Novel Direct Curve Comparison Metrics for Bioequivalence

Purpose. The object of this work was to devise four new direct curve comparison (DCC) metrics and examine each metric's distribution properties and performance characteristics. Methods. DCC metrics, Cmax, and AUCi were calculated from two bioequivalence studies of three sustained release carbamazepine formulations, where a range of profile similarity was observed. DCC metric values and their confidence intervals were compared to Cmax and AUCi. Results. The DCC metrics , _m, _a, and _s exhibited more favorable distributions than Cmax and AUCi ratios, which were frequently skewed. The DCC metrics performed differently than Cmax and AUCi ratios in profile comparisons due to the nature of the DCC metrics. Unlike Cmax and AUCi, the DCC metrics utilize all data points to directly compare entire profiles. Each DCC metric appears to measure exposure in a single assessment. Possible bioequivalence acceptance criteria are: 1.40, _m 0.35, _a 0.27, and _s 0.102. Conclusions. These DCC metrics, particularly p_m, are promising bioequivalence metrics for exposure.     

Should the acetylator phenotype be determined when prescribing hydralazine for hypertension?

Summary The role of acetylator phenotype in determining the response to hydralazine when it was added to diuretic and -blocker at doses not exceeding 200 mg daily was examined in 57 hypertensive patients. 81% of rapid acetylators needed 200 mg hydralazine daily compared to 38% of slow acetylators (p<0.01). Despite higher doses of hydralazine the blood pressure was controlled in only 27% of rapid acetylators compared to 65% of slow acetylators (p<0.02). The relation of acetylator phenotype to blood pressure response was statistically independent of initial blood pressure, age, sex, body weight and serum creatinine (p<0.005). Current recommendations on hydralazine dosage are unsatisfactory for the 40% of hypertensive patients who are rapid acetylators. We suggest measurement of the acetylator phenotype in patients who respond incompletely to 200 mg hydralazine daily. About 70% of these patients will be rapid acetylators in whom the dose of hydralazine can be increased safely.     

Arylamine <Emphasis Type="Italic">N</Emphasis>-acetyltransferase 2 slow acetylator polymorphisms in unrelated Iranian individuals

Objective To determine the frequency of mutations at the polymorphic gene coding for arylamine N-acetyltransferase 2 (NAT2, EC 2.3.1.5) and NAT2 genotypes associated with slow acetylation in healthy Iranian individuals.Methods The polymorphisms in the NAT2 gene from 88 unrelated healthy subjects (48 men/40 women) from the general Tehran population were discriminated using polymerase chain reaction (PCR) with allele-specific primers (341 C>T) and PCR-restriction fragment length polymorphism analysis (481 C>T, 590 G>A, and 857 G>A).Results Frequencies of the studied polymorphisms showed the most common alleles to be NAT2*4 (0.43) and NAT2*5, 481 C>T (0.32), followed by NAT2*6 (0.19) and NAT2*7 (0.06), previously referred to as WT, M1, M2, and M3, respectively. The most prevalent genotypes were NAT2*4/*5 [(31.8%; 95% confidence interval (CI): 29–34%] and *4/*4 (18.2%; 95% CI: 16–21%). When grouped according to the expected phenotypical effects, the resulting genotypes revealed the significant prevalence of the subjects with slow (32.9%) and intermediate (48.9%) acetylation status compared with wild-type rapid (18.2%) acetylators (P<0.01).Conclusions The overall allele pattern and acetylator status distribution in Iranians displayed the considerable prevalence of slow acetylators over rapid acetylators, similar to those of Caucasians except for a minor difference observed in the frequency of the NAT2*7 allele. Nucleic acid testing for common NAT2 mutations might be a potentially useful tool for an accurate phenotype interpretation and identification of Iranian individuals at risk.     

Effects of bisoprolol on blood pressure,serum lipids and HDL-cholesterol in essential hypertension

Summary Fifty patients with essential hypertension WHO Grades I–II have been treated for 3 months with bisoprolol, a new selective betablocker, in doses up to 40 mg once daily. Forty-three patients reached the preset target diastolic blood pressure of 90 mmHg on a mean daily dose of 16.8 mg bisoprolol. There was no effect on serum lipids and HDL-cholesterol during the study. The side-effects were mild and were those usually associated with beta-blocking therapy.     

Correlation of acetylator phenotype with peripheral, autonomic and central neuropathy in Northern Indian non-insulin-dependent diabetes mellitus patients

Objectives: Genetic susceptibility to diabetic neuropathy has been suspected and tentatively explored; however, diabetic autonomic and central neuropathies are poorly investigated areas. Previous trials correlating types of diabetes and diabetic neuropathy with acetylator dimorphisms have not been conclusive. The present study was designed to test peripheral neuropathy, autonomic neuropathy and integrity of central conduction pathways in patients of non-insulin-dependent diabetes mellitus (NIDDM), and to correlate the findings with the acetylator phenotype. Methods: Twenty-six patients of NIDDM with stable glycaemic control and 11 age- and sex-matched control subjects were recruited, clinically examined and investigated with glycaemic and lipid profile, renal function tests, nerve conduction studies (sensory and motor), auditory brain stem evoked responses (ABERs) and somatosensory evoked potentials (SEPs). Acetylator status of the subjects was determined by sulphadimidine test. Results: Out of 26 NIDDM patients, eight (30.7%; group 1A) were slow acetylators and 18 (69.3%; group 1B) were fast acetylators. The distribution of slow and rapid acetylators in both the groups was similar. Glycaemic and lipid profiles and 24-h urinary albumin excretion in groups 1A and 1B were also similar. Motor nerve conduction velocity, latency of F wave, sensory nerve conduction and amplitudes of sensory nerve action potentials were not different between fast and slow acetylator NIDDM patients. On testing for ABERs, there were no statistically significant differences in peak latencies of waves I, III and V; interpeak latencies (IPLs) I–III, III–V and I–V; amplitude of waves I, III and V on both sides between NIDDM patients and controls. However, peak latencies of wave III (P < 0.01), wave V (P < 0.005), IPLs I–III and I–V (P < 0.005), IPLs III–V (P < 0.05), and amplitudes of wave I (P < 0.05) and wave V (P < 0.05) on the left side were significantly different in slow acetylator NIDDM patients. Increase on the right side for the same group was statistically significant for IPLs I–III and I–V (P < 0.05). SEPs showed no statistically significant difference between NIDDM patients and controls, and slow and fast acetylator NIDDM patients. Conclusions: No significant association of acetylator status with peripheral neuropathy in NIDDM subjects was observed in the present study. However, central neural conduction, primarily tested by ABERs, was significantly delayed in slow acetylators compared with fast acetylator NIDDM patients. Hence, there may be a predisposition to neuropathy in this group of patients, and such a predisposition may be better detected by studying central rather than peripheral nervous conduction pathways in NIDDM patients. Received: 29 September 1998 / Accepted in revised form: 9 February 1999     

Studies on hydralazine

Summary After oral administration of a single 50 mg dose of hydralazine (Apresoline^®), the serum half-life (T1/2) and bioavailability (AUC_0–) were assessed in 16 healthy volunteers. The half-life was 2.57±0.14 h (S.E.) in 10 slow acetylators of sulphadimidine, and 2.18±0.15 h in 6 fast acetylators (difference not statistically significant). AUC_0– was significantly higher in slow acetylators, at 1.04±0.10 µg·hour·ml^–1, compared to 0.66±0.12 µg·hour·ml^–1 in the fast acetylators (p<0.025). Treatment with Apresoline^® 25 mg tid produced minimum serum concentrations at steady-state of 57.3±7.3 ng·ml^–1 and 33.4±4.2 ng·ml^–1 in 8 slow and 5 fast acetylators, respectively (p<0.05). The corresponding maximum concentrations were 228.8±20.3 ng·ml^–1 and 147.6±15.0 ng·ml^–1 in slow and fast acetylators, respectively (p<0.025). First-pass metabolism of hydralazine could explain the difference in bioavailability of the drug between fast and slow acetylators, without any corresponding difference in the elimination rate of the drug in the post-distributive phase.     

High dose transdermal nicotine therapy for heavy smokers: safety,tolerability and measurement of nicotine and cotinine levels

Transdermal nicotine has been shown to relieve nicotine withdrawal and to double smoking cessation rates compared to placebo in clinical trials. A 21 or 22 mg/day dose provides a steady state serum nicotine that is less than obtained from smoking. Limited information is available about higher nicotine patch doses. To define better the optimal dosing of nicotine patch therapy, we undertook an open-label study to determine the safety and tolerability of 44 mg/day dose for smoking cessation in subjects smoking 20 cigarettes per day. Forty smokers received 44 mg/day of transdermal nicotine for 4 weeks followed by 4 weeks of 22 mg/day. Of the 40 subjects enrolled, 38 (95%) completed the 4 weeks of 44 mg patch therapy and 36 (90%) completed the entire 8 weeks of patch therapy. Non-smokers at week 4 had a mean serum nicotine level of 23.4±11.7 ng/ml and cotinine of 152.2±87.3 ng/ml. Percent replacement was calculated by dividing the steady state level at week 4 by the baseline level while the subjects were smoking their usual number of cigarettes. Percent nicotine replacement for non-smokers at week 4 (while on 44 mg nicotine patch) averaged 158%±108.4, and for cotinine was 112.0±73.8. For nicotine, 33% of non-smokers at week 4 had 100% nicotine replacement and for cotinine 63% 100% replacement. Biochemically confirmed point prevalence smoking cessation rates were 65% and 55% at weeks 4 and 8 of patch therapy, respectively, and self-reported smoking cessation at 3 months was 50%. The most common effect was skin irritation at the patch site. A single subject was admitted for myocardial infarction following step-down from 44 to 22 mg of replacement nicotine. The subject was not smoking and the adverse event was deemed to be not related to the patch therapy. Sleep complaints were reported in 33% of subjects during the 44 mg phase. Other complaints were infrequent. We conclude that 44 mg per 24-h nicotine patch therapy in heavy smokers is safe, tolerable, and without significant adverse events.     

A simple high pressure liquid chromatographic method for the determination of fluorouracil to monitor patients on regional infusion for hepatic metastases

A rapid and sensitive high pressure liquid chromatographic method has been developed for the routine monitoring in serum of the antineoplastic agent fluorouracil, during continuous intraportal administration. Serum spiked with internal standard, bromouracil, was gently shaken for 10 min with ethylacetate at an acidic pH. The evaporated extract was dissolved in the mobile phase containing potassium phosphate buffer. Assays were performed at ambient temperature on a Chrompack LiChrosorb RP 18 column (2×100×3.0 mm) equipped with a guard column. The retention time of fluorouracil was 2–6 min. The calibration curve was linear from 25 to 2,000 ng/ml. The coefficient of variation was 1.6% for within-run precision and 2.9% for day-to-day precision. The mean recovery of fluorouracil was 57%.     

Teratology study of two isoglutamine derivatives

The embryotoxicity and teratogenicity of N-phthalyl isoglutamine (2), a metabolite of thalidomide, and of K-2004-1c, 2-(bicyclo[2.2.1]heptane-2-endo-3-endodicarboximido)-glutaric acid 1-amide (4), the main metabolite of the test compound K-2004 (proposed generic name: biglumide), a nonteratogenic congener of thalidomide, have been investigated in mice and rats. Whereas 2 proved to be highly teratogenic and embryotoxic, 4 showed none of these activities in the dose range from 50 to 400 mg/kg.     

Activity of Carbetimer in a human tumor cloning system

Summary The antitumor activity of Carbetimer was tested against 171 patient's tumors in a human tumor cloning system. Sixty-seven tumor specimens had adequate growth to be considered evaluable. In 21 specimens survival of tumor colony forming units was 50% that in control plates. Antitumor effect was most impressive in carcinomas of the breast, ovary, and lung. This information will be useful in planning disease oriented Phase II trials.Presented in part at the Annual Meeting of the American Society of Clinical Oncology, May 23–24, 1983.     

NAT2 genotype guided regimen reduces isoniazid-induced liver injury and early treatment failure in the 6-month four-drug standard treatment of tuberculosis: A randomized controlled trial for pharmacogenetics-based therapy

Objective

This study is a pharmacogenetic clinical trial designed to clarify whether the N-acetyltransferase 2 gene (NAT2) genotype-guided dosing of isoniazid improves the tolerability and efficacy of the 6-month four-drug standard regimen for newly diagnosed pulmonary tuberculosis.

Methods

In a multicenter, parallel, randomized, and controlled trial with a PROBE design, patients were assigned to either conventional standard treatment (STD-treatment: approx. 5 mg/kg of isoniazid for all) or NAT2 genotype-guided treatment (PGx-treatment: approx. 7.5 mg/kg for patients homozygous for NAT2*4: rapid acetylators; 5 mg/kg, patients heterozygous for NAT2*4: intermediate acetylators; 2.5 mg/kg, patients without NAT2*4: slow acetylators). The primary outcome included incidences of 1) isoniazid-related liver injury (INH-DILI) during the first 8 weeks of therapy, and 2) early treatment failure as indicated by a persistent positive culture or no improvement in chest radiographs at the8th week.

Results

One hundred and seventy-two Japanese patients (slow acetylators, 9.3 %; rapid acetylators, 53.5 %) were enrolled in this trial. In the intention-to-treat (ITT) analysis, INH-DILI occurred in 78 % of the slow acetylators in the STD-treatment, while none of the slow acetylators in the PGx-treatment experienced either INH-DILI or early treatment failure. Among the rapid acetylators, early treatment failure was observed with a significantly lower incidence rate in the PGx-treatment than in the STD-treatment (15.0 % vs. 38 %). Thus, the NAT2 genotype-guided regimen resulted in much lower incidences of unfavorable events, INH-DILI or early treatment failure, than the conventional standard regimen.

Conclusion

Our results clearly indicate a great potential of the NAT2 genotype-guided dosing stratification of isoniazid in chemotherapy for tuberculosis.     

A randomized phase II study of two schedules of bryostatin-1 (NSC339555) in patients with advanced malignant melanoma: A National Cancer Institute of Canada Clinical Trials Group study

Purpose: This study addressed theefficacy and toxicity of the novel compoundBryostatin-1 (NSC 339555), a novel agentwith antineoplastic, hematopoietic andimmunomodulatory activity in a variety ofin vitro and in vivo systems. Patients and methods: This phase IIstudy randomly assignedchemotherapy-naïve patients withuntreated metastatic melanoma andmeasurable disease to two schedules oftreatment: Arm A, 25 g/m²bryostatin-1 given as a 24 hour continuousinfusion weekly or Arm B,120 g/m² bryostatin-1 given as a72 hour continuous infusion every 2 weeks.Although objective response was assessedusing standard NCIC CTG criteria,antitumour activity was assessed using amultivariate endpoint incorporating bothresponse (CR and PR) and early progression(PD at 8 weeks). Seventeen patientswere randomized to each arm. Results: Arm A was better tolerated with 86.7% of15 evaluable patients receiving 90%of planned dose intensity versus 76.5% of17 evaluable patients in Arm B. On Arm B,three patients experienced serious adverseevents and three patients had to be removedfrom protocol therapy due to toxicity. Themost common side effect was myalgia (33%grade 1–2 on Arm A versus 65% on Arm Bwith 5 patients experiencing grade 3 andone patient grade 4). Lethargy was morecommon on Arm A but more severe on Arm B. Other side effects such as nausea, diarrheaand headache were generally mild tomoderate in nature and occurred with asimilar frequency on both arms. Hematologicand biochemical toxicity were minimal. This trial was closed early because theprotocol-stopping rule was met based onlack of required responses and on thenumber of early progressions on both arms.No partial or complete responses were seen;3 patients randomized to Arm A had stabledisease (duration 9–24 weeks) as did 4patients (duration 10–38 weeks) randomizedto Arm B. Conclusion: Arm A wasbetter tolerated than Arm B. We concludethat bryostatin-1 has little efficacy inthe treatment of metastatic melanoma witheither of the schedules studied.     

Long-term effects of glipizide on insulin secretion and blood glucose control in patients with non-insulin-dependent diabetes mellitus

Summary Of 23 patients with non-insulin-dependent diabetes mellitus (NIDDM), whose fasting blood glucose had not reached 6.0 mmol·l^–1 after 10 weeks of dietary regulation, 15, who had had a weight reduction of –2.8 kg by dietary control, did achieve a fasting blood glucose 6.0 mmol·l^–1 after addition of 20 mg glipizide daily. They had a sustained (2 years) increase in meal-induced insulin secretion (32% increase in postprandial C-peptide AUC), and a sustained reduction in postprandial hyperglycaemia (34% reduction in AUC). Ten of the patients took a mean daily dose <5mg (4.8 mg) and had a sustained increase in insulin secretion rate (increased C-peptide slope). The 15 patients had no elevation of basal insulin secretion and no impairment of weight reduction. The remaining 8 subjects, who showed little or no weight reduction on dietary control, had little or no reduction in fasting blood glucose despite long-term treatment with 20 mg glipizide daily, a less sustained increase in meal-induced insulin secretion, a smaller reduction of postprandial hyperglycaemia, and an increase in body weight. On diagnosis the 8 subjects did not differ from the other 15 subjects in age, body weight, blood glucose, HbA₁c, C-peptide or insulin, nor in their glucose and insulin responses to a test dose of glipizide; the main reason for the apparent drug failure appeared to be deficient compliance with dietary regulation rather than a primary inability to respond to sulphonylurea treatment. The findings indicate that glipizide is able to promote and maintain increased meal-induced insulin secretion and near-normal fasting and non-fasting blood glucose levels without continuous B cell stimulation. However, these improvements prevail mainly in subjects who persist with hypocaloric dietary regulation.     

Oral etoposide for patients with advanced adenocarcinoma of the pancreas

Purpose: Oral etoposide has been shown to be effective against some solid tumor types. This phase II study examined the efficacy of oral etoposide in patients with untreated advanced adenocarcinoma of the pancreas.Methods and patients: Previously untreated patients with measurable unresectable or metastatic disease were eligible for inclusion in this study. They were required to have a Zubrod performance status of 2 and normal hematological, renal, and hepatic functions. Written informed consent was obtained from all patients. The etoposide dose was 50 mg/m²/d given orally daily for 21 days with a 7-day rest period and was adjusted based on toxicity. Response was assessed after two courses of therapy.Results: Eighteen patients were enrolled and fourteen were evaluable for toxicity and response. Twelve patients developed progressive disease while two patients had only a minor response. The median number of courses was 2 (range, 1–4) and there were 29 total courses delivered. The median survival was 3.5 months (range, 1.6–25.9). There were no treatment-related deaths. Toxicity was moderate.Conclusions: Oral etoposide is not effective against advanced adenocarcinoma of the pancreas.     

Teratogenicity and embryotoxicity of some maleinimides

Maleinimide, the teratogenic structural central part of the thalidomide molecule, and 5 of its dichloro- and dibromo-derivatives have been investigated teratologically by tests on SWS mice. According to both the electrophilic properties and the spatial requirements of the substituents, the effects were found to be up to 100 times stronger than those of thalidomide, and up to 10 times stronger than those of phthalimide respectively. The results are referred to the distinct electron-acceptor behavior of the maleinimide compounds, which — due to their flat molelecular structures — are able to intercalate into the DNA double helix forming EDA complexes with nucleic acid bases as electron-donor molecules. The results can be interpreted as another confirmation of Jönsson's intercalation hypothesis of the thalidomide action.

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Zusammenfassung Maleinimid, das teratogene strukturelle Herzstück des Thalidomid-Moleküls, wurde zusammen mit 5 seiner Dichlor- bzw. Dibromderivate an der SWS-Maus teratologisch untersucht. Je nach Elektrophilität bzw. Raumfüllung der Substituenten übertraf die Wirksamkeit der untersuchten Verbindungen die von Thalidomid bis um das hundertfache und die von Phthalimid bis um das zehnfache. Diese Ergebnisse werden den ausgeprägten ElektronAkzeptor-Eigenschaften der Maleinimid-Verbindungen zugeschrieben, die aufgrund ihres planaren Molekülbaues an der DNS-Doppelhelix interkalieren und mit Nucleobasen als Elektron-Donor-Molekülen EDA-Komplexe bilden können. Damit wird Jönsson's Interkalations-Hypothese der Thalidomid-Wirkung erneut gestützt.

     

Enalapril versus atenolol in the treatment of hypertensive smokers

Summary A randomised crossover study has been done to compare the antihypertensive efficacy of enalapril and atenolol in 45 smoking, hypertensive men. Treatment was started with enalapril 20 mg/d or atenolol 50 mg/d and, if necessary, the doses were doubled after 4 weeks to achieve a sitting diastolic blood pressure 95 mm Hg, after which hydrochlorothiazide was added, if necessary.Both drugs lowered blood pressure significantly. However, enalapril was more efficient in lowering both systolic and diastolic blood pressure; the mean difference was significant after both 4 and 8 weeks in the sitting systolic (11.6 mm Hg and 7.9 mm Hg) and diastolic (3.3 mm Hg and 3.0 mm Hg) pressures and in the erect systolic pressures (8.2 mm Hg and 7.2 mm Hg), and after 8 weeks in the supine systolic pressure, too (8.9 mm Hg). The effect on enalapril was especially marked in moderate (<20 cigarettes/day) smokers. The need for diuretics was also significantly less in the enalapril group.It appears that angiotensin-converting enzyme inhibitors may be superior to -adrenoceptor blockers in the treatment of hypertensive smoking patients.     

Influence of acetylator phenotype on the pharmacokinetics of a new vasodilator antihypertensive,endralazine

Summary Five and 10 mg single oral doses of a new vasodilator antihypertensive, endralazine (E) were given on separate occasions to 17 normal male volunteers (8 slow, 7 heterozygous fast and 2 homozygous fast acetylators). The homozygous fast acetylators were excluded from statistical comparisons. Only small differences were observed in the pharmacokinetics of E between the phenotypes and there was no evidence of non-linearity at the 2 dose levels studied. Terminal half-lives ranged from 2.59 to 7.14 h with a mean of 4.30±1.08 h for the 5 mg dose and 4.25±1.09 h for the 10 mg dose. There was no significant difference in half-lives between slow and heterozygous fast acetylators. The mean area under the plasma level-time curve (AUC ₀ ) was 18.2% lower (p<0.05) in the heterozygous fast acetylators than in the slow acetylators following the 5 mg dose and 11.0% lower (p>0.05) following the 10 mg dose. Extremely rapid absorption of the drug precluded accurate estimation of absorption rates. The AUC ₀ of the acetylation metabolite (methyltriazoloendralazine) was small compared to that of E although higher in the heterozygous fast acetylators than in the slow acetylators (p<0.01).     

Weekly irinotecan plus UFT and leucovorin as first-line chemotherapy of patients with advanced colorectal cancer

Summary We evaluated the antitumoral efficacy and safety of CPT-11 125 mg/m² (weekly 90 min i.v. infusion; days 1, 8 and 15) combined with UFT (oral combination of tegafur and uracil) 200 mg/m²/day plus leucovorin (LV) 45 mg/m²/day (both divided into three separate oral doses every 8 h, days 1–21) every 4 weeks as first-line chemotherapy of metastatic colorectal cancer (CRC). Fifty-three patients 18 years old with histologically confirmed diagnosis of advanced CRC and bidimensionally measurable disease were enrolled. Three patients (6%) showed CR and 8 patients (15%) showed PR (ORR = 21% (95% CI, 10–32). Stable disease was reported in 19 patients (36%) [tumor control rate = 57% (95% CI, 43–70)]. The median time to progression and overall survival were 7.9 and 18.2 months, respectively (1-year rate = 74%; 2-years rate = 26%). CPT-11/UFT/LV treatment was well tolerated: the most reported grade 3/4 toxicities were neutropenia (11% of patients) and delayed diarrhea (28% of patients). No significant differences in response rate, survival or toxicity were found between younger (65 years) and older patients (> 65 years). Weekly CPT-11 plus UFT/LV was found effective and safe as first-line chemotherapy for metastatic CRC. The addition of CPT-11 to UFT/LV doubled the response rate compared to the results previously reported with UFT/LV, while myelosuppression remained low.     

Development and Validation of Two Solid-Phase Enzyme Immunoassays (ELISA) for Quantitation of Human Epidermal Growth Factors (hEGFs)

Purpose. The purpose of the present investigation was to develop and validate two separate enzyme-linked immunosorbent assays (ELISA) for quantitation of exogenous human epidermal growth factor (hEGFl -53) and its truncated fragment (hEGFl-48) in rat plasma. Methods. The present assay systems were based on the sandwiching of the antigen between a monoclonal mouse anti-hEGFl-53 antibody, pre-coated on a 96-well polystyrene plate, and a polyclonal rabbit anti-hEGFl-48 antibody, which is then detected with a peroxidase-labeled goat anti-rabbit antibody. Results. The calibration curves for hEGFl-48 and hEGFl -53 in plasma were validated over a concentration range of 7.8–250 and 62.5–1000 pg/ml, respectively. Determined from replicate assays of hEGFl-48 quality control samples, the intra-assay precision and accuracy were 8.8% RSD and within ± 9.8%; and the inter-assay precision and accuracy were 14.8% RSD and within ± 9.7% RE, respectively. Determined from replicate assays of hEGFl-53 quality control samples, the intra-assay precision and accuracy were 10.0% RSD and within ± 8.5%; and the inter-assay precision and accuracy were 10.0% RSD and within ± 5.7% RE, respectively. The limit of quantitation of the hEGFl-48 and hEGFl-53 assay using 200 µL plasma per well is 7.8 and 62.5 pg/ml, respectively. These two ELISA methods are specific to hEGFs and do not cross-react with mouse EGF or other growth factors (TGF, TGF, PDGF, and FGF) or lymphokines (IL₁ and TNF). These validated methods have been routinely applied to assay of plasma samples from various pharmacokinetic studies in rats receiving intravenous hEGFs. Both assay methods were also adapted to assay endogenous hEGFs in biological fluids of different animal species. Conclusions. Two sensitive ELISA methods have been validated for quantitation of hEGFl–53 and hEGFl–48 in rat plasma. Their utility has been demonstrated in the application of assaying immunoreactive concentrations of exogenous and endogenous epidermal growth factors.     

Phase I study of paclitaxel administered by ten-day continuous infusion

Purpose: Pre-clinical data have suggested that prolonged exposure to paclitaxel enhances its cytotoxicity, but various clinical trials utilizing long-term infusions of paclitaxel have been limited by unacceptable hematologic toxicity, most notably significant neutropenia. A phase I study of paclitaxel administered over 10 days, was performed to evaluate the hematologic and non-hematologic toxicities as well as to determine the maximum-tolerated dose for the 10-day infusion duration.Patients and methods: Twenty-nine solid tumor patients (predominantly non-small cell lung cancer and head and neck cancer) were treated with paclitaxel at doses ranging from 5 mg/m2/day to 25 mg/m2/day administered as a 10-day continuous infusion via a pump every 21 days. Dose escalation was permitted within individual patients. Dose-limiting toxicity (DLT) was defined as grade 3 or 4 non-hematologic toxicity, ANC 500 or platelet count 25,000 for 7 days or febrile neutropenia. The maximum tolerated dose (MTD) was defined as the highest dose level at which less than two out of six patients developed DLT. All of the patients had received prior chemotherapy; approximately two-thirds had received prior radiation as well. All patients received standard pre-medications for paclitaxel, including anti-histamines and corticosteroids. Prophylactic granulocyte colony-stimulating factor (G-CSF) was not used.Results: A total of 110 courses of paclitaxel were administered to 29 patients. The incidence of hematologic and non-hematologic toxicity was quite low among the patients treated at dose levels below 17 mg/m2/day. At higher doses, non-hematologic toxicities including arthralgias, myalgias, fatigue, nausea, stomatitis, and peripheral neuropathy were seen, although nearly all of the toxicities were less than grade 3 (NCI toxicity criteria). Hematologic toxicity mostly consisted of neutropenia and was more common at dose levels of 17 mg/m2/day or higher. Nevertheless, even at the highest dose levels (21 mg/m2/day and 25 mg/m2/day) grade 3 or 4 neutropenia occurred in only 50% of patients. Dose-limiting hematologic toxicity occurred in 2 of 4 patients treated at the 25 mg/m2/day dose level.Conclusion: Paclitaxel can be safely administered as a 10-day infusion. The MTD for this schedule is 210 mg/m2. Unlike the 96-hour paclitaxel infusions, dose-reduction for myelosuppression may not be necessary because the MTD of paclitaxel when administered over a 10-day infusion is similar to the MTD of paclitaxel when infused over 3 or 24 hours.