Abstract 3841: Therapeutic targeting of FLT3 mutations in AML via menin-MLL1 and FLT3 inhibition

Acute myeloid leukemias (AML) that are driven by MLL1 (KMT2A)-fusion proteins (MLL-f) or NPM1 mutations (NPM1mut) are both associated with aberrant expression of HOX and MEIS1 transcription factors and commonly harbor mutations in the gene encoding the receptor tyrosine kinase FLT3. Inhibition of the menin-MLL1 interaction has been shown to be a therapeutic opportunity in MLL-f driven leukemias and we recently demonstrated that this interaction is a dependency in NPM1mut AML. MI503 a specific small molecule menin-MLL1 inhibitor reduces dramatically cell growth and reverses leukemogenic gene expression including MEIS1 and FLT3. To determine global transcriptional changes associated with menin inhibition we performed RNA sequencing upon MI503 treatment in NPM1mut OCI-AML3 and MLL-f driven MV411 cells. MEIS1 and its putative target gene FLT3 were found to be among the most significantly downregulated genes. MEIS1 and FLT3 were consistently downregulated in various human and murine leukemia cell lines driven by MLL-f or NPM1mut. Allele specific qPCR confirmed profound downregulation of the mutant FLT3 allele in the MLL-f driven MV411 and MOLM13 cells as well as murine Npm1mut/+Flt3ITD/+ cells that all harbor a FLT3-ITD mutation. FLT3 surface expression was also substantially reduced upon MI503 treatment as assessed by FACS. Next, we assessed combinatorial menin- and FLT3 tyrosine kinase inhibition using MI503 and the 2nd generation FLT3 inhibitor AC220. The two drugs worked in a synergistic way to promote growth inhibition and enhanced apoptosis compared to single drug treatment or vehicle alone in MOLM13 and MV411 cells. HL60 and NB4 AML cells lacking NPM1mut, MLL-f, or FLT3-ITD showed no response. Drug synergism was also observed in the murine NPM1mut/+FLT3ITD/+ AML cells when combining MI503 with ponatinib a tyrosine kinase inhibitor with activity against the FLT3-ITD F692L resistance mutation that has been described in these cells. Of interest, ectopic expression of Hoxa9-Meis1 resulted in upregulation of Flt3 and rescued the antiproliferative effect of combined menin- and FLT3-inhibition. Combined menin- and FLT3 inhibition reduced FLT3 phosphorylation more than AC220 or MI503 alone most likely reflecting the joint effect of AC220 mediated inhibition of FLT3 phosphorylation and transcriptional FLT3 suppression via MI503. Transcriptional profiling revealed substantial silencing of FLT3 downstream signature genes including MYC upon combinatorial treatment. In vivo treatment of leukemic MV411 xenografts with combined MI503 and AC220 resulted in significantly enhanced reduction of leukemia burden that was observed with single drug treatment compared to vehicle controls. Altogether, our data show that simultaneous menin- and FLT3 inhibition has a synergistic effect against leukemogenic FLT3 signaling and may represent a novel therapeutic concept for MLL-f and NPM1mut driven AML with concomitant FLT3-ITD.

Citation Format: Margarita M. Dzama, Martha C. Taubert, Kerstin Kunz, Johanna Rausch, Chun-Wei Chen, Annalisa Mupo, Matthias Theobald, Thomas Kindler, Richard P. Koche, George S. Vassiliou, Scott A. Armstrong, Michael W. Kühn. Therapeutic targeting of FLT3 mutations in AML via menin-MLL1 and FLT3 inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3841.

Evaluation of left and right ventricular systolic and diastolic electromechanical synchrony in older people: a population-based observational study

It is unknown whether physiological ageing also goes along with electromechanical asynchrony of contraction. Aim of the study was to evaluate synchrony of contraction in older people with ("non-healthy") or without ("healthy") evidence for structural cardiac disease. In 547 persons (age 76.7+/-5.5 years, 306 male, 241 female) recruited from a population-based cohort of the ActiFE-Ulm study including a random sample of people >/=65 years old living in the region of Ulm, Germany, various PW- and TDI-Doppler based markers for asynchrony were obtained by echocardiography. Within a subgroup of 84 healthy subjects, at most minimal systolic and diastolic asynchrony was found. Concerning systolic asynchrony, similar observations were made within the non-healthy subgroup. However, extent of diastolic left ventricular intraventricular asynchrony and also - by tendency - diastolic interventricular asynchrony was increased in comparison to the healthy subgroup. To conclude, no evidence that physiological ageing might go along with relevant left or right ventricular systolic or diastolic electromechanical asynchrony was found in our study. Furthermore, our population-based data support the results from other clinical studies with rather selected cohorts that structural heart diseases might go along with increased diastolic asynchrony.

An atypical presentation of necrotising fasciitis

Necrotising fasciitis is a rare infection with a high mortality rate. Clinical manifestation may be influenced by an underlying disease state. We report a case of a 70-year-old man with an anaplastic large-cell lymphoma who presented with inconclusive signs of necrotising fasciitis following a neutropenic phase after chemotherapy. Surgical exploration did not reveal the typical macroscopic features of necrotising fasciitis. Microbiological investigations revealed Escherichia coli. The lack of massive tissue inflammation, probably due to the neutropenia in our patient, has not been described by other authors. Diagnostic uncertainties owing to masked or uncharacteristic signs in immune compromised patients may lead to a delayed surgical debridement, of which clinicians should be aware.

(18-Crown-6-κ6O)(pyrazolato-κ2N,N′)-potassium(I)

The asymmetric unit of the title compound, [K(C₃H₃N₂)(C₁₂H₂₄O₆)], is composed of a potassium cation bonded to the six O atoms of a crown ether mol­ecule and the two N atoms of a pyrazolate anion. The K⋯O distances range from 2.8416 (8) to 3.0025 (8) Å, and the two K⋯N distances are 2.7441 (11) and 2.7654 (11) Å. The K cation is displaced by 0.8437 (4) Å from the best plane through the six O atoms. The latter plane is almost perpendicular to the plane of the pyrazolate ring [dihedral angle 83.93 (3)°].

Setting ambiguity in C2/c with dibromidotetrakis(1H-pyrazole-kappaN2)manganese(II) as an example

trans-Dibromidotetrakis(1H-pyrazole-kappaN(3))manganese(II), [MnBr2(C3H4N2)4], crystallizes in the C2/c space group with the Mn atom located on a centre of inversion. As a result, there is just one half-molecule in the asymmetric unit. Geometric parameters are in the usual ranges. The Mn centre is octahedrally coordinated by four pyrazole residues in the equatorial plane and by two bromide ligands in the axial positions. The molecular conformation is stabilized by N-H...Br hydrogen bonds. The structure of the title compound had already been described [Lumme & Lindell (1987). J. Coord. Chem. 15, 383-392] in a different setting, with the Mn atoms located on inversion centres on Wyckoff position d (1/4, 1/4, 1/2; 3/4, 1/4, 0; 3/4, 3/4, 1/2; 1/4, 3/4, 0). In the conventional setting, however, the Mn atoms are situated on Wyckoff position a (0, 0, 0; 0, 0, 1/2; 1/2, 1/2, 0; 1/2, 1/2, 1/2). In this special case, if the c axis has the same length as the short diagonal of the ac plane, the transformation from one setting into the other yields almost indistinguishable cell parameters, and the possibility of confusion arises. This setting ambiguity could be the reason why two structures in different settings might be taken as polymorphs even though they can easily be transformed. As a result of this, care should always be taken to use the conventional setting.

Effect of age and sex on maturation of sensory systems and balance control

Maintenance of postural balance requires an active sensorimotor control system. Current data are limited and sometimes conflicting regarding the influence of the proprioceptive, visual, and vestibular afferent systems on posture control in children. This study investigated the development of sensory organization according to each sensory component in relation to age and sex. A total of 140 children (70 males, 70 females; mean age 10y [SD 4y]; age range 3y 5mo-16y 2mo) and 20 adults (10 males, 10 females; mean age 30y 6mo [SD 8y 4mo]; age range 17y 2mo-49y 1mo) were examined using the Sensory Organization Test. Participants were tested in three visual conditions (eyes open, blindfolded, and sway-referenced visual enclosure) while standing on either a fixed or a sway-referenced force platform. Mean equilibrium scores for the six balance conditions showed rapid increases and maturation ceiling levels for age-related development of the sensorimotor control system. Proprioceptive function seemed to mature at 3 to 4 years of age. Visual and vestibular afferent systems reached adult level at 15 to 16 years of age, revealing differences between young males and females. Characterizing balance impairments can contribute to the diagnostic evaluation of neuromotor disorders.

[The dilemma of the last vascular access]

Age and cardio-vascular pathologies in hemodialysis patients confront us with the increasing difficulties in finding vascular access. This implies the necessity to keep in place central venous catheters (CVC) and find alternative puncturing sites. CVC malfunction in dialysis is frequently encountered (87% of cases). A variety of salvage procedures are described in the literature amongst them the "stripping" and re-canalization methods. Stripping allows withdraw fibrin strands around the CVC with a success rate of 75 to 90% and a rather low complication rate, although this may not be well documented. Re-vascularization techniques allow the placement of a CVC even across a thrombosed vessel. Success rate here is 100% in a limited series of patients. In addition to the classical access sites, like internal jugular and subclavian vein exist, alternative sites such as the external jugular, femoral or even translumbar vein.

Bacillus Calmette-Guerin. Is monthly maintenance an option for transitional cell carcinoma of the bladder?

Purpose: Recently, a Southwest Oncology Group study (SWOG 8507) demonstrated increased efficacy for a bacillus Calmette-Guerin (BCG) maintenance (mtce) program (3 weekly treatments at 3 months, 6 months, and every 6 months thereafter for 3 years) following 6 weekly instillations with BCG as compared to no mtce ("6+3" protocol). The remarkable results from the mtce arm were unfortunately accompanied by grade 3 or 4 toxicity in 26%. In fact; only 16% of the patients in the maintenance arm received BCG at each of the 7 prescribed courses. Herein, we report on a series of 37 patients with high risk (rapidly recurring grade 2 or 3) Ta, T1 transitional cell carcinoma (TCC) or carcinoma in situ (TIS) of the bladder who received 6 weekly BCG treatments followed by monthly mtce for one year. Patients and Methods: This was a prospective, non-randomized trial of 37 patients with high risk superficial transitional cell carcinoma (TCC) who received one or two 6-week induction courses of intravesical Tice BCG, followed by monthly mtce for 12 months. Entry criteria were identical to those of SWOG 8507. The mean follow-up interval was 40.7 months. Results: Twenty eight of thirty-seven patients (75.7%) remained free of disease recurrence at a median of 40.7 (range 13-101) months. Only one patient progressed to muscle invasive disease. Only 1 of 37 (2.7%) patient experienced grade 3/4 toxicity. Conclusion: In this single institution, monthly maintenance protocol, freedom from recurrence was significant with dramatically less grade 3 or 4 toxicity than reported in SWOG 8507.

Cardiovascular morbidity and endothelial dysfunction in chronic haemodialysis patients: is homocyst(e)ine the missing link?

BACKGROUND

Haemodialysis patients exhibit an excessive burden of atherothrombotic disease, which is not explained adequately by traditional risk factors. Hyperhomocyst(e)inaemia, a consistent finding in uraemic patients, is now widely recognized as an independent risk factor for vascular disease. The aim of this study was to examine the hypothesis that hyperhomocyst(e)inaemia is associated with cardiovascular complications in dialysed patients.

METHODS

In a cohort of 63 stable chronic haemodialysis patients, we examined the causal relationship between hyperhomocyst(e)inaemia and vascular endothelial and haemostatic function. All their markers were determined before and after an 8-week course of a 10 mg per day oral folate supplementation, a manoeuvre known to decrease hyperhomocyst(e)inaemia in uraemic patients.

RESULTS

History of at least one cardiovascular atherothrombotic event was present in 47.6% of the haemodialysed patients, and radiographic evidence of vascular calcifications in 70%. Hyperhomocyst(e)inaemia was found in all patients, averaging 3.5-fold the upper limit of normal values (P<0.001), despite the lack of clinical and biological evidence of malnutrition. Fibrinogen, von Willebrand factor and plasminogen activator inhibitor type 1, but not endothelin 1, were significantly higher in haemodialysis patients than in controls. After adjustment for all variables, past history of cardiovascular events was independently associated with higher levels of homocyst(e)inaemia only (odds ratio (OR) 1.06; 95% confidence interval (CI) 1.01-1.12; P<0.026). The presence of aortic calcifications was independently and significantly associated with age (OR 1.37; 95% CI 1.07-1.75; P<0.025), homocyst(e)inaemia (OR 1.14; 95% CI 1.02-1.27; P<0.05) and fibrinogen concentration only (OR 9.74; 95% CI 1.25-75.2; P<0.05). None of the endothelial haemostatic factors was, however, related to homocyst(e)ine levels. Mid-term folate supplementation decreased plasma homocyst(e)ine levels significantly without achieving normal values. No significant change of endothelial-haemostatic markers was observed, however, despite the drop in plasma homocyst(e)ine.

CONCLUSIONS

Hyperhomocyst(e)inaemia is associated with increased cardiovascular risk in haemodialysis patients. Folate supplementation was partially effective in lowering hyperhomocyst(e)inaemia, but its usefulness in terms of reduction in cardiovascular morbidity and mortality remains to be determined in prospective trials.

Abysmal prognosis of patients with type 2 diabetes entering dialysis

INTRODUCTION

The importance of non-insulin-dependent diabetes mellitus (type II diabetes) as a leading cause of end-stage renal disease is now widely recognized. The purpose of this study was to assess life-prognosis and its predictors in a cohort of patients newly entering dialysis.

MATERIAL AND METHODS

Eighty-four consecutive type II diabetes patients (40% of all patients) starting dialysis between 01/01/95 and 31/12/96 were studied retrospectively, focusing on clinical data at inception and life-prognosis after a mean follow-up of 211 days. Patients were divided into three groups, according to onset of renal failure: acute 11% (9/84), chronic 61% (51/84) and acutely aggravated chronic renal failure 28% (25/84).

RESULTS

Patients (mean age 67 years) had long-standing diabetes (mean duration approximately 15 years), heavy proteinuria (approximately 3 g/24h) and diabetic retinopathy (67%). The average creatinine clearance (Cockcroft's formula) was 13 ml/min. Cardiovascular diseases were highly prevalent at the start of dialysis: history of myocardial infarction (26%), angina (36%) and acute left ventricular dysfunction (67%). More than 80% of the patients underwent the first session dialysis under emergency conditions, a situation in part related to late referral to the nephrology division (63% for chronic patients). A great majority of the patients were overhydrated when starting dialysis, as evidenced by the average weight loss of 6 kg, during the first month of dialysis, required to reach dry weight. Nearly 64% of the patients presented high blood pressure (> 140/90 mmHg) when starting dialysis despite antihypertensive therapy (mean: 2.3 drugs). The outcome of this type II diabetes population was dramatic: 32% (27/84) died after a mean follow-up of 211 days, mostly from cardiovascular diseases. The rate of recovery of renal function was low in both the acute and the acutely aggravated renal failure group (30% and 24%, respectively). Of note, iatrogenic nephrotoxic agents accounted for renal function impairment in nearly 30% of patients.

CONCLUSION

Our observational study illustrates the high burden of cardiovascular diseases contrasting with sub-optimal cardiovascular therapeutic interventions in type II diabetes patients entering dialysis. Factors aggravating renal failure were mainly iatrogenic, and therefore largely avoidable. Late referral generally implied a poor clinical condition at the start of dialysis.

Bioavailability of escin after administration of two oral formulations containing aesculus extract

In a steady-state cross-over study in 18 healthy volunteers, the relative bioavailability of beta-escin (CAS 11072-93-8) after oral administration of a new immediate release enteric-coated test formulation containing aesculus extract was evaluated in comparison with a prolonged-release reference preparation. The subject received the test and the reference preparation in randomised sequence for 7 days each with no washout period in between. The daily dose was 50 mg escin b.i.d. Blood samples for pharmacokinetic profiling were taken on the 7th treatment day of each period over a full 24-h cycle of two successive dosing intervals. For the determination of beta-escin serum concentrations, a highly specific radioimmunoassay (RIA) was used. Generally, escin serum concentrations were lower during the second dosing interval (night) than during the first interval, probably indicating a drug by food interaction. (The morning dose was given after overnight fasting whereas the evening dose was given between meals). Test and reference demonstrated bioequivalence with regard to the extent of absorption; for the AUC (0-24 h p.a.), the 90% confidence interval ranged from 84% to 114% (point estimate: 98%). The differences observed for rate parameters can be disregarded due to the generally slow elimination and the wide therapeutic concentration range of escin.

A cost analysis of a Helicobacter pylori eradication strategy in a large health maintenance organization

OBJECTIVES

We sought to describe the effect of a Helicobacter pylori eradication strategy on health care costs among a cohort of health maintenance organization (HMO) members with peptic ulcer disease (PUD).

METHODS

Patients were identified from an outpatient diagnosis database and verified at chart review to have new-onset PUD by upper endoscopy or upper gastrointestinal radiographic series. Health plan registration and accounting databases were used to track costs over 12 months after initial diagnosis. Costs were analyzed separately for an initial 2-month interval and a 10-month follow-up period. Inpatient and pharmacy costs are those directly attributable to PUD (either a PUD-related discharge diagnosis or an antiulcer medication prescription). Outpatient costs are total costs. All cost differences were adjusted for age and gender.

RESULTS

Twenty-seven of 93 patients meeting selection criteria received H. pylori treatment. During the 2-month treatment window, adjusted PUD-related inpatient costs were higher for the H. pylori treated group (difference, $234.00/person), whereas total outpatient costs and PUD-related pharmacy costs were similar. During the 10-month follow-up period, PUD-related inpatient and pharmacy adjusted costs were similar, but adjusted outpatient costs in the H. pylori treated group were lower than in the untreated group (difference, $508.00/person). Total adjusted follow-up period costs were $555.00/person less in the H. pylori treated group (p = 0.05). Total 12-month costs in the H. pylori treated group were $285.00/per person less than in untreated patients, (p > 0.2); 30% of H. pylori treated patients were still receiving antisecretory therapy 1 yr after diagnosis, compared to 41.9% of untreated patients.

CONCLUSIONS

H. pylori treatment is associated with a decreased cost of follow-up care for patients with PUD, primarily due to decreased outpatient utilization.

[Doppler echocardiography of left ventricular filling in chronic renal insufficiency: before and after dialysis]

Hemodialysis can achieve loss of body water, variable in the different water compartments, and that depends on the dry weight and the composition of the dialysate. We have studied echocardio-Doppler findings in 26 end stage renal disease patients (from 26 to 84 years), in whom 25 have hypertension, in sinusal rythm and ejection fraction above 55%. When they achieved a 3.52% decrease in body weight, without modification of heart rate and decrease in median arterial pression, these patients exhibited decrease in auricular (p = 0.001) and ventricular diameter both in systole and diastole (p = 0.001), in maximum velocity of E wave (p = 0.001) and E/A ratio. There was no significant reduction of maximum velocity of A wave, but 4 differents patterns of E/A ratio were demonstrated. The main determinant factor of these patterns was found to be the age of the patient.

Quality of life, health care utilization, and costs among women undergoing hysterectomy in a managed-care setting

OBJECTIVE

We compared quality of life, utilization, and costs for women undergoing elective abdominal, laparoscopically assisted vaginal, or vaginal hysterectomy within a managed-care organization.

STUDY DESIGN

A prospective study of 287 women who underwent an elective hysterectomy was performed.

RESULTS

Patients undergoing a vaginal hysterectomy reported returning to normal activity levels sooner and had more favorable quality-of-life scores than did those undergoing laparoscopically assisted vaginal hysterectomy or abdominal hysterectomy. Laparoscopically assisted vaginal hysterectomy was often nearly as favorable as vaginal hysterectomy, particularly at 28 days after the operation, whereas the abdominal hysterectomy group consistently reported the poorest postoperative quality-of-life scores. No significant differences were noted in utilization or costs in the 60-day preoperative period, whereas hospitalization and postoperative costs were highest among the abdominal hysterectomy group and lowest for those undergoing a vaginal hysterectomy.

CONCLUSIONS

Vaginal hysterectomy resulted in better quality-of-life outcomes and lower utilization and costs compared with laparoscopically assisted vaginal or abdominal hysterectomy.

Costs of acid-related disorders to a health maintenance organization

BACKGROUND

Little is known about the economic impact of the acid-related disorders (ARDs), which include dyspepsia, gastritis, gastroesophageal reflux disease (GERD), and peptic ulcer disease (PUD), in managed care patient populations.

OBJECTIVES

To describe the prevalence of medically attended ARDs, and their direct medical costs from the perspective of a large health maintenance organization (HMO).

METHODS

A total of 1,550 ARDs subjects (age > or = 18 years), were randomly sampled from outpatient diagnosis and pharmacy databases of the Kaiser Permanente Medical Care Program of Northern California and verified by chart review. Five age- and gender-matched controls were identified per subject. One-year prevalence, excess annual costs, and initial 6-month costs for incident cases were estimated using the HMO cost accounting system.

RESULTS

Total ARDs prevalence (5.8%) increases with advancing age. GERD is the most common ARD (2.9% overall prevalence). Annual per person attributable costs were $1,183, $471, and $431 respectively for PUD, GERD, and gastritis/dyspepsia. Excess inpatient costs for PUD explain its higher costs. Outpatient costs were somewhat higher for GERD ($279) than for PUD or gastritis/dyspepsia. Pharmacy costs were relatively low for each condition, in part because many patients were treated with generic cimetidine. Total annual HMO expenditures for ARDs were $59.4 million, with 40.6%, 36.8%, and 22.6% respectively for GERD, PUD, and gastritis/dyspepsia.

CONCLUSIONS

Acid-related disorders, particularly GERD and PUD, contribute substantially to the direct costs of medical care in this managed care population.

Economic evaluation of pharmacist involvement in disease management in a community pharmacy setting

This study evaluated the economic impact of patient-focused pharmacist intervention in the community retail setting in patients with hypertension, diabetes, asthma, and/or hypercholesterolemia. Specially trained pharmacists intervened by providing targeted patient education, performing systematic patient monitoring, offering feedback and behavior modification, and communicating regularly with patients' physicians to enable early intervention for drug-related problems. We evaluated prescription drug costs and total medical costs by comparing claims data from 188 patients enrolled in the program at three intervention pharmacies with data from 401 control patients at five nonparticipating pharmacies from the same retail chain. For all disease states, the average cost per prescription was significantly higher in the group receiving intervention than in the control group. Differences in total monthly prescription costs were significant only for patients with asthma, with higher monthly costs in the group receiving intervention. Substantial savings were demonstrated across all cost analyses for total monthly medical costs. Savings ranged from a conservative estimate of $143.95 per patient per month to $293.39 per patient per month when accounting for the possible influence of age, comorbid conditions, and disease severity. Our data indicate that pharmacist intervention in this community pharmacy-based disease management model substantially reduced monthly health care costs in patients with hypertension, hypercholesterolemia, diabetes, and asthma.

[Heparin-induced thrombocytopenia Type II (HIT II) A fatal complication of heparin use for thromboembolism prevention]

Heparin-induced thrombocytopenia type II (HIT II) is the most severe complication during prophylactic treatment with low doses of heparin. Five cases demonstrate the life-threatening consequences of this immune-mediated thromboembolic disease. In order to improve prognosis it is most important to start therapy just before diagnosis is assured by laboratory tests. First choice treatment is the low-molecular-weight heparinoid Orgaran. In patients with an episode of HIT II both low-molecular-weight heparin and unfractionated heparin will be contraindicated for a life time.

[Pharmaokinetics of beta-escin after administration of various Aesculus extract containing formulations]

With a specific radioimmunoassay the pharmacokinetics and relative bioavailability of escin was measured after administration of different formulations containing Aesculus-extract. Of special interest was the relative bioavailability of escin after administration of a newly developed film-coated tablet with sustained release in comparison to a reference formulation. In a cross-over steady-state study in 24 volunteers bioequivalence of test and reference preparation could be demonstrated. The 90% confidence interval of the AUC (O-tau) was 98.3 to 120.9%.

Lack of interaction between pantoprazole and digoxin at therapeutic doses in man

Substituted benzimidazole inhibitors of the gastric H+/K+ATPase may interact with the cytochrome P450 enzyme system and alter the pharmacokinetics of coadministered drugs. On the other hand, changes in intragastric pH might alter the absorption of other drugs. The primary aim of the present study was to determine whether pantoprazole modifies the steady-state serum concentrations of orally administered digoxin. Secondary aims were the influence of digoxin on the pharmacokinetics of pantoprazole as well as safety and tolerability. Eighteen healthy volunteers received a single oral dose of pantoprazole (40 mg) and serum concentrations were determined. Three to 10 days later, subjects received in a single-blind, randomized, crossover fashion oral beta-acetyldigoxin (0.2 mg) twice daily and concomitant oral pantoprazole (40 mg) or placebo once daily for 5 days. Serum concentrations of pantoprazole and digoxin were determined on day 5. Primary characteristics for confirmative assessment of no interaction were AUC and Cmax of digoxin. Lack of interaction in the sense of equivalence was concluded for both digoxin (with and without pantoprazole) and pantoprazole (with and without digoxin) as the 90%-confidence intervals of the respective AUC- and Cmax-ratios were within the equivalence range of 0.8-1.25. Pantoprazole did not influence the characteristic ECG modifications (T-wave) caused by digoxin. Both drugs were well tolerated and no adverse events or clinically relevant alterations in vital signs or clinical laboratory parameters were observed during treatment. In conclusion, pantoprazole and digoxin may be administered concomitantly without the need for dose adjustment.

Pantoprazole does not interact with nifedipine in man under steady-state conditions

The new H+/K(+)-ATPase inhibitor pantoprazole is extensively metabolized by the liver. As substituted benzimidazoles can interact with the cytochrome P450 system, the influence of pantoprazole on the steady-state pharmacokinetics of the calcium antagonist nifedipine was investigated. Nifedipine is widely used in the treatment of cardiovascular diseases and is mainly metabolized in the liver by CYP3A4. Additionally possible influence of gastric pH on the absorption of nifedipine is discussed. Twenty-four healthy volunteers (13 m/11 f) completed a randomized crossover study. As test they received orally 40 mg pantoprazole s.i.d. for 10 days and concomitantly 20 mg nifedipine sustained release (SR) b.i.d. from day 6 to 10. During the reference period 20 mg nifedipine SR were dosed b.i.d. for 5 days. Nifedipine and pantoprazole serum concentrations were measured over one dosing interval on the last day of each period. Lack of pharmacokinetic interaction was handled as an equivalence problem. The 90%-confidence intervals (CI) of the ratios of the primary characteristics AUC and Cmax of nifedipine were entirely within the equivalence range of 0.8-1.25. Hence no influence of pantoprazole on the pharmacokinetics of nifedipine was concluded, either by competition with the CYP3A4 or by the reduction of gastric acid secretion. As secondary criterion nifedipine had no relevant influence on the pantoprazole pharmacokinetic characteristics. All treatments were safe and well tolerated. No dose adjustment is required during concomitant treatment with nifedipine and pantoprazole.