Application of the triangular test to phase II cancer clinical trials

[Science in a crisis. Medical countermeasures in Ebola virus disease, 2016: lessons learned and perspectives]

In 2013, the world began to witness an unprecedented Ebola epidemic in West Africa that was smoldering by early 2016. Under this urgent circumstance, the global scientific community organized and made progress in identifying potential preventive countermeasures and therapeutics and accelerated the development of those promising interventions. Trials of experimental interventions soon emerged as a key component of the global response. Hence, an interdisciplinary issue ensued concerning how best to assess clinical safety and effectiveness of potential interventions prior to or concurrent with their broad use in humans. Key issues rely on the close collaboration between research and clinical teams involved in care in the field. Indeed, it is of prime importance to consider cultural dimensions when aiming to build trust within communities and flexibility to adapt trial procedures to field constraints. Trials implemented during the outbreak crisis illustrates challenging inputs for producing scientific and ethical gains for the benefits of vulnerable populations in the context of an international emerging or re-emerging infectious disease event. This includes rapid implementation of clinical research studies from the early phase of the next global outbreak on the basis of practical and ready-to-apply innovative methodological framework built during interepidemic periods.

Nine-year change in statistical design, profile, and success rates of Phase II oncology trials

We investigated nine-year trends in statistical design and other features of Phase II oncology clinical trials published in 2005, 2010, and 2014 in five leading oncology journals: Cancer, Clinical Cancer Research, Journal of Clinical Oncology, Annals of Oncology, and Lancet Oncology. The features analyzed included cancer type, multicenter vs. single-institution, statistical design, primary endpoint, number of treatment arms, number of patients per treatment arm, whether or not statistical methods were well described, whether the drug was found effective based on rigorous statistical testing of the null hypothesis, and whether the drug was recommended for future studies.

Triangular test design to evaluate tinidazole in the prevention of Plasmodium vivax relapse

BACKGROUND

There are very few drugs that prevent the relapse of Plasmodium vivax malaria in man. Tinidazole is a 5-nitroimidazole approved in the USA for the treatment of indications including amoebiasis and giardiasis. In the non-human primate relapsing Plasmodium cynomolgi/macaque malaria model, tinidazole cured one of six macaques studied with an apparent mild delay to relapse in the other five of 14-28 days compared to 11-12 days in controls. One study has demonstrated activity against P. vivax in man. Presented here are the results of a pilot phase II, randomized, open-label study conducted along the Thai-Myanmar border designed to evaluate the efficacy of tinidazole to prevent relapse of P. vivax when administered with chloroquine.

METHODS

This study utilized a modified triangular test sequential analysis which allows repeated statistical evaluation during the course of enrolment while maintaining a specified power and type 1 error and minimizing recruitment of subjects. Enrolment was to be halted when a pre-specified success/failure ratio was surpassed. The study was designed to have a 5% type 1 error and 90% power to show whether tinidazole would produce a relapse rate of less than 20% or greater than 45% through Day 63 of weekly follow-up after initiation of treatment and initial parasite clearance with 3 days of an oral weight based dosing of chloroquine and five days of 2 grams/day of tinidazole.

RESULTS

All subjects cleared their parasitaemia by Day 3. Six of the first seven subjects treated with tinidazole relapsed prior to Day 63 (average Day 48.3 (range 42-56)). This exceeded the upper boundary of the triangular test and enrolment to receive tinidazole was halted. A concurrent cohort of five subjects definitively treated with standard doses of primaquine and chloroquine (historically 100% effective) showed no episodes of recurrent P. vivax parasitaemia during the 63-day protocol specified follow-up period.

CONCLUSIONS

Tinidazole is ineffective in preventing relapse of P. vivax at the dose used. The macaque relapsing model appeared to correctly predict outcome in humans. Use of the modified triangular test allowed minimal enrolment and limited unnecessary exposure to the study drug and reduced costs. This adds weight to the ethical and economic advantages of this study design to evaluate similarly situated drugs.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00811096.

Safety and efficacy of miltefosine alone and in combination with sodium stibogluconate and liposomal amphotericin B for the treatment of primary visceral leishmaniasis in East Africa: study protocol for a randomized controlled trial

BACKGROUND

Treatment options for visceral leishmaniasis (VL) in East Africa are far from satisfactory due to cost, toxicity, prolonged treatment duration or emergence of parasite resistance. Hence there is a need to explore alternative treatment protocols such as miltefosine alone or in combinations including miltefosine, sodium stibogluconate (SSG) or liposomal amphotericin B. The aim of this trial is to identify regimen(s) which are sufficiently promising for future trials in East Africa.

METHODS/DESIGN

A phase II randomized, parallel arm, open-labelled trial is being conducted to assess the efficacy of each of the three regimens: liposomal amphotericin B with SSG, Liposomal amphotericin B with miltefosine and miltefosine alone. The primary endpoint is cure at day 28 with secondary endpoint at day 210 (6 months). Initial cure is a single composite measure based on parasitologic evaluation (bone marrow, spleen or lymph node aspirate) and clinical assessment. Repeated interim analyses have been planned after recruitment of 15 patients in each arm with a maximum sample size of 63 for each. These will follow group-sequential methods (the triangular test) to identify when a regimen is inadequate (<75% efficacy) or adequate (>90% efficacy). We describe a method to ensure consistency of the sequential analysis of day 28 cure with the non-sequential analysis of day 210 cure.

DISCUSSION

A regimen with adequate efficacy would be a candidate for treatment of VL with reasonable costs. The design allows repeated testing throughout the trial recruitment period while maintaining good statistical properties (Type I & II error rates) and reducing the expected sample sizes.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01067443.

An exact method for analysis following a two-stage phase II cancer clinical trial

This paper presents an exact method for the analysis of a phase II cancer clinical trial conducted using a two-stage design in which early stopping may be allowed for either futility or efficacy. The method provides a point and interval estimate of the response probability associated with the treatment under investigation and a p-value for testing whether this exceeds some standard null value. Two-stage designs are often used in phase II trials in oncology for reasons of ethics and efficiency, but this design feature is seldom taken into account when the results are analyzed. After any two-stage design or multi-stage design, the method for analysis should take into account the previous interim analyses performed, otherwise the results will be biased. In this paper, an approximate approach based on a log-odds ratio parameterisation will be compared with an exact method through the calculation of the precise coverage probabilities of each approach.

An algorithm for the design of group sequential triangular tests for single-arm clinical trials with a binary endpoint

Consider the problem of testing H(0):p ≤ p(0) vs H(1):p > p(0), where p could, for example, represent the response rate to a new drug. The group sequential TT is an efficient alternative to a single-stage test as it can provide a substantial reduction in the expected number of test subjects. Whitehead provides formulas for determining stopping boundaries for this test. Existing research shows that test designs based on these formulas (WTTs) may not meet Type I error and/or power specifications, or may be over-powered at the expense of requiring more test subjects than are necessary. We present a search algorithm, with program available from the author, which provides an alternative approach to triangular test design. The primary advantage of the algorithm is that it generates test designs that consistently meet error specifications. In tests on nearly 1000 example combinations of n (group size), p(0), p(1), α, and β the algorithm-determined triangular test (ATT) design met specified Type I error and power constraints in every case considered, whereas WTT designs met constraints in only 10 cases. Actual Type I error and power values for the ATTs tend to be close to specified values, leading to test designs with favorable average sample number performance. For cases where the WTT designs did meet Type I error and power constraints, the corresponding ATT designs also had the advantage of providing, on average, a modest reduction in average sample numbers calculated at p(0), p(1), and (p(0) + p(1))/2.

[Gadolinium-enhanced thoracic CTA: retrospective analysis of image quality and tolerability in 45 patients evaluated prior to the description of nephrogenic systemic fibrosis]

PURPOSE

To assess the accuracy and torerability of gadolinium-enhanced thoracic CTA using a 64 MDCT compared to a 16 MDCT. Because this study was started prior to the description of NSF, particular attention was paid to long-term follow-up of the patient population.

MATERIALS AND METHODS

The study protocol was approved by the ethics committee of our institution and informed consent was obtained from all patients. Fourteen patients (Group 1) (9 males and 5 females; mean age: 64.3 years) with contraindication to the administration of iodinated contrast material underwent thoracic CTA (collimation: 32 x 2 x 0.6 mm; pitch: 1.2) with gadolinium administration (0.5 mml/ml) at 0.4 mmol/kg injected at 6 ml/sec with evaluation of clinical and biological tolerability of the gadolinium based contrast agent. Results from this patient population were compared to results from a population of 31 patients (21 males; 10 females; mean age: 63.2 years) (Group 2) imaged on a 16 MDCT. All patients were folloowed-up for a mean time of 22.6 months.

RESULTS

Using a mean contrast volume (standard deviation) that was not significantly different (Group 1: 54.8+/-11 ml; Group 2: 53.4+/-6.9 ml) (p=0.94), patients in Group 1 underwent complete thoracic CTA whereas patients in Group 2 underwent CTA of only the middle third of the thoracic region. All CTA examinations were diagnostic for Group 1 and Group 2 patients; however, evaluation of subsegmental vessels was possible in a significantly larger proportion of patients in Group 1 (10/14; 72%) compared to Group 2 (6/31; 19%) (p=0.003). Mean attenuation values within pulmonary arterial branches were similar for Groups 1 and 2 (central arteries: 194.5+/-51.3 HU vs 180.6+/-53.8 HU; p=0.38) (lobar arteries: 208.5+/-52.5 HU vs 189.9+/-60.1 HU; p=0.33) (segmental arteries: 220.4+/-50.4 HU vs 201.5+/-54.7 HU; p=0.42). Transient alteration of renal function was recorded in one patient from Group 1 with severe pre-existing chronic renal failure. No change in renal function was observed for Group 2 patients. No case of NSF was reported in patients with pre-existing renal failure at the time of enrollment.

CONCLUSION

The use of gadolinium-based contrast agent for thoracic CTA using a 64 MDCT provides diagnostic quality examinations in all patients with improved image quality compared to a 16 MDCT. No complication other than transient alteration of renal function was observed. Because the likelihood of developing NSF may vary with the type of gadolinium-based contrast agent used, the least toxic agent should be used.

High efficacy with five days schedule of oral fludarabine phosphate and cyclophosphamide in patients with previously untreated chronic lymphocytic leukaemia

A multicentre single-arm study testing the efficacy and toxicity of the oral combination of fludarabine and cyclophosphamide (FC) over 5 d in 75 patients with untreated B cell-chronic lymphocytic leukaemia. Oral FC demonstrated high efficacy with overall (OR) and complete response (CR) rates of 80% and 53%, respectively. Out of the 30 CR patients studied for Minimal Residual Disease (MRD) using 4-colour flow-cytometry and the 22 using Clonospecific polymerase chain reaction, 22 (66%) and 16 (68%), respectively, were MRD negative. Median survival and median treatment-free interval had not been reached at 7 years of follow-up. Median progression-free survival (PFS) was 5 years. Toxicity was acceptable, with 52% and 16% of National Cancer Institute grade 3/4 neutropenia and infections, respectively. Gastrointestinal toxicity was mild. Oral FC demonstrated a high efficacy and an acceptable safety profile and may be considered as the standard first line treatment in chronic lymphocytic leukaemia.

Preradiation chemotherapy may improve survival in pediatric diffuse intrinsic brainstem gliomas: final results of BSG 98 prospective trial

Radiation therapy remains the only treatment that provides clinical benefit to children with diffuse brainstem tumors. Their median survival, however, rarely exceeds 9 months. The authors report a prospective trial of frontline chemotherapy aimed at delaying radiation until time of clinical progression. The aim was to investigate the possibility that radiotherapy would maintain its activity in children whose disease progressed after chemotherapy. Twenty-three patients took part in this protocol, the BSG 98 protocol, which consisted of frontline chemotherapy alternating hematotoxic and nonhematotoxic schedules. Each cycle included three courses delivered monthly; the first course was 1,3-bis(2-chloroethyl)-1-nitrosoureacisplatin, and the second and third were high-dose methotrexate. Three patients underwent one cycle; 5 patients each, two and three cycles; and 10 patients, four cycles. Twenty of the 23 patients eventually received local radiation therapy. A historical cohort of 14 patients who received at least local radiation therapy served as controls. Four patients experienced severe iatrogenic infections, and 11 patients required platelet transfusions. Median survival increased significantly in patients participating in the protocol compared to that in the historical controls (17 months, 95% confidence interval [CI], 10-23 months, vs. 9 months, 95% CI, 8-10 months; p = 0.022), though hospitalization was prolonged (57 vs. 25 days, p = 0.001). Although frontline chemotherapy alternating hematotoxic and nonhematotoxic schedules significantly increases overall median survival, its cost from infection and hospitalization deserves honest discussion with the children and their parents.

Expectations and Strategies Regarding Islet Transplantation: Metabolic Data From the GRAGIL 2 Trial

BACKGROUND

Whether islet transplantation should be aimed at restoring insulin independence or providing adequate metabolic control is still debated. The GRAGIL2 trial was designed as a phase 1-2 study where primary outcome was the rate of insulin independence, and secondary outcome was the success rate defined by a composite score based upon basal C-peptide, HbA1c, hypoglycemic events, and exogenous insulin needs.

METHODS

C-peptide negative type 1 brittle diabetic patients experiencing severe hypoglycemia were eligible to receive a maximum of two islet preparations totalizing 10,000 IE/kg or more, with a threshold of 5,000 IE/kg for the first infusion, according to the Edmonton protocol, within the Swiss-French GRAGIL multicentric network. A sequential analysis with a triangular test was performed in every five patients after 6- and 12-month follow-up. Maximal inefficiency was set at 40% and minimal efficiency at 66%.

RESULTS

From September 2003 to October 2005, 10 patients were included. Median waiting time was 6.7 months (first injection) and 9 weeks (second injection). All but one patient received 11,089+/-505 IE/kg: one received a single graft of 5398 IE/kg. At 6 months, insulin independence and composite success rates were 6 of 10 and 6 of 10, respectively. At 12 months, insulin independence was observed in 3 of 10 patients and success in 5 of 10 patients.

CONCLUSION

Based upon our sequential analysis settings, islet transplantation failed to achieve the primary goal, insulin independence, but tended to succeed in reaching the secondary goal, successful metabolic control. Currently it appears to be a successful biological closed-loop glucose control method for brittle diabetes.

Phase II multi-step planning methods in oncology: Comparison, recommendations and potential applications

Phase II clinical trials in oncology are commonly used to determine whether a new treatment has a sufficient response rate to be compared with the best standard therapy in phase III. The multi-step planning methods such as Fleming's procedure and the triangular test adapted for phase II trials were elaborated to terminate phase II trials early. We compared these methods considering a fixed number of steps (4 or 5) on their statistical properties: overall type II error and observed type II error, average number of subjects necessary to conclude, probability to conclude at each step and maximum number of subjects necessary to conclude. Fleming's procedure has an actual power similar to the theoretical power for low to high response rate. In contrast, triangular test has an actual power different from the theoretical power in a few situations: it was very high in case of a very low minimum response rate and very low (<20%) in case of a very high minimum response rate (>80%). In these situations, Fleming's procedure and triangular test were not compared and triangular test cannot be recommended. For intermediate response rate, triangular test required a lower average number of subjects to conclude, a larger number of subjects at each step and thus a larger maximum number of subjects. It provided a larger probability to conclude during the first steps. These advantages should be balanced with the risk to have to include a larger number of patients. Multi-step methods, when correctly used are useful for cytotoxic development when response rate is the end point. They can also be used in trials where toxicity is the end point, and could be of great interest for cytostatic development for example with biological surrogate endpoints. An example using real phase II data is also presented.

Methods of joint evaluation of efficacy and toxicity in phase II clinical trials

Phase II clinical trials in oncology are usually conducted to evaluate the anti-tumor effect. Because phase I trials are small studies, the maximum tolerated dose of a new drug may not be precisely established and the recommended dose used may lead to excessive toxicity. We investigate the methods proposed by Conaway-Petroni and Bryant-Day allowing early termination of phase II clinical trials and based on joint evaluation of treatment efficacy and safety. Both study designs are computed to minimize the expected accrual under the null hypothesis. As two criteria are considered, the null hypothesis is an area. Each method defines two specific type I error risks. Bryant-Day demonstrate that response and toxicity may be considered as independent (Phi=1). We compare the properties of these two methods with exact calculation according to objective criteria and present one example from a study conducted in France. The two methods differ with regard to the definition of the risks and the assumption of independence. They are similar in terms of expected accruals when Phi=1. Deviations from the assumption of independence induce minor consequences on the type I error risks when the constraint on the type II error risk is less than 15%. Choosing Phi has a minimal impact on expected accrual. Finally, one type I error risk (alpha00) defined by Conaway-Petroni dramatically increases in the case of deviation from the assumption made on Phi. Due to its robustness in relation to a deviation from the independence assumption, we recommend the use of the Bryant-Day method in clinical practice.

Are There Circumstances in Which Phase 2 Study Results Should Be Practice-Changing?

New pharmaceuticals, innovative combinations of approved agents, and novel treatment modalities have resulted in a marked increase in the need for clinical trials. Evidence for treatment efficacy is best derived from large phase 3 randomized, controlled clinical trials. However, phase 3 investigations are lengthy and expensive, and consume patient resources. Furthermore, some diseases and treatment indications are rare, and adequate numbers of patients for a definitive phase 3 trial do not exist. Consequently, it is imperative for clinicians to understand phase 2 trial design, since their interpretation is required to apply the findings in clinical practice appropriately. The complexity of phase 2 studies is explored, including unique designs, possible use of randomization, and other key elements necessary for interpretation of phase 2 trials. Specific examples and application of these concepts are discussed in this review.

Induction cisplatin-irinotecan followed by concurrent cisplatin-irinotecan and radiotherapy without surgery in oesophageal cancer: multicenter phase II FFCD trial

A recent phase I study showed that weekly cisplatin, irinotecan and concurrent radiotherapy can be administered with moderate toxicity in patients with oesophageal cancer. Patients with no prior treatment and oesophageal cancer stage I to III, performance status <3, caloric intake >1500 kcal day⁻¹ were included. Chemotherapy, with cisplatin 30 mg m⁻² and irinotecan 60 mg m⁻², was administered at days 1, 8, 22, 29, and concurrently with radiotherapy at days 43, 50, 64 and 71. Radiotherapy was delivered with 50 or 50.4 Gy in 25 fractions/5 weeks. Forty-three patients were included, 10 stage I, 19 stage II and 14 stage III. Mean age was 59.2 years (range 44–79). A total of 30 out of 43 (69.8%) patients underwent all planned treatment. During induction chemotherapy, 14 severe toxicities of grade 3 or 4 in 10 patients (23.3%) were reported with 57.1% due to haematoxicity. During chemoradiotherapy, 31 severe toxicities of grade 3 or 4 with 64.5% due to haematotoxicity were reported in 18 patients. One toxic death occurred (diarrhoea grade 4). The complete clinical response rate was 58.1% (95% CI: 43.4–72.8%). Overall survival rate at 1 and 2 years was 62.8%, (95% CI, 58.3–77.3%) and 27.9% (95% CI, 13.4–41.3%), respectively. In conclusion, cisplatin–irinotecan–radiotherapy is an active and well-tolerated regimen feasible in out-patients.

Topotecan as a radiosensitizer in the treatment of children with malignant diffuse brainstem gliomas: results of a French Society of Paediatric Oncology Phase II Study

BACKGROUND

The current Phase II study was conducted to evaluate the survival and toxicity observed in children with newly diagnosed brainstem gliomas who were treated with the daily radiotherapy with topotecan used as a radiosensitizer.

METHODS

Eligible patients were those ages 3-18 years with previously untreated tumors arising in the pons diagnosed within the previous 6 months. Histologic confirmation was not mandatory provided that the clinical and magnetic resonance imaging findings were typical for a diffusely infiltrating brainstem lesion. Treatment was comprised of a 6-week course of topotecan administered intravenously at a dose of 0.4 mg/m(2)/day over 30 minutes within 1 hour before irradiation. Radiotherapy was comprised of a once-daily treatment of 1.8 grays (Gy) per fraction to a total dose of 54 Gy.

RESULTS

Thirty-two patients were included in the current study between August 2000 and October 2002. All patients completed the combined treatment in accordance with the treatment design. Only partial responses were observed, occurring in 40% of the patients. The 9-month and 12-month survival rates were 34.4% +/- 8% and 25.5% +/- 8%, respectively. The median duration of survival for these 32 patients was 8.3 months. An intratumoral cystic/necrotic change was observed in five patients, with clinical impairment noted in two patients. One intratumoral hemorrhage occurred during radiotherapy, and was associated with transitory neurologic impairment.

CONCLUSIONS

The findings of the current study regarding newly diagnosed brainstem glioma patients treated with topotecan given as a radiosensitizing agent did not reproduce the encouraging results obtained in preclinical studies. Therefore, the concomitant combination of topotecan and radiotherapy at this schedule and these doses cannot be recommended for the treatment of patients with brainstem gliomas.

A 25-year review of sequential methodology in clinical studies

This paper explores the theoretical developments and subsequent uptake of sequential methodology in clinical studies in the 25 years since Statistics in Medicine was launched. The review examines the contributions which have been made to all four phases into which clinical trials are traditionally classified and highlights major statistical advancements, together with assessing application of the techniques. The vast majority of work has been in the setting of phase III clinical trials and so emphasis will be placed here. Finally, comments are given indicating how the subject area may develop in the future.

Impact of a mis-specification of the response rate under standard treatment in sequential clinical trials

Phase III trials are aimed at assessing whether new treatments have superior efficacy than standards. Sequential methods, such as the single triangular test (STT) and the double triangular test (DTT), allow for early stopping of such trials. They use stopping boundaries which depend, for a binary endpoint, on pi(0) and pi(1) (response rates under standard and new treatment, respectively) and alpha and beta (type I and II errors, respectively). Thus, a wrong estimation of pi(0) at planning phase might have an influence on their statistical properties. We assessed the extent of this influence by simulations regarding alpha, 1--beta, and average sample number (ASN) and compared the two methods with the one-sided and two-sided single-stage designs (SSD). There was no influence on alpha for any test and the power achieved by the one-sided or two-sided SSD was moderately affected by a wrong estimation of pi(0). However, important drifts (whose magnitude depended on chosen design) were observed for sequential methods concerning power and ASN in case of moderate under- or overestimation of pi(0) (+/-20% compared with its 'true' value). For example, when 'true' values of pi(0) and pi(1) are 0.30 and 0.40, respectively, using design values of 0.10 and 0.20, the power is 0.57 and 0.50 for the STT and DTT, respectively, instead of 0.95. When 'true' values of pi(0) and pi(1) are 0.10 and 0.20, respectively, using design values of 0.30 and 0.40, the ASN under H(0) is 1,309 and 2,019 for the STT and DTT, respectively, instead of 392 and 601, respectively, using the right design. Using sequential methods in comparative clinical trials with binary responses requires a precise knowledge of the response rate under standard treatment to avoid losses in power or inappropriate increases in sample size.

Treatment of chronic hepatitis C in patients unresponsive to interferon

AIM

About 45% of patients with chronic hepatitis C are unresponsive to the present reference treatment combining pegelated interferon plus ribavirin; before pegylated interferon was available the non-response rate was around 60%. This open multicenter pilot study, initiated before pegylated interferon became available, was designed to evaluate, in patients unresponsive to interferon monotherapy, the rate of biological and virological response and side-effects of the ribivirin-alpha 2b interferon combination.

METHODS

The combination protocol was ribavirin (1 to 1.2 g/d) plus alpha 2b interferon at induction doses (9 MU/d the first week; 4.5 MU/d the eleven following weeks; 3 MU/2 days the 36 following weeks).

RESULTS

Among the 27 included patients, 17 (63%) were viremia-negative (PCR) after 12 weeks of treatment, 9 (33%) were complete responders (undetectable viremia and normal transaminases) at the end of treatment (48 weeks) and of follow-up (72 weeks). Patients with non-1, non-4 genotypes who derived full benefit from this therapeutic strategy (6/7 (86%) were complete responders: 4/5 with genotype 3 and 2/2 with genotype 5). Quality-of-life was impaired during treatment, especially during the first 12 weeks of high-dose interferon therapy.

CONCLUSION

While waiting for new therapeutic possibilities, these good results suggest interferon induction at the beginning of treatment remains a valid option.

Subcutaneous Interleukin-2 and Interferon Alfa Administration in Patients With Metastatic Renal Cell Carcinoma: Final Results of SCAPP III, a Large, Multicenter, Phase II, Nonrandomized Study With Sequential Analysis Design—The Subcutaneous Administration Propeukin Program Cooperative Group

Purpose: This outpatient multicenter trial tested the hypothesis that subcutaneous administration of an interleukin-2 (IL-2)/interferon alfa (IFNα) combination produces a response rate greater than 20% in patients with renal cell carcinoma (RCC).

Patients and Methods: Patients with metastatic RCC received a 12-week induction treatment with subcutaneous IL-2 (5 days/wk, 9 and 18 million U/d)/IFNα (3 days/wk, 6 million U/d). After evaluation, patients with objective response or stable disease were randomly assigned to maintenance treatment or short consolidation treatment.

Results: Lack of benefit was shown at the 12th sequential analysis, and the trial was closed. At the end of the induction period, 26 (21%) of 122 patients had objective responses (including six complete responses). Thirty-three patients (27%) developed severe toxicity requiring dose reductions, delayed treatment, or treatment termination. Survival rates at one, two, and four years were 63%, 38%, and 17%, respectively. Three-year survival was 20% in patients with two poor prognosis factors and 37% in patients with one or no poor prognosis factors (P = .016). Three-year survival was significantly better (P < 10−3) in patients with erythrocyte sedimentation rate less than 35 mm (43%) compared with those with 1-hour sedimentation rate greater than 35 mm (19%).

Conclusion: This study confirms the importance of prognostic factors when initiating cytokine immunotherapy in patients with metastatic RCC and underlines the prognostic value of erythrocyte sedimentation rate before treatment initiation. Nonetheless, this subcutaneous IL-2/IFNα combination does not improve response rate or survival compared with subcutaneous IL-2 alone, although a definitive conclusion cannot be drawn in the absence of a randomized study comparing the two treatments.

Triangular test applied to the clinical trial of azithromycin against relapses in Plasmodium vivax infections

BACKGROUND

Sequential analysis enables repeated statistical analyses to be performed throughout a trial recruitment period, while maintaining a pre-specified power and type I error. Thus the trial can be stopped as soon as the information accumulated is considered sufficient to reach a conclusion. Sequential tests are easy to use and their statistical properties are especially suitable to trials with very straightforward objectives such as non-comparative phase II trials. We report on a phase II study based on the triangular test (TT) aiming at assessing the effectiveness of azithromycin in preventing Plasmodium vivax relapses.

METHODS

To test whether the P. vivax relapse rate was either <12% or >or= 45% in patients treated with azithromycin, a sequential analysis based on the TT was as used. Patients infected with P. vivax were treated with azithromycin, 1.2 g daily, for 7 days. The onset of a relapse infection was monitored.

RESULTS

Five patients presenting with an acute P. vivax infection were included in the study. All the patients were initially cured. Three patients reported mild gastrointestinal adverse effects. When the third patient relapsed, the sample path crossed the upper boundary of the TT, and the trial was stopped.

CONCLUSIONS

Using the triangular test, with only a small number of patients, we concluded that azithromycin was not effective enough in preventing P. vivax relapses to warrant further evaluation in phase III. It is suggested that a wider use of sequential analysis in phase II anti-infective drugs trials may have financial and ethical benefits.

Prospective randomized study of four novel chemotherapy regimens in patients with advanced nonsmall cell lung carcinoma: a minnie pearl cancer research network trial

BACKGROUND

The authors compared the toxicity, response rate, and progression free survival of four chemotherapy regimens for patients with advanced (Stage IIIB and IV) nonsmall cell lung carcinoma.

METHODS

A total of 267 patients entered this randomized Phase II trial on one of four arms: paclitaxel, carboplatin, and gemcitabine (Arm A); paclitaxel, carboplatin, and vinorelbine (Arm B); paclitaxel and gemcitabine (Arm C); and gemcitabine and vinorelbine (Arm D). Patient characteristics were similar in all treatment arms. At the time of tumor progression, patients were removed from study and were treated at the discretion of their physician.

RESULTS

Patients received a median of four courses of chemotherapy in all arms, and there was no difference in the dose delivered. There were no statistical differences in response rates (range, 32-45%), median progression free survival (range, 4.9-6.6 months), or progression free survival at 1 year (range, 8-19%). Actuarial survival in all four arms was not different, with a median survival ranging from 8.7 months to 10.7 months and a 1-year survival rate of 38-44%. Each arm was compared with a historic control with a median survival of 8 months. Arm D (gemcitabine and vinorelbine) approached significance at the 0.05 level.

CONCLUSIONS

Two-drug combinations containing the newer drugs without a platinum drug were less toxic than three-drug, platinum-based regimens. There were no significant differences in objective response rates or progression free survival when the four regimens were compared. The two-drug combination of gemcitabine and vinorelbine was the least toxic and, thus, may be superior. A Phase III trial comparing combined gemcitabine and vinorelbine with combined paclitaxel, carboplatin, and gemcitabine is ongoing.

Carboplatin before and during radiation therapy for the treatment of malignant brain stem tumours: a study by the Société Française d'Oncologie Pédiatrique

Childhood malignant brain stem tumours have a very poor prognosis with a median survival of 9 months despite radiotherapy. No chemotherapy has improved survival. However, carboplatin has been reported to have activity in glial tumours as well as antitumour synergy with radiation. Our aims were to test the response rate of these tumours to carboplatin alone and to evaluate the efficacy on survival of carboplatin alone followed by concurrent carboplatin and radiotherapy. Patients younger than 16 years with typical clinical and radiological presentation of infiltrating brain stem tumour, as well as histologically-documented cases in the atypical forms, were eligible. Two courses of carboplatin (1050 mg/m2 over 3 days) were administered initially. This treatment was followed by a chemoradiotherapy phase including five weekly carboplatin courses (200 mg/m2) and conventional radiotherapy. 38 eligible patients were included. No tumour response was observed after the initial phase. This schedule of first-line carboplatin followed by concurrent carboplatin and radiotherapy did not improve survival.

Comparison of the two-sided single triangular test to the double triangular test

Comparative clinical trials are designed to determine whether a new treatment has either superior or different efficacy than a standard, that is, if theta represents a measure of treatment difference, to test the null hypothesis H(0): theta = 0 against the alternative hypothesis H(1) of either superior (theta > 0, one-sided) or different (theta not equal 0, two-sided with H(1)(+): theta > 0 and H(-)(1): theta < 0) efficacy. The triangular test (TT), a group sequential method, allows for early stopping of such trials. Its one-sided version (single TT) and two-sided version (double TT) were implemented in the first release of PEST software. The third release of PEST proposed a modification of the single TT, allowing rejection of H(0) in favor of H(-)(1) when very early data show strong inferiority of the new treatment as compared with the standard. Thus, our aim was to compare this modified single TT, referred to as a two-sided test in PEST 3, with the double TT and two-sided single-stage design (SSD). The statistical properties of the SSD and double TT were perfectly similar under all hypotheses. The modified single TT was underpowered as compared to the two others (the probability of falsely accepting H(0) strictly under H(-)(1) was 0.65 instead of 0.05), but the average sample number function was lower than the one of the double TT under all H(-)(1) hypotheses (-56% strictly under H(-)(1)). We conclude that the modified single TT offers a two-sided conclusion with many fewer patients than the double TT, but at the expense of a strong decrease in power under H(-)(1).

Sequential analysis of matched dichotomous data from prospective case-control studies

Sequential analysis of randomized controlled clinical trials and epidemiological prospective (matched) case-control studies can have ethical or economical advantages above a fixed sample size approach. It offers the possibility to stop early when enough evidence for an apparent effect of the risk factor or lack of the expected effect is achieved. In clinical trials it is well accepted to stop the trial early in favour of the alternative hypothesis. In epidemiological studies, in general, the need is not felt to stop early in case of a clear exposure effect. Little attention has been paid, however, to early stopping and accepting the null hypothesis. In metabolic epidemiological studies, where analysis destroys the biological material, the question of efficient use of samples, for example, those stored in a biobank, becomes crucial. Also a slow accrual of cases or the costs of follow-up of a cohort nested study can make it desirable to stop a study early once it becomes clear that no relevant exposure effect will be found. Matching can further reduce the amount of information necessary to reach a conclusion. We derived test statistics Z (efficient score) and V (Fisher's information) for the sequential analysis of studies with dichotomous data where each case can be matched to one or more controls. A variable matching ratio is allowed. These test statistics can be entered into the software PEST to monitor the course of the study. The double sequential probability ratio test and the double triangular test were evaluated with simulated data for odds ratios equal to 1.5, 2.0 and 2.5 and various type I and type II error probabilities both under H(0) and under H(1). Our simulations resulted in average and median values for the amount of information (V) that are far less than those for a fixed sample size study. Efficiency gain ranges from 32 per cent to 60 per cent. The proposed sequential analysis was applied in an investigation on the possible relationship between the polymorphism of the MTHFR-gene and rectal cancer in a cohort of women with cases matched by age to one and to three controls. A sequential analysis of matched data can lead to early stopping in favour of H(0) or H(1), thus conserving valuable resources for future testing. A sequentially designed study can be more economical and less arbitrary than a study that makes use of conditional power or conditional coverage probability calculations to decide early stopping.

Exact sequential tests for single samples of discrete responses using spending functions

Sequential tests are increasingly used to reduce the expected sample size of trials in medical research. The majority of such methods are based on the assumption of normality for test statistics. In clinical trials yielding a single sample of discrete data, that assumption is often poorly satisfied. In this paper we show how a novel application of the spending function approach of Lan and DeMets can be used together with exact calculation methods to design sequential procedures for a single sample of discrete random variables without the assumption of normality. A special case is that of binomial data and the paper is illustrated by the design of a cytogenetic study which motivated this work.

Radiotherapy followed by high dose busulfan and thiotepa: a prospective assessment of high dose chemotherapy in children with diffuse pontine gliomas

BACKGROUND

The role of high dose chemotherapy (HDC) in patients with pediatric brain tumors currently is ill-defined. The purpose of this pilot study was to assess the feasibility and the benefit of HDC after radiotherapy in a group of children with newly diagnosed diffuse pontine gliomas.

METHODS

Patients eligible for study were ages 3-18 years with diffuse intrinsic tumors arising in the pons, who were not treated previously with radiotherapy or chemotherapy. Histologic confirmation was not mandatory, provided clinical findings and magnetic resonance imaging were typical. Patients were given focal radiotherapy followed 2-3 months later by HDC. Busulfan (150 mg/m(2) on Days 8, 7, 6, and 5) and thiotepa (300 mg/m(2) on Days 4, 3, and 2) were administered prior to autologous bone marrow transplantation. Survival was the endpoint, and the statistical procedure was based on sequential subgroup analysis.

RESULTS

Thirty-six patients were entered on to the study, 12 of whom underwent stereotactic biopsy or open surgery at the time of diagnosis. One patient eventually was excluded due to inappropriate eligibility criteria. All 35 eligible patients received irradiation. Early progression (9 patients) and parental refusal (2 patients) precluded the use of HDC in 11 patients. Three patients died of HDC-related complications. All 21 patients who survived HDC eventually died of disease progression. The median survival time was 10 months for the study group. The median survival time in the subgroup of patients who received HDC was 10 months (range, 3-26 months). Statistical analysis did not suggest any evidence of survival benefit.

CONCLUSIONS

For patients with diffuse pontine gliomas, survival using this aggressive treatment modality does not appear to be any better than that reported for conventional radiotherapy.

Decision theoretic designs for phase II clinical trials with multiple outcomes

In many phase II clinical trials, it is essential to assess both efficacy and safety. Although several phase II designs that accommodate multiple outcomes have been proposed recently, none are derived using decision theory. This paper describes a Bayesian decision theoretic strategy for constructing phase II designs based on both efficacy and adverse events. The gain function includes utilities assigned to patient outcomes, a reward for declaring the new treatment promising, and costs associated with the conduct of the phase II trial and future phase III testing. A method for eliciting gain function parameters from medical collaborators and for evaluating the design's frequentist operating characteristics is described. The strategy is illustrated by application to a clinical trial of peripheral blood stem cell transplantation for multiple myeloma.

Treatment of early AIDS-related Kaposi's sarcoma with oral all-trans-retinoic acid: results of a sequential non-randomized phase II trial. Kaposi's Sarcoma ANRS Study Group. Agence Nationale de Recherches sur le SIDA

OBJECTIVE

To assess the efficacy and safety of all-trans-retinoic acid (ATRA), a retinoid with antitumour activity that inhibits in vitro the growth of Kaposi's sarcoma cells, in patients with low-risk AIDS-associated Kaposi's sarcoma.

DESIGN

Non-randomized phase II study, using a group sequential procedure to determine whether the response rate to ATRA was above 10%.

SETTING

Nine referral French centres.

PATIENTS

Twenty HIV-seropositive men with CD4 cells > or = 200 x 10(6)/l, low-risk Kaposi's sarcoma [T0I0S0 according to the classification of AIDS Clinical Trials Group (ACTG)] not previously treated with systemic anti-Kaposi's sarcoma agents, and with at least four measurable lesions were included.

INTERVENTIONS

ATRA was given orally 45 mg/m2 daily for 12 weeks.

MAIN OUTCOME MEASURE

Tumour response evaluated according to ACTG criteria.

RESULTS

Nineteen patients were evaluated for response: partial response, stabilization and progression were found in eight (42%), seven (37%), and four (21%) patients, respectively. Gradual flattening and lightening of lesions was observed in responders after at least 2 months of ATRA. All patients with partial response at week 12 pursued ATRA for another 15+/-7 weeks. Further improvement was observed in six patients. Median duration of response was 332 days. Cheilitis, transient headaches and skin dryness were the main toxicities noted. No significant changes in HIV viral burden or serum interleukin-6 pathways were observed.

CONCLUSIONS

ATRA is well tolerated and effective enough in Kaposi's sarcoma patients to warrant further evaluation.

The group sequential triangular test for phase II cancer clinical trials

In cancer, phase II clinical trials are usually noncomparative. Their purpose is to determine whether a new chemotherapy is effective enough to warrant further evaluation in phase III. Therefore, in order to meet ethical requirements, decision-making methods must allow for early termination when inefficacy (or efficacy) is clear. We previously extended the Triangular Test, a group sequential method initially proposed for phase III trials, to phase II trials and demonstrated its advantages (i.e., type I error rate alpha and power close to the nominal values, reduction of the sample size) over other methods. The aim of this paper is to present the Triangular Test from a practical standpoint that will facilitate its application to phase II clinical trials in oncology. After summarizing the minimal theoretical knowledge required to use the method appropriately, we discuss its use in the design and analysis of a phase II cancer trial.

A comparison of methods for phase II cancer clinical trials: advantages of the triangular test, a group sequential method

In cancer, the purpose of Phase II studies is to determine whether the response rate p to a new treatment is greater than a prespecified value p0, defined as the largest response rate for which Phase III studies are not worthwhile. It concerns, for example, determining whether the response rate to a new drug is greater than 20%. The main problem is of a decision making nature, and amounts to the comparison of an observed percentage with a theoretical percentage. One way of resolving it is to perform a single statistical analysis after the inclusion of a predetermined number of patients N, but it is not always possible because of high values of N. Furthermore, this approach presents ethical problems when elements in favor of inefficacy or efficacy are available early in the trial. For these reasons, several authors have developed methods which allow to perform repeated analyses and possibly to reach an early conclusion of the study: two-stage, multistage, sequential and group sequential methods. This article considers the main decision making methods proposed in the literature for Phase II studies in oncology. The bibliographic study, which highlights the interest of using group sequential methods, and especially the Triangular Test, is confirmed by a comparative study of the statistical properties of the different methods.

A sequential procedure for a phase II efficacy trial in hypercholesterolemia

The design of a phase II placebo-controlled efficacy trial to evaluate a new treatment for hypercholesterolemia using a sequential procedure is presented. The sequential procedure used is the triangular test which offers flexibility of monitoring and allows early stopping even when the null hypothesis is "accepted." The primary response is reduction in total serum cholesterol level, which is assumed to be normally distributed with unknown variance. The treatment difference is parameterized in terms of the standardized difference between the means. The accuracy of the error rates of the triangular test using this parameterization is compared with the test based on the difference between the means.