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Results for “randomized crossover trial”

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PubMed1994

Bioequivalence of 20-mg once-daily tamoxifen relative to 10-mg twice-daily tamoxifen regimens for breast cancer.

PURPOSE: We studied the bioequivalence of a new once-daily regimen of tamoxifen citrate relative to the standard twice-daily regimen of tamoxifen citrate, an established antiestrogenic treatment for breast cancer. PATIENTS AND METHODS: Of 30 women with breast cancer, 27 completed this open, two-period, crossover randomized trial. During one 3-month period, patients took one standard 10-mg tamoxifen tablet twice daily; during the preceding or following 3-month period, patients took one of the new 20-mg tablets once daily. Pharmacokinetic profiles and safety parameters were assessed at the end of each 3-month treatment period. RESULTS: Overall, measured concentrations of tamoxifen and its principal active metabolite, N-desmethyltamoxifen, remained relatively constant over the 24-hour sampling periods at the end of each treatment sequence. For both compounds, the percentage differences of the geometric means for all pharmacokinetic parameters indicated bioequivalence of the once-daily regimen of tamoxifen relative to the standard twice-daily regimen. Both treatment sequences were well tolerated; reported adverse events occurred at similar frequencies with the two treatment regimens. CONCLUSION: The 20-mg tamoxifen tablet taken once daily was bioequivalent to the 10-mg tamoxifen tablet taken twice daily, with no difference in relative risk. The once-daily treatment is a simpler regimen and may facilitate compliance, which may enhance therapeutic outcomes during long-term treatment of breast cancer.

Administration, Oral↗

PubMed1993

The effect of pyridostigmine on bronchial hyperreactivity.

We examined the effect of pyridostigmine (PY) at a dose of 30 mg orally three times a day on nonspecific bronchial hyperreactivity in ten normal nonsmokers (NNS), ten smokers (SM), and ten mild asthmatics (AS). We conducted a double-blind, placebo-controlled, crossover trial, randomly assigning subjects to receive either placebo (PL) or PY before undergoing bronchoprovocation challenge with eucapnic voluntary hyperventilation (EVH) using dry gas. Compliance with PY was confirmed by measuring red blood cell acetylcholinesterase (Achase) levels during both days of testing. While taking PL, the mean (+/- SEM) falls in FVC and FEV1 after the bronchoprovocation were as follows: NNS, 1.0 percent (+/- 0.6) FVC and 4.3 percent (+/- 1.0) FEV1; SM, 2.4 percent (+/- 1.1) FVC and 2.7 percent (+/- 1.3) FEV1; AS, 5.3 percent (+/- 2.3) FVC and 11.5 percent (+/- 2.8) FEV1. The mean decreases in FVC and FEV1 while taking PY were as follows: NNS, 1.8 percent (+/- 0.7) FVC and 4.3 percent (+/- 0.8) FEV1; SM, 3.8 percent (+/- 1.4) FVC and 5.2 percent (+/- 1.6) FEV1; AS, 4.4 percent (+/- 1.3) FVC and 11.8 percent (+/- 2.8) FEV1. Within each category, using a paired t test to compare the results on each day of testing, no statistically significant differences were noted. Pyridostigmine at the tested dose has no significant effect on nonspecific bronchial hyperreactivity in normal NNS, SM, or AS.

Adult↗

PubMed1995

The reversibility of airway obstruction to an inhaled beta 2-adrenergic agent is less satisfactory after methacholine testing in asthmatic subjects.

AIMS: The aim of this work was to compare the response to an inhaled beta 2-adrenergic agent in two situations: (1) spontaneous airway obstruction in asthmatic subjects who had withheld treatment with the medication for more than 12 hs; and (2) after methacholine-induced airway obstruction once airway caliber had recovered to the premethacholine test value. SUBJECTS AND METHODS: Sixteen asthmatic subjects who showed a 20% or more improvement in FEV1 after inhaled beta 2-adrenergic agent (B2) (salbutamol, 200 micrograms) entered a double-blind crossover randomized trial in which the following tests were carried out: (1) FEV1 response after inhaling a placebo or active B2; (2) FEV1 response after inhaling a placebo or active B2 after a methacholine test that had induced a 20% or more reduction in FEV1, once FEV1 had recovered to the premethacholine value after inhaling salbutamol in an open fashion. RESULTS: As expected, the mean percent improvement in FEV1 in the spontaneous airway obstruction situation was 21.7 +/- 8.5% after inhaling the active B2 and 2.2 +/- 1.8% after placebo B2 (p < 0.001). Following recovery after methacholine challenge, the FEV1 was slightly superior (mean difference of 146 mL) to the premethacholine value before inhaling the active or placebo B2. In this situation, the percent improvement in FEV1 after inhaling the active B2 was only 7.5 +/- 4.4% and not significantly different from after inhaling placebo B2 (4.9 +/- 5.4%). Consequently, the end FEV1 value after inhaling active B2 was significantly higher in a situation of spontaneous airway obstruction than after methacholine-induced airway obstruction (mean difference = 110 mL; p = 0.02). CONCLUSION: After a methacholine test, the reversibility of an inhaled beta 2 agent is not significantly different from a placebo and is less satisfactory than in a situation of spontaneous airway obstruction. The mechanism for this needs to be explored but it is not secondary to persisting airway obstruction.

Adult↗

PubMed1997

Salmeterol reduces dyspnea and improves lung function in patients with COPD.

STUDY OBJECTIVE: To investigate the short-term effects of inhaled salmeterol on the perception of dyspnea and lung function in patients with COPD. DESIGN: Double-blind, crossover, randomized trial comparing inhaled salmeterol and inhaled placebo over 4 h. SETTING: Pulmonary function laboratory at university medical center. PATIENTS: Sixteen patients with symptomatic COPD and at least 200-mL increase in FEV1 after inhalation of two puffs (180 microg) of albuterol. INTERVENTIONS: Visit 1 was used for familiarization. At visits 2 and 3 (2 to 3 days apart), patients inhaled either two puffs of salmeterol (42 microg) or placebo. MEASUREMENTS AND RESULTS: Lung function and dyspnea were measured at 0.5, 2, and 4 h after inhalation of the study medication. Dyspnea was measured by the -5 to +5 category scale at rest and by the 0 to 10 category-ratio scale while breathing through inspiratory resistances of 5, 15, and 30 cm H20/L/s. Age was 66+/-8 years (mean+/-SD). FEV1 was 0.97+/-0.331 (51+/-13% predicted). There were significantly higher values for FEV1 and FVC (at all time periods) and lower values for functional residual capacity (at all time periods) and residual volume (at 4 h) with salmeterol than with placebo. There were significantly lower dyspnea ratings on the -5 to +5 category scale (p=0.03 at 2 h and p=0.02 at 4 h) and for the mean dyspnea scores during resistive breathing with salmeterol compared with placebo (p=0.002). CONCLUSIONS: Inhaled salmeterol reduced dyspnea, increased airflow, and reduced hyperinflation over 4 h in patients with symptomatic COPD.

Administration, Inhalation↗

PubMed1997

Effect of pretreatment with heparin on pulmonary and cutaneous response.

Although anticoagulant properties of glycosaminoglycan heparin are primary in medicine, a variety of other biological functions related to heparin have been suggested. Since heparin is a selective inhibitor of inositol triphosphate (IP3) receptors that are involved in release of calcium in mast cells and many other cells, it is possible that heparin may act as a natural anti-inflammatory molecule and modify these reactions. Therefore, the purpose of the present study was to determine the role of heparin in allergic inflammatory responses: the pulmonary reaction and the cutaneous response, in a double-blind, placebo-controlled, crossover randomized trial. To evaluate the effect of heparin on methacholine-induced bronchoconstriction, nebulized heparin (20,000 units) was administered to 12 asthmatics and nonspecific challenge was performed immediately thereafter. Measurements of Raw and SGaw were obtained before and 1 hr after nebulization of heparin. In 12 other allergic subjects, heparin (25 U/kg) was given intravenously 10 min before skin prick test. We demonstrated that pretreatment with heparin reduced skin test reactivity from 24.06 +/- 1.2 mm to 18.26 +/- 2.27 mm and increased the methacholine PC20 value from 1.69 +/- 0.48 mg/ml to 8.14 +/- 3.11 mg/ml (p < 0.05), but did not prevent an increase in Raw and/or a decrease in SGaw. Heparin modified the methacholine-induced bronchoconstrictor response, but this did not reflect a protective effect in airway resistance and specific conductance. These data suggest that anti-inflammatory effects of heparin are time-dependent and/or that heparin may have a transient inhibitory role in allergic reactions.

Administration, Inhalation↗

PubMed2001

Gender differences in the disposition of metronidazole.

OBJECTIVE: Gender is usually considered to be one of the factors influencing disposition of drugs, but the evidence available is sometimes conflicting and information for a large number of frequently used drugs is lacking. An evaluation of sex differences in the disposition ofmetronidazole was carried out during a bioequivalence study. SUBJECTS AND METHODS: Twenty-four volunteers (12 males and 12 females) were included in an open, single-dose, two-sequence, crossover randomized trial with a one-week washout interval. All volunteers received in each period, a single 250 mg dose of one of the two study formulations of metronidazole. Venous blood samples were collected immediately before and at 15 time points in an 48-hour interval after drug administration; metronidazole concentrations were determined by HPLC. Non-compartmental pharmacokinetic analysis was performed and log-transformed AUC(0-infinity) and Cmax were tested for bioequivalence. Sex differences were evaluated by means of a 4-factor (sex, sequence, treatment and period) ANOVA. RESULTS: The studied formulations were found bioequivalent according to international standards: average 90% confidence interval for AUC(0-infinity) was 98 to 104 and for Cmax 93 to 115. After correction for the administered dose/kg, AUC was about 12% lower in females than in males (p = 0.0388) and, therefore, a higher calculated oral Cl/kg was found in females. Apparent distribution volume, after correction for weight, was significantly higher in males (p = 0.0019). Metronidazole half-life and MRT were shorter in females than in males (p - 0.0014 and p = 0.0002, respectively). CONCLUSIONS: Data obtained in this study suggest that metronidazole clearance in females is about 12% higher than in males although these differences are probably of no clinical relevance.

Adult↗

PubMed1990

Crossover study of thalidomide vs placebo in severe recurrent aphthous stomatitis.

A multicentric crossover randomized trial of 100 mg of thalidomide vs placebo each for 2 months was conducted in patients with severe aphthous stomatitis of more than 6 months' duration. Seventy-three patients were included. Complete remission was obtained in 32 patients who received thalidomide and in 6 patients who received placebo. The confidence interval of the difference between the two treatments ranged from 25% to 53%. Most of the patients who did not achieve a complete remission had a dramatic improvement with regard to the number of aphthae when they were receiving thalidomide. Thirteen of 17 patients who had a complete remission while they were receiving thalidomide had a recurrence with placebo, 19 +/- 9 (mean +/- SD) days after stopping this drug. Side effects were significantly more frequent with thalidomide, especially drowsiness and constipation. We concluded that thalidomide in a dosage of 100 mg/d is an effective treatment of severe aphthous stomatitis but is not without some risk.

Adult↗

PubMed1993

[Antiemetic efficacy of granisetron in the treatment of pediatric cancer--(1). Clinical evaluation of granisetron at a dose of 40 micrograms/kg].

Seventeen children with various types of cancer were studied on the effectiveness of antiemetic drug, granisetron, by a crossover randomized trial; receiving granisetron (40 micrograms/kg; n = 53) or conventional antiemetics, during intensive chemotherapy. In the patients given granisetron nausea and vomiting were well controlled (83.0%), compared with 33.3% of conventional (non granisetron) group. The mean number of vomiting episodes for each 6h-period over 24h after chemotherapy was reduced markedly in the patients given granisetron, compared with conventional therapy. One patient developed paraesthesia of the hand after injection of granisetron as the adverse effect, which recovered to normal spontaneously after 3 hrs. Our data indicated that antiemetic effect of granisetron was superior to conventional antiemetic drugs, both in terms of clinical effectiveness and usefulness.

Adolescent↗

PubMed1995

Chloromethylisothiazolone/methylisothiazolone (CMI/MI) use test with a shampoo on patch-test-positive subjects. Results of a multicentre double-blind crossover trial.

A randomized, multicentre, double-blind, 2-period crossover study with 2 shampoos was performed on subjects patch-test-positive to 100 ppm CMI/MI. One shampoo was preserved with 15 ppm a.i. CMI/MI, the other with 0.3% imidazolidinyl urea (IU). 27 subjects from 5 European dermatology clinics participated. 1 subject discontinued use after severe adverse reactions to the CMI/MI-preserved shampoo and did not evaluate the other shampoo. Another 2 subjects developed moderate symptoms with the CMI/MI-preserved shampoo and discontinued its use, but tolerated the IU-preserved shampoo for the full 2-week period. 2 subjects discontinued use after 1 or 2 washes after severe adverse reactions to the IU-preserved shampoo. 1 of these subjects tolerated the CMI/MI-preserved shampoo for 2 weeks without any untoward effects. However, the majority of subjects had negative findings on the scalp, face, neck, and hands for both shampoos. The physicians' global evaluation data indicated that shampoo with CMI/MI caused fewer skin problems than shampoo with IU (38% versus 27%, n.s.), with over 1/3 of the subjects (35%) having no skin problems with either preservative. The current study showed that most subjects previously sensitized to CMI/MI can successfully use shampoo preserved with CMI/MI. Since some subjects previously sensitized to CMI/MI, or possibly to IU, may develop clinical reactions, it would still be prudent for the clinician to advise alternative products to patients with sensitivity to a shampoo or cosmetic ingredient. Full ingredient labelling will ensure that this is possible. As the overall rate of adverse effects in sensitized individuals was low, studies of this nature should also be conducted for other allergens.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross-Over Studies↗

PubMed2003

A prospective, randomized, open labeled crossover trial of fosinopril and theophylline in post renal transplant erythrocytosis.

Angiotensin converting enzyme inhibitors (ACEI) and theophylline have been reported to decrease the elevated hemoglobin (Hgb) and hematocrit (Hct) levels in the renal transplant recipients with erythrocytosis. We conducted a prospective randomized, open labeled, crossover trial with theophylline, and an ACEI, fosinopril in nine stable renal transplant recipients with erythrocytosis. Aim of the study was to determine and compare the efficacy of these medications in stable renal transplant patients. At three months, compared to baseline, fosinopril significantly reduced the elevated hemoglobin (Hgb 17.2 +/- 0.6 vs. 14.9 +/- 1.4 gm/dL, p = 0.0023), and hematocrit levels (Hct 51.3 +/- 2.4 vs. 43.7 +/- 4.6%, p = 0.003). In contrast theophylline therapy was associated with a non-significant rise in hemoglobin (17.4 +/- 0.7 vs. 18.1 +/- 0.9gm/dL, p > 0.05) and hematocrit (52.4 +/- 2.7 vs. 54.7 +/- 3.9%, p > 0.05). With fosinopril compared to theophylline, there was a significant difference in the change in hemoglobin (baseline to three months 2.8 +/- 1.7 vs. -0.7 +/- 0.69 gm/dL respectively, p = 0.017), and the change in hematocrit (baseline to three months 9 +/- 6 vs. -2.3 +/- 2.7% respectively, p = 0.027). Four patients (44.4%) did not tolerate theophylline and did not complete the theophylline arm. To conclude, in our study, fosinopril effectively decreased the elevated hemoglobin and hematocrit in patients with post transplant erythrocytosis, and was superior to theophylline, while theophylline was ineffective and poorly tolerated in this condition.

Adult↗

PubMed2006

A thermoplastic mandibular advancement device for the management of non-apnoeic snoring: a randomized controlled trial.

This randomized, controlled, crossover trial assessed the effectiveness of an adjustable, thermoplastic, mandibular advancement device (MAD), the TheraSnore, in the management of non-apnoeic snoring. Twenty-three adults who had been referred for a MAD wore the appliance in both a non-advanced and advanced position for 4-6 weeks: the starting position of the MAD was randomized. The outcomes were assessed at baseline and after each phase of MAD wear using questionnaires [(Epworth Sleepiness Scale, snoring history, sleep disturbance, side-effects of the appliance) and a visual analogue scale (daytime sleepiness)]. Eleven subjects had overnight sleep studies at baseline and with the appliance in each position to assess snoring frequency (snores/hour), oxygen saturation, and apnoea hypopnoea index. Supine radiographs were used to examine the oropharyngeal airway at baseline and in response to both appliance positions. In comparison with the non-advanced appliance, the advanced MAD reduced the snores per hour from a median of 398 to 17 (P = 0.002). Sleeping partners reported a marked improvement in their own daytime tiredness (P = 0.002) and sleep disturbance (P = 0.001) when the subject wore the active appliance. The most common side-effect was a dry mouth and 64 per cent of subjects considered the appliance bulky. Radiographic analysis revealed significant vertical opening associated with the appliance and small but significant post-lingual changes with protrusion. The results suggest that the advanced TheraSnore MAD is effective in the treatment of snoring in two out of three non-apnoeic snorers, their sleeping partners derive benefits from this form of treatment, and that complaints of bulkiness and dry mouth may to be related to the inherent vertical opening of the TheraSnore.

Adult↗

PubMed1988

Does lacrimal duct occlusion decrease intraocular pressure in patients refractory to medical treatment for glaucoma? A randomized, sham-controlled, crossover trial.

We temporarily occluded lacrimal ducts with dissolvable collagen inserts in a randomized, double masked, sham-controlled crossover trial to test whether longer ocular contact of eye drops lowers intraocular pressure in patients with refractory glaucoma. Patients were randomized to the sequence temporary lacrimal duct occlusion----21 day washout----sham occlusion (6 patients), or the reverse order (5 patients); all maintained their usual medication. Compliance was greater than 90% for every patient as assessed by medication diaries kept by each patient's medication partner. There was no treatment effect (bivariate Wilcoxon chi 2 = 0.10, p = 0.95) or treatment-period interaction (chi 2 = 2.87, p = 0.24). However, whichever treatment was received first significantly lowered intraocular pressure (left eye first period X:[ipr50] = 3.0: [-6.0, -1.0] mmHg, right eye = -3.0:[-6.0, -1.0] mmHg, bivariate response chi 2 = 5.92, p = 0.05). Although lacrimal duct occlusion appears to have no clinical benefit, more careful supervision of eye drop administration may be efficacious for treating some patients with medically refractory glaucoma.

Collagen↗

PubMed1984

Effect of oral diuretics on pulmonary mechanics in infants with chronic bronchopulmonary dysplasia: results of a double-blind crossover sequential trial.

In a randomized double-blind crossover trial with sequential analysis, the effects of oral diuretics were compared with the effects of placebo on pulmonary mechanics in ten infants with bronchopulmonary dysplasia (BPD). Pulmonary mechanics were measured before and at the end of a week of treatment with oral diuretics (chlorothiazide, 20 mg/kg/dose and spironolactone, 1.5 mg/kg/dose) given twice daily, or placebo. Mean airway resistance decreased 35.3 cm H2O/L/s, mean specific airway conductance increased 0.095 1/L/s/cm H2O, and mean dynamic pulmonary compliance increased 1.74 mL/cm H2O during treatment with diuretics (all P less than .001), but not during treatment with placebo. The infants' rate of weight gain decreased on the first three days of diuretic treatment, but was thereafter comparable with weight gain during treatment with placebo. Fluid intake was similar in infants receiving diuretics and placebo. But, infants receiving diuretics not only had significantly increased urine output, osmolal clearance, and potassium and phosphorus excretion, but these infants also retained less fluid, and, in addition, excreted less calcium than infants receiving placebo. It is concluded that oral diuretics improve lung function in infants with chronic bronchopulmonary dysplasia; however, potassium and phosphorus depletion are potential complications of treatment.

Administration, Oral↗

PubMedDate not supplied

Efficacy of Bach-flower remedies in test anxiety: a double-blind, placebo-controlled, randomized trial with partial crossover.

Bach-flower remedies are a type of alternative medication used increasingly for over-the-counter self-help purposes. We studied the efficacy of a combination of Bach-flower remedies in subjects with test anxiety in a randomized, placebo-controlled, blinded parallel group design, with crossing over the placebo group to remedies after the first phase. Anxiety was measured by a standardized, validated test anxiety questionnaire (the German version of the Test Anxiety Inventory, TAI-G). Fifty-five of 61 subjects with self-reported test anxiety gave valid data. There was no significant difference between the groups, but a significant decrease of test anxiety in all groups was present. We conclude that Bach-flower remedies are an effective placebo for test anxiety and do not have a specific effect.

Adult↗

PubMed2003

Lamotrigine in treatment-resistant schizophrenia: a randomized placebo-controlled crossover trial.

BACKGROUND: There is no evidence from randomized, controlled trials that demonstrate effectiveness for any pharmacological treatment in clozapine-resistant schizophrenia. Since the introduction of chlorpromazine, all antipsychotics with proven efficacy on positive symptoms have been dopamine antagonists, but recent experimental data suggest that ketamine-induced positive schizophreniform symptoms in healthy subjects can be controlled by a glutamate antagonist lamotrigine. The hypothesis tested was that lamotrigine is more effective than placebo in the treatment of positive schizophrenic symptoms when combined with clozapine. METHODS: Thirty-four hospitalized treatment-resistant patients having chronic schizophrenia participated in a double-blind, placebo-controlled, 14-week, crossover trial where 200 mg/day lamotrigine was gradually added to their ongoing clozapine treatment. Clinical assessments were made by the Positive and Negative Syndrome Scale at the beginning and end of each treatment period. RESULTS: In intention-to-treat analysis, lamotrigine treatment was more effective in reducing positive (effect size.7, p =.009) and general psychopathological (effect size.6, p =.030) symptoms, whereas no improvement was observed in negative symptoms. CONCLUSIONS: These results provide the first evidence from a randomized controlled trial of an effective pharmacological treatment with an anticonvulsant agent in treatment-resistant schizophrenia and indicate that both positive and general psychopathological symptoms in patients with schizophrenia can be controlled by a drug that is not a dopamine antagonist. The results are in line with previous experimental data suggesting that excessive glutamate neurotransmission contributes to the positive symptoms of schizophrenia.

Adult↗

PubMed2003

[The effectiveness of ergotamine treatment in chronic headache disorders: a double-blind, randomized, crossover, placebo controlled trial].

BACKGROUND: Postulated mechanism of migraine headache is a result of vascular spasm (primary) and dilatation with edema of the perivascular space (secondary). Thus we use drugs not the only during acute phase of headache but in prevention, also. Drugs containing ergotamine are well known and were used for years in the treatment of migraines. In this study we tried to investigate the role of multicomponent drugs containing ergotamine in the treatment of migraine in the adult workers group. MATERIALS AND METHODS: Experiments were performed with the use of double blind, randomized, crossover, placebo controlled study. Drug, Hydacorn, is a multicomponent drug where one tablet contains 1 mg of dihydroergo-tamine, 40 mg of caffeine and 100 mg of diphenylhydantoine. 36 adults were enrolled (27 females and 9 males). Patients were examined 5 times every 2 weeks. During the 3rd visit the drug was changed to Hydacorn and placebo. RESULTS: During the 1st visit the intensity of pain did not differ significantly. After start of treatment the pain intensity did not differ significantly versus the 1st visit in placebo group. In the Hydacorn group we observed the significant reduction of pain intensity vs 1st visit and vs placebo. After drug change the significant reduction was present vs placebo (during the 5th visit only) and vs the 1st visit. Pain intensity during the 4th visit did not differ significantly vs placebo probably because of long action time for ergotamine. CONCLUSIONS: Our results suggest that Hydacorn is very effective and safe in the prevention of migraines.

Adolescent↗

PubMed1986

Effect of naloxone on exercise-induced angina pectoris: a randomized double blind crossover trial.

To determine whether endogenous opioids play a role in modulating the appreciation of chest pain in angina pectoris, the specific opioid antagonist, Naloxone, was used. The hypothesis was that the appearance time of ischemic myocardial pain should decrease after Naloxone if centrally mediated pain perception is significantly influenced by the endorphin system in angina pectoris. A randomized double blind clinical trial was conducted in 5 men with effort-induced angina pectoris associated with ST segment changes. Three multi-stage exercise tests, using the Bruce protocol were performed on the same day and time, on three successive weeks. Chest pain was reported 4.3 +/- 0.3 (SEM) minutes after starting exercise on the first or baseline test. On subsequent tests patients received either Naloxone 2 mg IV or a similar volume of saline placebo. Angina pectoris occurred significantly (p. less than 0.05) earlier (1.6 +/- 0.2 minutes) after Naloxone compared to placebo. There were no significant differences in myocardial ischemia indicated by ST segment changes and no significant differences in resting or exercise blood pressure and heart rate between Naloxone and placebo. Thus, these data focus attention on a neglected area of myocardial ischemic pain and suggest that endogenous opioids play a significant role in the recognition of the pain of effort-related angina pectoris.

Adult↗

PubMed2002

Sample size correction for treatment crossovers in randomized clinical trials with a survival endpoint.

Sample size determination in randomized clinical trials usually relies on the determination of survival rates at the time of analysis in both groups, under the null and the alternative hypotheses, the type I and II error rates and on other assumptions, such as proportional hazards in most cases. However, in numerous clinical trials for malignant chronic diseases, it is currently common that a patient allocated to the conventional treatment group would receive the experimental treatment in case of disease progression or relapse. Such crossovers are usually not taken into account when computing the sample size of the trial, but generally result in a decreased power of the trial. In this work, we aimed to correct the sample size of such trials to control the power, under an exponential survival assumption.

Cross-Over Studies↗