The impact of COVID-19 on clinical research for Neglected Tropical Diseases (NTDs): A case study of bubonic plague

Background Among the many collaterals of the COVID-19 pandemic is the disruption of health services and vital clinical research. COVID-19 has magnified the challenges faced in research and threatens to slow research for urgently needed therapeutics for Neglected Tropical Diseases (NTDs) and diseases affecting the most vulnerable populations. Here we explore the impact of the pandemic on a clinical trial for plague therapeutics and strategies that have been considered to ensure research efforts continue. Methods To understand the impact of the COVID-19 pandemic on the trial accrual rate, we documented changes in patterns of all-cause consultations that took place before and during the pandemic at health centres in two districts of the Amoron’I Mania region of Madagascar where the trial is underway. We also considered trends in plague reporting and other external factors that may have contributed to slow recruitment. Results During the pandemic, we found a 27% decrease in consultations at the referral hospital, compared to an 11% increase at peripheral health centres, as well as an overall drop during the months of lockdown. We also found a nation-wide trend towards reduced number of reported plague cases. Discussion COVID-19 outbreaks are unlikely to dissipate in the near future. Declining NTD case numbers recorded during the pandemic period should not be viewed in isolation or taken as a marker of things to come. It is vitally important that researchers are prepared for a rebound in cases and, most importantly, that research continues to avoid NTDs becoming even more neglected.

Futility and toxicity monitoring without halting for interim analyses.

e13579 Background: Many trial designs with futility or toxicity monitoring require that accrual halt to wait for currently enrolled patients to complete their assessment window. However, logistics often prevent this. In these cases, the performance of those designs might be compromised. This study examines the performance of 2 popular designs when enrollment is not halted at interim. Methods: Simulations were run to examine the effect of continuous enrollment on the operating characteristics (OCs) of a Simon’s 2-stage design for futility monitoring and a design using Bayesian posterior probabilities for toxicity monitoring. Both sets of 10,000 simulations examined the OCs when accrual rate was 0.5, 1.5, 3 and 5 patients/month with an assessment window of 30, 60 and 180 days. Results: The first scenario examined the OCs of a Simon design with 12 patients in the first stage and 21 at the end of the second stage. Regardless of accrual rate, the expected number of patients (EN0) increased and probability of early termination (PET0) decreased under the null hypothesis. Rate of change increased as assessment window increased. EN0 was 16 and PET0 was 54% when halting enrollment between stages. With continuous enrollment, EN0 ranged from 16-19, 17-21, and 18-21 patients for the 30-, 90- and 180-day assessment windows. PET0 ranged from 54%-50% with a 30-day assessment window. It halved to 24% with 3 patients/month enrolled and a 90-day window. PET0 was essentially 0 with a 180-day window and an enrollment of 3 patients/month. OCs for toxicity monitoring were examined for the early stopping rule Pr(toxicity rate > 0.3 | data) > 0.85 with toxicity rate ̃ beta(1, 1) with a maximum sample size of 20 and cohort size of 5. Expected number of patients (EN) increased and probability of early termination (PET) decreased as accrual rate increased, with rate of change increasing as assessment window increased. When the true probability of toxicity was 50% and enrollment halted between cohorts, EN was 10 patients and PET was 78%. EN was 17 and PET 54% with an assessment window of 30 days and 5 patients were enrolled per month. With a 90-day assessment window and 3 patients/month enrolled, EN was 16 and PET 59%. EN was 20 and PET was 12% with a 180-day assessment window and 3 patients were enrolled per month. Similar results were noted for cohorts of size 10 and a maximum number of 40 patients. Conclusions: The performance of designs that require halting enrollment while waiting for results of an interim analysis can be compromised by continuous accrual when assessment windows are lengthy and the accrual is fast. In these circumstances, consideration should be given to designs, such as Bayesian multiple imputation for delayed outcomes (Cai et al Stat Med 2014) and TOP2 (Lin et al JNCI 2019), that do not require accrual halt to make real-time interim analysis in the presence of pending patients, which protects patients from excessive toxicity or a futile intervention.

Examining recruitment feasibility and related outcomes in adults post-stroke

Background There are limited effective and evidence-based interventions for upper extremity hemiparesis post-stroke. To prepare for an RCT and minimize misuse of resources, there is value in conducting a feasibility study. Objective To examine the feasibility of recruitment and other related outcomes for an intense upper limb intervention. Methodology Feasibility outcomes included retention, adherence, accrual rate, sample characteristics, and identification of productive recruitment methods. Other outcomes included satisfaction with the study, fidelity, and equipoise of both staff and participants. Results Participants were enrolled at a rate of 1.33 per month. The recruitment timeline had to be extended by 4 months, to meet the target of 16 randomized participants. Staggered recruitment was the most successful strategy. We found that following up with individuals who missed initial appointments prior to study enrollment led to decreased adherence. Conclusion It is feasible to recruit and retain post-stroke participants for an intense intervention study. Trial registration NCT02277028

Prevention of post-cardiac surgery vitamin D deficiency in children with congenital heart disease: a pilot feasibility dose evaluation randomized controlled trial

Background The vast majority of children undergoing cardiac surgery have low vitamin D levels post-operative, which may contribute to greater illness severity and worse clinical outcomes. Prior to the initiation of a large phase III clinical trial focused on clinical outcomes, studies are required to evaluate the feasibility of the study protocol, including whether the proposed dosing regimen can safely prevent post-operative vitamin D deficiency in this high-risk population. Methods We conducted a two-arm, double-blind dose evaluation randomized controlled trial in children requiring cardiopulmonary bypass for congenital heart disease. Pre-operatively, participants were randomized to receive cholecalciferol representing usual care (< 1 year = 400 IU/day, > 1 year = 600 IU/day) or a higher dose approximating the Institute of Medicine tolerable upper intake level (< 1 year = 1600 IU/day, > 1 year = 2400 IU/day). The feasibility outcomes were post-operative vitamin D status (primary), vitamin D-related adverse events, accrual rate, study withdrawal rate, blinding, and protocol non-adherence. Results Forty-six children were randomized, and five withdrew prior to surgery, leaving 41 children (21 high dose, 20 usual care) in the final analysis. The high dose group had higher 25-hydroxyvitamin D concentrations both intraoperatively (mean difference + 25.9 nmol/L; 95% CI 8.3–43.5) and post-operatively (mean difference + 17.2 nmol/L; 95% CI 5.5–29.0). Fewer participants receiving high-dose supplementation had post-operative serum 25-hydroxyvitamin D concentrations under 50 nmol/L, compared with usual care (RR 0.31, 95% CI 0.11–0.87). Post-operative vitamin D status was associated with the treatment arm and the number of doses received. There were no cases of hypercalcemia, and no significant adverse events related to vitamin D. While only 75% of the target sample size was recruited (limited funding), the consent rate (83%), accrual rate (1.5 per site month), number of withdrawals (11%), and ability to maintain blinding support feasibility of a larger trial. Conclusions Pre-operative daily high-dose supplementation improved vitamin D status pre-operatively and at time of pediatric ICU admission. The protocol for a more definitive trial should limit enrollment of children with at least 30 days between randomization and surgery to allow adequate duration of supplementation or consider a loading dose. Trial registration ClinicalTrials.gov, NCT01838447. Registered on April 24, 2013

Multiple Complications in Emergency Surgery

Background While the use of the failure-to-rescue (FTR) metric, or death after complication, has expanded beyond elective surgery to emergency general surgery (EGS), little is known about the trajectories patients take from index complication to death. Methods We conducted a retrospective cohort study of EGS operations using the National Surgical Quality Improvement Project (NSQIP) dataset, 2011-2017. 16 major complications were categorized as infectious, respiratory, thrombotic, cardiac, renal, neurologic, or technical. We tabulated common combinations of complications. We then use logistic regression analyses to test the hypotheses that (1) increase in the number and frequency of complications would yield higher FTR rates and (2) secondary complications that span a greater number of organ systems or mechanisms carry a greater associated FTR risk. Results Of 329 183 EGS patients, 69 832 (21.2%) experienced at least 1 complication. Of the 11 195 patients who died following complication (16.0%), 8205 (63.4%) suffered more than 1 complication. Multivariable regression analyses revealed an association between the number of complications and mortality risk (odds ratio [OR] 2.37 for 2 complications vs 1, P < .001). There was a similar increase in mortality with increased complication accrual rate (OR 3.29 for 0.2-0.4 complications/day vs <0.2, P < .001). Increasing the number of types of complication were similarly associated with mortality risk. Discussion While past FTR analyses have focused primarily on index complication, a broader consideration of ensuing trajectory may enable identification of high-risk cohorts. Efforts to reduce mortality in EGS should focus on attention to those who suffer a complication to prevent a cascade of downstream complications culminating in death.

Phase II study of antidisialoganglioside antibody, dinutuximab, in combination with GM-CSF in patients with recurrent osteosarcoma (AOST1421): A report from the Children’s Oncology Group.

10508 Background: Treatment of patients with recurrent osteosarcoma (OS) is challenging and novel effective therapies are urgently needed. This study evaluated disease control rate (DCR) in patients with recurrent pulmonary OS, when treated with dinutuximab plus cytokine therapy as compared to a historical benchmark. The rationale for dinutuximab was the ubiquitous ( > 95%) GD2 positivity in OS tumors and cell lines. Methods: AOST1421 was a single-arm phase 2 study. Patients with recurrent pulmonary OS in complete surgical remission were eligible. Patients received five cycles of dinutuximab 70mg/m2/cycle with GM-CSF. Two different dinutuximab infusion schedules were used - 35mg/m2/day over 20 hours (2-day) and 17.5mg/m2/day over 10 hours (4-day) schedule. Primary end point was DCR, defined as proportion of patients event-free at 12 months from enrollment. Events were progressive disease or death within 12 months attributed to treatment or progression. The historical benchmark was AOST0221 with a 12-month DCR of 20% (95% CI 10-34%). Success was defined as ≥16/ 39 patients ( > 40%) event-free at 12 months from enrollment. Secondary objectives included toxicity evaluation and dinutuximab pharmacokinetics (PK). Results: Forty-one patients were enrolled from Nov 2015 - Jan 2018. Thirty nine were eligible and evaluable (age 7-26 yr; median 15 yr). Data current to December 31, 2019 was used for analysis. Accrual rate was higher than expected (22.1 vs. 19.2 patients/ yr.) despite a concurrently open competing study. One of 136 administered therapy cycles met criteria for unacceptable toxicity when one patient receiving the 2-day schedule died after cycle 2 due to an unknown cause, attributed as probably related to protocol therapy. The protocol was revised to allow only the 4-day schedule. Other ≥ Grade 3 toxicities occurring in > 10 % participants were expected dinutuximab toxicities such as pain, diarrhea, hypoxia and hypotension. Dinutuximab did not demonstrate sufficient evidence of efficacy as 27/ 39 patients experienced an event for a DCR of 30.7% (95% CI 17- 47%). PK studies are pending and will be reported. Conclusions: Dinutuximab toxicity in adolescent and young adult OS patients was similar to younger patients. While GD2 remains a relevant target in OS, combination of dinutuximab with GM-CSF did not meet the targeted successful DCR in patients with completely resected tumor. Other strategies for targeting GD2 or dinituximab combination therapy may still be warranted. Clinical trial information: NCT02484443.

Modelling the patient accrual with truncated Gaussian mixture distribution for the accurate estimation of sample size in survival trials

In survival trials with fixed trial length, the patient accrual rate has a significant impact on the sample size estimation or equivalently, on the power of trials. A larger sample size is required for the staggered patient entry. During enrollment, the patient accrual rate changes with the recruitment publicity effect, disease incidence and many other factors and fluctuations of the accrual rate occur frequently. However, the existing accrual models are either over-simplified for the constant rate assumption or complicated in calculation for the subdivision of the accrual period. A more flexible accrual model is required to represent the fluctuant patient accrual rate for accurate sample size estimation. In this paper, inspired by the flexibility of the Gaussian mixture distribution in approximating continuous densities, we propose the truncated Gaussian mixture distribution accrual model to represent different variations of accrual rate by different parameter configurations. The sample size calculation formula and the parameter setting of the proposed accrual model are discussed further.

Challenges on participation in a cooperative group of childhood renal tumors in Brasil

SUMMARY OBJECTIVE Children with renal tumors included in clinical trials have significantly better outcomes. In Brasil, the enrollment of patients in clinical trials remains challenging. Here we aimed to describe participation accrual in the Brazilian Wilms Tumor Study Group (BWTSG) and to identify barriers to trial registration of children with renal tumors. METHODS We determined the numbers of renal tumor diagnoses in 105 hospital-based cancer registries from 2001-2009. We then compared these totals with the numbers of renal tumor cases registered in the BWTSG from the same hospitals during the same time period. We also invited members of the Brazilian Pediatric Oncology Society to complete a 5-point Likert-type scale questionnaire regarding their opinions of the importance of participation in cooperative group trials. RESULTS The accrual rate of patient participation per hospital varied from 25% to 76%, and was highest in the South region. The accrual rate of hospital participation also varied according to the region (20-31%) and was highest in the Southeast region. For the questionnaire regarding the importance of participation in cooperative groups, the responses showed an agreement of >75% on 10 of the 13 statements. CONCLUSION Our results demonstrated low accrual of participation in a cooperative group trial in Brasil. We identified variations in registration rates according to geographic region and hospital, which may help targeted efforts to increase registration rates. The survey responses demonstrated that colleagues understand the importance of trial participation.

Redefining the Multiple Sclerosis Severity Score (MSSS): The effect of sex and onset phenotype

Background: The Multiple Sclerosis Severity Score (MSSS) is a widely used measure of the disability progression rate. However, the global MSSS may not be the best basis for comparison between all patient groups. Objective: We evaluated sex-specific and onset phenotype–specific MSSS matrices to determine if they were more effective than the global MSSS as a basis for comparison within these subsets. Methods: Using a large international dataset of multiple sclerosis (MS) patient records and the original MSSS algorithm, we constructed global, sex-specific and onset phenotype–specific MSSS matrices. We compared matrices using permutation analysis. Results: Our final dataset included 30,203 MS cases, with 28.9% males and 6.5% progressive-onset cases. Our global MSSS matrix did not differ from previously published data ( p > 0.05). The progressive-onset-specific matrix differed significantly from the relapsing-onset-specific matrix ( p < 0.001), with lower MSSS attributed to cases with the same Expanded Disability Status Score (EDSS) and disease duration. When evaluated with a simulation, using an onset-specific MSSS improved statistical power in mixed cohorts. There were no significant differences by sex. Conclusion: The differences in the disability accrual rate between progressive- and relapsing-onset MS have a significant effect on MSSS. An onset-specific MSSS should be used when comparing the rate of disability progression among progressive-onset cases and for mixed cohorts.