Interpretation of active-control randomised trials: the case for a new analytical perspective involving averted events

Active-control trials, where an experimental treatment is compared with an established treatment, are performed when the inclusion of a placebo control group is deemed to be unethical. For time-to-event outcomes, the primary estimand is usually the rate ratio, or the closely-related hazard ratio, comparing the experimental group with the control group. In this article we describe major problems in the interpretation of this estimand, using examples from COVID-19 vaccine and HIV pre-exposure prophylaxis trials. In particular, when the control treatment is highly effective, the rate ratio may indicate that the experimental treatment is clearly statistically inferior even when it is worthwhile from a public health perspective. We argue that it is crucially important to consider averted events as well as observed events in the interpretation of active-control trials. An alternative metric that incorporates this information, the averted events ratio, is proposed and exemplified. Its interpretation is simple and conceptually appealing, namely the proportion of events that would be averted by using the experimental treatment rather than the control treatment. The averted events ratio cannot be directly estimated from the active-control trial, and requires an additional assumption about either: (a) the incidence that would have been observed in a hypothetical placebo arm (the counterfactual incidence) or (b) the efficacy of the control treatment (relative to no treatment) that pertained in the active-control trial. Although estimation of these parameters is not straightforward, this must be attempted in order to draw rational inferences. To date, this method has been applied only within HIV prevention research, but has wider applicability to treatment trials and other disease areas.

A multicenter, randomized, double-blind, duloxetine-controlled, non-inferiority trial of desvenlafaxine succinate extended-release in patients with major depressive disorder

BACKGROUND

Desvenlafaxine and duloxetine are selective serotonin and norepinephrine reuptake inhibitors. Their efficacy has not been directly compared using statistical hypotheses. This study evaluated the non-inferiority of desvenlafaxine extended-release (XL) to duloxetine in patients with major depressive disorder (MDD).

METHODS

In this study, 420 adult patients with moderate-to-severe MDD were enrolled and randomly assigned (1:1) to receive 50 mg (once daily [QD]) of desvenlafaxine XL (n = 212) or 60 mg QD of duloxetine (n = 208). The primary endpoint was evaluated using a non-inferiority comparison based on the change from baseline to 8 weeks in the 17-item Hamilton Depression Rating Scale (HAMD₁₇) total score. Secondary endpoints and safety were evaluated.

RESULTS

Least-squares mean change in HAM-D₁₇ total score from baseline to 8 weeks was -15.3 (95% confidence interval [CI]: -17.73, -12.89) in the desvenlafaxine XL group and - 15.9 (95% CI, -18.44, -13.39) in the duloxetine group. The least-squares mean difference was 0.6 (95% CI: -0.48, 1.69), and the upper boundary of 95% CI was less than the non-inferiority margin (2.2). No significant between-treatment differences were found in most secondary efficacy endpoints. The incidence of the most common treatment-emergent adverse events (TEAEs) was lower for desvenlafaxine XL than for duloxetine for nausea (27.2% versus 48.8%) and dizziness (18.0% versus 28.8%).

LIMITATIONS

A short-term non-inferiority study without a placebo arm.

CONCLUSIONS

This study demonstrated that desvenlafaxine XL 50 mg QD was non-inferior to duloxetine 60 mg QD in efficacy in patients with MDD. Desvenlafaxine had a lower incidence of TEAEs than duloxetine did.

Optimizing (O) rifapentine-based (RI) regimen and shortening (EN) the treatment of drug-susceptible tuberculosis (T) (ORIENT) using an adaptive seamless design: study protocol of a multicenter randomized controlled trial

BACKGROUND

Standard treatment for drug-susceptible tuberculosis (DS-TB) includes a multidrug regimen requiring at least 6 months of treatment, and this lengthy treatment easily leads to poor adherence. There is an urgent need to simplify and shorten treatment regimens to reduce interruption and adverse event rates, improve compliance, and reduce costs.

METHODS

ORIENT is a multicenter, randomized controlled, open-label, phase II/III, non-inferiority trial involving DS-TB patients to evaluate the safety and efficacy of short-term regimens compared with the standardized six-month treatment regimen. In stage 1, corresponding to a phase II trial, a total of 400 patients are randomly divided into four arms, stratified by site and the presence of lung cavitation. Investigational arms include 3 short-term regimens with rifapentine 10 mg/kg, 15 mg/kg, and 20 mg/kg, while the control arm uses the standardized six-month treatment regimen. A combination of rifapentine, isoniazid, pyrazinamide, and moxifloxacin is administered for 17 or 26 weeks in rifapentine arms, while a 26-week regimen containing rifampicin, isoniazid, pyrazinamide, and ethambutol is applied in the control arm. After the safety and preliminary effectiveness analysis of patients in stage 1, the control arm and the investigational arm meeting the conditions will enter into stage 2, which is equivalent to a phase III trial and will be expanded to recruit DS-TB patients. If all investigational arms do not meet the safety conditions, stage 2 will be canceled. In stage 1, the primary safety endpoint is permanent regimen discontinuation at 8 weeks after the first dose. The primary efficacy endpoint is the proportion of favorable outcomes at 78 weeks after the first dose for both two stages.

DISCUSSION

This trial will contribute to the optimal dose of rifapentine in the Chinese population and suggest the feasibility of the short-course treatment regimen containing high-dose rifapentine and moxifloxacin for DS-TB.

TRIAL REGISTRATION

The trial has been registered on ClinicalTrials.gov on 28 May 2022 with the identifier NCT05401071.

A randomized controlled trial of thrice-weekly versus thrice-daily oral ferrous fumarate treatment in adult patients with iron-deficiency anemia

Iron deficiency anemia (IDA) is a common health problem in developing countries. Many studies have shown that low-dose oral iron could have similar efficacy and less gastrointestinal effects in iron deficiency without anemia. This prospective open-labeled randomized controlled study was designed to compare the response of 200 mg ferrous fumarate thrice-weekly (TIW) as not inferior to the thrice-daily (TID) regimen and to assess the incidence of adverse events (AEs) between two regimens in treating adult patients with IDA. The primary endpoint was either an increase in Hb ≥ 3 g/dL, having Hb of 12 g/dL in females or 13 g/dL in males at the 12th week of treatment. Secondary outcomes included adverse events (AEs), red blood cell indices, iron profiles, and patient compliance. Sixty-four patients were randomized: 32 in the TIW arm and the other 32 in the TID arm. The response rates were not different between two arms either with intention to treat analysis (72.0%, 95%CI 56.6-88.5 vs. 71.9%, 95%CI 53.3-86.3, p = 0.777); or per-protocol analysis (88.9%, 95%CI 70.8-97.6 vs. 88.5%, 95%CI 69.8-97.6, p = 1.0), respectively. The trial demonstrated non-inferiority at a margin of 23%. Although the iron profile response of the TID arm was earlier than the TIW arm, almost all patients recovered from anemic symptoms at week 4, and hematologic responses were not different at week 12. There were more gastrointestinal AEs in the TID arm. In conclusion, this study showed that the TIW was non-inferior to the TID iron treatment of IDA patients but less AEs and costs.

Effectiveness of Yishen Tongbi decoction versus methotrexate in patients with active rheumatoid arthritis: A double-blind, randomized, controlled, non-inferiority trial

BACKGROUND

Yishen Tongbi decoction (YSTB) which is an herbal formula, has been used for the treatment of rheumatoid arthritis (RA) for more than ten years with a better curative effect. Methotrexate (MTX) is an effective anchoring agent used to treat rheumatoid arthritis. There were, however, no head-to-head comparative randomized controlled trials comparing traditional Chinese medicine (TCM) to MTX, Therefore, we performed this double-blind, double-model, randomized controlled trial of the efficacy and safety of YSTB and MTX in the treatment of active RA for 24 weeks.

METHODS

Patients who met the enrollment criteria were randomly selected (1:1) to receive either YSTB therapy (YSTB 150 ml once daily + MTX placebo 7.5-15 mg once weekly) or MTX therapy (MTX 7.5-15 mg once weekly + YSTB placebo 150 ml once daily) in treatment cycles lasting 24 weeks. The percentage of patients who achieve a clinical disease activity index (CDAI) response at week 24 is the primary efficacy outcome. A 10% risk differential non-inferiority margin was previously defined. The Chinese Clinical Trials Registry has recorded this trial (ChiCTR-1,900,024,902, registered on August 3rd 2019, http://www.chictr.org.cn/index.aspx).

RESULTS

Out of 118 patients whose eligibility was determined from September 2019 to May 2022, 100 patients (n = 50 for each group) were enrolled in the research overall. The 24-week trial was completed by 82% (40/49) of the YSTB group's patients and 86% (42/49) of the MTX group's patients. In the intention-to-treat analysis, 67.4% (33/49) of patients in the YSTB group met the main outcome of CDAI response criteria at week 24, compared to 57.1% (28/49) in the MTX group. The risk difference was 0.102 (95% CI -0.089 to 0.293), which demonstrated the non-inferiority of YSTB to MTX. After further testing for superiority, the ratio of CDAI responses achieved by the YSTB and MTX groups was not statistically significant (p = 0.298). At the same time, in week 24, secondary outcomes such as the ACR 20/50/70 response, the European Alliance of Associations for Rheumatology good or moderate response, remission rate, simplified disease activity index response, and low disease activity rate all showed similar statistically significant patterns. There was statistically significant attainment of ACR20 (p = 0.008) and EULAR good or moderate response (p = 0.009) in two groups at week 4. The intention-to-treat analysis results and the per-protocol analysis results were in agreement. The incidence of drug-related adverse events was not statistically different between the two groups (p = 0.487).

CONCLUSIONS

Previous studies have used TCM as an adjunct to conventional therapy, and few of them have directly compared it with MTX. In order to lessen disease activity in RA patients, this trial demonstrated that YSTB compound monotherapy was non-inferior to MTX monotherapy and had superior efficacy following short-term treatment. This study provided evidence-based medicine in the treatment of RA with compound prescriptions of TCM and contributed to promoting phytomedicine use in RA patients.

Comparison of weight change between face-to-face and digital delivery of the English National Health service diabetes prevention programme: An exploratory non-inferiority study with imputation of plausible weight outcomes

Worldwide evidence suggests face-to-face diabetes prevention programmes are effective in preventing and delaying the onset of type 2 diabetes by encouraging behaviour change towards weight loss, healthy eating, and increased exercise. There is an absence of evidence on whether digital delivery is as effective as face-to-face. During 2017-18 patients in England were offered the National Health Service Diabetes Prevention Programme as group-based face-to-face delivery, digital delivery ('digital-only') or a choice between digital and face-to-face ('digital-choice'). The contemporaneous delivery allowed for a robust non-inferiority study, comparing face-to-face with digital only and digital choice cohorts. Changes in weight at 6 months were missing for around half of participants. Here we take a novel approach, estimating the average effect in all 65,741 individuals who enrolled in the programme, by making a range of plausible assumptions about weight change in individuals who did not provide outcome data. The benefit of this approach is that it includes everyone who enrolled in the programme, not restricted to those who completed. We analysed the data using multiple linear regression models. Under all scenarios explored, enrolment in the digital diabetes prevention programme was associated with clinically significant reductions in weight which were at least equivalent to weight loss in the face-to-face programme. Digital services can be just as effective as face-to-face in delivering a population-based approach to the prevention of type 2 diabetes. Imputation of plausible outcomes is a feasible methodological approach, suitable for analysis of routine data in settings where outcomes are missing for non-attenders.

Safety and immunogenicity of SII-NVX-CoV2373 (COVID-19 vaccine) in adults in a phase 2/3, observer-blind, randomised, controlled study

Background

NVX-CoV2373, a Covid-19 vaccine was developed in the USA with ∼90% efficacy. The same vaccine is manufactured in India after technology transfer (called as SII-NVX-CoV2373), was evaluated in this phase 2/3 immuno-bridging study.

Methods

This was an observer-blind, randomised, phase 2/3 study in 1600 adults. In phase 2, 200 participants were randomized 3:1 to SII-NVX-CoV2373 or placebo. In phase 3, 1400 participants were randomized 3:1 to SII-NVX-CoV2373 or NVX-CoV2373 (940 safety cohort and 460 immunogenicity cohort). Two doses of study products (SII-NVX-CoV2373, NVX-CoV2373 or placebo) were given 3 weeks apart. Primary objectives were to demonstrate non-inferiority of SII-NVX-CoV2373 to NVX-CoV2373 in terms of geometric mean ELISA units (GMEU) ratio of anti-S IgG antibodies 14 days after the second dose (day 36) and to determine the incidence of causally related serious adverse events (SAEs) through 180 days after the first dose. Anti-S IgG response was assessed using an Enzyme-Linked Immunosorbent Assay (ELISA) and neutralizing antibodies (nAb) were assessed by a microneutralization assay using wild type SARS CoV-2 in participants from the immunogenicity cohort at baseline, day 22, day 36 and day 180. Cell mediated immune (CMI) response was assessed in a subset of 28 participants from immunogenicity cohort by ELISpot assay at baseline, day 36 and day 180. The total follow-up was for 6 months. Trial registration: CTRI/2021/02/031554.

Findings

Total 1596 participants (200 in Phase 2 and 1396 in Phase 3) received the first dose. SII-NVX-CoV2373 was found non-inferior to NVX-CoV2373 (anti-S IgG antibodies GMEU ratio 0.91; 95% CI: 0.79, 1.06). At day 36, there was more than 58-fold rise in anti-S IgG and nAb titers compared to baseline in both the groups. On day 180 visit, these antibody titers declined to levels slightly lower than those after the first dose (13-22 fold-rise above baseline). Incidence of unsolicited and solicited AEs was similar between the SII-NVX-CoV2373 and NVX-CoV2373 groups. No adverse event of special interest (AESI) was reported. No causally related SAE was reported.

Interpretation

SII-NVX-CoV2373 induced a non-inferior immune response compared to NVX-CoV2373 and has acceptable safety profile.

Funding

SIIPL, Indian Council of Medical Research, Novavax.

Application of opioid-free general anesthesia for gynecological laparoscopic surgery under ERAS protocol: a non-inferiority randomized controlled trial

BACKGROUND

Enhanced recovery after surgery (ERAS) is now widely used in various surgical fields including gynecological laparoscopic surgery, but the advantages of opioid-free anesthesia (OFA) in gynecological laparoscopic surgery under ERAS protocol are inexact.

AIMS

This study aims to assess the effectiveness and feasibility of OFA technique versus traditional opioid-based anesthesia (OA) technique in gynecological laparoscopic surgery under ERAS.

METHODS

Adult female patients aged 18 ~ 65 years old undergoing gynecological laparoscopic surgery were randomly divided into OFA group (Group OFA, n = 39) with esketamine and dexmedetomidine or OA group (Group OA, n = 38) with sufentanil and remifentanil. All patients adopted ERAS protocol. The primary outcome was the area under the curve (AUC) of Visual Analogue Scale (VAS) scores (AUC_VAS) postoperatively. Secondary outcomes included intraoperative hemodynamic variables, awakening and orientation recovery times, number of postoperative rescue analgesia required, incidence of postoperative nausea and vomiting (PONV) and Pittsburgh Sleep Quality Index (PSQI) perioperatively.

RESULTS

AUC_VAS was (Group OFA, 16.72 ± 2.50) vs (Group OA, 15.99 ± 2.72) (p = 0.223). No difference was found in the number of rescue analgesia required (p = 0.352). There were no between-group differences in mean arterial pressure (MAP) and heart rate (HR) (p = 0.211 and 0.659, respectively) except MAP at time of surgical incision immediately [(Group OFA, 84.38 ± 11.08) vs. (Group OA, 79.00 ± 8.92), p = 0.022]. Times of awakening and orientation recovery in group OFA (14.54 ± 4.22 and 20.69 ± 4.92, respectively) were both longer than which in group OA (12.63 ± 3.59 and 18.45 ± 4.08, respectively) (p = 0.036 and 0.033, respectively). The incidence of PONV in group OFA (10.1%) was lower than that in group OA (28.9%) significantly (p = 0.027). The postoperative PSQI was lower than the preoperative one in group OFA (p = 0.013).

CONCLUSION

In gynecological laparoscopic surgery under ERAS protocol, OFA technique is non-inferior to OA technique in analgesic effect and intraoperative anesthesia stability. Although awakening and orientation recovery times were prolonged compared to OA, OFA had lower incidence of PONV and improved postoperative sleep quality.

TRIAL REGISTRATION

ChiCTR2100052761, 05/11/2021.

Risk difference, relative risk, and odds ratio for non-inferiority clinical trials with risk rate endpoint

Non-inferiority (NI) clinical trials are widely used to evaluate whether the new experimental treatment is not unacceptably worse than the current active-control treatment by more than a pre-specified non-inferiority margin (NI margin). However, choosing either an absolute difference [risk difference (RD)] or a relative difference [relative risk (RR) and odds ratio (OR)] to evaluate efficacy in NI clinical trials is still controversial. In this study, we aim to evaluate the performance of abovementioned three metrics for testing NI clinical trials with risk rate endpoint. Herein, extensive Monte Carlo simulations based on various parameter settings (NI margin as well as risk rates in the experimental group and active-control group) are conducted to compare the Type I error rate, statistical power, and the necessary sample size to achieve a desired power for testing NI using RD, RR, and OR. We show that testing NI using RD not only controls well the Type I error and achieves the highest statistical power but also requires the smallest sample size compared to RR and OR. In practice, however, the choice among three metrics still needs to be based upon clinical interpretations and regulatory perspectives.

Phase 3 Study of Subcutaneous Versus Intravenous Ravulizumab in Eculizumab-Experienced Adult Patients with PNH: Primary Analysis and 1-Year Follow-Up

INTRODUCTION

This study compared the pharmacokinetics (PK) of the ravulizumab on-body delivery system for subcutaneous (SUBQ) administration with intravenous (IV) ravulizumab in eculizumab-experienced patients with paroxysmal nocturnal hemoglobinuria (PNH).

METHODS

Patients with PNH received SUBQ ravulizumab (n = 90) or IV ravulizumab (n = 46) during the 10-week randomized treatment period; all patients then received SUBQ ravulizumab during an extension period (< 172 weeks; data cutoff 1 year). Primary endpoint was day 71 serum ravulizumab trough concentration (C_trough). Secondary endpoints were ravulizumab C_trough and free C5 over time. Efficacy endpoints included change in lactate dehydrogenase (LDH), breakthrough hemolysis (BTH), transfusion avoidance, stabilized hemoglobin, and Treatment Administration Satisfaction Questionnaire (TASQ) score. Safety, including adverse events (AEs) and adverse device effects (ADEs), was assessed until data cutoff.

RESULTS

SUBQ ravulizumab demonstrated PK non-inferiority with IV ravulizumab (day 71 SUBQ/IV geometric least-squares means ratio 1.257 [90% confidence interval 1.160-1.361; p < 0.0001]). Through 1 year of SUBQ administration, ravulizumab C_trough values were > 175 μg/mL (PK threshold) and free C5 < 0.5 μg/mL (PD threshold). Efficacy endpoints remained stable: mean (standard deviation, SD) LDH percentage change was 0.9% (20.5%); BTH events, 5/128 patients (3.9%); 83.6% achieved transfusion avoidance; 79.7% achieved stabilized hemoglobin. Total TASQ score showed improved satisfaction with SUBQ ravulizumab compared with IV eculizumab (mean [SD] change at SUBQ day 351, - 69.3 [80.1]). The most common AEs during SUBQ treatment (excluding ADEs) were headache (14.1%), COVID-19 (14.1%), and pyrexia (10.9%); the most common ADE unrelated to a device product issue was injection site reaction (4.7%). Although many patients had ≥ 1 device issue-related ADE, full SUBQ dose administration was achieved in 99.9% of attempts.

CONCLUSIONS

SUBQ ravulizumab provides an additional treatment choice for patients with PNH. Patients may switch to SUBQ ravulizumab from IV eculizumab or ravulizumab without loss of efficacy.

TRIAL REGISTRATION

NCT03748823.

Endovascular thrombectomy with or without intravenous alteplase in acute stroke: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND AND PURPOSE

This study investigated clinical outcomes after direct endovascular thrombectomy (EVT) compared to bridging therapy (EVT with prior intravenous alteplase) in acute stroke within 4.5 h after onset.

METHODS

PubMed and Embase were searched for eligible randomized controlled trials. The primary outcome was the rates of neurological functional independence defined as modified Rankin scale score 0-2 at 90 days, whose non-inferiority margin was set at - 15%, - 10%, - 6.5%, - 5%, and - 1.3% for its risk difference (RD).

RESULTS

We included six studies enrolling 2334 participants. The crude cumulative rates of functional independence were 49.0% with direct EVT vs 50.9% with bridging therapy, without significant difference (Odd ratio [OR] = 0.93, 95% confidence interval [CI] 0.79-1.09) between two groups, where the pooled RD was - 2% (95% CI - 6 to 2%) whose lower 95% CI bound fell within non-inferiority margins of - 15%, - 10%, -6.5%, but not - 5% and - 1.3%. Between the two groups, no significant difference was found in excellent function rate (30.2% vs 30.6%, OR = 0.99, 95% CI 0.82-1.18) with RD of 0% (95% CI - 3 to 4%), mortality rate (16.0% vs 15.0%, OR = 1.08, 95% CI 0.86-1.35) with RD of 1% (95% CI - 2 to 4%), and symptomatic intracranial hemorrhage rate (4.3% vs 5.0%, OR = 0.86, 95% CI 0.58-1.27) with RD of 0% (95% CI - 2 to 1%).

CONCLUSIONS

No statistical difference was found in functional and safety outcomes between direct EVT and bridging therapy groups in acute stroke within 4.5 h after symptom onset. EVT alone was non-inferior to bridging therapy for several, but not the more stringent, non-inferiority margins.

Assessing the subjective quality of smartphone anterior segment photography: a non-inferiority study

PURPOSE

To assess the subjective quality of anterior segment photos taken from a smartphone camera adapted to the slit lamp compared to a commercial inbuilt slit-lamp camera.

METHODS

Non-inferiority study. Five paired images of the anterior segment of normal eyes were taken using an iPhone 11 (Apple, Inc., Calif., USA) camera attached to a universal slit-lamp adaptor and a commercial inbuilt slit-lamp camera (Haag-Streit Diagnostics, Bern, Switzerland). Images were collated into a survey in which ophthalmology students, residents, registrars, and consultants participated to select the image taken from the inbuilt slit-lamp camera. If the image quality was subjectively indistinguishable, we expected a 50:50 split for each photograph that was presented. We selected a 10% non-inferiority margin, with the hypothesis that no less than 40% of images believed to be from the conventional camera were in fact from the smartphone camera.

RESULTS

There were 27 respondents in the survey: ophthalmology consultants (n = 7), registrars (n = 10), residents (n = 7), intern (n = 1) and students (n = 2). The mean correct identification across the respondents was 11.3 out of 25 (45.2%) images. Overall, the smartphone camera was non-inferior to the inbuilt slit-lamp camera (p < 0.001). The non-inferiority of the smartphone camera was significant for consultants (47.4%, p < 0.01), registrars (47.6%, p < 0.001) and residents (37.7%, p < 0.0001).

CONCLUSIONS

Anterior segment images obtained with a smartphone camera were non-inferior to the commercial inbuilt slit-lamp camera. Smartphone cameras may be a non-inferior tool for communication of anterior segment images having implications for the ease of access to quality telehealth consultations.

Molecular testing to deliver personalized chemotherapy recommendations: risking over and undertreatment

BACKGROUND

In the adjuvant setting of cancer treatment, de-escalation strategies have the goal of omitting or minimizing treatment in patients, without compromising outcomes. Historically, eligibility for adjuvant treatment solely relied on the patient's clinical and tumor's pathological characteristics. At the turn of the century, based on new biological understanding, molecular-based strategies were tested and sometimes implemented.

MAIN BODY

However, we illustrate how molecularly based de-escalation strategies may paradoxically lead to overtreatment. This may happen when the novel approach is tested in lieu of standard management and may not yield the same results when being implemented in addition to usual practice. In the DYNAMIC trial, adjuvant chemotherapy decision in stage II colon cancer was compared between a circulating tumor DNA (ctDNA)-based approach and the standard care. We show this may result in more patients receiving oxaliplatin-based chemotherapy and may expose a similar proportion of patients to chemotherapy if the novel strategy is implemented in addition to usual practice. The other potential risk is undertreatment. We provide an illustration of early breast cancer, where the decision of adjuvant chemotherapy based on the gene expression signature MammaPrint may lead to inferior outcomes as compared with the clinico-pathologic strategy. This may also happen when non-inferiority designs have large margins. Among solutions, it should be acknowledged that clinico-pathological features, like T4 in colon cancer, may not be abandoned and replaced by novel strategies in real-life practice. Therefore, novel strategies should be tested in addition to standard of care, and not in lieu of. Second, de-escalation trials should focus on the settings where the standard of care has a widespread agreement. This would avoid the risk of testing non-inferiority against an ineffective therapy, which guarantees successes without providing informative data.

CONCLUSION

Simply because a molecular test is rational does not mean it can improve patient outcomes. Here, we highlight how molecular test-based strategies may result in either overtreatment or undertreatment. In the rapidly evolving field of medicine, where technological advances may be transformative, our piece highlights scientific pitfalls to be aware of when considering running such trials or before implementing novel strategies in daily practice.

Dengzhan Shengmai capsule versus Aspirin in the treatment of carotid atherosclerotic plaque: A single-centre, non-inferiority, prospective, randomised controlled trial

BACKGROUND

Aspirin is an effective antiplatelet agent for the treatment of carotid atherosclerosis. However, the high risk of bleeding events associated with the drug makes it necessary to seek a safer alternative, with similar or more efficacy than aspirin. Dengzhan Shengmai (DZSM) capsules have been widely used to treat carotid atherosclerosis, and if proven to be non-inferior to aspirin, it may be preferable over the latter for carotid atherosclerosis treatment due to its numerous advantages. We conducted a randomised trial to test the non-inferiority of DZSM to aspirin for the treatment of carotid atherosclerotic plaques.

METHODS

We performed a single-centre, prospective, open-label, randomised non-inferiority trial. Patients with carotid atherosclerotic plaques were enrolled and randomly assigned (1:1) to receive either DZSM capsules or aspirin. The follow-up period was 12 months. The primary outcome was the mean change in carotid intima-media thickness (IMT). Secondary outcomes included ischaemic events, rate of lumen stenosis, lipid levels, and plaque scores, length, counts, and vulnerability. Adverse events and laboratory test results were recorded as safety outcomes. The non-inferiority of DZSM was demonstrated when the lower limit of the one-sided 97.5% confidence interval (CI) of the difference in IMT between groups was more than -0.06 mm (margin of non-inferiority). This trial has been registered at ClinicalTrials.gov (CHiCTR1900021365).

RESULTS

From 1 April 2019 to 30 September 2019, 150 patients were enrolled, and there was no statistical difference in demographics between the groups. Intention-to-treat analysis showed that the decrease in IMT(_∆IMT) was 0.216 ± 0.160 and 0.225 ± 0.149 mm in the DZSM and aspirin groups, respectively. The one-sided 97.5% CI for the difference between _∆IMTs was (-0.0593, +∞). The non-inferiority of DZSM was demonstrated (P_{non-inferiority} = 0.0234). There was no significant difference in the incidence of ischaemic events between the groups (P = 1.0). The DZSM group had significantly reduced plaque scores (P < 0.0001), length (P < 0.0001), and counts (P < 0.0001), and improved plaque vulnerability (P < 0.0001). The DZSM group also had reduced levels of low-density lipoprotein cholesterol (LDL-C) (P < 0.0001). Finally, the DZSM group had a lower incidence of total adverse events (14.7% vs. 28%, P = 0.046), especially gastrointestinal discomfort (5.3% vs. 16%, P = 0.034). Although there was no significant difference in bleeding events (0 vs. 5.3%, P = 0.120), the DZSM group tended to have a lower incidence.

CONCLUSION

This trial demonstrated that DZSM was not inferior, in efficacy, to aspirin in treating carotid atherosclerotic plaques, and was found to be superior to aspirin in terms of safety. This study provides a new approach for treating carotid plaques, especially in aspirin-intolerant patients.

Use of rubber dam versus cotton roll isolation on composite resin restorations' survival in primary molars: 2-year results from a non-inferiority clinical trial

BACKGROUND

This non-inferiority randomised clinical trial aimed to evaluate the survival of direct bulk fill composite resin restorations in primary molars using different methods of moisture control: rubber dam isolation (RDI-local anaesthesia and rubber dam) and cotton roll isolation (CRI-cotton roll and saliva ejector). Secondary outcomes included baseline and 2-year incremental cost, self-reported child's pain scores and patient behaviour during the restorative procedure.

METHODS

A total of 174 molars (93 children) with dentine caries lesions were randomly allocated to study groups (RDI or CRI) and restored with bulk fill composite resin by trained operators. Two blinded examiners assessed the restorations for up to 24 months. Wong-baker faces and Frankl's behaviour rating scales were used for accessing the child's pain and behaviour, respectively. The primary outcome (restoration survival) was analysed using the two-sample non-inferiority test for survival data using Cox Regression (non-inferiority/alternative hypothesis HR > 0.85; CI = 90%). Bootstrap Linear regression was used for cost analysis and logistic regression for pain and behaviour analysis (α = 5%).

RESULTS

After 2-years, 157 restorations were evaluated (drop-out = 9.7%). The survival rate was RDI = 60.4% and CRI = 54.3%. The non-inferiority hypothesis was accepted by the Cox Regression analysis (HR = 1.33; 90% CI 0.88-1.99; p = 0.036). RDI was 53% more expensive when compared to the CRI group. No differences were found between the groups regarding pain (p = 0.073) and behaviour (p = 0.788).

CONCLUSION

Cotton roll isolation proved to be non-inferior when compared to rubber dam for composite restorations longevity in primary molars. Furthermore, the latest presented the disadvantage of higher cost and longer procedure time. Clinical Significance The moisture control method does not influence the longevity of composite restorations in primary molars. Cotton roll isolation proved to be non-inferior to rubber dam isolation and is a viable option for restoring primary molars. Clinical trial registration registered NCT03733522 on 07/11/2018. The present trial was nested within another clinical trial, the CARies DEtection in Children (CARDEC-03-NCT03520309).

Concurrent chemoradiotherapy with cisplatin given once-a-week versus every-three weekly in head and neck squamous cell carcinoma: Non-inferior, equivalent, or superior?

Cisplatin-based concurrent chemoradiotherapy is the contemporary standard-of-care in curative-intent management of loco-regionally advanced head and neck squamous cell carcinoma. The most optimal dose-schedule of concurrent cisplatin remains debatable with widespread variability in clinical practice. High-quality evidence in favour of cisplatin-based chemoradiotherapy is largely based on high-dose cisplatin given as 100 mg/m² every three-weekly for up to three cycles. However, such dosing is typically associated with high rates of significant acute hematological and renal toxicity prompting the need for alternative lesser toxic dose-schedules. Compliance to three doses of three-weekly high-dose cisplatin is reportedly suboptimal with nearly 40% of patients unable to receive the third cycle thereby achieving cumulative cisplatin dose of 200 mg/m² which is generally regarded sufficient for beneficial anti-tumor effect. The most common alternative schedule is low-dose (20-50 mg/m²) cisplatin once-weekly during radiotherapy. Such low-dose weekly regimens have undergone less rigorous prospective evaluation versus RT alone but continue to be widely used in co-operative group trials and routine clinical practice. In the last decade, several small prospective randomized controlled trials have reported significantly lesser toxicity and comparable disease-related outcomes with low-dose weekly cisplatin. However, two recent randomized controlled trials have re-ignited the debate globally due to their contradictory results, inferences, and conclusions. Through this commentary, we critically appraise and summarize the existing evidence-base to inform contemporary clinical practice and guide future research. There is increasingly emerging evidence that chemoradiotherapy with once-weekly cisplatin is non-inferior to three-weekly cisplatin for disease-related outcomes in curative-intent management of loco-regionally advanced head and neck cancer.

A randomized, double-blind, phase III, non-inferiority clinical trial comparing the efficacy and safety of TA4415V (a proposed Trastuzumab biosimilar) and Herceptin (Trastuzumab reference product) in HER2-positive early-stage breast Cancer patients

Background

This study compared efficacy and safety of TA4415V, a trastuzumab biosimilar, with reference trastuzumab in patients with human epidermal growth factor receptor 2–positive (HER2-positive) early-stage breast cancer treated in the neoadjuvant setting in Iran.

Methods

Patients were randomly assigned to receive neoadjuvant TA4415V or reference trastuzumab concurrently with docetaxel (TH phase) for 4 cycles after treatment with 4 cycles of doxorubicin and cyclophosphamide (AC phase). Chemotherapy was followed by surgery. The primary endpoint was the comparison of pathologic complete response (pCR) rate in the per-protocol population. Secondary endpoints included comparisons of overall response rate (ORR), breast-conserving surgery (BCS), safety, and immunogenicity.

Results

Ninety-two participants were analyzed in the per-protocol population (TA4415V, n = 48; reference trastuzumab, n = 44). The pCR rates were 37.50% and 34.09% with TA4415V and reference drug, respectively. The 95% CI of the estimated treatment outcome difference (− 0·03 [95% CI − 0.23 to 0.16]) was within the non-inferiority margin. No statistically significant difference was observed between the groups for other efficacy variables in the ITT population: ORR (89.13% vs. 83.33%; p = 0.72) and BCS (20.37% vs. 12.96%; p = 0.42) in the TA4415V and reference drug group, respectively.

At least one grade 3 or 4 adverse events occurred in 27 (50%) patients in the TA4415V group versus 29 (53.70%) in the reference trastuzumab group (p = 0.70). The decrease in left ventricular ejection fraction (LVEF), as an adverse event of special interest (AESI) for trastuzumab, was compared between treatment groups in TH phase. Results demonstrated an LVEF decrease in 7 (12.96%) and 9 (16.67%) patients in TA4415V and reference trastuzumab groups, respectively (p = 0.59). Anti-drug antibodies (ADA) were not detected in any samples of groups.

Conclusions

Non-inferiority for efficacy was demonstrated between TA4415V and Herceptin based on the ratio of pCR rates in HER2-positive early breast cancer patients. In addition, ORR and BCS, as secondary endpoints, were not significantly different. Safety profile and immunogenicity were also comparable between the two groups.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00599-x.

Comparison of 8 weeks standard treatment (rifampicin plus clarithromycin) vs. 4 weeks standard plus amoxicillin/clavulanate treatment [RC8 vs. RCA4] to shorten Buruli ulcer disease therapy (the BLMs4BU trial): study protocol for a randomized controlled multi-centre trial in Benin

Background

Buruli ulcer (BU) is a neglected tropical disease caused by Mycobacterium ulcerans that affects skin, soft tissues, and bones, causing long-term morbidity, stigma, and disability. The recommended treatment for BU requires 8 weeks of daily rifampicin and clarithromycin together with wound care, physiotherapy, and sometimes tissue grafting and surgery. Recovery can take up to 1 year, and it may pose an unbearable financial burden to the household.

Recent in vitro studies demonstrated that beta-lactams combined with rifampicin and clarithromycin are synergistic against M. ulcerans. Consequently, inclusion of amoxicillin/clavulanate in a triple oral therapy may potentially improve and shorten the healing process.

The BLMs4BU trial aims to assess whether co-administration of amoxicillin/clavulanate with rifampicin and clarithromycin could reduce BU treatment from 8 to 4 weeks.

Methods

We propose a randomized, controlled, open-label, parallel-group, non-inferiority phase II, multi-centre trial in Benin with participants stratified according to BU category lesions and randomized to two oral regimens: (i) Standard: rifampicin plus clarithromycin therapy for 8 weeks; and (ii) Investigational: standard plus amoxicillin/clavulanate for 4 weeks. The primary efficacy outcome will be lesion healing without recurrence and without excision surgery 12 months after start of treatment (i.e. cure rate). Seventy clinically diagnosed BU patients will be recruited per arm. Patients will be followed up over 12 months and managed according to standard clinical care procedures. Decision for excision surgery will be delayed to 14 weeks after start of treatment. Two sub-studies will also be performed: a pharmacokinetic and a microbiology study.

Discussion

If successful, this study will create a new paradigm for BU treatment, which could inform World Health Organization policy and practice. A shortened, highly effective, all-oral regimen will improve care of BU patients and will lead to a decrease in hospitalization-related expenses and indirect and social costs and improve treatment adherence. This trial may also provide information on treatment shortening strategies for other mycobacterial infections (tuberculosis, leprosy, or non-tuberculous mycobacteria infections).

Trial registration

ClinicalTrials.gov NCT05169554. Registered on 27 December 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06473-9.

Immunogenicity and safety of an egg culture-based quadrivalent inactivated non-adjuvanted subunit influenza vaccine in subjects ≥3 years: A randomized, multicenter, double-blind, active-controlled phase III, non-inferiority trial

Subunit influenza vaccine only formulated with surface antigen proteins has better safety profiles relative to split-virion influenza vaccine. Compared to the traditional quadrivalent split-virion influenza vaccine, a novel quadrivalent subunit influenza vaccine is urgently needed in China. We completed a phase 3, randomized, double-blind, active-controlled, non-inferiority clinical study at two sites in Henan Province, China. Eligible volunteers were split into four age cohorts (3-8 years, 9-17 years, 18-64 years, and ≥ 65 years, based on their dates of birth) and randomly assigned (1:1) to the subunit and the split-virion ecNAIIV4 groups. All volunteers were intramuscularly administered a single vaccine dose at baseline, and children aged 3-8 years received a boosting dose at day 28. And the immune response was evaluated by measuring hemagglutinin-inhibition antibody titers against the four vaccine strains in blood samples. Safety profiles had nonsignificant differences between the study groups in ≥ 3 years cohort. Most adverse reactions post-vaccination, both local and systemic, were mild to moderate and resolved within 3 days. And no serious adverse events occurred. The immunogenicity of the trial vaccine was non-inferior to the comparator. Further, a two-dose vaccine series can provide better seroprotection than that of a one-dose series in children aged 3-8 years, with clinically acceptable safety profiles. Clinical Trials Registration. ChiCTR2100049934.

Systematic review and non-inferiority meta-analysis of randomised phase II/III trials on S-1-based therapy versus 5-fluorouracil- or capecitabine-based therapy in the treatment of patients with metastatic colorectal cancer

BACKGROUND

S-1 is an oral fluoropyrimidine that is increasingly used in Western countries for the treatment of metastatic colorectal cancer (mCRC). We conducted a non-inferiority meta-analysis on the efficacy of S-1-based therapy versus 5-fluorouracil (5-FU)- or capecitabine-based therapy in the treatment of patients with mCRC.

METHODS

MEDLINE, Embase, the Cochrane Central Register of Controlled Trials and Opengrey were searched for randomised clinical trials until May 2021. Data were extracted for progression-free survival (PFS), overall survival (OS), objective response rate (ORR) and adverse events. Pooled effect estimates, stratified by treatment line, with corresponding 99% confidence intervals (CI) were presented. For PFS, a pre-defined non-inferiority margin (ΔNI) of 1.25 was selected.

RESULTS

Ten studies (n = 2117) were included, of which six studies reported PFS and OS data and 10 studies reported ORR data. S-1-based therapy was shown to be non-inferior to 5-FU/capecitabine-based therapy in terms of PFS (HRtotal 0.95, 99% CI 0.83-1.08) with its CI upper limit well below ΔNI, and at least as efficacious in terms of OS (HRtotal 0.93, 99% CI 0.81-1.07), and ORR (RRtotal 1.06, 99% CI 0.90-1.24).

CONCLUSIONS

S-1-based therapy is non-inferior to 5-FU/capecitabine-based therapy in the treatment of mCRC regarding PFS and at least as efficacious as 5-FU/capecitabine-based therapy in terms of ORR and OS. These data support the use of S-1 in mCRC patients who are intolerant to 5-FU/capecitabine-based treatment.

To investigate treat and extend versus pro re nata regimen in neovascular age-related macular degeneration: results from the IDEM study

PURPOSE

The purpose of this study is to report the 24-month outcomes of a pro re nata (PRN) compared with a treat and extend (T&E) regimen in patients previously treated for neovascular age-related macular degeneration (nAMD).

METHODS

This was a 2-year prospective, single-center study. Previously treated patients for nAMD were randomized into two regimen groups: T&E and PRN groups. Main outcome measured was change in best corrected visual acuity (BCVA) from baseline to month 24. Secondary outcomes encompassed anatomical features such as central retinal thickness (CRT), number of intravitreal injections (IVI), and visits required.

RESULTS

A total of 124 eyes received the T&E (n = 61) or PRN (n = 63) regimen. At month 24, the mean BCVA change was -4.4 early treatment diabetic retinopathy study (ETDRS) letters (T&E) and -3.4 ETDRS letters (PRN), with a difference of +1.1 ETDRS letters (95% CI [-2.25]; p = 0.006). The mean change in CRT was -10.6 µm (T&E) and -7.9 µm (PRN), with a difference of +2.6 µm (95% CI [+19.2]; p = 0.004). The T&E group had received a mean of +4.6 more injections (95% CI [-7.06; -2.12]; p < 0.001) at month 24.

CONCLUSION

There was statistically proven non-inferiority between the PRN and T&E regimens in terms of visual and anatomical outcomes at 24 months, with significantly more IVI administered in the T&E regimen.

A non-inferiority trial comparing two killed, whole cell, oral cholera vaccines (Cholvax vs. Shanchol) in Dhaka, Bangladesh

Bangladesh remains cholera endemic with biannual seasonal peaks causing epidemics. At least 300,000 severe cases and over 4,500 deaths occur each year. The available oral cholera vaccineshave not yet been adopted for cholera control in Bangladesh due to insufficient number of doses available for endemic control. With a public private partnership, icddr,b initiated a collaboration between vaccine manufacturers in Bangladesh and abroad. A locally manufactured Oral Cholera Vaccine (OCV) named Cholvax became available for testing in Bangladesh. We evaluated the safety and immunogenicity of this locally produced Cholvax (Incepta Vaccine Ltd) inexpensive OCV comparatively to Shanchol (Shantha Biotechnics-Sanofi Pasteur) which is licensed in several countries. We conducted a randomized non-inferiority clinical trial of bivalent, killed oral whole-cell cholera vaccine Cholvax vs. Shanchol in the cholera-endemic area of Mirpur, Dhaka, among three different age cohorts (1-5, 6-17 and 18-45 years) between April 2016 and April 2017. Two vaccine doses were given at 14 days apart to 2,052 healthy participants. No vaccine-related serious adverse events were reported. There were no significant differences in the frequency of solicited (7.31% vs. 6.73%) and unsolicited (1.46% vs. 1.07%) adverse events reported between the Cholvax and Shanchol groups. Vibriocidal antibody responses among the overall population for O1 Ogawa (81% vs. 77%) and O1 Inaba (83% vs. 84%) serotypes showed that Cholvax was non-inferior to Shanchol, with the non-inferiority margin of -10%. For O1 Inaba, GMT was 462.60 (Test group), 450.84 (Comparator group) with GMR 1.02(95% CI: 0.92, 1.13). For O1 Ogawa, GMT was 419.64 (Test group), 387.22 (Comparator group) with GMR 1.12 (95% CI: 1.02, 1.23). Cholvax was safe and non-inferior to Shanchol in terms of immunogenicity in the different age groups. These results support public use of Cholvax to contribute for reduction of the cholera burden in Bangladesh. ClinicalTrials.gov number: NCT027425581.

TIMELAPSE study-efficacy of low-dose amitriptyline versus cognitive behavioral therapy for chronic insomnia in patients with medical comorbidity: study protocol of a randomized controlled multicenter non-inferiority trial

Background

Insomnia is common in people with long-term medical conditions and is related to increased mortality and morbidity. Cognitive behavioral therapy for insomnia (CBT-I) is first choice treatment and effective for people with insomnia and comorbid long-term medical conditions. However, CBT-I has some limitations as it might not always be available or appeal to patients with medical conditions. Furthermore, a small proportion of patients do not respond to CBT-I. Preliminary evidence and clinical experience suggest that low-dose amitriptyline (AM) might be an effective alternative to treat insomnia in patients with medical comorbidity. In this randomized controlled trial, we will determine whether AM is non-inferior to the first choice treatment for insomnia, CBT-I.

Methods/design

This study will test if treatment with low-dose amitriptyline for insomnia in patients with medical comorbidity is non-inferior to CBT-I in a multicenter randomized controlled non-inferiority trial. Participants will be 190 adults with a long-term medical condition and insomnia. Participants will be randomly allocated to one of two intervention arms: 12 weeks AM (starting with 10 mg per day, and if ineffective at 3 weeks, doubling this dose) or 12 weeks of CBT-I consisting of 6 weekly sessions and a follow-up session 6 weeks later. The primary outcome is subjective insomnia severity, measured with the Insomnia Severity Index (ISI). The primary endpoint is at 12 weeks. Secondary outcomes include sleep quality (e.g., sleep efficiency), questionnaires on daytime functioning (physical functioning and impairment of functioning), and symptoms (e.g., fatigue, pain, anxiety) at 12 weeks and 12 months post treatment and relapse of insomnia until 12 months after treatment.

Discussion

Irrespective of the outcome, this study will be a much-needed contribution to evidence based clinical guidelines on the treatment of insomnia in patients with medical comorbidity.

Trial registration

Dutch Trial Register NTR NL7971. Registered on 18 August 2019

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05868-4.

The evaluation of noninferiority for renal composite outcomes between sodium-glucose cotransporter inhibitors in Japan

BACKGROUND

In Japan, six types of sodium-glucose cotransporter inhibitors (SGLT2Is) are currently in use. Here, we evaluated differences in renal composite outcomes between SGLT2Is with or without evidence of cardio vascular outcome trials (CVOTs).

METHODS

We retrospectively surveyed 536 Japanese patients with type 2 diabetes mellitus with chronic kidney disease who received SGLT2Is for more than 1 year. Patients were classified as having received empagliflozin, canagliflozin, or dapagliflozin (n = 270, Evidence (+) group) or as having received ipragliflozin, tofogliflozin, or luseogliflozin (n = 266, Evidence (-) group). The propensity score matching method was performed.

RESULT

On matched cohort model including 205 cases in each group, there were no significant differences in the incidence of renal composite outcomes (n = 28 [14%] in the Evidence (+) group, n = 21 [10%] in the Evidence (-) group for the matched model; p = 0.29) between groups. Cox hazard analyses in the matched cohort model showed that the risk ratio for renal composite outcomes in the Evidence (-) group was 0.73 (95% confidence interval: 0.40-1.32), which was greater than the noninferiority margin of 1.22.

CONCLUSION

Three SGLT2Is with no CVOT's evidence did not show noninferiority compared with other SGLT2Is with evidences.

177Lu-PSMA-617 versus docetaxel in chemotherapy-naïve metastatic castration-resistant prostate cancer: a randomized, controlled, phase 2 non-inferiority trial

Purpose

Lutetium-177 prostate-specific membrane antigen-617 (¹⁷⁷Lu-PSMA-617) in end-stage metastatic castration-resistant prostate cancer (mCRPC) has reported favourable outcomes. In this study, we aimed to prospectively compare the efficacy and safety of ¹⁷⁷Lu-PSMA-617 and docetaxel in chemotherapy-naïve mCRPC patients.

Methods

This was a randomized, parallel-group, open-label, phase 2, and non-inferiority trial. Chemotherapy-naïve patients with mCRPC and high PSMA-expressing lesions on ⁶⁸ Ga-PSMA-11 PET/CT were randomly assigned in 1:1 ratio to ¹⁷⁷Lu-PSMA-617 (6.0–7.4 GBq/cycle, every 8 weeks, up to 4 cycles) or docetaxel (75 mg/m²/cycle, every 3 weeks, up to 10 cycles). The primary end-point was best prostate-specific antigen response rate (PSA-RR), defined according to Prostate Cancer Clinical Trials Working Group-3 as proportion of patients achieving ≥ 50% decline in PSA from baseline. Non-inferiority margin of − 15% was pre-specified for PSA-RR.

Results

Between December 2019 and March 2021, 40 of the 45 patients assessed for eligibility underwent randomization. Fifteen of 20 patients in ¹⁷⁷Lu-PSMA-617 arm and 20/20 patients in docetaxel arm received treatment per protocol. Of these, best PSA-RR in the ¹⁷⁷Lu-PSMA-617 arm was 60% (9/15) versus 40% (8/20) in the docetaxel arm. The difference in the PSA-RRs between the two arms was 20% (95% confidence interval, CI: − 12–47, P = 0.25), meeting the pre-specified criterion for non-inferiority in per-protocol analysis. Further, progression-free survival rates at 6 months were 30% and 20% in the ¹⁷⁷Lu-PSMA-617 and docetaxel arms respectively (difference 10%, 95% CI: − 18–38, P = 0.50). Overall, treatment-emergent grade ≥ 3 adverse events occurred less frequently with ¹⁷⁷Lu-PSMA-617 than with docetaxel (6/20, 30% versus 10/20, 50%, respectively, P = 0.20). Quality-of-life outcomes improved significantly in ¹⁷⁷Lu-PSMA-617 arm compared to docetaxel arm (P < 0.01).

Conclusion

¹⁷⁷Lu-PSMA-617 was demonstrated to be safe and non-inferior to docetaxel in the treatment of mCRPC and could, thus, be potentially employed earlier in the disease course rather than being solely reserved for advanced end-stage disease.

Clinical trial registration

Clinical Trials Registry-India, CTRI/2019/12/022282.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05618-3.