Biomedical subjects

J L Grem

Publications and source records attributed to J L Grem.

At least 73 records · Page 4Linked to original sources

PubMed1993

Phase II study of fluorouracil, leucovorin, and interferon alfa-2a in metastatic colorectal carcinoma.

PURPOSE: To test the activity of a regimen of interferon alfa-2a (IFN alpha-2a) 5 x 10(6) U/m2 subcutaneously (SC) days 1 through 7 combined with leucovorin 500 mg/m2/d intravenously (IV) over 30 minutes and fluorouracil (5-FU) 370 mg/m2/d through IV push 1 hour after leucovorin days 2 through 6 in a phase II study. PATIENTS AND METHODS: Forty-six patients with a good performance status (PS) with measurable colorectal cancer and no prior therapy for metastatic disease were entered. Cycles were repeated at 3-week intervals if toxicity had resolved. The 5-FU dose was increased by 15% if toxicity was mild, and decreased by 15% for grade 3 to 4 nonhematologic or grade 4 hematologic toxicity. RESULTS: Three complete responses (CRs) and 21 partial responses (PRs) were seen among 44 assessable patients (54%; 95% confidence interval, 39% to 70%). A moderately strong association was noted between PS and response: PS O (n = 26), two CRs and 15 PRs (65%); PS 1 (n = 13), one CR and six PRs (54%); PS 2 (n = 5), zero CRs and zero PRs (0%; two-tailed P = .026). With a median follow-up duration of 18.8 months, the median time to treatment failure (TTF) and survival were 7.8 months and 16.3 months, respectively. Doses were escalated to 425 mg/m2/d 5-FU in 10 patients, but only four tolerated the higher dose. When expressed as the most severe degree of toxicity experienced by each patient across all cycles, grade 3 to 4 toxicity of the following types was observed; mucositis, 37%; diarrhea, 40%; rash, 7%; fatigue, 14%; granulocytopenia, 13%. Dose-limiting toxicity at 370 mg/m2/d 5-FU eventually occurred in 28 patients (61%). Twelve patients (26%) required an IFN alpha-2a dose reduction for constitutional toxicity. CONCLUSION: This regimen has promising activity in advanced colorectal cancer, particularly in patients with an Eastern Cooperative Oncology Group (ECOG) PS of 0 to 1.

Adult↗

PubMed1993

Antimetabolites.

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Antimetabolites, Antineoplastic↗

PubMed1993

Neoadjuvant chemotherapy for locally advanced gastric adenocarcinoma.

Gastric adenocarcinoma is typically diagnosed at an advanced stage, and even with "curative" gastrectomy, most patients die of recurrent disease. Neoadjuvant chemotherapy for locally advanced gastric cancer is an experimental treatment strategy that may increase resectability and improve survival for patients afflicted with an almost uniformly fatal neoplasm. At our institution, we are evaluating the efficacy of fluorouracil, leucovorin, and interferon alfa-2A administered for three cycles, followed by surgery and consolidation therapy for patients with T3-4, N1-2, M0 gastric adenocarcinoma. The rationale for the use of neoadjuvant therapy combined with radical extirpative surgery in this setting and related issues are discussed.

Adenocarcinoma↗

PubMed1992

Decreased catabolism of fluorouracil in peripheral blood mononuclear cells during combination therapy with fluorouracil, leucovorin, and interferon alpha-2a.

BACKGROUND: We previously reported that recombinant interferon alpha-2a (IFN alpha-2a) therapy was associated with a dose-dependent decrease in fluorouracil (5-FU) clearance. PURPOSE: In this study, we used peripheral blood mononuclear cells (PBMCs), which are responsive to IFNs, as surrogate tissue to determine whether the change in clearance might be explained by decrease in 5-FU catabolism during IFN alpha-2a therapy. METHODS: The study population consisted of 45 patients with adenocarcinoma arising in the gastrointestinal tract. Thirty-seven patients received therapy containing IFN alpha-2a at a median dose of 5 million U/m2 per day (range, 1.7-7.5 million U/m2 per day) starting on day 1 and continuing through either day 7 or day 14 in conjunction with intravenous high-dose leucovorin (LV) followed by bolus 5-FU on days 2-6. Eight patients received the same schedule of 5-FU and LV daily for 5 days without IFN alpha-2a but with granulocyte-macrophage colony-stimulating factor starting on day 6 and ending at least 3 days prior to the start of the next cycle. Peripheral blood was collected during 70 cycles on days 1, 2, and 4 prior to the daily treatment with IFN alpha-2a + 5-FU+LV and during 19 cycles on days 1 and 4 prior to the daily treatment with 5-FU+LV without IFN alpha-2a. In a given patient cycle, matched samples were drawn at approximately the same time of day. PBMCs were isolated, and the intact cells were exposed to 4 microM [3H]5-FU, and the formation of [3H]dihydrofluorouracil was determined by reverse-phase high-performance liquid chromatography. RESULTS: In 47 matched patient cycles from IFN alpha-2a + 5-FU+LV-treated patients in which samples were available on days 1, 2, and 4, 5-FU catabolism decreased by 20% (P2 = .03) and 41% (P2 = .0001) from the baseline catabolic rate (2.5 +/- 0.2 pmol/min per 10(6) cells [mean +/- SE]) on days 2 and 4, respectively. Using information from all paired samples, the mean change from baseline on day 2 was -0.4 +/- 0.2 pmol/min per 10(6) cells (n = 54; P2 = .05), and the change from baseline on day 4 was -1.3 +/- 0.3 pmol/min per 10(6) cells (n = 63; P2 = .0001). In contrast, changes in 5-FU catabolism were not evident in the PBMCs of the reference population receiving 5-FU+LV without IFN alpha-2a. CONCLUSIONS: The magnitude of the change in 5-FU catabolism is similar to the magnitude of the decrease in 5-FU clearance in our previous study. These observations suggest that changes in 5-FU catabolism during therapy with IFN alpha-2a, 5-FU, and LV may account for the decreased 5-FU clearance.

Adenocarcinoma↗

PubMed1992

Metabolism and RNA incorporation of cyclopentenyl cytosine in human colorectal cancer cells.

We studied the cytotoxicity and metabolism of the investigational cytidine analogue cyclopentenyl cytosine (CPE-C) in three human colorectal cancer cell lines: HCT 116, SNU-C4, and NCI-H630. CPE-C potently inhibited cell growth and decreased clonogenic capacity at concentrations achieved in murine and primate pharmacologic studies. CPE-C produced a concentration-dependent depletion of CTP, accompanied by changes in the dCTP pools. CPE-C exposure was associated with an accumulation of cells in the S phase at 48 hr. [3H]CPE-C was metabolized predominantly to the triphosphate (CPE-CTP) form. Saturation of phosphorylation to the monophosphate form occurred above 5-10 microM. Plateau CPE-CTP pools were of a magnitude similar to that of the physiologic ribonucleotide triphosphate pools. The intracellular half-life of CPE-CTP was 24 hr. After a 24-hr exposure to 0.5 microM CPE-C, CPE-CTP was detected for up to 96 hr post-drug removal, accompanied by persistent depletion of the CTP pools. Cesium sulfate density centrifugation of purified nucleic acids indicated that [3H]CPE-C incorporated into RNA, but was not detected in DNA. Agarose-gel electrophoresis of RNA from [3H]CPE-C-treated cells indicated that it localized predominantly in low molecular weight (4-8 S) RNA species. When CPE-C was administered concurrently with [3H]adenosine (Ado), the proportion of [3H]Ado migrating with low molecular weight RNA species increased. Concurrent exposure to 10 microM cytidine (Cyd), sufficient to replete CTP pools, provided essentially complete protection against lethality resulting from a 24-hr exposure to less than or equal to 0.5 microM CPE-C. While 10 microM Cyd substantially decreased CPE-CTP formation and CPE-C-RNA incorporation during the initial 3 hr of exposure compared to CPE-C alone, after 24 hr the levels were not significantly different. Cyd rescue did not affect the accumulation of [3H]CPE-C or [3H]Ado into low molecular weight RNA species after a 24-hr exposure to CPE-C. Our results indicate that depletion of CTP and dCTP pools is an important component of CPE-C cytotoxicity. While CPE-C incorporation into RNA may not be the critical cytotoxic event during a 24-hr exposure to CPE-C, it may play a role during prolonged exposure to CPE-C. CPE-C is a highly potent new agent and merits clinical evaluation in the treatment of colorectal cancer.

Adenosine↗

PubMed1992

A phase I trial of 5-fluorouracil, leucovorin, and dipyridamole given by concurrent 120-h continuous infusions.

A phase I trial of 5-fluorouracil (FUra) and leucovorin (LV) given with and without dipyridamole (DP) by concurrent 120-h continuous infusion was performed in 27 patients with advanced solid malignancies, 8 of whom had previously received FUra. The LV and DP doses were fixed at 500 mg/m2 daily and 7.7 mg/kg daily, respectively, whereas the FUra dose was escalated. Level 3 (450 mg/m2 FUra daily) represented the maximum tolerated dose for both FUra/LV+DP and FUra/LV. Dose-limiting stomatitis (greater than or equal to grade 3 or grade 2 occurring during the infusion) was encountered in 75% of the first courses given at level 4 (600 mg/m2 daily). Stomatitis was observed in 44/78 (56%) courses. Diarrhea was infrequent and mild. DP infusions were complicated by mild to moderate headache, which was controlled with narcotic analgesics, and mild to moderate nausea/vomiting. FUra-related toxicity was not enhanced by DP administration. Limited pharmacokinetic sampling at levels 3 and 4 revealed mean steady-state FUra concentrations of around 1.0 microM with infusions of FUra/LV+DP. Among three paired courses given with and without DP, no statistically significant difference was found in the total body clearance of FUra (P = 0.44). One partial response was seen in a patient with metastatic gastric carcinoma. For phase II trials, we recommend that concurrent 120-h continuous infusions of FUra (450 mg/m2 daily) and LV (500 mg/m2 daily) be given with and without DP (7.7 mg/kg daily) every 21 days.

Adult↗

PubMed1992

Antimetabolites.

Research efforts over the past year further elucidate the determinants of sensitivity and mechanisms of resistance to the antimetabolites fluorouracil, methotrexate, and cytarabine. Progress has been made in clarifying the complex regulation of target enzyme expression for these antimetabolites. Advances in analytical methodology should facilitate quantitation of thymidylate synthase content in tumor tissue prior to and following fluorouracil-based therapy. Information concerning the basis for certain drug interactions may guide rational dose rates and schedules for clinical trials. A better understanding of the clinical pharmacology of these agents has suggested strategies to minimize their toxicity while maintaining therapeutic activity.

Animals↗

PubMed1992

Antimetabolites.

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Animals↗

PubMed1992

Biochemical modulation of fluorouracil with leucovorin and interferon: preclinical and clinical investigations.

Leucovorin and interferon are capable of modulating the cytotoxicity of fluorouracil (5-FU). Preclinical studies demonstrate that d,l-leucovorin is rapidly metabolized in human breast and colon cells into the various one-carbon substituted folate pools and to the polyglutamated state. While increases in intracellular folate pools are proportional to the exposure concentration of leucovorin, relatively large increases in leucovorin concentrations (50- to 100-fold) are required to produce small intracellular changes (twofold). Polyglutamation is favored by prolonged exposures to leucovorin. Polyglutamate forms have a prolonged intracellular retention and a higher affinity for the target enzyme, thymidylate synthase. Ratios of up to 20:1 inactive to active leucovorin stereo-isomers had essentially no effect on the intracellular metabolism of the active isomer. Interferon gamma interacts with 5-FU in H630 colon cancer cells at the level of thymidylate synthase and enhances cytotoxicity of 5-FU by eliminating the 5-FU-induced acute overexpression of the target enzyme. No alterations in the intracellular metabolism or nucleic acid incorporation of 5-FU could be demonstrated with the addition of interferon gamma. A clinical trial combining interferon-alfa-2a (IFN-alpha-2a) (subcutaneous days 1 to 7) with 5-FU and leucovorin (given IV days 2 to 6) demonstrated that these agents could be combined with acceptable toxicity. While the addition of interferon did not allow dose escalation of 5-FU, it resulted in a significant increase in drug exposure (1.5-fold) compared with matched cycles of 5-FU plus leucovorin without interferon. The overall response rate in this pilot study of 13 untreated patients with gastrointestinal adenocarcinoma was 46%, including two complete responses. There were no responses in eight patients who had previously failed therapy with 5-FU.

Colonic Neoplasms↗

PubMed1992

Biochemical modulation of fluorouracil by dipyridamole: preclinical and clinical experience.

In the HCT 116 human colon carcinoma cell line, dipyridamole, an inhibitor of nucleoside transport, increases the toxicity of 5-fluorouracil (5-FU) in a dose-dependent manner. While dipyridamole inhibits thymidine transport, interference with thymidine salvage did not appear to be a critical factor. Dipyridamole altered 5-FU metabolism, producing a selective increase in fluorodeoxyuridine monophosphate levels by blocking the efflux of fluorodeoxyuridine. Deoxyuridine monophosphate levels were greatly increased when cells were exposed to 5-FU alone, and were even larger with the addition of dipyridamole. Dipyridamole did not alter the absolute amount of 5-FU incorporated into either RNA or DNA. Exposure to either 5-FU or dipyridamole alone was associated with the generation of alkaline labile sites in newly synthesized DNA. Concurrent exposure to 5-FU with dipyridamole resulted in a striking increase in the alkaline labile sites. Thus, increased DNA damage appears to correlate with the enhanced cytotoxicity of this combination. The results of a clinical trial evaluating concurrent intravenous infusion of 5-FU with dipyridamole over 72 hours are reviewed. At maximally tolerated doses of infusional dipyridamole, the steady-state concentration of bioactive, non-protein-bound drug is in the range of 25 nM. While this concentration may be sufficient to perturb thymidine salvage in some cell types, it is 20-fold lower than the optimal concentration of bioactive dipyridamole needed to modulate 5-FU toxicity, metabolism and DNA damage in the HCT 116 tissue culture model. In addition, an unexpected pharmacokinetic interaction was seen: dipyridamole increased 5-FU clearance and decreased its steady-state plasma concentration. It remains to be determined whether dipyridamole with 5-FU alone or with leucovorin will translate into an improved therapeutic outcome.

Colonic Neoplasms↗

PubMed1991

Sequence-dependent interaction of 5-fluorouracil and arabinosyl-5-azacytosine or 1-beta-D-arabinofuranosylcytosine.

We studied the cytotoxicity of arabinosyl-5-azacytosine (Ara-AC), a dCyd antagonist which inhibits DNA synthesis, in combination with 5-fluorouracil (FUra) in two human colon cancer cell lines, HCT 116 and SNU-C4. Clonogenic assays done following sequential or concurrent 24-hr exposures to Ara-AC and FUra showed that the sequence Ara-AC followed by FUra resulted in more than additive lethality in the HCT 116 cell lines and additive lethality in the SNU-C4 cells. In contrast, the reverse sequence, FUra followed by Ara-AC, was antagonistic in both cell lines. A similar interaction between FUra and 1-beta-D-arabinofuranosylcytosine (Ara-C) was evident in HCT 116 cells; at concentrations which individually diminished viability by 34 and 62%, respectively, the sequence Ara-C followed by FUra decreased viability by 97%. Pulse-labeling with [3H]dUrd showed profound inhibition of DNA synthesis by the sequence Ara-AC followed by FUra, with over 90% inhibition lasting for up to 48 hr following Ara-AC exposure. When FUra preceded Ara-AC, however, earlier recovery from inhibition of DNA synthesis occurred. FUra pretreatment did not appreciably alter the quantity or distribution of [3H]Ara-AC or [3H]Ara-C nucleotides after a 4- to 6-hr exposure. Pre-exposure to FUra decreased Ara-AC incorporation into DNA by 37 and 73% at 6 hr in HCT 116 and SNU-C4, respectively. FUra pretreatment also inhibited Ara-C incorporation into DNA by over 50% at 6 and 24 hr. The antagonism of Ara-AC and Ara-C cytotoxicity by FUra pretreatment can thus be explained by diminished incorporation of the dCyd analogs into DNA resulting from inhibition of DNA synthesis by FUra-induced dTTP and dCTP depletion. In contrast, when Ara-AC or Ara-C preceded FUra, their incorporation into DNA was not disturbed, and prolonged inhibition of DNA synthesis was observed.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1991

Cardiac complications observed in elderly patients following 2'-deoxycoformycin therapy.

Deoxycoformycin (dCF) is an investigational nucleoside with significant activity in hairy cell leukemia, cutaneous T-cell lymphoma, and chronic lymphocytic leukemia. During a 4-year period, 11 patients have experienced cardiac events as a complication of dCF therapy under NCI sponsorship. The cases are presented and recommendations for the administration of dCF to patients with pre-existing heart disease are made.

Aged↗

PubMed1991

Clinical use of thymidine as a rescue agent from methotrexate toxicity.

Thymidine has been available for clinical research as a rescue agent since 1978 under sponsorship of the Division of Cancer Treatment, National Cancer Institute. Renal insufficiency following administration of high dose methotrexate results in prolonged exposure to toxic concentrations of drug. Thymidine has been used in conjunction with leucovorin and alkaline hydration to protect patients with acute renal dysfunction from life-threatening methotrexate toxicity. The outcome of eight cases in which thymidine was released under the special exception mechanism to treat patients who developed acute renal failure following methotrexate are reported. The clinical trials using thymidine in combination with methotrexate in patients with normal renal function are also reviewed.

Adolescent↗

PubMed1991

Modulation of cytosine arabinoside toxicity by 3-deazauridine in a murine leukemia model.

3-Deazauridine (DAUrd), a competitive inhibitor of CTP synthetase, inhibits both RNA and DNA synthesis. Murine leukemia cells resistant to cytosine arabinoside (ara-C) due to a deletion of deoxycytidine kinase are collaterally sensitive to DAUrd, which inhibits the de novo production of CTP and hence results in dCTP depletion. We evaluated DAUrd in combination with the palmitate derivative of ara-C (palmO-ara-C) in mice bearing L1210 leukemia cells with a subpopulation resistant to ara-C. Both simultaneous administration and a sequential schedule of palmO-ara-C at its maximally tolerated dose (MTD), followed by DAUrd treatment, failed to produce a therapeutic gain. We also studied whether non-toxic doses of DAUrd (15-250 mg/kg i.p. at h 0 and 6 on days 4 and 8) could modulate the antileukemic activity of palmO-ara-C (7.5-120 mg/kg i.p. at h 3 on days 4 and 8). The addition of DAUrd produced a modest (but statistically significant) prolongation of life span and a further 2-log10 reduction in tumor burden compared to the same dose of palmO-ara-C alone, and resulted in long-term survivors in five of 30 treated animals. Two-dimensional dose-response analysis of the survival data indicated a positive drug interaction (p less than or equal to 0.01) when the dosage of DAUrd was modeled to reflect an apparent threshold effect. Cyclopentenyl cytosine (CPE-C; 0.625-2.5 mg/kg i.p. at h 0 and 6 on days 4 and 8), a more potent inhibitor of CTP synthetase, was also given with palmO-ara-C. This combination resulted in an additional 2-6 log10 units of cell kill and occasional long-term survivors at palmO-ara-C dosages that alone resulted in no more than 2 log10 units of cell kill and no long-term survivors. However, DAUrd and CPE-C given with palmO-ara-C increased host toxicity, compromising the tolerable dose of palmO-ara-C. Single-agent palmO-ara-C given at its MTD produced a similar reduction in tumor burden and increase in life span compared to the highest palmO-ara-C dose that could be given in combination with either modulator.

3-Deazauridine↗

PubMed1991

A pilot study of interferon alfa-2a in combination with fluorouracil plus high-dose leucovorin in metastatic gastrointestinal carcinoma.

Thirty-one assessable patients with metastatic adenocarcinoma of the gastrointestinal tract were entered onto a pilot study designed to assess the impact of recombinant interferon alpha-2a (rIFN alpha-2a) on the toxicity and pharmacokinetics of fluorouracil (5-FU) and leucovorin (LV). Patients received an initial cycle of 5-FU (370 or 425 mg/m2/d) with LV (500 mg/m2/d) for 5 days. If tolerated, the patient received the same dose of 5-FU/LV for the second cycle on days 2 to 6, with rIFN alpha-2a at 5 x 10(6) or 10 x 10(6) U/m2/d on days 1 to 7, or with 3 x 10(6) U/m2/d on days 1 to 14. In 26 matched cycles, rIFN alpha-2a administration was associated with an increased incidence of dose-limiting mucositis and diarrhea and a significantly lower median platelet nadir; rIFN alpha-2a did not significantly affect the median WBC or granulocyte nadir. Dose-limiting toxicity occurred in all six patients entered at 425 mg/m2/d of 5-FU/LV within two cycles. The majority of patients treated with 370 mg/m2/d of 5-FU/LV and 10 x 10(6) U/m2/d rIFN alpha-2a experienced grade 3 to 4 mucositis and diarrhea, whereas patients receiving 3 x 10(6) and 5 x 10(6) U/m2/d rIFN alpha-2a had acceptable toxicity. Administration of rIFN alpha-2a was associated with a dose-dependent decrease in 5-FU clearance. The increase in the area under the 5-FU concentration-time curve (AUC) was 1.3-fold and 1.5-fold in patients receiving 5 x 10(6) and 10 x 10(6) U/m2/d rIFN alpha-2a, respectively. Thus, the increase in 5-FU toxicity with rIFN alpha-2a may be explained by alterations in 5-FU pharmacokinetics. In 22 patients without prior 5-FU therapy, three complete (13.6%) and seven partial (31.8%) responses were seen, for an overall response rate of 45.4% (95% confidence interval, 24.4% to 67.8%). Since the 5 x 10(6) U/m2/d dose of rIFN alpha-2a increased the 5-FU drug exposure and was associated with acceptable toxicity, we recommend its further evaluation as given on days 1 to 7 in combination with 5-FU 370 mg/m2/d, with high-dose LV given on days 2 to 6.

Adenocarcinoma↗

PubMed1991

Adjuvant treatment of node-positive colon carcinoma with levamisole and 5-fluorouracil.

Levamisole, an anthelminthic drug, has been studied clinically as a nonspecific immunomodulator in the adjuvant treatment of a variety of malignancies. Over a decade ago, a small, non-randomized trial of levamisole versus no further therapy after primary surgical resection of colorectal carcinoma showed a survival benefit for the cohort receiving levamisole, particularly among patients with transmural penetration or positive regional nodes. Since this seminal trial, numerous adjuvant trials of levamisole alone or in combination with 5-fluorouracil have been conducted. Two randomized, placebo-controlled trials failed to show a benefit of levamisole in patients with node-positive colon carcinoma. Three adjuvant trials have shown a therapeutic benefit of levamisole plus 5-fluorouracil compared to observation. Adjuvant therapy with levamisole and 5-fluorouracil reduced the risk of cancer recurrence by 41% and the death rate by 33% in patients with node-positive disease. The results of this trial have defined a new standard of care in the treatment of patients with Stage C colon carcinoma.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1991

Antimetabolites.

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Animals↗

PubMed1991

Current treatment approaches in colorectal cancer.

Fluorouracil (5-FU) is still the mainstay of adjuvant treatment for colorectal cancer. Two trials have shown a disease-free and overall survival benefit for 5-FU combined with levamisole in patients with node-positive colon cancer. This regimen is fairly well tolerated and devoid of long-term sequelae, and is now considered standard treatment for node-positive colon cancer. One trial showed a modest improvement in disease-free survival for the semustine/vincristine/5-FU combination; the leukemogenicity and renal toxicity caused by semustine have prevented this regimen from being adopted. Although administering 5-FU directly into the portal vein may improve disease-free survival, most trials have failed to demonstrate a reduction in the incidence of hepatic metastases. This technique, therefore, remains investigational. Several trials in rectal cancer show an advantage for 5-FU combined with semustine and radiation therapy in terms of disease-free survival, overall survival, or both; the contribution of semustine has been questioned and is currently being investigated. In patients with metastatic disease, hepatic arterial infusion of floxuridine produces a higher objective response rate than intravenous administration, but has not resulted in a survival benefit; hepatobiliary toxicity limits the duration of therapy. Biochemical modulation of 5-FU with leucovorin increases the response rate produced by 5-FU alone; a survival benefit has also been observed. N-(phosphonacetyl)-L-aspartate has shown initial promise in combination with high-dose 5-FU infusions. Among the many new drugs tested, only tauromustine seems worthy of further study.

Antineoplastic Combined Chemotherapy Protocols↗