Concurrent Arm Research Articles

Concurrent versus sequential or no triazole anti-fungal therapy in patients undergoing 7 + 3 plus midostaurin induction for FLT-3 acute myelogenous leukemia.

Midostaurin is a multikinase inhibitor approved for the treatment of adult patients with newly diagnosed FMS-like tyrosine kinase 3 mutated (FLT3m) acute myeloid leukemia (AML). Azole antifungal medications are commonly used in AML and are known to interact with anti-cancer drugs such as midostaurin through the CYP3A pathway. However, there are no midostaurin related dose modifications recommended with strong CYP3A inhibitors. We retrospectively reviewed 40 patients between 2017-2022 and compared efficacy and safety outcomes in patients who received azole antifungals concurrently to those who did not receive an azole or received it sequentially to midostaurin for treatment of FLT3m AML. Median age of both groups was approximately 55 years and 70% of patients harbored FLT-3 internal tandem duplication mutations. Most patients in the concurrent arm were on either posaconazole (33%) or isavuconazole (50%) for antifungal prophylaxis and micafungin (72%) for the sequential/no azole arm. Overall CR/CRi rate with concurrent versus sequential/no azole were 72% and 77%, and non-hematologic grade 3 toxicities were 22% and 40% (p = 0.21), respectively. Rates of dose reductions (6% vs. 0%, p = 0.26) and held doses (17% vs. 14%, p = 0.79) were not different between concurrent and sequential/no azole. There were no differences in the rates of new fungal infection during induction between the two groups. Azoles given concurrently or sequentially with midostaurin were found to be equally safe and effective in the treatment of newly diagnosed FLT3 AML. Additional confirmatory studies are needed due to our limited sample size.

Propensity score weighted multi-source exchangeability models for incorporating external control data in randomized clinical trials.

Among clinical trialists, there has been a growing interest in using external data to improve decision-making and accelerate drug development in randomized clinical trials (RCTs). Here we propose a novel approach that combines the propensity score weighting (PW) and the multi-source exchangeability modelling (MEM) approaches to augment the control arm of a RCT in the rare disease setting. First, propensity score weighting is used to construct weighted external controls that have similar observed pre-treatment characteristics as the current trial population. Next, the MEM approach evaluates the similarity in outcome distributions between the weighted external controls and the concurrent control arm. The amount of external data we borrow is determined by the similarities in pretreatment characteristics and outcome distributions. The proposed approach can be applied to binary, continuous and count data. We evaluate the performance of the proposed PW-MEM method and several competing approaches based on simulation and re-sampling studies. Our results show that the PW-MEM approach improves the precision of treatment effect estimates while reducing the biases associated with borrowing data from external sources.

Neoadjuvant pembrolizumab, dabrafenib and trametinib in BRAFV600-mutant resectable melanoma: the randomized phase 2 NeoTrio trial

Immune checkpoint inhibitors and BRAF-targeted therapy each improve survival in melanoma. Immune changes early during targeted therapy suggest the mechanisms of each drug class could work synergistically. In the non-comparative, randomized, phase 2 NeoTrio trial, we investigated whether targeted therapy could boost the proportion of patients achieving long-term recurrence-free survival with neoadjuvant immunotherapy in resectable stage III BRAFV600-mutant melanoma. Sixty patients (42% females) were randomized to pembrolizumab alone (n = 20), sequential therapy (dabrafenib plus trametinib followed by pembrolizumab; n = 20) or concurrent (triple) therapy (n = 20), followed by surgery and adjuvant therapy. The primary outcome was pathological response; secondary outcomes included radiographic response, recurrence-free survival, overall survival, surgical outcomes, peripheral blood and tumor analyses and safety. The pathological response rate was 55% (11/20; including six pathological complete responses (pCRs)) with pembrolizumab, 50% (10/20; three pCRs) with sequential therapy and 80% (16/20; ten pCRs) with concurrent therapy, which met the primary outcome in each arm. Treatment-related adverse events affected 75–100% of patients during neoadjuvant treatment, with seven early discontinuations (all in the concurrent arm). At 2 years, event-free survival was 60% with pembrolizumab, 80% with sequential therapy and 71% with concurrent therapy. Recurrences after major pathological response were more common in the targeted therapy arms, suggesting a reduction in response ‘quality’ when targeted therapy is added to neoadjuvant immunotherapy. Risking the curative potential of immunotherapy in melanoma cannot be justified. Pending longer follow-up, we suggest that immunotherapy and targeted therapy should not be combined in the neoadjuvant setting for melanoma. ClinicalTrials.gov registration: NCT02858921.

Comparison of Outcome of Concurrent Chemoradiotherapy and Sequential Chemoradiotherapy in Locally Advanced, Inoperable Squamous Cell Carcinoma of Head and Neck Region

Background: Head and neck cancer is prevalent in Bangladesh, with a majority of patients presenting with locally advanced, inoperable disease. This study aimed to compare the effectiveness and accessibility of concurrent and sequential (CCRT with RT) chemoradiotherapy in treating this condition, addressing a debate among oncologists. Materials and Methods: A quasi-experimental study at Rajshahi Medical College Hospital (June 2019 - May 2020) involved 60 inoperable head and neck cancer patients, comparing concurrent chemoradiotherapy with Cisplatin and sequential chemoradiotherapy with Paclitaxel and Cisplatin, monitoring treatment response and toxicities. Results: The mean age was 56.1 (±9.5) years in Arm-A and 56.9 (±9.4) years in Arm-B. The primary endpoint was loco-regional control and early toxicities. In the final response, 14 weeks after the completion of treatment, the overall loco-regional control rate was 86.67% and 76.67% in Arm-A and Arm-B, respectively. Severe toxicities include grade 3 reaction only and happened 18(58%) vs 13(42%) in Arm-A and Arm-B, respectively. Among severe toxicities, mucositis and skin reaction were higher in the concurrent Arm and anemia and neutropenia were higher in the sequential Arm. However, there was no actual difference in the two treatment modalities (p=>0.05). The overall treatment time was short in concurrent chemoradiotherapy (49 vs 133 days) and lower treatment cost as well, which was statistically significant (p=<0.0001). Conclusion: concurrent chemoradiotherapy proves cost-effective and accessible, demonstrating outcomes similar to sequential chemoradiotherapy. It stands as a viable treatment choice for locally advanced, inoperable head and neck squamous cell carcinoma.

Impact of geographical cohorting, multidisciplinary rounding and incremental case management support on hospital length of stay and readmission rates: a propensity weighted analysis

Hospital length of stay (LOS) in the USA has been increasing since the start of the COVID-19 pandemic, with numerous negative outcomes, including decreased quality of care, worsened patient satisfaction...

Effect of neoadjuvant concurrent three-dimensional conformal chemoradiotherapy with conventional two-dimensional chemoradiotherapy in locally advanced rectal cancer

Background: Rectal carcinoma is a prevalent clinical condition, and treatment hinges on factors like tumor specifics, staging, grading, and histopathological characteristics. While surgery remains the primary treatment, neoadjuvant chemoradiotherapy, particularly using 3D-CRT, has proven effective in reducing local recurrence rates for locally advanced cases. Alternatively, 2D-RT is considered for neoadjuvant treatment. This study aimed to compare the impact of neoadjuvant concurrent three-dimensional conformal chemoradiotherapy with conventional two-dimensional chemoradiotherapy in the context of locally advanced rectal cancer. Methods: In this multicentre quasi-experimental study, 60 patients with biopsy-proven adenocarcinoma and clinically confirmed locally advanced rectal cancer, were divided into Group A (receiving oral capecitabine with three-dimensional conformal radiotherapy) and Group B (receiving the same capecitabine dose with 50 Gy two-dimensional radiotherapy). After surgery within 6-12 weeks, outcomes were analysed. Results: After neoadjuvant chemoradiotherapy, clinical complete response rates were 16.7% in Group A and 10.0% in Group B, with a higher pathological complete response in Group A (10.0% vs. 3.3%). Tumor downsizing occurred in 83.3% of Group A and 73.3% of Group B, and sphincter-sparing surgery was achieved in 73.3% of Group A and 56.7% of Group B. Grade 2 toxicities included anemia (10.0% vs. 13.3%), leucopenia (13.3% vs. 20.0%), diarrhoea (10.0% vs. 16.7%), proctitis (13.3% vs. 40.0%), and urinary toxicity (10.0% vs. 20.0%). Grade-1 toxicities were nausea (20.0% vs. 40.0%), vomiting (20.0% vs. 36.7%), mucositis (56.7% vs. 60.0%), hand-foot syndrome (33.3% vs. 40.0%), and urinary toxicity (43.3% vs. 56.67%), with significant proctitis in Group A (p=0.012). Other toxicities showed non-significant p-values (>0.05). Conclusions: Tumour response was not statistically significant between the patients of concurrent 3D-CRT and 2D-RT Arms. But the patients of 3D-CRT arm showed better response arithmetically. Also, there was an observable significant reduction of toxicities (lower gastrointestinal) in the 3D-CRT arm.

Leveraging external control data in the design and analysis of neuro-oncology trials: Pearls and perils.

Randomized controlled trials have been the gold standard for evaluating medical treatments for many decades but they are often criticized for requiring large sample sizes. Given the urgent need for better therapies for glioblastoma, it has been argued that data collected from patients treated with the standard regimen can provide high-quality external control data to supplement or replace concurrent control arm in future glioblastoma trials. In this article, we provide an in-depth appraisal of the use of external control data in the context of neuro-oncology trials. We describe several clinical trial designs with particular attention to how external information is utilized and address common fallacies that may lead to inappropriate adoptions of external control data. Using 2 completed glioblastoma trials, we illustrate the use of an assessment tool that lays out a blueprint for assembling a high-quality external control data set. Using statistical simulations, we draw caution from scenarios where these approaches can fall short on controlling the type I error rate. While this approach may hold promise in generating informative data in certain settings, this sense of optimism should be tampered with a healthy dose of skepticism due to a myriad of design and analysis challenges articulated in this review. Importantly, careful planning is key to its successful implementation.

Prospective Study to Compare Efficacy of Conventional Chemoradiotherapy with Hypofractionated Chemoradiotherapy in Locally Advanced Carcinoma of Oropharynx.

Chemoradiotherapy is the standard treatment for advanced Oropharyngeal squamous cell carcinoma (OPSCC). Upcoming hypofractionation has led to better compliance and non-inferior results in various sites such as breast and prostate cancer etc. This study prospectively compared a dose-intensified schedule in advanced OPSCC with standard hypofractionation. Patients with advanced stage III and IV OPSCC suitable for radical chemoradiotherapy were eligible. Patients were alternatively allocated to both the treatment arms. Arm A planned to receive 64 Gy in 25 fractions (#) with concurrent cisplatin and Arm B received standard fractionation 70 Gy in 35 # with concurrent cisplatin. All patients completed a median follow up of 6 to 18 months. The primary end point was acute toxicity (less than 3 months) and late toxicity at 1 year. Secondary end point was disease free survival and overall survival at 1 year. 44 patients in arm A and 49 patients in arm B were recruited over 18 months. 34 patients completed full-dose radiotherapy in both arms. Maximum acute toxicity in arm A in terms of skin reaction was Grade II in 47.05% cases and mucositis grade II in 67.6% cases. In arm B grade II skin toxicity was seen in 47.1% and mucositis grade II was seen in 79.4 % cases. Ryle's tube dependency was seen in 38.2 % cases in arm A and 50% in arm B. Complete response rate at 3 months was equivalent in both arms in Arm A (100%), and in Arm B (96.7%). Disease free survival (DFS), Overall survival (OS) at 3 month, 6 months, and 12 months was comparable. 64 Gy in 25 fractions with concomitant chemotherapy is tolerable in patients with equivalent results and better compliance. Shorter fractionation schedule is more acceptable and we look forward for more randomized control trials.

Leveraging external evidence using Bayesian hierarchical model and propensity score in the presence of covariates

In recent decades, there has been growing interest in leveraging external data information for clinical development as it improves the efficiency of the design and inference of clinical trials when utilized properly and more importantly, alleviates potential ethical and recruitment challenges. When it is of interest to augment the concurrent study's control arm using external control data, the potential outcome heterogeneity across data sources, also known as prior-data conflict, should be accounted for. In addition, in the outcome modeling, inclusion of prognostic covariates that may have impact on the outcome can avoid efficiency loss or potential bias. In this paper, we propose a Bayesian hierarchical modeling strategy incorporating covariate-adjusted meta-analytic predictive approach (cMAP) and also introduce a propensity score (PS) based sequential procedure that integrates the cMAP. In the simulation study, the proposed methods are found to have advantages in the estimation, power, and type I error control over the standard methods such as PS matching alone and hierarchical modeling that ignores the covariates. An illustrative example is used to illustrate the procedure.

A phase I study of bintrafusp alfa and NHS-IL12 (M9241) alone and in combination with stereotactic body radiation therapy (SBRT) in patients with metastatic genitourinary (GU) malignancies.

4571 Background: Bintrafusp alfa is a novel bifunctional fusion protein targeting PD-L1 and TGF-β which has demonstrated clinical efficacy in some tumor types and a manageable safety profile. M9241 is an immunocytokine that allows targeting of the pro-inflammatory IL-12 cytokine to exposed DNA in necrotic portions of tumors. SBRT can help promote anti-tumor responses and may potentially synergize with immunotherapy by inducing DNA damage. Methods: This is an open label, non-randomized, three arm phase I trial of bintrafusp alfa and M9241 combination therapy administered alone (Arm 1), or with either sequential (Arm 2), or concurrent (Arm 3) SBRT. Eligible patients must have metastatic non-prostate GU cancers with measurable disease. Bintrafusp alfa was used at a flat dose of 1200mg (q2w) for arms 1-3 and a fixed dose of SBRT (24Gy in 3 fractions) was used for arms 2-3. M9241 was administered at 16.8mcg/kg (q4w) for Arm 1 and decreased if side effects occur. Arm 1 used bintrafusp alfa and M9241 alone, with the maximum tolerated dose (MTD) of M9241 being dose level 1 (DL1) for Arm 2. Arm 2 used SBRT followed by bintrafusp alfa and M9241, with the MTD of M9241 being DL1 for Arm 3. Arm 3 used concurrent SBRT with bintrafusp alfa and M9241. The primary objective was to determine the safety and highest tolerable doses of each arm. Secondary objectives include objective response rate (ORR), progression free survival (PFS), and overall survival (OS). Results: Study enrollment began in 12/2019, with interim safety analyses performed quarterly. A total of 16 patients have enrolled, 12 in Arm 1, three in Arm 2, and one in Arm 3 at data cutoff 1/2/23. The first six patients enrolled in Arm 1 had no DLTs allowing Arm 2 to open, Arm 2 had no DLTs after 3 patients enrolled allowing Arm 3 to open. At data cut off four of 16 patients remained on treatment. The median age was 63 and 19% were female. The most frequent TRAEs were fatigue (grade 2, 38%), lipase increase (grade 2+3, 31%), and anemia (grade 2+3, 31%). Grade 3 hematuria occurred in 2 patients (13%); a grade 4 creatinine increase occurred in one (8%). There were no grade 5 TRAEs. Two (13%) patients had treatment discontinued and 5 (31%) had dose reductions due to AEs. Of the 16 patients enrolled on study, 11 were evaluable at data cutoff. Currently three patients (38%) on Arm 1 and one patient (50%) in Arm 2 had objective responses, corresponding to an ORR of 36.4% (4/11). All responses have been partial responses. On Arm 1 the responding patients included one with small cell carcinoma of the renal pelvis, one with Leydig cell tumor, and one with urothelial carcinoma. On Arm 2 the responding patient had a Sertoli cell tumor. Conclusions: The use of bintrafusp alfa and M9241 either alone or in combination with sequential or concurrent SBRT has shown clinical activity in pts with GU tumors and has not been associated with any DLTs. Clinical trial information: NCT04235777 .

SA59 Literature Review of Statistical Methods Comparisons through Simulations When Using External Control Arm for Regulatory or HTA Submissions

Using a historical control or external control arm (ECA) to augment or replace a concurrent control arm in a randomized trial is a hot topic given the challenge of patient recruitment in rare diseases or during COVID-19 pandemic. The FDA released draft guidance in 2021 on effectiveness and safety submissions using real-world evidence. While the guidance focuses mainly on elements of study design and data source selection, there is a lack of consensus in the selection of appropriate statistical methods when constructing an ECA. This study discusses rigorous statistical methodology for ECA-supported trials in regulatory or HTA submissions. Targeted literature reviews of statistical simulations comparing methods for ECA in statistical journals were performed. The articles compared commonly used ECA-construction and analysis methods were selected and summarized, including but not limited to propensity score (PS)-based matching, weighting, and stratification, and PS plus Bayesian integrated approaches. Type I error, power, bias, and coverage probability are common criteria used to compare different methods. When imbalances only exist in known baseline covariates and the outcome distributions are the same between the trial concurrent control and ECA, the PS method alone or paired with commensurate prior yield almost unbiased estimates, good Type I errors, and coverage probability. PS plus Bayesian approaches have wider interval width and lower power compared with PS-only methods. When there is a change in the outcome distribution over time, the PS (matching or IPTW) and commensurate prior integrated methods yield the smallest biases among all methods. PS and Bayesian integrated methods outperformed the PS-only methods in terms of bias and Type I error when outcome distribution changed with current trial control. A “sweet spot” that balances all criteria through trial-specific simulations could provide the ideal setting of trial analyses plan based on specific trial design and scenarios.

Combination Treatment with Sipuleucel-T and Abiraterone Acetate or Enzalutamide for Metastatic Castration-Resistant Prostate Cancer: STAMP and STRIDE Trials.

We present long-term outcomes from 2 randomized studies [STAMP (with abiraterone, NCT01487863) and STRIDE (with enzalutamide, NCT01981122)] that were performed to study the impact of sequential or concurrent administration of androgen receptor-targeting agents (ARTAs) on sipuleucel-T immune response and overall survival (OS) in metastatic castration-resistant prostate cancer (mCRPC). Sipuleucel-T was administered per current prescribing information. Results from STRIDE are presented together with updated STAMP results. Survival status of patients was updated using demographic information to query the National Death Index (NDI). Kaplan-Meier methodology was used to analyze survival. Updated data reduced patient censoring in each study compared with the original analyses; the 95% confidence intervals (CIs) for OS are now estimable. Updated median OS (95% CI) is 33.3 (24.1-40.7) months for STAMP and 32.5 (26.0-45.1) months for STRIDE. There was no notable impact on median OS [HR, 0.727 (0.458-1.155); P = 0.177, reference = STRIDE]. OS with sequential administration was similar to concurrent administration [NDI update: HR, 0.963 (0.639-1.453); P = 0.845, reference = concurrent arm]. Sipuleucel-T potency, measured as antigen-presenting cell (APC) activation, was higher in subsequent infusions compared with the first infusion. Humoral responses (IgG + IgM antibody titers) to PA2024 and prostatic acid phosphatase were significantly elevated versus baseline. No new safety signals were observed. Median OS was consistent regardless of whether the agents were administered sequentially or concurrently, including after NDI update. Results suggest that sipuleucel-T induces an immunologic prime-boost effect after initial sipuleucel-T exposure, even when combined with ARTAs.

Review article: The need for more efficient and patient‐oriented drug development pathways in NASH—setting the scene for platform trials

Non-alcoholic steatohepatitis (NASH) constitutes a significant unmet medical need with a burgeoning field of clinical research and drug development. Platform trials (PT) might help accelerate drug development while lowering overall costs and creating a more patient-centric environment. This review provides a comprehensive and nuanced assessment of the NASH clinical development landscape. Narrative review and expert opinion with insight gained during the EU Patient-cEntric clinicAl tRial pLatforms (EU-PEARL) project. Although NASH represents an opportunity to use adaptive trial designs, including master protocols for PT, there are barriers that might be encountered owing to distinct and sometimes opposing priorities held by these stakeholders and potential ways to overcome them. The following aspects are critical for the feasibility of a future PT in NASH: readiness of the drug pipeline, mainly from large drug companies, while there is not yet an FDA/EMA-approved treatment; the most suitable design (trial Phase and type of population, e.g., Phase 2b for non-cirrhotic NASH patients); the operational requirements such as the scope of the clinical network, the use of concurrent versus non-concurrent control arms, or the re-allocation of participants upon trial adaptations; the methodological appraisal (i.e. Bayesian vs. frequentist approach); patients' needs and patient-centred outcomes; main regulatory considerations and the funding and sustainability scenarios. PT represent a promising avenue in NASH but there are a number of conundrums that need addressing. It is likely that before a global NASH PT becomes a reality, 'proof-of-platform' at a smaller scale needs to be provided.

Outcome of neoadjuvant chemotherapy followed by concurrent chemoradiotherapy versus concurrent chemoradiotherapy alone in non-metastatic locally advanced non-small cell lung cancer – A prospective and randomized study

Background: Sequential chemoradiotherapy and concurrent chemoradiotherapy are two treatment options for locally advanced non-small cell lung cancer (NSCLC). Still there is limited data regarding which is the better treatment option. Aims and Objectives: This study is to compare the response rate and toxicity pattern between induction (neoadjuvant) chemotherapy followed by concurrent chemoradiotherapy versus concurrent chemoradiotherapy alone in locally advanced NSCLC patients. Materials and Methods: A total of 48 Stage III NSCLC patients were selected for the study and were randomized into two arms with a 1:1 ratio. Patients of ARM-1 received concurrent chemoradiotherapy alone of a total dose of 66Gy/33# over 6 and ⅟2 weeks with paclitaxel (50 mg/m2) and carboplatin (Area under curve [AUC] 2) once every week. The study arm (ARM-2) received two cycles of induction chemotherapy with paclitaxel (175 mg/m2) and carboplatin (AUC 6) every 3 weeks and concurrent chemoradiotherapy (same CRT as on ARM-1). Results: In our study, overall response rate (Complete response+Partial response) in Arm 1 and Arm 2 was 62% and 71%, respectively. The treatment was very tolerated in our study. A mean follow-up of 12 months by Kaplan–Meier survival analysis showed a statistically non-significant difference in disease-free survival in both arms. Progression-free survival was numerically superior in the induction chemotherapy arm but the difference was statistically non-significant. Acute hematological toxicity was numerically more in the concurrent chemoradiotherapy arm, but statistically not significant. Acute lung toxicity, acute pharynx, and esophagus toxicity were numerically more in the induction chemotherapy arm but statistically non-significant. Conclusion: There was no significant difference between induction chemotherapy followed by concurrent chemoradiotherapy and concurrent chemoradiotherapy alone in the present study population.

LB1528A. Fluvoxamine for Outpatient Treatment of Covid-19: A Decentralized, Placebo-controlled, Randomized, Platform Clinical Trial

Abstract Background The effectiveness of fluvoxamine to shorten symptom duration or prevent hospitalization among outpatients with mild-to-moderate coronavirus 2019 (COVID-19) is unclear. Tolerability has also been identified as a potential limiting factor for 100 mg twice daily of fluvoxamine. We evaluated the efficacy of low-dose fluvoxamine 50 mg twice daily for 10 days compared with placebo for the treatment of early mild-to-moderate COVID-19. Methods ACTIV-6 is an ongoing, decentralized, double-blind, randomized, placebo-controlled platform trial testing repurposed medications in outpatients with confirmed SARS-CoV-2 infection. Non-hospitalized adults aged ≥ 30 years, experiencing ≥ 2 symptoms of acute infection for ≤ 7 days were randomized to fluvoxamine 50 mg twice daily for 10 days or placebo. The primary outcome was time to sustained recovery, defined as the third of 3 consecutive days without symptoms. Secondary outcomes included composites of hospitalization or death with or without urgent care or emergency department visit by day 28. Results Of those eligible for the fluvoxamine arm, 675 were randomized to and received fluvoxamine; 619 received concurrent placebo. Sixty-six percent of the study population reported at least 2 doses of a COVID-19 vaccine. There was no evidence of improvement in time to recovery with fluvoxamine compared with placebo (hazard ratio [HR] 0.96, 95% credible interval [CrI] 0.86–1.06; posterior probability for benefit [HR > 1]=0.2). Sixteen participants (2.4%) in the fluvoxamine arm had urgent care or emergency department visits or were hospitalized compared with 11 (1.8%) in the pooled, concurrent placebo arm (HR 1.5, 95% CrI 0.5–3.0; posterior probability for benefit [HR < 1]=0.1725). No participant in either arm was hospitalized, and no deaths occurred. Adverse events were uncommon in both arms. Conclusion Treatment with low-dose fluvoxamine 50 mg dosed twice daily for 10 days did not result in improved time to recovery among outpatients with COVID-19 in the United States during the delta and omicron variant surges. Disclosures All Authors: No reported disclosures.

LB1528B. Inhaled Fluticasone for Outpatient Treatment of Covid-19: A Decentralized, Placebo-controlled, Randomized, Platform Clinical Trial

Abstract Background The effectiveness of inhaled corticosteroids to shorten time to symptom resolution or prevent hospitalization or death among outpatients with mild-to-moderate coronavirus 2019 (Covid-19) is unclear. Methods ACTIV-6 is an ongoing, decentralized, double-blind, randomized, placebo-controlled platform trial testing repurposed medications in outpatients with confirmed SARS-CoV-2 infection. Non-hospitalized adults aged ≥ 30 years, experiencing ≥ 2 symptoms of acute infection for ≤ 7 days were randomized to inhaled fluticasone furoate 200 μg once daily for 14 days or placebo. The primary outcome was time to sustained recovery, defined as the third of 3 consecutive days without symptoms. Secondary outcomes included composites of hospitalization or death with or without urgent care or emergency department visit by day 28. Results Of those eligible for the fluticasone arm, 656 were randomized to and received inhaled fluticasone; 621 received concurrent placebo. There was no evidence of improvement in time to recovery with fluticasone compared with placebo (hazard ratio [HR] 1.01, 95% credible interval [CrI] 0.91–1.12; posterior probability for benefit [HR > 1]=0.56). Twenty-four participants (3.7%) in the fluticasone arm had urgent care or emergency department visits or were hospitalized compared with 13 (2.1%) in the pooled, concurrent placebo arm (HR 1.9, 95% CrI 0.8–3.5; posterior probability for benefit [HR< 1]=0.03). Three participants in each arm were hospitalized, and no deaths occurred. Adverse events were uncommon in both arms. Conclusion Treatment with inhaled fluticasone furoate for 14 days did not result in improved time to recovery among outpatients with Covid-19 in the United States during the delta and omicron variant surges. Disclosures All Authors: No reported disclosures.

LB1528. Results from ACTIV-6: A Decentralized, Double-Blinded, Randomized, Placebo-Controlled Platform Trial of Repurposed Drugs for the Treatment of Mild-to-Moderate COVID-19

Abstract Background The effectiveness of fluvoxamine to shorten symptom duration or prevent hospitalization among outpatients with mild-to-moderate coronavirus 2019 (COVID-19) is unclear. Tolerability has also been identified as a potential limiting factor for 100 mg twice daily of fluvoxamine. We evaluated the efficacy of low-dose fluvoxamine 50 mg twice daily for 10 days compared with placebo for the treatment of early mild-to-moderate COVID-19. Methods ACTIV-6 is an ongoing, decentralized, double-blind, randomized, placebo-controlled platform trial testing repurposed medications in outpatients with confirmed SARS-CoV-2 infection. Non-hospitalized adults aged ≥ 30 years, experiencing ≥ 2 symptoms of acute infection for ≤ 7 days were randomized to fluvoxamine 50 mg twice daily for 10 days or placebo. The primary outcome was time to sustained recovery, defined as the third of 3 consecutive days without symptoms. Secondary outcomes included composites of hospitalization or death with or without urgent care or emergency department visit by day 28. Results Of those eligible for the fluvoxamine arm, 675 were randomized to and received fluvoxamine; 619 received concurrent placebo. Sixty-six percent of the study population reported at least 2 doses of a COVID-19 vaccine. There was no evidence of improvement in time to recovery with fluvoxamine compared with placebo (hazard ratio [HR] 0.96, 95% credible interval [CrI] 0.86–1.06; posterior probability for benefit [HR > 1]=0.2). Sixteen participants (2.4%) in the fluvoxamine arm had urgent care or emergency department visits or were hospitalized compared with 11 (1.8%) in the pooled, concurrent placebo arm (HR 1.5, 95% CrI 0.5–3.0; posterior probability for benefit [HR < 1]=0.1725). No participant in either arm was hospitalized, and no deaths occurred. Adverse events were uncommon in both arms. Conclusion Treatment with low-dose fluvoxamine 50 mg dosed twice daily for 10 days did not result in improved time to recovery among outpatients with COVID-19 in the United States during the delta and omicron variant surges. Disclosures All Authors: No reported disclosures.

MSR60 Literature Review of Statistical Methods Comparisons Through Simulations When Using External Control Arm for Regulatory or HTA Submissions

Using a historical control or external control arm (ECA) to augment or replace a concurrent control arm in a randomized trial is a hot topic given the challenge of patient recruitment in rare diseases or during COVID-19 pandemic. FDA released several draft guidance in 2021 on effectiveness and safety submissions using real-world evidence. While the guidance focuses mainly on elements of study design and data source selection, there is a lack of consensus in the selection of appropriate statistical methods when constructing an ECA. This study aims to discuss rigorous statistical methodology for ECA-supported trial in regulatory or HTA submissions. Targeted literature reviews of statistical simulations comparing methods for ECA in statistical journals were performed. The articles compare commonly used ECA-construction and analysis methods were selected and summarized, including but not limited to propensity-score (PS) based- matching, weighting, stratification, and PS plus Bayesian integrated approaches. Type I error, power, bias, and coverage probability are common criteria used to compare different methods. When imbalances only exist in known baseline covariates and the outcome distribution are the same between the trial concurrent control and ECA, PS method alone or paired with commensurate prior yield almost unbiased estimates, good Type I errors, and coverage probability. PS plus Bayesian approaches have wider interval width and lower power compared with PS only methods. When there is a change in the outcome distribution over time, PS (matching or IPTW) and commensurate prior integrated method yield smallest biases among all methods. PS and Bayesian integrated methods outperformed the PS only methods in terms of bias and type I error when outcome distribution changed with current trial control. A “sweet spot” that balances all criteria through trial-specific simulations could provide the ideal setting of trial analyses plan based on specific trial design and scenarios.

Treatment options for resectable hypopharyngeal squamous cell carcinoma: A systematic review and meta-analysis of randomized controlled trials.

There is uncertainty in the treatment options for resectable hypopharyngeal squamous cell carcinoma. A systematic review of randomised controlled trials (RCTs) was performed. Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, Science Citation Index, and Conference Proceedings databases and trial registries were searched until November 2020 for randomized controlled trials performed on resectable hypopharyngeal squamous cell carcinoma. Two systematic review authors independently identified studies and extracted data. The primary outcomes evaluated were overall survival, disease-free survival, any recurrence, local recurrence, loco-regional recurrence, distal recurrence and laryngectomy-free survival. The secondary outcomes were response rates following neoadjuvant treatment and comparison of treatment-related toxicity. Assessment of risk of bias was performed for the selected studies using Cochrane's tool for assessing risk of bias. The studies were evaluated for the quality of evidence using GRADE (Grading of Recommendations, Assessment, Development and Evaluations). Risk ratios (RR), rate ratios, and hazard ratios (HR) were calculated along with 95% confidence intervals (95% CI). The Meta-analysis was performed using a random-effects model. Five RCTs met the inclusion criteria for this review. The risk of bias was unclear or high for the trials. Non-organ preservation(n = 140) versus organ preservation (n = 144) (two trials): no statistically significant difference could be identified for any of the primary outcomes. Concurrent chemoradiotherapy (n = 37) versus sequential chemotherapy followed by radiotherapy (n = 34) (one trial): no statistically significant difference was noted between the two treatment arms for overall survival, disease-free survival and loco-regional recurrence. Laryngectomy-free survival was found to be superior in concurrent chemoradiotherapy arm (HR:0.28, 95% CI 0.13, 0.57). Induction chemotherapy followed by concurrent chemoradiotherapy (n = 53) versus induction chemotherapy followed by radiotherapy (n = 60) (one trial): no statistically significant difference was noted between the treatment arms for overall survival, disease-free survival and laryngectomy-free survival. Preoperative radiotherapy (n = 24) versus postoperative radiotherapy (n = 23) (one trial): overall survival was found to be better in the postoperative radiotherapy arm (HR:2.44, 95% CI1.18, 5.03). No statistically significant difference was noted in terms of treatment-related toxicity. There are considerable uncertainties in the management of resectable hypopharyngeal cancer. PROSPERO registration: CRD42019155613.

CLRM-17 USE OF EXTERNAL CONTROL DATA FOR PLANNING AND ANALYZING GBM TRIALS: READY FOR PRIME TIME?

Randomized controlled trials (RCT) have been the gold standard for evaluating medical treatments for many decades. Randomization reduces systematic biases resulting from treatment or patient selection, whereby the improvement in clinical outcomes may be attributed to the experimental therapy under study. However, RCTs are often criticized for requiring large sample sizes and taking a long time to complete. For newly diagnosed glioblastoma (GBM), the clinical trial landscape has seen little progress since the establishment of the standard of care (SOC) by Stupp. Given the urgent need for better therapies, it has been argued that data collected from patients treated with the SOC from past GBM trials can provide high-quality external control data to supplement concurrent control arm in future trials, thereby increasing drug development efficiency by reducing the number of patients treated with SOC. Herein we consider a new design approach that leverages historical control data in the design and analysis of phase 3 GBM trials. At the first stage, patients are randomized with an equal probability to standard (concurrent control) arm and experimental arm. An interim analysis entails an outcome comparison between the concurrent and external control arms. If comparability is established, the external control data are carried forward to be combined with concurrent control data at the second stage where the randomization ratio is adapted to favor the experimental therapy, thereby reducing the number of patients treated in the concurrent control arm. Using completed phase 3 GBM trials, we elucidate the potential gain in design efficiency and draw caution to scenarios where it may fall short on meeting statistical criteria. We highlight practical challenges in its implementation and conclude that the new method is not ready for definitive phase 3 GBM studies at the current time. This work represents a critical appraisal of this new concept in GBM.