Accrual and statistical power failure in published adjuvant phase III oncology trials: a comprehensive analysis from 2013 to 2023.

BACKGROUND: In a competitive landscape with many ongoing adjuvant randomised controlled trials (RCTs), the prevalence of trials that failed to recruit their targeted sample size and were inadequately powered is unclear. The aims of the study are (i) to determine the percentage of trials with accrual and statistical power failure and (ii) to evaluate their potential impact on the drug development process. MATERIALS AND METHODS: A systematic review was carried out to identify adjuvant phase III oncology RCTs reported between 2013 and 2023 across all solid tumours. No restrictions were applied regarding the type of intervention or journal of publication. The percentage of trials with accrual failure and power failure was estimated as well as their association with the efficacy endpoints. Logistic regression models were used to estimate the odds ratio (OR) and its 95% confidence interval (CI). RESULTS: A total of 282 RCTs met the inclusion criteria with a median sample size of 661 patients and a median accrual period of 4.3 years. Most of these studies were superiority trials (83.0%). Accrual failure was observed in 22.0% of the studies, finishing recruitment without achieving the targeted sample size. Overall, 39.7% of the studies experienced power failure, having less power than specified in the protocol at the date of the read-out. Among superiority RCTs evaluating intermediate survival endpoints, only 31.1% presented statistically significant results. Trials with power failure were less likely to present statistically significant results (37.9% versus 21.9%, P = 0.04). The association was consistent across all cancer types. In the subset of non-inferiority trials, 35.0% formally demonstrated non-inferiority of the experimental arm. CONCLUSIONS: Nearly 40% of adjuvant phase III RCTs experienced power failure, and the reduction in power significantly impacted the final study results. There is a need for procedural refinements in the design and implementation of future adjuvant RCTs to mitigate these fallacies.

Results of the c-TRAK TN trial: a clinical trial utilising ctDNA mutation tracking to detect molecular residual disease and trigger intervention in patients with moderate- and high-risk early-stage triple-negative breast cancer.

BACKGROUND: Post-treatment detection of circulating tumour DNA (ctDNA) in early-stage triple-negative breast cancer (TNBC) patients predicts high risk of relapse. c-TRAK TN assessed the utility of prospective ctDNA surveillance in TNBC and the activity of pembrolizumab in patients with ctDNA detected [ctDNA positive (ctDNA+)]. PATIENTS AND METHODS: c-TRAK TN, a multicentre phase II trial, with integrated prospective ctDNA surveillance by digital PCR, enrolled patients with early-stage TNBC and residual disease following neoadjuvant chemotherapy, or stage II/III with adjuvant chemotherapy. ctDNA surveillance comprised three-monthly blood sampling to 12 months (18 months if samples were missed due to coronavirus disease), and ctDNA+ patients were randomised 2 : 1 to intervention : observation. ctDNA results were blinded unless patients were allocated to intervention, when staging scans were done and those free of recurrence were offered pembrolizumab. A protocol amendment (16 September 2020) closed the observation group; all subsequent ctDNA+ patients were allocated to intervention. Co-primary endpoints were (i) ctDNA detection rate and (ii) sustained ctDNA clearance rate on pembrolizumab (NCT03145961). RESULTS: Two hundred and eight patients registered between 30 January 2018 and 06 December 2019, 185 had tumour sequenced, 171 (92.4%) had trackable mutations, and 161 entered ctDNA surveillance. Rate of ctDNA detection by 12 months was 27.3% (44/161, 95% confidence interval 20.6% to 34.9%). Seven patients relapsed without prior ctDNA detection. Forty-five patients entered the therapeutic component (intervention n = 31; observation n = 14; one observation patient was re-allocated to intervention following protocol amendment). Of patients allocated to intervention, 72% (23/32) had metastases on staging at the time of ctDNA+, and 4 patients declined pembrolizumab. Of the five patients who commenced pembrolizumab, none achieved sustained ctDNA clearance. CONCLUSIONS: c-TRAK TN is the first prospective study to assess whether ctDNA assays have clinical utility in guiding therapy in TNBC. Patients had a high rate of metastatic disease on ctDNA detection. Findings have implications for future trial design, emphasising the importance of commencing ctDNA testing early, with more sensitive and/or frequent ctDNA testing regimes.

Tracking evolution of aromatase inhibitor resistance with circulating tumour DNA analysis in metastatic breast cancer.

Background: Selection of resistance mutations may play a major role in the development of endocrine resistance. ESR1 mutations are rare in primary breast cancer but have high prevalence in patients treated with aromatase inhibitors (AI) for advanced breast cancer. We investigated the evolution of genetic resistance to the first-line AI therapy using sequential ctDNA sampling in patients with advanced breast cancer. Patients and methods: Eighty-three patients on the first-line AI therapy for metastatic breast cancer were enrolled in a prospective study. Plasma samples were collected every 3 months to disease progression and ctDNA analysed by digital droplet PCR and enhanced tagged-amplicon sequencing (eTAm-Seq). Mutations identified in progression samples by sequencing were tracked back through samples before progression to study the evolution of mutations on therapy. The frequency of novel mutations was validated in an independent cohort of available baseline plasma samples in the Study of Faslodex versus Exemestane with or without Arimidex (SoFEA) trial, which enrolled patients with prior sensitivity to AI. Results: Of the 39 patients who progressed on the first-line AI, 56.4% (22/39) had ESR1 mutations detectable at progression, which were polyclonal in 40.9% (9/22) patients. In serial tracking, ESR1 mutations were detectable median 6.7 months (95% confidence interval 3.7-NA) before clinical progression. Utilising eTAm-Seq ctDNA sequencing of progression plasma, ESR1 mutations were demonstrated to be sub-clonal in 72.2% (13/18) patients. Mutations in RAS genes were identified in 15.4% (6/39) of progressing patients (4 KRAS, 1 HRAS, 1 NRAS). In SoFEA, KRAS mutations were detected in 21.2% (24/113) patients although there was no evidence that KRAS mutation status was prognostic for progression free or overall survival. Conclusions: Cancers progressing on the first-line AI show high levels of genetic heterogeneity, with frequent sub-clonal mutations. Sub-clonal KRAS mutations are found at high frequency. The genetic diversity of AI resistant cancers may limit subsequent targeted therapy approaches.

Treatment of the axilla in patients with primary breast cancer and low burden axillary disease: Limitations of the evidence from randomised controlled trials.

Invasive breast cancer is the second most common cancer worldwide. It is known to metastasise to the regional axillary lymph nodes but there has been debate over what is the best way to stage and treat the axilla in patients presenting with primary breast cancer. Multiple trials over the last two decades have led to a change in practice from routine axillary lymph node dissection to sentinel lymph node biopsy in patients who are clinically lymph node negative preoperatively. This has resulted in new questions regarding subsequent treatment of some patients. This review will critically appraise the evidence on axillary treatment in patients with low burden axillary disease and highlight limitations of relevant randomised controlled trials.

Epirubicin dose and sequential hormonal therapy-Mature results of the HMFEC randomised phase III trial in premenopausal patients with node positive early breast cancer.

BACKGROUND: The hormonal manipulation 5-Fluoro-uracil Epirubicin Cyclophosphamide (HMFEC) trial was developed at a time of uncertainty around the dose intensity of chemotherapy given to premenopausal patients with node positive breast cancer and to the benefits of tailored endocrine therapy in such patients. PATIENTS AND METHODS: HMFEC was a multi-centre, phase III, open label, randomised controlled trial with a 2 × 2 factorial design. Eligible patients were premenopausal with node positive early breast cancer; significant cardiac disease or uncontrolled hypertension was exclusion criterion. Patients were allocated to receive either eight cycles of FE50C or FE75C (given 3 weekly) with or without hormone manipulation (HM; tamoxifen or luteinising hormone releasing hormone (LHRH) agonists according to residual hormone levels at the end of chemotherapy) irrespective of ER status. The primary end-point was disease free survival (DFS). Principal analyses were by intention to treat (ITT); however, to reflect contemporary practice, subgroup analyses according to ER status were also conducted. The mature follow-up now available from this modest sized trial enables presentation of definitive results. RESULTS: Between 1992 and 2000 a total of 785 patients were randomised into the HMFEC trial (203 FE50C-HM, 191 FE50C+HM, 198 FE75C-HM, 193 FE75C+HM). At a median follow-up of 7.4 years, 245 DFS events have been reported (92 ER-, 153 ER+/unknown). The effects on DFS were not statistically significantly different according to epirubicin dose (hazard ratio [HR] = 0.82, 95% confidence interval [CI] 0.63-1.06; p = 0.13 FE75C versus FE50C); however, FE75C appeared to induce more alopecia and neutropenia. No statistically significant evidence was observed to support an improvement in DFS in patients allocated HM either overall (HR = 0.88, 95% CI 0.68-1.13; p = 0.32) or in patients with ER+/unknown disease (HR = 0.85, 95% CI 0.62-1.17; p = 0.32) although effect sizes are consistent with worthwhile clinical effects. Overall, there was no evidence of a difference in survival between any of the four treatment groups of the trial. CONCLUSION: Higher doses of epirubicin cause more adverse events in the absence of clear improvement in overall survival. Endocrine therapy with either tamoxifen or goserelin provided no significant added benefit to cytotoxic chemotherapy in this group of patients. TRIAL REGISTRATION NUMBER: ISRCTN98335268.

NEOCENT: a randomised feasibility and translational study comparing neoadjuvant endocrine therapy with chemotherapy in ER-rich postmenopausal primary breast cancer.

Neoadjuvant endocrine therapy is an alternative to chemotherapy for women with oestrogen receptor (ER)-positive early breast cancer (BC). We aimed to assess feasibility of recruiting patients to a study comparing chemotherapy versus endocrine therapy in postmenopausal women with ER-rich primary BC, and response as well as translational endpoints were assessed. Patients requiring neoadjuvant therapy were randomised to chemotherapy: 6 × 3-weekly cycles FE100C or endocrine therapy: letrozole 2.5 mg, daily for 18-23 weeks. Primary endpoints were recruitment feasibility and tissue collection. Secondary endpoints included clinical, radiological and pathological response rates, quality of life and translational endpoints. 63/80 patients approached were eligible, of those 44 (70, 95% CI 57-81) were randomised. 12 (54.5, 95% CI 32.2-75.6) chemotherapy patients showed radiological objective response compared with 13 (59.1, 95% CI 36.4-79.3) letrozole patients. Compared with baseline, mean Ki-67 levels fell in both groups at days 2-4 and at surgery [fold change: 0.24 (95% CI 0.12-0.51) and 0.24; (95% CI 0.15-0.37), respectively]. Plasma total cfDNA levels rose from baseline to week 8 [fold change: chemotherapy 2.10 (95% CI 1.47-3.00), letrozole 1.47(95% CI 0.98-2.20)], and were maintained at surgery in the chemotherapy group [chemotherapy 2.63; 95% CI 1.56-4.41), letrozole 0.95 (95% CI 0.71-1.26)]. An increase in plasma let-7a miRNA was seen at surgery for patients with objective radiological response to chemotherapy. Recruitment and tissue collection endpoints were met; however, a larger trial was deemed unfeasible due to slow accrual. Both regimens were equally efficacious. Dynamic changes were seen in Ki-67 and circulating biomarkers in both groups with increases in cfDNA and let-7a miRNA persisting until surgery for chemotherapy patients.

Long-term assessment of quality of life in the Intergroup Exemestane Study: 5 years post-randomisation.

BACKGROUND: The Intergroup Exemestane Study (IES) (ISRCTN11883920) demonstrated improved survival for postmenopausal women with ER-positive/unknown primary breast cancer who switched to exemestane after 2-3 years tamoxifen, compared with those continuing on tamoxifen to complete 5 years therapy. This was achieved without detriment to on-treatment quality-of-life (QoL). We report on- and post-treatment QoL impact in IES. METHODS: A total of 582 patients from 8 countries participated in the QoL substudy. Functional Assessment of Cancer Therapy-Breast (FACT-B) and endocrine symptom subscale (ES) were completed at baseline, 3, 6, 9, 12, 18, 24, 30, 36, 48 and 60 months. The primary endpoint was FACT-B Trial Outcome Index (TOI); secondary endpoints included severity of individual endocrine symptoms. RESULTS: Both the groups showed gradual improvement in overall QoL and lessening of total endocrine symptoms post treatment compared with baseline (P<0.002). There was no evidence of any between-group differences in TOI. Vasomotor complaints remained high on treatment. Vaginal discharge was more frequent (P<0.01) with tamoxifen up to 24 months from baseline. In both the groups, post-treatment libido did not recover to baseline levels. CONCLUSION: Clinical benefits of switching to exemestane are accompanied by good overall QoL. Although some symptoms persist, the majority of endocrine symptoms improve after treatment completion.

Adjuvant chemotherapy in older women (ACTION) study - what did we learn from the pilot phase?

BACKGROUND: The ACTION trial was initiated to provide evidence from a randomised trial on the effects of chemotherapy in women aged over 70 years where evidence for risk and benefit are lacking. METHODS: This was a randomised, phase III clinical trial for high risk, oestrogen receptor (ER) negative/ER weakly positive early breast cancer. The trial planned to recruit 1000 women aged 70 years and older, randomised to receive 4 cycles of anthracycline chemotherapy or observation. The primary endpoint was relapse-free interval. The trial included a pilot phase to assess the acceptability and feasibility of recruitment. RESULTS: The trial opened at 43 UK centres. Information on number of patients approached was available from 38 centres. Of the 43 eligible patients that were approached, 39 were not randomised due to patients declining entry. After 10 months only 4 patients had been randomised and after discussion with the research funder, the trial was closed and funding terminated. CONCLUSION: Despite widespread support at several public meetings, input from patient groups including representation on the Trial Management Group, the trial failed to recruit due to the inability to convince patients to accept randomisation. It would therefore seem that randomising the patients to receive chemotherapy vs observation is not a viable design in the current era for this patient population.

Survival and safety of exemestane versus tamoxifen after 2-3 years' tamoxifen treatment (Intergroup Exemestane Study): a randomised controlled trial.

BACKGROUND: Early improvements in disease-free survival have been noted when an aromatase inhibitor is given either instead of or sequentially after tamoxifen in postmenopausal women with oestrogen-receptor-positive early breast cancer. However, little information exists on the long-term effects of aromatase inhibitors after treatment, and whether these early improvements lead to real gains in survival. METHODS: 4724 postmenopausal patients with unilateral invasive, oestrogen-receptor-positive or oestrogen-receptor-unknown breast cancer who were disease-free on 2-3 years of tamoxifen, were randomly assigned to switch to exemestane (n=2352) or to continue tamoxifen (n=2372) for the remainder of a 5-year endocrine treatment period. The primary endpoint was disease-free survival; overall survival was a secondary endpoint. Efficacy analyses were intention-to-treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN11883920. RESULTS: After a median follow-up of 55.7 months (range 0-89.7), 809 events contributing to the analysis of disease-free survival had been reported (354 exemestane, 455 tamoxifen); unadjusted hazard ratio 0.76 (95% CI 0.66-0.88, p=0.0001) in favour of exemestane, absolute benefit 3.3% (95% CI 1.6-4.9) by end of treatment (ie, 2.5 years after randomisation). 222 deaths occurred in the exemestane group compared with 261 deaths in the tamoxifen group; unadjusted hazard ratio 0.85 (95% CI 0.71-1.02, p=0.08), 0.83 (0.69-1.00, p=0.05) when 122 patients with oestrogen-receptor-negative disease were excluded. CONCLUSIONS: Our results suggest that early improvements in disease-free survival noted in patients who switch to exemestane after 2-3 years on tamoxifen persist after treatment, and translate into a modest improvement in overall survival.

Relative potential for selection of quinolone-resistance-determining-region mutations in Streptococcus pneumoniae by gemifloxacin, gatifloxacin and moxifloxacin.

Serial passage of a clinical isolate of Streptococcus pneumoniae, in the presence of moxifloxacin, gatifloxacin or gemifloxacin, gave rise to resistant isolates. Non-susceptibility as defined by Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS) breakpoints arose on Days 10, 11, and 12 with gatifloxacin, gemifloxacin, and moxifloxacin respectively. Moxifloxacin and gatifloxacin selected for a single step quinolone-resistant-determining-region (QRDR) mutation in DNA gyrase (GyrA) on Day 4 and 7 respectively, whereas gemifloxacin selected simultaneously for multi-step mutations in gyrase and topoisomerase IV (ParC) on Day 17 and activated a non-reserpine inhibited efflux mechanism by Day 4. As found in clinical isolates, mutations included Ser-81-Phe and Glu-85-Lys in GyrA and Ser-79-Phe or Asp-83-Tyr in ParC. At high MICs, moxifloxacin showed a previously unreported 4 amino-acid deletion in GyrB as well as a more unusual substitution Ser-79-Leu/Ile in ParC. Gemifloxacin showed a 2- to 16-fold greater activity than moxifloxacin or gatifloxacin against strains with two or more QRDR mutations, however, its potency did not translate to nonsusceptibility and gemifloxacin MIC values were either at or well above the CLSI nonsusceptible breakpoint concentration.

Interspecies recombination contributes minimally to fluoroquinolone resistance in Streptococcus pneumoniae.

Analysis of 71 ciprofloxacin-resistant (MIC > or = 4 microg/ml) Streptococcus pneumoniae clinical isolates revealed only 1 for which the quinolone resistance-determining regions of the parC, parE, and gyrB genes were genetically related to those of viridans group streptococci. Our findings support the occurrence of interspecies recombination of type II topoisomerase genes; however, its contribution to the emergence of quinolone resistance among pneumococci appears to have been minimal.

A nosocomial outbreak of fluoroquinolone-resistant Streptococcus pneumoniae.

Over the course of a 20-month period, in a hospital respiratory ward in which ciprofloxacin was often used as empirical antimicrobial therapy for lower respiratory tract infections (LRTIs), 16 patients with chronic bronchitis developed nosocomial LRTIs caused by penicillin- and ciprofloxacin-resistant Streptococcus pneumoniae (serotype 23 F). The minimum inhibitory concentration (MIC) of ciprofloxacin for all isolates from the first 9 patients was 4 microg/mL, in association with a parC mutation. Isolates from the subsequent 7 patients all had a ciprofloxacin MIC of 16 microg/mL, in association with an additional mutation in gyrA. The MICs for this isolate were 8 microg/mL of levofloxacin (resistant), 2 microg/mL of moxifloxacin and gatifloxacin (intermediately resistant), and 0.12 microg/mL of gemifloxacin. This outbreak demonstrates the ability of S. pneumoniae to acquire multiple mutations that result in increasing levels of resistance to the fluoroquinolones and to be transmitted from person to person.

Fluoroquinolone resistance in clinical isolates of Streptococcus pneumoniae: contributions of type II topoisomerase mutations and efflux to levels of resistance.

We report on amino acid substitutions in the quinolone resistance-determining region of type II topisomerases and the prevalence of reserpine-inhibited efflux for 70 clinical isolates of S. pneumoniae for which the ciprofloxacin MIC is >/=4 microgram/ml and 28 isolates for which the ciprofloxacin MIC is

Genetic locus for streptolysin S production by group A streptococcus.

Group A streptococcus (GAS) is an important human pathogen that causes pharyngitis and invasive infections, including necrotizing fasciitis. Streptolysin S (SLS) is the cytolytic factor that creates the zone of beta-hemolysis surrounding GAS colonies grown on blood agar. We recently reported the discovery of a potential genetic determinant involved in SLS production, sagA, encoding a small peptide of 53 amino acids (S. D. Betschel, S. M. Borgia, N. L. Barg, D. E. Low, and J. C. De Azavedo, Infect. Immun. 66:1671-1679, 1998). Using transposon mutagenesis, chromosomal walking steps, and data from the GAS genome sequencing project (www.genome.ou.edu/strep. html), we have now identified a contiguous nine-gene locus (sagA to sagI) involved in SLS production. The sag locus is conserved among GAS strains regardless of M protein type. Targeted plasmid integrational mutagenesis of each gene in the sag operon resulted in an SLS-negative phenotype. Targeted integrations (i) upstream of the sagA promoter and (ii) downstream of a terminator sequence after sagI did not affect SLS production, establishing the functional boundaries of the operon. A rho-independent terminator sequence between sagA and sagB appears to regulate the amount of sagA transcript produced versus transcript for the entire operon. Reintroduction of the nine-gene sag locus on a plasmid vector restored SLS activity to the nonhemolytic sagA knockout mutant. Finally, heterologous expression of the intact sag operon conferred the SLS beta-hemolytic phenotype to the nonhemolytic Lactococcus lactis. We conclude that gene products of the GAS sag operon are both necessary and sufficient for SLS production. Sequence homologies of sag operon gene products suggest that SLS is related to the bacteriocin family of microbial toxins.

Insertion mutagenesis of the ferric pyoverdine receptor FpvA of Pseudomonas aeruginosa: identification of permissive sites and a region important for ligand binding.

Insertion of an 18-amino-acid-encoding sequence within the fpvA gene identified permissive sites at residues Y350, A402, R451, R521, and R558, consistent with these residues occurring in extramembranous loop regions of the protein. Insertions at R451, R521, and R558 did not adversely affect receptor function, although insertions at Y350 and A402 compromised ferric pyoverdine binding and uptake. The latter region likely contributes to or interacts with the ligand-binding site.