (DM and MNNG) showed a lack of a preferential cytotoxicity between the parental and the different NER. deficient cell lines, emphasizing the importance of other repair systems such as 3-methyladenine glycosylase and O6 alkyl-guanine-DNA-alkyl-transferase. ERCC1, ERCC2, ERCC3 and ERCC4, but not ERCC6 gene products seem to be involved in removing the lesions caused by Tallimustine and CC1065, minor groove alkylating agents that alkylate N3 adenine in a sequence-specific manner. ERCC6-deficient cells were as sensitive as the parental cell line to all the cytotoxic drugs tested, except DDP. These data emphasize the importance of the CHO mutant cell lines with specific defects in the DNA repair system for investigating the mechanism of action of different anti-cancer agents.

3-methyladenine-DNA-glycosylase and O6-alkyl guanine-DNA-alkyltransferase activities and sensitivity to alkylating agents in human cancer cell lines.

The activities and the expression of 3-methyladenine glycosylase (3-meAde gly) and O6-alkylguanine-DNA-alkyltransferase (O6 ATase) were investigated in ten human cancer cell lines. Both 3-meAde gly and O6 ATase activities were variable among different cell lines. mRNA levels of the O6 ATase gene, appeared to be related to the content of O6 ATase in different cell lines, whereas no apparent correlation was found between mRNA of 3-meAde gly and the enzyme activity. No correlation was found between the activity of the two enzymes and the sensitivity to alkylating agents of different structures such as CC-1065, tallimustine, dimethylsulphate (DMSO), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), cis-diamminedichloroplatinum (cDDP) and melphalan (L-PAM). The most striking finding of this study is that a correlation exists between the activity of O6 ATase and 3-meAde gly in the various cell lines investigated (P<0.01), suggesting a common mechanism of regulation of two DNA repair enzymes.

Changes in doxorubicin distribution and toxicity in mice pretreated with the cyclosporin analogue SDZ PSC 833.

SDZ PSC 833 (PSC 833) is a cyclosporin A analogue that is under clinical investigation in combination with doxorubicin (Dx) or other anticancer agents as a type-1 multidrug resistance (MDR-1)-reversing agent. The present study was focused on the effects of PSC 833 on the distribution and toxicity of Dx in non-tumor-bearing CDF1 male mice. Mice were given PSC 833 i.p. at 30 min before i.v. Dx treatment. Dx levels were determined by a high-performance liquid chromatography (HPLC) assay at different times during a 72-h period following Dx treatment in the serum, heart, intestine, liver, kidney, and adrenals of mice. In all tissues, Dx area under the concentration-time curve (AUC) values were much greater in mice receiving 10 mg/kg Dx in combination with 12.5 or 25 mg/kg PSC 833 than in mice receiving Dx alone. The highest increase in Dx concentrations was found in the intestine, liver, kidney, and adrenals. Lower, albeit significant, differences were found in the heart. PSC 833 did not appear to influence either urinary or fecal Dx elimination or Dx metabolism to a great extent. Doses of PSC 833 devoid of any toxicity potentiated the acute and delayed toxicity of Dx dramatically. The mechanism responsible for this enhanced toxicity has not yet been elucidated but is likely to be related to an increased tissue retention of Dx due to inhibition of the P-glycoprotein (Pgp) pump by PSC 833, as has recently been proposed for cyclosporin A.

3T3 NIH murine fibroblasts and B78 murine melanoma cells expressing the Escherichia coli N3-methyladenine-DNA glycosylase I do not become resistant to alkylating agents.

The role of alkylation of the N3 position of adenine in the cytotoxicity of alkylating agents in mammalian cells is still undefined. By co-transfecting NIH3T3 murine fibroblast and murine B78 H1 melanoma cells with pSG5tag and pSV2neo, we obtained clones expressing the mRNA of the bacterial tag gene coding for N3-methyladenine-DNA glycosylase I (Gly I), which specifically repairs N3-methyladenine. The levels of Gly I were 400 times higher in NIH3T3 pSG5tag (clone 3.9.4) and 12-33 times higher in B78 H1 tag clones (2A4, 2A6, 2C3 and 2D1) than in the respective control cells. The sensitivity to alkylating agents was evaluated in tag-expressing cells in comparison with pSG5, pSV2neo co-transfected control cells. As regards the cytotoxic activity of methylating agents (N-methylnitrosourea, N-methyl-N'-nitro-N-nitrosoguanidine, dimethylsulfate and temozolomide) and other alkylators with different structure and different interactions with DNA such as CC-1065 and FCE-24517 (minor groove binders known to bind to N3 of adenine), 4-[bis(2-chloroethyl)amino]-L-phenylalanine and cis-diamminedichloroplatinum II, cytotoxicity was the same for tag-expressing and non-expressing cells. These results suggest that the increased expression of N3-methyladenine-DNA glycosylase is not necessarily a crucial mechanism for the resistance of cells to alkylating agents.