A simple outpatient treatment with oral ifosfamide and oral etoposide for patients with small cell lung cancer (SCLC)

For the first time in a clinical study oral Ifosfamide was used: 65 elderly or unfit patients with small cell lung cancer (SCLC) were treated as outpatients with fractionated oral Ifosfamide and Etoposide. Forty patients (62%) had extensive stage (ED) disease. The median age of the patients was 66 years. In the 60 patients evaluable for response the objective response rate was 90% with a complete response (CR) rate of 32% and a partial response (PR) rate of 58%. The overall median survival of all 65 patients was 11 months (13 months for LD, 9.5 months for ED). In those patients with LD achieving a CR or a PR radiotherapy was given to the mediastinum. No prophylactic cranial irradiation was given. There was a rapid improvement in the responding patients' performance status and symptoms generally with the first treatment cycle. Overall haematological toxicity was mild, with intravenous antibiotics only being required in 4% of the courses and with only one treatment-related death from septicaemia. A higher than expected rate of CNS toxicity was seen (30%). This was generally mild and always fully reversible and consisted mainly of forgetfulness, occasionally hallucinations, nightmares and somnolence. In only one case did encephalopathy necessitate early termination of treatment. This raises the question of whether Ifosfamide metabolism differs quantitatively or qualitatively when given by the oral route as opposed to the usual intravenous route. We conclude that this simple outpatient based treatment gives a high response rate with rapid improvement in symptoms.

Carboplatin, ifosfamide and etoposide with mid-course vincristine and thoracic radiotherapy for 'limited' stage small cell carcinoma of the bronchus

Forty-two patients with small cell lung cancer were treated with a combination of carboplatin, ifosfamide and etoposide. Vincristine was given on day 14 of each course, the courses being repeated every 28 days for a maximum of six. Thoracic radiotherapy was given 4 weeks after the last course of chemotherapy but no prophylactic cranial radiotherapy was administered. Thirty patients had clinically limited state disease, the remaining patients having contralateral neck lymphadenopathy and/or pleural effusions. Elevated enzyme levels (alkaline phosphatase, LDH, ALT, GGT) were noted in 69% of patients. Twenty-four patients (57%) achieved a complete response (CR) when assessed one month after the end of treatment. A further 21% of patients had a partial response (PR). Median duration of CR was 14 months and of PR 8 months. Cerebral metastases were the sole site of relapse in 13% of the CR patients. Myelosuppression was severe with a median nadir of neutropenia of 0.2 x 10(9) cells 1-1. However, 74% of the patient group received all six courses of chemotherapy and only 16 courses (7%) were delayed because of toxicity. There were three deaths associated with treatment-related neutropenia. The median survival of the total group was 14 months, with an actuarial 2 year survival of 37% and a minimum follow-up of 18 months. [A recent analysis, March 1989, demonstrated a 33%, 2 year actual survival.]

High-dose, double alkylating agent chemotherapy with DTIC, melphalan, or ifosfamide and marrow rescue for metastatic malignant melanoma

Thirty-seven patients with widely metastatic malignant melanoma were treated with one of three chemotherapy regimens, incorporating high-dose dacarbazine (DTIC). The chemotherapy was followed by autologous bone marrow rescue which was harvested under local anesthesia in 25 of the patients. The three regimens comprised a 24-hour infusion of DTIC (Regimen A for patients less than 45 years of age, 4.3 to 10.5 g/m2; B, if greater than 45 years of age 2.7 to 4.0 g/m2; and later C, if greater than 45 years of age 7.0 to 8.0 g/m2). The second alkylating agent was given at +8 and +16 hours from the start of DTIC. The total doses of the melphalan ranged from 60 to 130 mg/m2 for Regimen A and 30 to 40 mg/m2 for Regimen B. Ifosfamide 5.0 to 8.0 g/m2 was given instead of melphalan in Regimen C. The response rates for the regimens were 81% (25% CR) for A, 27% (11% CR) for B, and 20% (with no complete responders) for Regimen C. There was no statistically significant difference between the three regimens for survival with a median value of 6 months. One of the 16 patients treated with the very high dose Regimen A died of septicemia and three of ten patients in Regimen C died within the first 2 weeks of treatment. There was statistically significant greater myelosuppression, stomatitis, and diarrhea in the very high dosage DTIC and melphalan (Regimen A) compared with the other two regimens. No significant difference in response rate or toxicity was observed for the different dosages escalated within each of the three regimens. Although hematologic and gastrointestinal toxicity were very severe, no unusual side effects were noted except for one episode of severe acute renal failure in the high-dose DTIC and melphalan, Regimen A. Responses occurred mainly in nonvisceral, nodal, and cutaneous sites and occasionally in pulmonary metastases. The Karnofsky performance improved 4 to 6 months after treatment notably with the high-dose DTIC and melphalan therapy. No survival benefit for the combination chemotherapy despite the high dosages was detected and such an approach currently cannot be recommended.

Increased nonrenal clearance and increased diuretic efficiency of furosemide in cystic fibrosis

The pharmacokinetics of furosemide and its diuretic effect were studied in six patients with cystic fibrosis (CF) and in six age-matched healthy volunteers. Furosemide was given intravenously at a dose of approximately 0.5 mg/kg. Renal excretion of furosemide was decreased in CF because nonrenal clearance was more than twice as high as in controls (p = 0.03). Nonrenal clearance correlated with the volume of distribution (r2 = 0.52, p = 0.01), which makes a difference in the distribution and binding determinants for clearance. Another reason for increased nonrenal clearance could be induction of drug metabolism in CF, but the excretion of furosemide conjugate did not differ significantly between the groups. Although 26% less furosemide was excreted in CF than in controls (p = 0.03), the diuretic response (calculated as excretion of water and electrolytes) did not differ. Thus the diuretic efficiency was higher in CF for Na+ (p = 0.02), Cl- (p = 0.01), K+ (p = 0.07), and volume (p = 0.005). This difference is probably secondary to the different rates of delivery of furosemide into urine.

Intraindividual variability in the relative systemic availability of cyclosporin after oral dosing

We have measured total and unbound plasma concentrations of cyclosporin A in seven healthy men after single oral doses (12 mg per kg body weight) on two occasions at least two weeks apart. There was an up to two-fold intraindividual and a more than three-fold interindividual variation in the AUCs of both total and unbound drug. The intraindividual variability in the AUC of cyclosporin is similar to that of many other drugs and needs to be taken into account in the planning of pharmacokinetic studies.

Synthetic peptide homologous to beta protein from Alzheimer disease forms amyloid-like fibrils in vitro

Progressive amyloid deposition in senile plaques and cortical blood vessels may play a central role in the pathogenesis of Alzheimer disease. We have used x-ray diffraction and electron microscopy to study the molecular organization and morphology of macromolecular assemblies formed by three synthetic peptides homologous to beta protein of brain amyloid: beta-(1-28), residues 1-28 of the beta protein; [Ala16]beta-(1-28), beta-(1-28) with alanine substituted for lysine at position 16; and beta-(18-28), residues 18-28 of the beta protein. beta-(1-28) readily formed fibrils in vitro that were similar in ultrastructure to the in vivo amyloid and aggregated into large bundles resembling those of senile plaque cores. X-ray patterns from partially dried, oriented pellets showed a cross-beta-conformation. A series of small-angle, equatorial maxima were consistent with a tubular fibril having a mean diameter of 86 A and a wall composed of pairs of cross-beta-pleated sheets. The data may also be consistent with pairs of cross-beta-sheets that are centered 71-A apart. [Ala16]beta-(1-28) formed beta-pleated sheet assemblies that were dissimilar to in vivo fibrils. The width of the 10-A spacing indicated stacks of about six sheets. Thus, substitution of the uncharged alanine for the positively charged lysine in the beta-strand region enhances the packing of the sheets and dramatically alters the type of macromolecular aggregate formed. beta-(18-28) formed assemblies that had even a greater number of stacked sheets, approximately equal to 24 per diffracting domain as indicated by the sharp intersheet reflection. Our findings on these homologous synthetic assemblies help to define the specific sequence that is required to form Alzheimer-type amyloid fibrils, thus providing an in vitro model of age-related cerebral amyloidogenesis.

The debrisoquin hydroxylation phenotype does not predict the metabolism of phenytoin

Phenytoin plasma elimination kinetics and accrual of phenytoin metabolites in urine were studied in seven rapid and five slow hydroxylators of debrisoquin. There was no interphenotypic difference in phenytoin clearance, plasma half-life, volume of distribution, maximum rate of metabolism (Vmax), or Michaelis-Menton constant (Km). The total recovery of metabolites as percentage of given dose and the metabolite profiles in urine were similar for the two debrisoquin hydroxylator phenotypes. Similarly, no differences were observed between the groups with respect to stereoselective production of either dihydrodiol or para-phenolic metabolites of phenytoin. The debrisoquin hydroxylation phenotype was also investigated in 74 epileptic patients treated with phenytoin. Vmax and Km were graphically estimated from plasma concentrations at varying phenytoin dosage regimens in 36 of the patients. There was no correlation between the debrisoquin hydroxylation index and Vmax or Km. We conclude that the debrisoquin hydroxylation phenotype has no predictive value in guiding phenytoin dosage.

On the question of dose-dependent chloroquine elimination of a single oral dose

Subjects (n = 45) were randomly given single oral doses of 2 (n = 11), 3 (n = 9), 5 (n = 8), 10 (n = 10), or 15 mg/kg (n = 7) chloroquine base. Chloroquine was analyzed by HPLC in serum samples taken at 3 to 168 hr after dosing. AUCs, calculated for the time period of 0 to 168 hr were proportional to the doses. Mean AUC value increased 6.7 times when the dose was increased 7.5 times (from 2 to 15 mg/kg). These data do not support the existence of significant capacity-limited chloroquine elimination within the dose range studied.

Oxidation of (R)- and (S)-propranolol in human and dog liver microsomes. Species differences in stereoselectivity

Propranolol is an adrenergic beta receptor antagonist whose kinetics is complicated by dose-dependency, formation of active metabolites and stereoselective availability. To get some insight of the possible metabolic factors behind this, we have incubated the two optical isomers (R)- and (S)-propranolol with human and dog liver microsomes. Propranolol and its oxidized metabolites 4-hydroxypropranolol (4-OH-P) and N-desisopropylpropranolol (nor-P) were analyzed using high-performance liquid chromatography and fluorometric detection. The oxidation rates varied markedly between human livers. Most of metabolized propranolol was recovered as 4-OH-P and nor-P and more propranolol was oxidized than glucuronidated. Formation rates of 4-OH-P and nor-P were approximately half-maximal at propranolol concentrations than can occur in the liver in vivo. The ratio between formation of these metabolites varied markedly between livers. Human livers formed 4-OH-P and nor-P most rapidly from (R)-propranolol, whereas dog livers formed 4-OH-P most rapidly from (S)-propranolol. We suggest that the interindividual differences in the capacity of the livers to metabolize propranolol largely should contribute to the kinetic variations observed between patients in vivo and the gradual saturation of 4-hydroxylation and N-desisopropylation of propranolol are likely to contribute to the dose-dependent kinetics.

Clinical experience with the objective symmetry detector method for gammaencephalography

The objective symmetry detector method for gammaencephalography previously described has been further developed. A rapid micro-computerized automatic measuring device has been constructed and the method used in screening of neurologic patients. The previously chosen classification boundaries between normal and pathologic isotope distributions were not entirely satisfactory for clinical screening of patients with neurologic symptoms. By use of new classification boundaries, 87 per cent of patients with brain tumours could be separated from patients with neurologic symptoms but without gross brain lesions and from neurologically healthy subjects.

Salivary gland scintigraphy. Diagnostic verification of parotid saliva flow through the maxillary sinus and nose

The diagnostic value of salivary gland scintigraphy in patients without access to the salivary gland duct orfice is exemplified and discussed. The necessity for careful dental examination and treatment in patients with an oroantral fistula is emphasised.

Effect of pentobarbital on the disposition of alprenolol

Alprenolol was administered orally and intravenously to 5 healthy subjects before and after 10 to 14 daily doses of 0.1 gm pentobarbital. The area under the plasma concentration time curve after an oral 200-mg dose decreased from 706 +/- 277 to 154 +/- 48 ng/ml-hr (mean and SD) with the barbiturate treatment, but there was no significant change in elimination rate. The change in area corresponded to an increase in extraction by the liver from 0.72 +/- 0.13 to 0.93 +/- 0.01. The disposition of a 5.0-mg intravenous dose of alprenolol did not change significantly after pentobarbital treatment. There was no indication of a marked change in hepatic blood flow estimated from the clearance of alprenolol after intravenous administration. It is concluded that pentobarbital administration induces the metabolism of alprenolol in man and that the pharmacokinetic theories derived for hepatic extraction of drugs subject to a high metabolic clearance can be successfully applied.

First pass hydroxylation of nortriptyline: concentrations of parent drug and major metabolites in plasma

Nortriptyline was given orally and intramuscularly to six depressed patients. Plasma concentrations of parent drug and the unconjugated and conjugated principal metabolite, 10-hydroxynortriptyline, were determined by mass fragmentography. There was a significant decrease in the area under the nortriptyling plasma concentration- time curve after the oral route of administration, whilst the elimination rate was unchanged. With the oral dose, plasma concentrations of the metabolites were higher and peaked earlier than after intramuscular administration, whilst the opposite was true for the parent compound. This proves that the difference in bioavailability between the two routes of administration was due to first pass metabolism. As determined from the ratio between corresponding areas, the relative bioavailability of the oral dose was 66 +-21 S.D. per cent. This fraction is higher than that reported previously when intravenous nortriptyline was used as the reference dosage form.

Objective symmetry detector method for gammaencephalography. VI. Comparison with subjective evaluation of brain scintigraphy

The diagnostic accuracy of brain scintigraphy and the objective symmetry detector method for gamma encephalography is compared. The objective symmetry detector method was found more efficient in separating brain tumour patients from normal than a group of ten radiologists interpreting brain scintigrams.

Objective symmetry detector method for gammaencephalography. V. Variation in the subjective analysis of brain scintigrams

The variation caused by the subjective interpretation of brain scintigrams was evaluated and found considerable. It was concluded that the objective analysis of results offered by the objective symmetry detector method for gammaencephalography is advantageous, especially in the screening of large patient materials with a low incidence of brain lesion cases.