Phase I and pharmacologic study of the novel indoloquinone bioreductive alkylating cytotoxic drug E09.

BACKGROUND: A novel bioreductive alkylating indoloquinone compound, E09 [3-hydroxy-5-aziridinyl-1-methyl-2-(1H-indole-4,7-indione)- prop-F128b-en-alpha-ol], has been shown to have distinct antitumor activity against solid tumors, excellent activity under hypoxic conditions, but no notable bone marrow toxicity in preclinical models. PURPOSE: A phase I study was carried out to determine the toxicity, maximum tolerated dose (MTD), pharmacology, and antitumor response of E09. METHODS: E09 was administered as a 5-minute intravenous infusion once every 3 weeks to 32 patients with solid tumors. The starting dose of 2.7 mg/m2 was one tenth of the mouse equivalent of lethal dose to 10% of animals (MELD10). Dose was escalated by 100% until the area under the curve (AUC) at the MELD10 was reached, following a Fibonacci-like schedule. The pharmacokinetics of E09 and its metabolite E05A with an open aziridine ring was determined using a new high-pressure liquid chromatographic method and noncompartmental calculation of kinetic parameters. The sigmoid Emax model was used to fit pharmacokinetic parameters to toxicity. The renal function and proteinuria were quantitated and were further evaluated by determining renal clearance ratios of immunoglobulin G (IgG) to albumin and pancreatic amylase to salivary amylase. RESULTS: The 32 patients were treated with a total of 85 assessable courses of E09. The dose-limiting toxicity was proteinuria, which was accompanied by sodium and water retention. All symptoms were reversible on day 15 except in two patients, who developed acute renal failure. The ratios of IgG to albumin and pancreatic amylase to salivary amylase suggested a loss of glomerular negative charge consistent with a minimal change glomerulopathy. The pharmacokinetics of E09 showed its rapid elimination from the central compartment but with wide interpatient variation in the overall disposition of the drug. Total plasma clearance of E09 ranged from 3.2 to 24 L/min. The AUC of E09 was linearly related to the administered dose. The relationship between the AUC and proteinuria was best fitted by the sigmoid Emax model (r = .98). In two patients with adenocarcinoma of unknown primary site and in a third patient with bile duct cancer, a partial response was observed. CONCLUSIONS: The MTD of E09 was determined to be 27 mg/m2. The standard approach of drug administration is considered unsuitable because of potential renal toxicity and wide variability in the pharmacokinetics of E09. Individual dose adjustments based on plasma concentration measurements are recommended to combine maximally achievable exposure with tolerable toxicity.

Histologic conversion in the non-Hodgkin's lymphomas.

Between July 1, 1971 and December 31, 1978, 150 patients with favorable subtypes of non-Hodgkin's lymphoma [nodular poorly differentiated lymphocytic (NLPD), nodular mixed, or diffuse well differentiated lymphocytic] were entered into prospective randomized clinical trials at Stanford University. Treatments included involved field, total lymphoid, or whole body irradiation, single alkylating agent chemotherapy, combination chemotherapy with cyclophosphamide, vincristine and prednisone (CVP) or with cyclophosphamide, vincristine, procarbazine, and prednisone (C-MOPP), or various combinations of chemotherapy and irradiation. The initial complete response rate (CR) was 79%. Among patients who achieved a CR, 31% later relapsed. There were 78 patients who either failed to achieve a CR or achieved a CR and later relapsed. Histologic conversion (change from initially favorable to an unfavorable subtype of non-Hodgkin's lymphoma) was documented in 22/78 patients (28%). However, the actuarial risk for conversion was actually much greater (60% at 8 yr). The median time to documentation of conversion was 51 mo. The most common type of histologic conversion was from NLPD to diffuse histiocytic lymphoma. Documented histologic conversion was often associated with a more aggressive clinical behavior of the lymphoma, and the median survival after conversion was less than 1 yr. However, those patients who achieved a CR after conversion had a more favorable outcome (actuarial survival 75% at 5 yr). No specific risk factors predictive of histologic conversion could be identified.

Response of glutamine metabolism to glutamine-supplemented parenteral nutrition.

BACKGROUND: Increasing evidence suggests that glutamine is important for the function of many organ systems and supports the use of glutamine-enriched total parenteral nutrition (TPN) during severe illness. However, the effect of prolonged glutamine supplementation on glutamine kinetics has not been studied. OBJECTIVE: We investigated the effect of 8-10 d of TPN enriched with glutamine dipeptides on glutamine kinetics. DESIGN: Twenty-three preoperative patients were randomly allocated to receive either TPN enriched with glutamine dipeptides (60 micromol glutamine*kg body wt(-1)*h(-1)) or isonitrogenous, isoenergetic, glutamine-free TPN. A primed, continuous, 6-h intravenous infusion of L-[5-(15)N]glutamine and L-[1-(13)C]leucine was given before (baseline) and 8-10 d after the TPN solutions were administered. Baseline measurements were performed after a 40-h administration of a standard solution of glucose and amino acids (no glutamine). RESULTS: Glutamine-enriched TPN increased the total appearance rate of glutamine (P: < 0.05) but did not inhibit or increase the endogenous appearance rate. The standard TPN solution also increased the glutamine appearance rate (P: < 0.05), but the change was much smaller than in the glutamine-supplemented group (P: < 0.01). The plasma glutamine concentration did not rise significantly during either treatment, suggesting increased tissue glutamine utilization, especially in the glutamine-supplemented group. CONCLUSION: In view of the enhanced glutamine requirements in response to trauma and disease by tissues such as those of the gut, the immune system, and the liver, increased glutamine availability during glutamine-enriched TPN may be beneficial preoperatively in patients with gastrointestinal disease.

The effect of hydralazine on the tumor cytotoxicity of the hypoxic cell cytotoxin RSU-1069: evidence for therapeutic gain.

The effect of the vasodilator hydralazine on both the tumor and systemic toxicity of RSU-1069 has been evaluated in C57B1 mice bearing Lewis lung tumors. The results obtained indicate that both hydralazine and RSU-1069 are cytotoxic to the Lewis lung tumor on their own. However, administration of hydralazine (5 mg/kg PO) at times up to either 3 hr before or 3 hr after RSU-1069 (0.1 mg/g IP) results in a level of cell killing greater than expected from additive effects. This potentiation by hydralazine was observed with doses of RSU-1069 from 0.01 to 0.1 mg/g. The results obtained using excision assays were confirmed using in situ growth delay as the endpoint. Growth delay (+/- s.e.m.) values for tumors to double in volume of 1.5 (+/- 1.2), 2.0 (+/- 1.3) and 6.0 (+/- 0.9) were obtained for hydralazine (5 mg/kg PO) alone, RSU-1069 (0.1 mg/g IP) alone and for hydralazine administered at the same time as RSU-1069 respectively. In contrast to the potentiating effect of hydralazine on the tumor cytotoxicity of RSU-1069, it had no significant effect on the systemic toxicity of RSU-1069 as measured by LD50/30d. No detailed studies to examine the mechanism responsible for the potentiation of tumor cytotoxicity have been performed in the present study. However, the results obtained would be consistent with previous reports that vasodilators such as hydralazine can selectively reduce tumor blood flow and thus oxygenation. Such reduced tumor oxygenation would increase the cytotoxic effects of RSU-1069 which is known to be more toxic to cells at reduced oxygen levels.

Potentiation of the tumor cytotoxicity of melphalan by vasodilating drugs.

Previous studies have shown that several vasoactive drugs can selectively reduce blood flow and increase hypoxia in experimental tumor systems. Our studies with one such agent, the vasodilator hydralazine, have clearly demonstrated that it can increase the tumor cytotoxicity of drugs which are known to be more toxic under hypoxic conditions. We have now extended our investigations to determine whether such selective reductions in tumor blood flow induced by hydralazine can increase the tumor cytotoxicity of other classes of cancer chemotherapeutic drugs. Our initial studies have involved the alkylating agent melphalan. Administration of hydralazine (5 mg/kg IP) at various times before or after melphalan results in increased tumor cytotoxicity in the Lewis lung carcinoma. An enhancement factor of between 2 and 3 was obtained in this tumor system. Similar results are observed if the vasodilator cadralazine is used. In contrast to the enhancement of the tumor cytotoxicity of melphalan by hydralazine, systemic toxicity is only increased by a factor of 1.2. Therefore, therapeutic gain may accrue from the use of vasodilating agents in combination with melphalan. Studies using spheroids to establish the mechanism responsible for the enhanced tumor cytotoxicity indicate that both hypoxia and pH can influence melphalan toxicity.

Histological evidence for nonperfused vasculature in a murine tumor following hydralazine administration.

The effect of the vasodilator hydralazine on tumor vascular function has been evaluated in C3H/He mice bearing subcutaneously implanted SCCVII squamous cell carcinoma. Changes in microregional perfusion following hydralazine administration were observed using a double fluorescent staining technique. Hydralazine-induced alterations in tumor blood flow were measured using laser Doppler flowmetry. The results obtained indicate that hydralazine causes a dose-dependent reduction in functional tumor vasculature implying complete flow stasis and/or vascular collapse in some vessels. Fifteen minutes after a dose of 10 mg/kg intravenously, perfusion in 36 +/- 5% (SEM) of tumor vessels was completely abolished. In addition to cessation of perfusion in individual vessels, hydralazine eliminated flow in large patches of vasculature distributed non-uniformly throughout the tumor. Hydralazine (10 mg/kg i.v.) resulted in a 67 +/- 5% (SEM) reduction in tumor red blood cell (RBC) flow as measured by laser Doppler techniques. The mean number of moving red blood cells declined by 35 +/- 8%, suggesting a reduction in microvascular volume. These results support the hypothesis that following hydralazine administration, perfusion stops completely in some blood vessels probably as a result of vascular collapse or flow stasis.

The management of carcinoma of the anal canal by external beam radiotherapy, experience in Vancouver 1971-1988.

From 1971 to 1988 72 cases of carcinoma of the anal canal were treated by external beam radiotherapy, most commonly by 5000 cGy in 20 fractions given over 4 weeks. The actuarial survival at 5 years was 66% and the disease specific survival 78%. Nine patients had inguinal node metastases at diagnosis; their 5-year disease specific survival was 75%. 63 patients were inguinal node negative at presentation; their 5-year disease specific survival was 78%, by UICC 1987 staging: T1 71%, T2 88%, T3 41%, T4 42%. 17 patients developed local recurrence; 10 were suitable for abdominoperineal (AP) resection which was successful in 7. The probability of local control was related to T stage. 13 patients were left with a colostomy because of recurrence, 2 had a colostomy for radiation damage and 4 had their local recurrence managed palliatively, without a colostomy. As a result, 53 of the 72 patients (74%) were left with a functional anus. Severe late complications occurred in 6 (8%).

Glutamine: the pivot of our nitrogen economy?

Glutamine serves as a shuttle of useful nontoxic nitrogen, supplying nitrogen from glutamine-producing (eg, muscle) to glutamine-consuming tissues. True production rates of glutamine are difficult to measure, but probably are less than 60 to 100 g/d for a 70-kg man. During catabolic stress increased amounts of glutamine are released from muscle, consisting of protein derived glutamine, newly synthesized glutamine, and glutamine losses from the intramuscular free pool. The large and rapid losses of free muscle glutamine are difficult to restore, presumably as a result of disturbances in the Na+ electrochemical gradient across the cell membrane. Whereas increased amounts of glutamine are released from muscle, glutamine consumption by the immune system (liver, spleen) also is enhanced. Thus, during catabolic stress changes occur in the flow of glutamine between organs. These changes are not necessarily reflected by alterations in the whole-body appearance rate of glutamine. In contrast with the gut, where glutamine is taken up in a concentration dependent manner, the immune system actively takes up glutamine despite decreased plasma concentrations. Supplementation with glutamine influences uptake by both the gut and the immune system, as evidenced by increased mucosal glutamine concentrations and gut glutathione production. There is evidence suggesting that this improves gut barrier function. Although the benefit of glutamine supplementation is most evident from experimental studies, clinical studies on the effect of glutamine do exist and suggest that glutamine supplementation has beneficial effects with regard to patient outcome.

'Moderate-risk' ovarian cancer (stage I, grade 2; stage II, grade 1 or 2) treated with cisplatin chemotherapy (single agent or combination) and pelvi-abdominal irradiation.

We placed patients with invasive epithelial ovarian cancer into four distinct prognostic groups: 'low', 'moderate', 'high' and 'extreme' risk. The 'moderate-risk' group contained all residual negative, stage I and II patients with two exceptions: stage Ia or b, grade 1 cancers and grade 3 cancers. They were treated with primary surgery, usually including bilateral salpingo-oophorectomy, hysterectomy and omentectomy. Chemotherapy was then given (cisplatin at 100 mg m-2 every 2 weeks for three cycles) followed by pelvi-abdominal irradiation (2250 cGy in 10 fractions to the pelvis and 2250 cGy in 22 fractions to the whole abdomen including pelvis). An early cohort with ascites or positive washings instead received six cycles of cisplatin and cyclophosphamide at 75 mg m-2 and 600 mg m-2 every 4 weeks with the same pelvi-abdominal irradiation sandwiched between cycles 3 and 4. One-hundred and nine patients were treated between November 1983 and December 1989. Median follow-up was 4.7 years (range 0.7-9 years). The 5-year actuarial overall and failure-free survivals were 81% and 76%, respectively. Chronic toxicity, although usually minor, included 15% with peripheral neuropathy or ototoxicity and 23% with chronic abdominal complaints. Our combined-modality results are similar to those obtained by other centers utilizing either pelvi-abdominal irradiation alone or cisplatin-based chemotherapy alone.

Cimetidine improves GFR-estimation by the Cockcroft and Gault formula.

In some patients with renal disease 24-hour cimetidine aided creatinine clearances cannot equal GFR even after administration of the maximum daily dose of cimetidine. Short duration cimetidine aided creatinine clearances can equal GFR but are inconvenient for clinical use and can be inaccurate due to incomplete urine collection. We studied how accurately GFR can be estimated without the need to collect urine, by applying the Cockcroft and Gault formula (CCock) on a single plasma creatinine concentration, after oral administration of 3 x 800 mg cimetidine during the preceding 24 hours. GFR was measured as standard clearance, using continuous infusion of 125I-iothalamate. Nineteen patients with various renal diseases, plasma creatinine < 180 mumol/l and body mass index between 15 and 30 kg/m2 were included. After cimetidine administration, plasma creatinine values remained stable for 6 hours, despite rapidly decreasing plasma cimetidine values during the same period, in all 15 patients with GFR > 40 ml/min/1.73 m2. Tubular creatinine secretion was blocked completely in 14 of them. With cimetidine both accuracy and precision of the Cockcroft clearance improved: the mean (+/- SD) ratio of CCock to GFR decreased from 1.28 (+/- 0.21) to 0.98 (+/- 0.11) (p < 0.001) and the standard deviation of the difference (CCock-GFR) decreased from 9.23 to 7.07 ml/min/1.73 m2 (p < 0.05). With cimetidine the Cockcroft clearance correlated well with GFR (r = 0.974, p < 0.001) and this was as good as the correlation, between GFR and a 4-hour standard creatinine clearance (r = 0.972, p < 0.001). In conclusion, with a minimum of inconvenience, this method provides the clinician with accurate information on GFR for the outpatient follow-up of patients with a mild-to-moderate decrease in renal function, provided that no gross discrepancy between total bodyweight and muscle mass is present.