Use of [177Lu]Lu-DOTA-TATE in the treatment of gastroenteropancreatic neuroendocrine tumours: Results of a UK cost-effectiveness modelling study

Aim

To evaluate the cost-effectiveness of [¹⁷⁷Lu]Lu-DOTA-TATE versus relevant comparators for the treatment of neuroendocrine tumours located in the gastrointestinal tract (GI-NETs) and the pancreas (P-NETs).

Materials and methods

A three-state partitioned survival model was developed to perform a cost-utility analysis of [¹⁷⁷Lu]Lu-DOTA-TATE versus standard of care (high dose Octreotide LAR), everolimus and sunitinib. Effectiveness data for SoC, everolimus and sunitinib were obtained from published Kaplan–Meier survival curves. Given a lack of head-to-head effectiveness data, matching adjusted indirect comparisons (MAICs) were performed to population-adjust [¹⁷⁷Lu]Lu-DOTA-TATE survival data based on prognostic factors and derive estimates of relative effectiveness. Health state utilities were estimated from real-world evidence. Drug acquisition costs were taken from nationally published sources (BNF, NICE), and administration costs were based on treatment protocols in [¹⁷⁷Lu]Lu-DOTA-TATE studies, combined with nationally published unit costs (PSSRU, DoH reference costs). Incidence of adverse events were estimated using published sources. A discount rate of 3.5% was applied to both utilities and costs, and deterministic and probabilistic sensitivity analyses were performed. Costs were included from an NHS perspective and presented in 2017/18 GBP (and PPP Euros for base case).

Results

In GI-NETs, the incremental cost-effectiveness ratio (ICER) of [¹⁷⁷Lu]Lu-DOTA-TATE compared to SoC and everolimus was £26,528 (€27,672) and £24,145 (€25,186) per QALY, respectively. In P-NETs, the ICER of [¹⁷⁷Lu]Lu-DOTA-TATE compared to SoC was £22,146 (€23,101) or £28,038 (€29,251) dependent on matched population, and £21,827 (€22,766) and £15,768 (€16,445) compared to everolimus and sunitinib, respectively.

Conclusions

At a willingness to pay threshold of £30,000, [¹⁷⁷Lu]Lu-DOTA-TATE is likely to be a cost-effective treatment option for GI-NET and P-NET patients versus relevant treatment comparators (NHS perspective).

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A three-state partitioned survival model of GEP-NET patients was developed.

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Base case ICERs for [¹⁷⁷Lu]Lu-DOTA-TATE were under £30,000 per QALY for all comparators.

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[¹⁷⁷Lu]Lu-DOTA-TATE is cost-effective for the treatment of GEP-NETs from a NICE perspective.

Symptom Diaries of Patients with Midgut Neuroendocrine Tumors Treated with 177Lu-DOTATATE

We report the impact of 177Lu DOTATATE treatment on abdominal pain, diarrhea, and flushing, symptoms that patients with advanced midgut neuroendocrine tumors (NETs) often find burdensome. Methods: All patients enrolled in the international randomized phase 3 Neuroendocrine Tumors Therapy (NETTER-1) trial (177Lu-DOTATATE plus standard-dose octreotide long-acting repeatable [LAR], n = 117; high-dose octreotide LAR, n = 114) were asked to record the occurrence of predefined symptoms in a daily diary. Change from baseline in symptom scores (mean number of days with a symptom) was analyzed using a mixed model for repeated measures. Results: Patients (intent-to-treat) who received 177Lu-DOTATATE experienced a significantly greater decline from baseline in symptom scores than patients who received high-dose octreotide LAR. For 177Lu-DOTATATE, the mean decline in days with abdominal pain, diarrhea, and flushing was 4.10, 4.55, and 4.52 days per 4 weeks, respectively, compared with 0.99, 1.44, and 2.54 days for high-dose octreotide LAR. The mean differences were 3.11 days (95% confidence interval, 1.35-4.88; P = 0.0007) for abdominal pain, 3.11 days (1.18-5.04; P = 0.0017) for diarrhea, and 1.98 days (0.08-3.88; P = 0.0413) for flushing, favoring 177Lu-DOTATATE. A positive repeated measures correlation was found between diary-recorded symptom scores and questionnaire-recorded pain, diarrhea, and flushing. Conclusion: In addition to efficacy and quality of life benefits, symptom diaries from NETTER-1 demonstrated that treatment with 177Lu DOTATATE was associated with statistically significant reductions in abdominal pain, diarrhea, and flushing, constituting the core symptoms of patients with progressive midgut NETs, compared with high-dose octreotide LAR, supporting a beneficial effect of 177Lu DOTATATE on HRQoL.

Lutetium oxodotreotide (177Lu-Dotatate) for the treatment of unresectable or metastatic progressive gastroenteropancreatic neuroendocrine tumors: a cost-effectiveness analysis for Scotland

Background

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) represent a heterogenous group of tumors. Findings from the phase III NETTER-1 trial showed that treatment of unresectable/metastatic progressive gastrointestinal (GI) NETs with ¹⁷⁷Lu-Dotatate resulted in a significant improvement in progression-free survival (PFS) and overall survival (OS) compared with best supportive care (BSC) with high dose octreotide long-acting repeatable (LAR) 60 mg. A health economic analysis was performed using input data from clinical studies and data derived from an indirect comparison to determine the cost-effectiveness of ¹⁷⁷Lu-Dotatate in the treatment of GI-NETs and pancreatic NETs (P-NETs) in Scotland.

Methods

Cost-effectiveness analysis was performed from the payer perspective using a three-state partitioned survival model. In the base case ¹⁷⁷Lu-Dotatate was compared with BSC in gastrointestinal (GI)-NETs using clinical data from the NETTER-1 trial. A secondary analysis comparing ¹⁷⁷Lu-Dotatate with BSC, everolimus or sunitinib in patients with P-NETs was also performed using hazard ratios inferred from indirect comparisons. The base case analysis was performed over a 20-year time horizon with an annual discount rate of 3.5% for both costs and clinical outcomes.

Results

For unresectable/metastatic progressive GI-NETs treatment with ¹⁷⁷Lu-Dotatate led to a gain in quality-adjusted life expectancy of 1.33 quality-adjusted life years (QALYs) compared with BSC due to extended PFS and OS. Mean total lifetime costs were GBP 35,701 higher with ¹⁷⁷Lu-Dotatate, leading to an incremental cost-effectiveness ratio (ICER) of GBP 26,830 per QALY gained.

In analyses in patients with P-NETs ¹⁷⁷Lu-Dotatate was associated with ICERs below GBP 30,000 per QALY gained in comparisons with BSC, sunitinib and everolimus.

Conclusions

Cost-effectiveness analyses demonstrated that, in Scotland, from the payer perspective, ¹⁷⁷Lu-Dotatate at the set acquisition cost is a cost-effective treatment option for patients with unresectable or metastatic progressive GI-NETs or P-NETs.

Cost-effectiveness of lutetium (177Lu) oxodotreotide vs everolimus in gastroenteropancreatic neuroendocrine tumors in Norway and Sweden

BACKGROUND

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) represent a relatively rare and heterogenous group of tumors. Currently available treatment options for patients with progressive GEP-NETs include lutetium (¹⁷⁷Lu) oxodotreotide (¹⁷⁷Lu-Dotatate) and everolimus [as well as sunitinib for patients with pancreatic NETs (P-NETs)].

AIM

To perform a health economic analysis to determine the cost-effectiveness of ¹⁷⁷Lu-Dotatate compared with everolimus in patients with unresectable or metastatic midgut-NETs or P-NETs in both Sweden and Norway.

METHODS

Simulations were performed using a three-state partitioned survival model and analyses were performed separately for patients with midgut-NETs and P-NETs. Clinical input data were sourced from an indirect comparison that utilized survival data from clinical trials of ¹⁷⁷Lu-Dotatate and everolimus. The analyses were performed from the healthcare payer perspective over a time horizon of 20 years. For Sweden, future costs and clinical outcomes were discounted at 3% per annum. For Norway, a discount rate of 4% per annum was applied.

RESULTS

For Sweden, improved survival outcomes and higher lifetime costs with ¹⁷⁷Lu-Dotatate resulted in an incremental cost-effectiveness ratio (ICER) of SEK 391194 per quality-adjusted life year (QALY) gained for midgut NETs and SEK 16764 per QALY gained for P-NETs for ¹⁷⁷Lu-Dotatate compared with everolimus. For Norway, the corresponding ICERs were NOK 244444 per QALY gained and NOK 106451 per QALY gained, respectively. One-way sensitivity analyses revealed that the results were most sensitive to changes in drug acquisition costs and health state utility values.

CONCLUSION

In both Sweden and Norway, from a healthcare provider perspective, ¹⁷⁷Lu-Dotatate is likely to be considered cost-effective relative to everolimus for the treatment of patients with unresectable or metastatic, progressive midgut-NETs or P-NETs. 

Quality of life in patients with gastroenteropancreatic tumours: A systematic literature review

BACKGROUND

Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) are slow-growing cancers that arise from diffuse endocrine cells in the gastrointestinal tract (GI-NETs) or the pancreas (P-NETs). They are relatively uncommon, accounting for 2% of all gastrointestinal malignancies. The usual treatment options in advanced GEP-NET patients with metastatic disease include chemotherapy, biological therapies, and peptide receptor radionuclide therapy. Understanding the impact of treatment on GEP-NET patients is paramount given the nature of the disease. Health-related quality of life (HRQoL) is increasingly important as a concept reflecting the patients’ perspective in conjunction with the disease presentation, severity and treatment.

AIM

To conduct a systematic literature review to identify literature reporting HRQoL data in patients with GEP-NETs between January 1985 and November 2019.

METHODS

The PRISMA guiding principles were applied. MEDLINE, Embase and the Cochrane library were searched. Data extracted from the publications included type of study, patient population data (mid-gut/hind-gut/GI-NET/P-NET), sample size, intervention/comparators, HRQoL instruments, average and data spread of overall and sub-scores, and follow-up time for data collection.

RESULTS

Forty-three publications met the inclusion criteria. The heterogeneous nature of the different study populations was evident; the percentage of female participants ranged between 30%-60%, whilst average age ranged from 53.8 to 67.0 years. Eight studies investigated GI-NET patients only, six studies focused exclusively on P-NET patients and the remaining studies involved both patient populations or did not report the location of the primary tumour. The most commonly used instrument was the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30 (n = 28) with consistent results across studies; the GI-NET-specific module Quality of Life Questionnaire-GINET21 was used in six of these studies. A number of randomised trials demonstrated no HRQoL changes between active treatment and placebo arms. The Phase III NETTER-1 study provides the best data available for advanced GEP-NET patients; it shows that peptide receptor radionuclide therapy can significantly improve GEP-NET patients’ HRQoL.

CONCLUSION

HRQoL instruments offer a means to monitor patients’ general disease condition, disease progression and their physical and mental well-being. Instruments including the commonly used European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30 and GINET21 lack, however, validation and a defined minimal clinical important difference specifically for GI-NET and P-NET patients.

Adjunctive psychosocial therapies for the treatment of schizophrenia

Antipsychotic pharmacotherapy is the standard of care for the treatment of schizophrenia. Although pharmacotherapy effectively improves some symptoms, others can remain. Pharmacotherapy alone also tends to produce only limited improvement in social functioning and quality of life. Supportive psychosocial therapies have been used as adjuncts to pharmacotherapy to help alleviate residual symptoms and to improve social functioning and quality of life. Additionally, therapies with psychoeducational components can focus on improving medication adherence and reducing relapse and rehospitalization. This review describes the major psychosocial therapeutic strategies that have been used effectively in patients with schizophrenia (cognitive-behavioral therapy, family intervention, social skills, and cognitive remediation), with emphasis on their utility in improving medication adherence. Therapies that integrate various psychosocial therapeutic approaches are also discussed. It is concluded that psychosocial therapy is an effective adjunct to pharmacotherapy for schizophrenia. However, these therapies vary significantly in the functional domains that they address. It is therefore important to identify the form of psychosocial intervention most likely to benefit the individual patient, and to recognize that the effectiveness of any psychosocial intervention could be influenced by such factors as the presence and severity of psychotic or affective symptoms or cognitive impairment.

Pharmacokinetics of ibafloxacin following intravenous and oral administration to healthy Beagle dogs

The pharmacokinetics of ibafloxacin, a new veterinary fluoroquinolone antimicrobial agent, was studied following intravenous (i.v.) and oral administration to healthy dogs. The mean absolute bioavailability of ibafloxacin after oral doses of 7.5, 15 and 30 mg/kg ranged from 69 to 81%, indicating that ibafloxacin was well absorbed by dogs. Ibafloxacin was also absorbed rapidly [time of maximum concentration (t(max)) 1.5 h], reaching a mean maximum concentration (C(max)) of 6 microg/mL at 15 mg/kg, well distributed in the body [large volume of distribution at steady state (V(ss)) and V(area) of 1.1 L/kg and 4 L/kg, respectively], and exhibited an elimination half-life of 5.2 h and a low total body clearance (8.7 mL/min/kg). Both C(max) and area under the concentration-time curve (AUC) showed dose proportionality over the dose range tested (7.5-30 mg/kg). The pharmacokinetics of ibafloxacin was similar following single and repeated dosage regimens, implying no significant accumulation in plasma. Food promoted the absorption of ibafloxacin by increasing C(max) and AUC, but did not change t(max). High amounts of the metabolites, mainly 8-hydroxy- and, 7-hydroxy-ibafloxacin were excreted in urine and faeces, either unchanged or as glucuronide conjugates. Following oral administration of 15 mg ibafloxacin/kg, the total recovery of ibafloxacin, its metabolites and conjugates in urine and faeces was 61.9-99.9% of the dose within 48 h.

The effect of nimodipine monotherapy and combined treatment with ketamine and lignocaine in aneurysmal subarachnoid haemorrhage

The clinical effects of nimodipine monotherapy were compared with the effects of nimodipine combined with ketamine and lignocaine (combination therapy) in a single-centre, one investigator, open study in patients with proven aneurysmal subarachnoid haemorrhage (aSAH). After clipping of the aneurysm, nimodipine was administered intravenously until day 5-7 after clipping. Thereafter the intravenous nimodipine was substituted by oral doses of nimodipine. These were decreased gradually and then discontinued within the following 6 days. For combination therapy, nimodipine was given together with both a bolus injection of 1 microgram/kg ketamine followed by an infusion of the drug at a rate of 3 micrograms/kg/min and a bolus injection of 1.5 mg/kg lignocaine followed by an infusion of the drug at a rate of 12 micrograms/kg/min. During the study period, 173 patients were admitted to the hospital with subarachnoid haemorrhage (SAH). Of these patients, 115 with a proven aneurysm were operated on and evaluated: 66 patients received nimodipine monotherapy and 49 were given nimodipine combined with ketamine and lignocaine. These subgroups were comparable in terms of the baseline characteristics (age, Hunt and Hess score). The (baseline corrected) Hunt and Hess scores after surgery and a 0-5 clinical outcome score were applied as indices for clinical effects. Patients receiving nimodipine monotherapy and combined therapy showed a significant clinical improvement compared to baseline (P = 0.001 and P = 0.006, respectively). The beneficial effect of nimodipine monotherapy is in line with previous double-blind, placebo-controlled studies. Although nimodipine monotherapy seems to be more effective than combined treatment, this was not statistically significant. Our data indicate that combined treatment with ketamine and lignocaine is not more effective than nimodipine monotherapy in patients with mild aSAH, but this does not rule out an effect in severe cases. There was no indication of a pharmacodynamic interaction between nimodipine and co-medication. No serious or clinically relevant adverse reactions were noted during the study.

No pharmacokinetic or pharmacodynamic interaction between theophylline and the leukotriene biosynthesis inhibitor BAY x 1005

An open, randomized, three-period crossover study was conducted to compare the steady-state pharmacokinetics, pharmacodynamics, and tolerability of concomitant administration of BAY x 1005 and theophylline in 12 healthy volunteers. BAY x 1005 (250 mg twice daily; treatment A) and theophylline (400 mg twice daily; treatment B), were administered alone and concomitantly (treatment C) for 6 days with a final morning dose on day 7. The treatments were separated by washout periods of at least 5 days. Pharmacokinetic parameters were derived from concentrations of BAY x 1005 and theophylline as measured by high-performance liquid chromatography in plasma collected before the morning dose on days 5 and 6 and at various times on day 7 of each period until 24 hours after drug administration. Adverse events, vital signs, electrocardiograms, and clinical laboratory studies were monitored as safety parameters. Levels of leukotriene B4 (LTB4) were assessed in plasma collected on days 1 and 7. The treatments were well tolerated by all participants. The ratios of maximum concentration (Cmax) and area under the concentration-time curve for one 12-hour dosing interval (AUC tau) for treatment C versus B for theophylline on day 7 was 98% for both parameters. For BAY x 1005, the ratios of treatment C versus treatment A were 94% for Cmax and 101% for AUC tau. Plasma LTB4 remained virtually unchanged during either treatment. Steady-state concentrations of theophylline were not affected by concomitant BAY x 1005 intake, and addition of theophylline had no clinically relevant effect on steady-state plasma concentrations of BAY x 1005. The combination of theophylline and BAY x 1005 did not lead to a change in nature, intensity, or frequency of adverse events.

A comparative study of the steady-state pharmacokinetics of immediate-release and controlled-release diltiazem tablets

We have studied the controlled-release properties and relative systemic availabilities of two dosages of the same controlled-release (CR) diltiazem tablet formulation by comparing them at steady state with those of an immediate-release formulation. We measured 24-hour plasma concentration profiles during 4-day treatments with diltiazem 90 mg CR tablet bd diltiazem 120 mg CR tablet bd, and conventional diltiazem 60 mg immediate-release (IR) tablet tid. The study had a randomized, three-way crossover design. Twelve healthy men (38-52 y) participated. Trough plasma concentrations were determined on days 3 and 4. The 24-h plasma concentration-time profiles were assessed after the last morning dose on day 4 of each period. The following steady-state pharmacokinetic values were calculated: the minimum plasma concentration (Cmin), the maximum plasma concentration (Cmax), the time interval during which the plasma concentration exceeded 75% of Cmax (t75), the area under the plasma concentration-time curve (AUC72-96), the peak-to-trough fluctuation (PTF), and the area-under-the-curve fluctuation (AUCF). Steady state was achieved on day 3. The pharmacokinetics were comparable. For diltiazem CR 90 mg and diltiazem CR 120 mg, AUC84-96 (night) was approximately 75% of AUC72-84 (daytime). The diltiazem plasma concentration increased slowly from about 6 h after the evening dose of both CR tablets, resulting in relatively high plasma concentrations in the early morning hours. Only during treatment with diltiazem CR 120 mg were the plasma concentrations of diltiazem maintained above the minimum therapeutic plasma concentration of 50 micrograms.l-1 throughout the full 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Human pharmacokinetics of orally administered (24 R)-hydroxycalcidiol

To gain an insight in the regulation of (24R)-hydroxycalcidiol, we studied the pharmacokinetics of orally administered (24R)-hydroxycalcidiol in 6 healthy subjects without calcium supplementation, in 4 healthy subjects with calcium supplementation and in 6 patients with primary hyperparathyroidism. Various quantities related to calcium and vitamin D metabolism were also monitored. In the healthy subjects without calcium supplementation, the basal (24R)-hydroxycalcidiol concentration (Cb) in serum was 2.4 +/- 0.8 nmol/l (mean +/- SD, n = 5), the terminal serum half-time (t 1/2) 7.2 +/- 1.4 days, the production rate 0.05 +/- 0.01 nmol/kg.day, and the production rate/[calcidiol] ratio (1.5 +/- 0.4 x 10(-3) l/kg.day). In the healthy subjects studied, the serum concentration vs time curves exhibited a second maximum after administration, possibly due to binding by intestinal cells or (partial) uptake by the lymph system. In the calcium-supplemented healthy subjects, the pharmacokinetic quantities were not significantly different while the area under the serum concentration-time curve and the estimated bioavailability were significantly decreased. Basal concentration (Cb), production rate and the production rate/[calcidiol] ratio were significantly lower in patients with primary hyperparathyroidism but t 1/2 was unchanged. Exogenous (24R)-hydroxycalcidiol had no clear effect on calcium and vitamin D metabolism. In conclusion, a) exogenous (24R)-hydroxycalcidiol has no clear effect on calcium and vitamin D metabolism, b) clearance and production rate of (24R)-hydroxycalcidiol are not affected by calcium supplementation, c) bioavailability is lower in the calcium-supplemented state, d) basal concentration (Cb) and production rate are significantly decreased in patients with hyperparathyroidism.

Reaction kinetics of cisplatin and its monoaquated species with the modulating agents (di)mesna and thiosulphate

The reactive and rapidly excreted thiol mesna (2-mercaptoethane-sulphonate sodium) has the potential to reduce the dose-limiting nephrotoxicity of cisplatin by chemical neutralisation of the latter in the kidney. The reaction kinetics of cisplatin with mesna and its disulphide, dimesna, was studied at 37 degrees C in unbuffered 0.15 mol/l NaCl (pH 5.3) and in 0.15 mol/l NaCl buffered with 0.02 mol/l Hepes (pH 7.4). The reaction mixtures were analysed for intact cisplatin. In the presence of mesna or dimesna 0.5 mol/l as anticipated in urine for conditions of renal protection, the half-life (t1/2) of 0.2 mmol/l cisplatin was less than 6 min. t1/2 of 151 and 629 min were found in the presence of mesna and dimesna concentrations of 5 mmol/l and 3 mmol/l, respectively, anticipated in plasma under conditions of renal protection. Cis-diamminemonoaquamonochloroplatinum(II) 0.2 mmol/l reacted rapidly with 50 mmol thiosulphate and 0.5 mol/l (di)mesna (t1/2 less than or equal to 1 min). This platinum species also reacted rapidly with 2.6 mmol/l thiosulphate (t1/2 less than 1 min), a concentration reached in plasma for conditions under renal protection. Reaction of the monoaquated form of cisplatin proceeded slowly in the presence of dimesna or mesna concentrations (less than 5 mmol/l), as anticipated in plasma under renal protecting conditions. It is hypothesised that renal protection by the strong nucleophiles, thiosulphate, mesna and dimesna occurs rather by neutralisation of the aquated species in the lumen of the renal tubulus than by neutralisation of intact cisplatin, and that neutralisation of these species in plasma contributes significantly to the protecting effect.

Calcium supplementation reduces vertebral bone loss in perimenopausal women: a controlled trial in 248 women between 46 and 55 years of age

To study the effect of calcium supplementation on perimenopausal bone loss, 295 women were randomized into a control group and 2 supplementation groups receiving, respectively, 1000 and 2000 mg elemental calcium/day for a period of 2 yr. We observed a significant decrease in lumbar bone loss in relation to the calcium supplementation (mean loss after 2 yr of 3.5% in the control group vs. 1.3% and 0.7% in the 1000 and 2000 mg groups, respectively), a significant increase in urinary calcium excretion, and a significant decrease in the urinary hydroxyproline/creatine ratio, serum alkaline phosphatase, osteocalcin, and 1,25-dihydroxyvitamin D. The effect of calcium supplementation on lumbar bone loss was significant in the first year of supplementation, but not in the second. However, the urinary hydroxyproline/creatinine ratio and the serum alkaline phosphatase level remained significantly decreased in the treatment groups at the end of the study; this was not the case for serum osteocalcin. Calcium supplementation did not have a significant effect on metacarpal cortical bone loss. The difference in biochemical parameters between the 2 supplementation groups was small. No significant interaction was observed between the menopausal status of the subjects and the effect of calcium supplementation. We conclude that calcium supplementation retards lumbar bone loss in the first year of calcium supplementation by reducing bone turnover. However, the effect on lumbar bone loss over a longer time span is still uncertain.

Short-term effects of Org OD 14 and 17 beta-oestradiol on bone and lipid metabolism in early post-menopausal women

The effects of 8 weeks of daily oral treatment with 1 mg 17 beta-oestradiol (E2), 2.5 mg Org OD 14 [7 alpha, 17 alpha)-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn-3-one) , a steroid with weak androgenic, weak oestrogenic and weak progestational activity, or placebo on calcium and lipid metabolism were compared in 21 healthy, early post-menopausal women in a randomised double-blind study. The treatment period was followed by a treatment-free period of 8 weeks to study the reversibility of drug-induced effects. The results show that both E2 and Org OD 14 reduce bone resorption, as indicated by the decreases in the urinary hydroxyproline/creatinine and calcium/creatinine ratios in 2-h fasting urine. In contrast to E2, Org OD 14 did not reduce serum calcium levels. As regards lipid parameters, E2 reduced the concentration of serum cholesterol and Org OD 14 decreased serum levels of high-density-lipoprotein cholesterol and triglycerides. All these effects appeared to be reversible after cessation of treatment. It is concluded that both of these steroids reduce bone resorption in early post-menopausal women, but that their mechanisms of action are most likely different.

Effect of a single infusion of aminohydroxypropylidene on calcium and bone metabolism in healthy volunteers monitored during 2 months

Recently, bisphosphonates have been used to prevent postmenopausal bone loss. As the effects of bisphosphonates on normal bone metabolism are unknown, 3-amino-1-hydroxypropylidene-1,1-diphosphonate (APD) was studied in healthy subjects. The effects of a single 20-mg APD infusion on biochemical parameters of calcium and bone metabolism were investigated during 2 months in 10 healthy male volunteers. This single moderate dose of APD reduced biochemical parameters of bone resorption during the time of follow-up. After 2 months, urinary hydroxyproline excretion was still below the basal level. The decreased serum calcium levels did not return to basal values. Biochemical parameters of bone formation, serum alkaline phosphatase and osteocalcin, showed a slight increase during the first month after stimulation of the parathyroids and a corresponding increase in serum 1,25-dihydroxyvitamin D. These formation parameters decreased thereafter, probably representing coupling between bone resorption and bone formation.

Human pharmacokinetics of orally administered strontium

Pharmacokinetics of orally administered SrCl2 (2.5 mmol) were studied in six healthy male volunteers. In the overall plasma concentration time (C-t) curves, two absorption phases were observed due to two dominant intestinal absorption loci. A method was devised to obtain separately the plasma C-t curves associated with each of the two absorption loci (curve 1 and curve 2). These curves and the overall plasma C-t curve were analyzed with a nonlinear estimation program (PCNONLIN). Pharmacokinetic parameters (mean +/- SD, n = 6) calculated from the overall curve were as follows: peak plasma concentration (Cmax) 3.55 +/- 1.22 micrograms/ml and area under the plasma C-t curve (AUC affinity) 9138 +/- 1930 micrograms.min/ml. The pharmacokinetic parameters calculated from curve 1 were as follows: terminal plasma elimination half-life time 47.3 +/- 7.9 hour, the plasma elimination half-life time of the preceding phase 5.2 +/- 3.3 hour, Cmax 1 3.09 +/- 0.95 micrograms/ml, the first-order absorption rate constant for absorption locus 1 (Ka,1) 5.7 +/- 1.2 * 10(-2) minute-1 and the time lag (tlag,1) 11.7 +/- 7.9 minute. In three of the subjects the pharmacokinetic parameters of absorption locus 2 could be evaluated: Ka,2 = 4.6 +/- 0.4 * 10(-2) minute-1, tlag,2 = 77.3 +/- 4.0 minute, tmax,2 = 153 +/- 16 minute, Cmax,2 = 0.9 +/- 0.4 micrograms/ml and AUC 2 affinity = 1204 +/- 565 micrograms. minute/ml. and AUC2 affinity = 0.14, indicating that 14% of the absorbed dose was absorbed via the second locus.(ABSTRACT TRUNCATED AT 250 WORDS)

Reaction kinetics of cisplatin and its monoaquated species with the (potential) renal protecting agents (di)mesna and thiosulfate. Estimation of the effect of protecting agents on the plasma and peritoneal AUCs of CDDP

Using simple kinetic modelling, we estimated the effect of nucleophilic (renal) protecting agents (thiosulfate, mesna, diethyldithiocarbamate) on the half-life and the area under the concentration-time curve (AUC) of cis-diamminedichloroplatinum(II) (CDDP) in plasma and peritoneum. Our basic assumptions were that (a) under non-protecting conditions, the elimination of intact CDDP from plasma and peritoneum is a first-order process determined by the elimination-rate constant (k), and (b) under conditions of renal protection the elimination of CDDP is a first-order process determined by kCDDP,P = kCDDP+kN.[N], with kCDDP,P representing kCDDP under conditions of protection; kN, the second-order rate constant for direct interaction of the protecting nucleophile (N) and CDDP; and [N], the (steady-state) concentration of N. Half-lives under conditions of protection were 0.693/kCDDP,P. AUCs were obtained by integration of the first-order equations. The inactivation-indicating parameter was defined as being the ratio of the AUC under protecting conditions to the AUC under non-protecting conditions (Rinact). Rinact is approximately given by kCDDP/kCDDP,P. For renal protection with i.v. thiosulfate (TS, 2 g m-2h), the estimates of Rinact were 0.61 in plasma and 0.7 in the peritoneal cavity for i.p. injected CDDP and 0.87 in plasma for i.v. CDDP, indicating inactivation of CDDP under such conditions. Estimates of Rinact were 0.84 or 0.96 in plasma and 0.87 in the peritoneal cavity for supposed conditions of renal protection by systemic mesna (4.4 g m-2 h), suggesting only minor inactivation of i.p. or i.v. injected CDDP under such conditions. Under reported conditions of protection achieved with 4.4 g m-2 h systemic diethyldithiocarbamate (DDTC). Rinact was greater than 0.65 or 0.87 in plasma and greater than 0.75 in the peritoneal cavity for i.p. or i.v. injected CDDP, respectively. Thus, DDTC inactivates CDDP to a comparable or lesser extent than does TS.

Quantification of strontium in plasma and urine with flameless atomic absorption spectrometry

This analytical method for determination of Sr in plasma and urine involves flameless atomic absorption spectrophotometry (FAAS). Drying, charring, and atomization were optimized with respect to temperature, temperature ramp, and duration for Sr in dilute HNO3 and Sr in plasma diluted 20-fold with dilute HNO3. Calibration curves (r greater than 0.995) were linear in the concentration range 5-250 micrograms/L for Sr in various media, with intercepts negligibly small except for the calibration curves in 1:1-diluted plasma and undiluted urine. The estimated detection limits for Sr in 20-fold-diluted plasma and 50-fold-diluted urine were 2 and 3 micrograms/L, respectively. Endogenous Sr in plasma and urine was estimated at 16 (SD 8) micrograms/L and 158 (SD 26) micrograms/L (n = 6), respectively. Intra- and interassay CVs were 9.1% and 5.3% for 20-fold-diluted plasma at a Sr concentration of 25 micrograms/L, and 6.9% and 4.8% at a concentration of 250 micrograms/L. The respective CVs were 8.2% and 1.2% for 50-fold-diluted urine at the low concentration, and 4.0% and 4.6% at the high concentration. In a pharmacokinetic pilot study of 2.5 mmol of Sr orally administered to a healthy volunteer, the peak plasma concentration of Sr, 4.4 mg/L, decayed bi-exponentially [t1/2, alpha = 24 h, t1/2, beta = 77 h]; the estimated first-order absorption rate constant was 0.005 min-1; and the observed decay (day 0-6) of the urinary Sr/creatinine ratio closely paralleled the plasma decay [t1/2 = 70 h].

Quantification of strontium in plasma and urine with flameless atomic absorption spectrometry

This analytical method for determination of Sr in plasma and urine involves flameless atomic absorption spectrophotometry (FAAS). Drying, charring, and atomization were optimized with respect to temperature, temperature ramp, and duration for Sr in dilute HNO3 and Sr in plasma diluted 20-fold with dilute HNO3. Calibration curves (r greater than 0.995) were linear in the concentration range 5-250 micrograms/L for Sr in various media, with intercepts negligibly small except for the calibration curves in 1:1-diluted plasma and undiluted urine. The estimated detection limits for Sr in 20-fold-diluted plasma and 50-fold-diluted urine were 2 and 3 micrograms/L, respectively. Endogenous Sr in plasma and urine was estimated at 16 (SD 8) micrograms/L and 158 (SD 26) micrograms/L (n = 6), respectively. Intra- and interassay CVs were 9.1% and 5.3% for 20-fold-diluted plasma at a Sr concentration of 25 micrograms/L, and 6.9% and 4.8% at a concentration of 250 micrograms/L. The respective CVs were 8.2% and 1.2% for 50-fold-diluted urine at the low concentration, and 4.0% and 4.6% at the high concentration. In a pharmacokinetic pilot study of 2.5 mmol of Sr orally administered to a healthy volunteer, the peak plasma concentration of Sr, 4.4 mg/L, decayed bi-exponentially [t1/2, alpha = 24 h, t1/2, beta = 77 h]; the estimated first-order absorption rate constant was 0.005 min-1; and the observed decay (day 0-6) of the urinary Sr/creatinine ratio closely paralleled the plasma decay [t1/2 = 70 h].

Specific cation effect in the reaction of nitroprusside with cysteine, acetophenone and sulfite (Legal and Boedeker reaction)

The colour formation of cysteine (I), acetophenone (II) and sulfite (III) with the sodium and tetrabutylammonium (TBA) salt of nitroprusside (NP2-) in aqueous solution was studied. The intensity of colour formation depends strongly on the nature and concentration of the cations and increases in the order TBA less than Li less than Na less than K less than Rb less than Cs (in case of cysteine TBA and Li are interchanged). This specific cation effect was known for the Boedeker reaction (III) and is now also demonstrated for the Legal reaction (I and II). The adduct formation between NP2- and I to III is based on an anion-anion interaction. The role of the cation is to reduce the Coulombic repulsion between the reactants by ion-pair formation. The efficiency of ion-pair formation corresponds with the order given before except for TBA, which behaves divergently.

Nitroprusside, antihypertensive drug and analytical reagent. Review of (photo)stability, pharmacology and analytical properties

A review of physical, chemical, analytical and pharmacological properties of nitroprusside is presented. In view of the pharmaceutical applications of nitroprusside special attention is given to the discussion of the (photo)degradation, the stability of the pharmaceutical formulations, the application as a reagent in pharmaceutical analysis and the redox behaviour.