Early Stopping Rules Research Articles

A single-arm phase II study of ADT with PD-1 blockade and docetaxel in men with metastatic hormone-sensitive prostate cancer.

TPS271 Background: Overall survival of men with de novo metastatic, hormone-sensitive prostate cancer (mHSPC) is improved by treatment intensification with docetaxel and hormone therapy compared to androgen deprivation therapy (ADT) alone. However, castration-resistant prostate cancer (CRPC) invariably develops. Reprogramming the immune system in the mHSPC setting is a novel approach to delay progression to CRPC. In the hormone-sensitive setting, ADT induces a robust and functional immune infiltrate into the tumor microenvironment (TME), with upregulation of immune checkpoint molecules (PD-1 and PD-L1). These effects diminish as castration resistance emerges. Docetaxel causes immunogenic tumor cell death and stimulates antigen presentation. We hypothesize that leveraging the immunogenic effects of ADT with PD-1 blockade and docetaxel will promote antitumor immune killing and improve clinical outcomes. Methods: This is an open-label, single-arm, phase II study of ADT, cemiplimab, and docetaxel in patients with de novo mHSPC (N=20). Subjects will receive continuous ADT, followed by a two-cycle lead-in of cemiplimab prior to the standard six cycles of docetaxel. Cemiplimab will be continued q3weeks for one year or until disease progression or intolerable side effect. The primary endpoint is undetectable PSA at 6 months. Secondary endpoints include time to development of CRPC and radiographic response. Subjects will be monitored for toxicity using a Bayesian adaptive study design with an early stopping rule for toxicity. Correlative studies will determine the effects of ADT and PD-1 blockade on the TME by comparing baseline and on-treatment biopsies using transcriptional data from single-cell RNA-sequencing and standard immunohistochemistry (IHC). Serum samples will also be collected to quantify the effects of therapy on circulating levels of immunosuppressive cytokines. The study is open with 3 patients currently enrolled at the time of submission. Clinical trial information: NCT03951831.

Bicalutamide with or without metformin for biochemical recurrence in prostate cancer patients (BIMET-1).

85 Background: Metformin (MET) may play a role as an anti-proliferative and anti-carcinogenic agent. Epidemiological studies have demonstrated that MET is associated with decreased prostate cancer (PCa) incidence, including decreased PCa specific mortality in diabetic men with PCa. Preclinical studies have shown synergistic effect of MET with bicalutamide, thus prompting this clinical trial evaluating the combination (NCT02614859). Methods: This was an open label, randomized, phase II trial of pts with biochemically recurrent PCa, PSA doubling time 3-9 months, normal testosterone, and BMI > 25. Pts were randomized (2:1) either to MET 1000 mg twice daily orally or observation for initial 8 weeks. Bicalutamide 50 mg orally daily was added to both arms after 8 weeks. Total duration of treatment was 32 weeks. The primary objective was to determine number of pts with undetectable PSA ( < 0.2 ng/mL) at the end of study with key secondary objectives of evaluating PSA declines of ≥ 85%, PSA responses to MET alone and safety. An early stopping rule for futility was set at 39 pts, but due to slow accrual, an unplanned interim analysis was undertaken. Results: 28 patients were randomized between December 2015 and September 2019. Treatment was well tolerated with no dose reductions or treatment discontinuation. No Grade 3 treatment-related adverse events were observed. Conclusions: PSA responses were seen in 50% pts with MET monotherapy after 8 weeks. Although well tolerated, there was no difference in PSA at 32 weeks between the two arms. The trial will be stopped early due to poor accrual and inability to achieve its primary endpoint. Ongoing larger studies of MET in PCa (STAMPEDE) will define it’s utility in prostate cancer. Clinical trial information: NCT02614859. [Table: see text]

Carbapenem use in critically ill patients.

To review available data on carbapenem use in ICU. Carbapenem is a broad spectrum well tolerated antibiotic family that keep an excellent activity to extended spectrum β-lactamases and AmpC hyperproducer and in susceptible Pseudomonas aeruginosa and Acinetobacter baumannii. It becomes a drug of choice for empirical therapy of suspected sepsis in known or presumably known ESBLE carriers. Carbapenems remained the drug of choice for severe ESBLE infections. In severe critically ill patients, high off-label dose is necessary especially in patients with sepsis and glomerular hyperfiltration. Nevertheless, large spectrum of carbapenems leads to initial overuse. The increase in the overall consumption in the past years with lack of systematic re-evaluation observed is responsible of and carbapenem-selection pressure that contribute to the increase of carbapenem-resistant enterobacteriaceae, A. Baumannii and P. Aeruginosa in ICUs. Carbapenems remained a cornerstone of antibiotic therapy of severe infections. Emerging carbapenem resistance is related to the increase of carbapenem consumption. High doses are recommended for early therapy followed by systematic reevaluation on a daily basis with shift to narrow spectrum antimicrobials if possible and early stopping rules.

Smoothed residual stopping for statistical inverse problems via truncated SVD estimation

This work examines under what circumstances adaptivity for truncated SVD estimation can be achieved by an early stopping rule based on the smoothed residuals $\|(AA^{\top })^{\alpha /2}(Y-A\widehat{\mu }^{(m)})\|^{2}$. Lower and upper bounds for the risk are derived, which show that moderate smoothing of the residuals can be used to adapt over classes of signals with varying smoothness, while oversmoothing yields suboptimal convergence rates. The range of smoothness classes for which adaptation is possible can be controlled via $\alpha $. The theoretical results are illustrated by Monte-Carlo simulations.

A Convolutional Neural Network-Based Anthropomorphic Model Observer for Signal Detection in Breast CT Images Without Human-Labeled Data

Various imaging parameters in X-ray computed tomography (CT) should be examined and optimized by task-based assessment of human observer performance. Recently, convolutional neural networks (CNNs) have been introduced as anthropomorphic model observers. However, when human-labeled data are not available or limited, CNNs with an existing training strategy do not produce good performance agreement with human observers. The purpose of this study is to propose new training strategies for a CNN-based anthropomorphic model observer without human-labeled data for signal-known-exactly and background-known-statistically detection tasks. We acquired cone-beam CT projection data of breast background volume and reconstructed the projection data using the Feldkamp-Davis-Kress algorithm with 12 different imaging conditions including viewing image planes. Training data for the CNN were labeled utilizing conventional model observers. We employed an early stopping rule to reflect internal noise during the CNN training. To examine the CNN performance, we used three different training-testing schemes. The performance agreement between the human and model observers was measured via a Bland-Altman plot, the root-mean-squared error (RMSE), and the Pearson's correlation coefficient ($r$ ) of their proportion correct values. Throughout the three different training-testing schemes, CNNs with the proposed training strategies yielded narrower limits of agreements (with a bias lower than 0.03) and higher scores in both RMSE and $r$ than the conventional model observers. This indicates the proposed training strategies enable the CNN-based anthropomorphic model observer to have good performance agreement with human observers and generalize better to different imaging conditions than conventional anthropomorphic model observers.

Lessons Learned from Deescalation Trials in Favorable Risk HPV-Associated Squamous Cell Head and Neck Cancer-A Perspective on Future Trial Designs.

In recent years several clinical studies have investigated deintensified treatments in human papillomavirus (HPV)-associated head and neck squamous cell carcinoma. Two large phase III trials, RTOG 1016 and De-ESCALaTE, which attempted to reduce toxicity by replacing radiotherapy in combination with cisplatin with the use of cetuximab in combination with radiotherapy, recently suggested that radiotherapy + cetuximab leads to inferior survival compared with standard therapy (observed HRs of 1.45 and 5 in RTOG 1016 and De-ESCALaTE), as well as increased rates of locoregional failure. These unexpected results should prompt a careful examination of deintensification trials, both in HPV-associated oropharyngeal cancer and in other contexts. Statistical designs for deintensification studies should be consistent with the study aims of reducing toxicities while maintaining survival nearly identical to the standard of care. We suggest criteria to design future deintensification trials and discuss important operating characteristics, including tradeoffs between power and stringent early stopping rules to reduce the number of patients exposed to inferior treatments. Using retrospective analyses of previous clinical studies, we compared designs with different operating characteristics. As an example, using outcomes data from RTOG 1016 and De-ESCALaTE, we conducted analyses to determine advantages of (i) stringent futility early-stopping rules and of (ii) study designs that leverage both toxicity and efficacy endpoints for interim analyses. We show that increasing the frequency of interim-futility analyses has little impact on power, but the average study duration and number of subjects enrolled before the trial is closed for inferiority can decrease substantially (from 57.8 to 18 months, and from 764 to 645 subjects). Moreover, the number of observed deaths during the study can be reduced by up to 68%.

A Multicenter, Open-Label Feasibility Study of Daratumumab with Dose-Adjusted EPOCH in Newly Diagnosed Plasmablastic Lymphoma: AIDS Malignancy Consortium 105

Background: Plasmablastic lymphoma (PBL) is an aggressive large B-cell lymphoma commonly associated with HIV, immunosuppression, old age, and autoimmune disorders, but can be seen in immunocompetent patients. Intensive regimens, including EPOCH, have only a median overall survival between 9 to 15 months. Complete response rates are 40% to 65%. Patients with refractory or relapsed disease typically have a dismal prognosis. Little progress has been made in treating PBL without a single dedicated clinical trial to date. PBL has morphologic and immunophenotypic characteristics overlapping high-grade B-cell lymphoma and multiple myeloma. It is CD20 negative and positive for plasma cell markers, including CD38, CD138, and MUM-1/IRF-4, with a proliferation index typically > 90%. Daratumumab (DARA) is a human IgG1k anti-CD38 monoclonal antibody (mAb). CD38 is a transmembrane receptor with enzymatic activity highly expressed on the surface of plasma cells and plasmablasts. DARA induces directed cell killing of CD38 expressing cells including complement dependent cytotoxicity and antibody-dependent cell cytotoxicity (ADCC). DARA has significant activity as a single agent and part of combination therapy in myeloma. In non-Hodgkin lymphoma (NHL), DARA resulted in synergistic reduction of tumor growth when combined with rituximab and CHOP (R-CHOP) in follicular lymphoma systemic xenograft models and induced dose-dependent ADCC on mantle cell and follicular lymphoma cells lines in the presence of peripheral blood mononuclear cells in vitro (Pérez-Galán P, et al. Hematol Oncol. 2017). In addition, in vivo models using DLBCL (SU-DHL-6) cells injected in SCID mice showed superiority of DARA in combination with CHOP vs DARA alone (63% vs 55%, p <0.01). In a patient-derived DLBCL model with high CD38 expression, DARA with CHOP or R-CHOP showed tumor regression, and tumors did not regrow when treatment with DARA was stopped after 3 doses. (Doshi P, et al. Haematologica. 2014). We designed an innovative approach to treat PBL using a combination of chemotherapy and directed immunotherapy with a mAb. We hypothesize that adding the potent CD38-directed mAb DARA to DA-EPOCH is safe and feasible and results in improved outcomes in PBL similar to the benefit seen with adding rituximab to a CHOP or EPOCH backbone in other DLBCL subtypes. This will be the first clinical trial dedicated to patients with PBL. Study Design and Methods: This is a non-randomized, multicenter study conducted by the AIDS Malignancy Consortium. Both HIV negative and HIV positive PBL patients ≥ 18 years old with Stage II to IV PBL or Stage I with elevated LDH and/or bulky tumor, who have measurable disease and adequate organ function are eligible. HIV positive patients must have CD4 ≥ 100 cells/μL and be on concurrent combination antiretroviral therapy (cART) or agree to start cART. Key exclusion criteria include receiving ≥ 1 prior cycle of combination chemotherapy, hepatitis B seropositivity, and active CNS involvement. DARA will be given in conjunction with DA-EPOCH every 21 days for 6 cycles. DARA 16 mg/kg will be administered intravenously weekly for the first 3 cycles on days 1, 8, and 15, then on day 1 for cycles 4-6. The primary aim is to determine the percentage of newly diagnosed PBL patients who complete ≥ 3 cycles of DARA with DA-EPOCH irrespective of HIV status. We expect that 85% of patients will complete ≥ 5 cycles of DA-EPOCH alone based on the CALGB 50303 study (Bartlett NL, et al. JCO. 2019). Allowing for a lower proportion completing with the addition of DARA, we hypothesize that > 75% of patients will complete ≥ 3 cycles of protocol treatment. An early stopping rule for completing <3 cycles will be employed. The planned enrollment is 15 patients. Correlations with clinical outcomes will include immunohistochemistry on tumor specimens and peripheral blood to study EBV clearance and identify predictive biomarkers. We will study non-invasive monitoring by circulating tumor DNA using plasma DNA mutation panels and clonal immunoglobulin. Disclosures Tan: Merck: Research Funding; Bayer: Research Funding; Takeda: Research Funding; Janssen: Research Funding. Barta:Takeda: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Seattle Genetics: Honoraria, Research Funding; Celgene: Research Funding; Mundipharma: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Mundipharma: Honoraria; Bayer: Consultancy, Research Funding. Noy:NIH: Research Funding; Pharamcyclics: Research Funding; Janssen: Consultancy; Medscape: Honoraria; Prime Oncology: Honoraria; Raphael Pharma: Research Funding. OffLabel Disclosure: Daratumumab is being used off-label on this clinical trial.

Early-Phase Platform Trials: A New Paradigm for Dose Finding and Treatment Screening in the Era of Precision Oncology.

Applications in early-phase cancer trials have motivated the development of many statistical designs since the late 1980s, including dose-finding methods, futility screening, treatment selection, and early stopping rules. These methods are often proposed to address the conventional cytotoxic therapeutics for neoplastic diseases and cancer. Recent advances in precision medicine have motivated novel trial designs, most notably the idea of master protocol (eg, platform trial, basket trial, umbrella trial, N-of-1 trial), for the evaluation of molecularly targeted cancer therapies. In this article, we review the concepts and methodology of early-phase cancer trial designs with a focus on dose finding and treatment screening and put these methods in the context of platform trials of molecularly targeted cancer therapies. Because most cancer trial designs have been developed for cytotoxic agents, we will discuss how these time-tested design principles hold relevance for targeted cancer therapies, and we will delineate how a master protocol may serve as an efficient platform for safety and efficacy evaluations of novel targeted therapies.

A pragmatic, adaptive clinical trial design for a rare disease: The FOcal Cerebral Arteriopathy Steroid (FOCAS) trial

BackgroundPediatric stroke investigators identified as their top research priority a clinical trial of corticosteroids for focal cerebral arteriopathy (FCA). However, FCA is both rare and an acute condition making it infeasible to enroll the large sample sizes needed for standard, confirmatory clinical trials. We present a pragmatic approach to clinical trial design that may inform the approach to other rare disorders. MethodsWe surveyed pediatric stroke experts to determine the level of evidence that would impact their clinical management of FCA. Incorporating survey results, a randomized, group sequential Bayesian adaptive design was proposed based on a quantitative radiologic outcome measure (change from baseline in change in the FCA Severity Score). Using accumulating information, the design determines whether intervention is better than control with high probability. ResultsAmong 21 (100%) respondents, the probability of corticosteroid efficacy that would lead the experts to treat was 30% (median). The probability of efficacy that would make them unwilling to randomize (because they would feel all children should receive corticosteroids) was 70%. Simulation studies with the proposed design showed that a total of 42 subjects controls the type I error rate at the desired level 0.20 and yields a smaller average sample size and trial duration compared to a conventional design. ConclusionsDesigns in rare diseases require special considerations; this is especially true for this childhood disease, which is both uncommon and acute. This design has incorporated expert consensus to establish the criteria for success, formal monitoring rules for safety, and early stopping rules.

Bias regularization in neural network models for general insurance pricing

Generalized linear models have the important property of providing unbiased estimates on a portfolio level. This implies that generalized linear models manage to provide accurate prices on a portfolio level. On the other hand, neural networks may provide very accurate prices on an individual policy level, but state-of-the-art use of neural networks does not pay any attention to unbiasedness on the portfolio level. This is an implicit consequence of applying early stopping rules in gradient descent methods for model fitting. In the present paper we discuss this deficiency and we provide two different techniques to overcome this drawback of neural network model fitting.

A two-stage phase II clinical trial design with nested criteria for early stopping and efficacy.

We propose a two-stage design for a single arm clinical trial with an early stopping rule for futility. This design employs different endpoints to assess early stopping and efficacy. The early stopping rule is based on a criteria determined more quickly than that for efficacy. These separate criteria are also nested in the sense that efficacy is a special case of, but usually not identical to, the early stopping endpoint. The design readily allows for planning in terms of statistical significance, power, expected sample size, and expected duration. This method is illustrated with a phase II design comparing rates of disease progression in elderly patients treated for lung cancer to rates found using a historical control. In this example, the early stopping rule is based on the number of patients who exhibit progression-free survival (PFS) at 2months post treatment follow-up. Efficacy is judged by the number of patients who have PFS at 6months. We demonstrate our design has expected sample size and power comparable with the Simon two-stage design but exhibits shorter expected duration under a range of useful parameter values.

Strategies for validating biomarkers using data from a reference set.

Candidate biomarkers discovered in the laboratory need to be rigorously validated before advancing to clinical application. However, it is often expensive and time-consuming to collect the high quality specimens needed for validation; moreover, such specimens are often limited in volume. The Early Detection Research Network has developed valuable specimen reference sets that can be used by multiple labs for biomarker validation. To optimize the chance of successful validation, it is critical to efficiently utilize the limited specimens in these reference sets on promising candidate biomarkers. Towards this end, we propose a novel two-stage validation strategy that partitions the samples in the reference set into two groups for sequential validation. The proposed strategy adopts the group sequential testing method to control for the type I error rate and rotates group membership to maximize the usage of available samples. We develop analytical formulas for performance parameters of this strategy in terms of the expected numbers of biomarkers that can be evaluated and the truly useful biomarkers that can be successfully validated, which can provide valuable guidance for future study design. The performance of our proposed strategy for validating biomarkers with respect to the points on the receiver operating characteristic curve are evaluated via extensive simulation studies and compared with the default strategy of validating each biomarker using all samples in the reference set. Different types of early stopping rules and boundary shapes in the group sequential testing method are considered. Compared with the default strategy, our proposed strategy makes more efficient use of the limited resources in the reference set by allowing more candidate biomarkers to be evaluated, giving a better chance of having truly useful biomarkers successfully validated.

The national blueprint for future factor VIII inhibitor clinical trials: NHLBI State of the Science (SOS) Workshop on factor VIII inhibitors.

Inhibitor formation is a major complication of haemophilia for which clinical trials are planned. Despite emerging novel haemostatic agents, challenges of rare disease trials are limited subjects and lack of an organized research organization with strategic resources and partnerships. The charge to Working Group 1 was to establish scientific priorities and innovative implementation strategies to conduct inhibitor prevention and eradication trials. To determine feasibility of trial design and strategic resources and partnerships to be leveraged, two clinical trial concepts were considered. For the Inhibitor Prevention Trial, we considered adaptive design with early stopping rules, dynamic randomization and Master Protocol models to reduce sample size; and registries to provide concurrent controls and natural history data. For the Inhibitor Eradication Trial using gene therapy, an adaptive design was considered in a small number of subjects, and, if safe and meeting regulatory requirements, enrolment would be expanded. A Haemophilia Clinical Trials Group (HCTG) infrastructure was envisioned, with uniform procedures and standardized outcomes, data collection and assays, within which trial concepts would be developed, vetted and prioritized by a Steering Committee, and submitted to NIH and other research sponsors for review and funding. Mechanistic studies would be embedded within the trials, early stage investigators trained and mentored, and the research infrastructure established within the haemophilia centre (HTC) network and supported by partnerships with foundations, community, federal partners and industry. The success of inhibitor trials will depend on innovative trial design and an organized HCTG research infrastructure, leveraged through community partnerships.

Simulation Practices for Adaptive Trial Designs in Drug and Device Development

Adaptive clinical trials are the cornerstone of modern drug and device development. The most recent US legislation calls for higher efficiency in designing clinical trials with emphasis on expanding the utilization of complex innovative designs that cannot be developed without simulations. It is well recognized that clinical trial simulation is a fundamental tool to explore, compare, and understand the operating characteristics, statistical properties, and adaptive decisions embedded in different designs to answer the given research questions. This article provides insights from industry on the development of a simulation report from a group of statisticians brought together under the sponsorship of the Drug Information Association Adaptive Design Scientific Working Group. This effort intends to illustrate the key common elements required to ensure higher consistency and clarity in conducting and reporting simulations of adaptive clinical trials, eliminate unnecessary barriers in communicating technical design aspects to different audiences, and facilitate the assessment of pros and cons of candidate designs. The design-dependent elements of a simulation report applicable to specific types of adaptive trials are presented with the examples of dose-escalation designs, dose-ranging studies, trials with sample size re-estimation and early stopping rules, and confirmatory multistage designs.

Time-trend impact on treatment estimation in two-arm clinical trials with a binary outcome and Bayesian response adaptive randomization

ABSTRACTClinical trial design and analysis often assume study population homogeneity, although patient baseline profile and standard of care may evolve over time, especially in trials with long recruitment periods. The time-trend phenomenon can affect the treatment estimation and the operating characteristics of trials with Bayesian response adaptive randomization (BRAR). The mechanism of time-trend impact on BRAR is increasingly being studied but some aspects remain unclear. The goal of this research is to quantify the bias in treatment effect estimation due to the use of BRAR in the presence of time-trend. In addition, simulations are conducted to compare the performance of three commonly used BRAR algorithms under different time-trend patterns with and without early stopping rules. The results demonstrate that using these BRAR methods in a two-arm trial with time-trend may cause type I error inflation and treatment effect estimation bias. The magnitude and direction of the bias are affected by the parameters of the BRAR algorithm and the time-trend pattern.

Sporadic angiomyolipomas (AMLs) growth kinetics while on everolimus (SAGE).

560 Background: Level I evidence exists demonstrating the efficacy of the mTOR inhibitor everolimus (EVE) in decreasing tumor volume of syndromic angiomyolipomas (AMLs) among patients with Tuberous Sclerosis. No prospective data are available regarding the effect of mTOR inhibition on growth kinetics in patients with sporadic AMLs. Methods: We conducted a multi-institutional, prospective, phase 2 trial with an optimal two-stage Simon design in patients presenting with > 3cm sporadic AMLs who were candidates for surgical or percutaneous intervention. Response was defined as ≥25% volumetric reduction of the AML. Planned enrollment was 43 patients to test the null hypothesis at a 5% level of significance with 80% power. Baseline, 4- and 6-month volumetric analysis was performed by dynamic contrast-enhanced MRI (DCE-MRI). Patients received EVE 10mg for four 28-day cycles, at which point EVE was discontinued in those with < 25% volumetric reduction. Those with ≥ 25% volumetric reduction received two additional cycles of EVE. Dose reductions and interruptions were allowed to 5 mg QOD. Conservative stopping rules were established for toxicity, given the benign nature of AMLs. Results: The early stopping rules for both efficacy and toxicity were invoked. We enrolled 20 patients (median age = 68) from 5 centers with 21 sporadic AMLs. 11/20 (55%) patients completed 4 cycles of EVE, while 7/20 (35%) completed 6 cycles. Median days on treatment was 88 (2 cycles). 4/20 (20%) patients were withdrawn due to toxicity, while 8/20 (40%) withdrew due to personal preference. Dose reductions were required in 6/20 (30%) patients, and 5/20 (25%) patients had grade 3 toxicities which resolved upon discontinuation or dose reduction of EVE. At 4-month MRI, 10/16 (62.5%) patients had a ≥25% reduction in volume (mean = 54.1% decrease). At 6-month MRI, 8/12 (66.6%) patients had a ≥25% reduction in volume (mean = 51.5% decrease). Conclusions: EVE was effective in reducing tumor volume in patients with sporadic AMLs but was associated with a high rate of treatment termination due to patient preference or prespecified AEs. Neoadjuvant EVE may be useful in potentiating surgical resection of large or anatomically complex AMLs. Clinical trial information: NCT02539459.

Bias Regularization in Neural Network Models for General Insurance Pricing

Generalized linear models have the important property of providing unbiased estimates on a portfolio level. This implies that generalized linear models manage to provide accurate prices on a portfolio level. On the other hand, neural networks may provide very accurate prices on an individual policy level, but state-of-the-art use of neural networks does not pay attention to unbiasedness on a portfolio level. In fact, this is an implicit consequence of using early stopping rules in gradient descent methods for model fitting. In the present paper we discuss this deficiency and we provide two different techniques that remove this drawback of neural network model fitting.

Randomized Trial in Unfit, Elderly Chronic Lymphocytic Leukemia (CLL) Patients with Comorbidities of Dose-Reduced Oral Fludarabine and Cyclophosphamide Plus Obinutuzumab (FC+G) Versus Chlorambucil Plus Obinutuzumab (Cbl+G) As Front-Line Therapy

BACKGROUNDThe prior Australasian Leukaemia and Lymphoma Group (ALLG) CLL5 Study showed dose-reduced oral fludarabine and cyclophosphamide plus rituximab (FCR3) was safe, tolerable and effective in fit elderly patients for front-line therapy for CLL. The German CLL11 Study showed chlorambucil plus obinutuzumab (Cbl+G) was superior to chlorambucil alone or with rituximab in unfit patients requiring initial therapy. We conducted a randomized study to assess the safety, tolerability, and efficacy of dose-reduced FC + obinutuzumab (G) (FC+G) versus Cbl+G in unfit (i.e. with comorbidity), elderly patients with CLL.METHODSPatients aged ≥65 years and considered “unfit” defined by co-morbidities using the Cumulative Illness Rating Scale [CIRS] ≥6 were eligible for the ALLG CLL7 study. Patients with any single organ system score ≥4 were excluded. Previously untreated patients with progressive CLL aged ≥65 and CIRS ≥6 were randomised to one of 2 therapy arms: (i) Chlorambucil 0.5mg/kg D1+15 p.o. + obinutuzumab (“G”) (i.v. 1000mg/m2 cycle 1, Day 1, 8, 15, and 1000mg/m2 D1 cycles 2-6), or (ii) FC(rd)+G: F-24mg/m2 p.o. and C-150mg/m2 p.o. D1-3 + G (same schedule above) at 4 weekly intervals for planned 6 cycles. Early stopping for toxicity was mandated: treatment could be delayed for 2 weeks for grade 3+ toxicity, but if unresolved by 2 weeks, patients were taken off study. The primary end-point was grade 3+ non-hematological, and grade 4 hematological adverse events. Secondary objectives were overall response rate (ORR), complete remission (CR), partial remission (PR), progression-free survival (PFS) and overall survival (OS) and minimal residual disease (MRD) negativity. Final staging was performed between 2-3 months following final treatment cycle.RESULTSPatient characteristics Patient recruitment was terminated early due to poor recruitment. At the time of study closure, there were 32 patients, with 15 on Cbl+G and 17 on FC(rd)+G. The mean age was 74.2 years (range 66-85 years) with 23 females (71.9%) and 9 males (28.1%). The CIRS score was 6 in 4 patients (12.5%), 6-8 in 14 (43.8%), 8-10 in 11 (34.4%) and >10 in 3 (9.4%). Binet stage at registration was stage A 18.2%, B 27.3% and C 54.5%.Tolerability Both therapies were tolerable with 15/17 (88.2%) completing all 6 cycles of FC(rd)+G and 12/15 (92.3%) completing six cycles of Cbl+G.Toxicity Most toxicity was hematological and manageable. Grade 3/4 hematological toxicity was more common with FC(rd)+G than Cbl+G occurring in 60% with FC(rd)+G and 38.5% with Cbl+G (Table 1). There was one death due to progressive CLL on the FC(rd)+G arm.Response rate A complete remission (CR), confirmed by bone marrow (BM) trephine, was achieved in 86.6% of patients on FC(rd)+G versus (vs) 53.9% on Cbl+G, partial response (PR/nPR) in 1 (6.7%) on FC(rd)+G, and 6 (46.2%) on Cbl+G, and either stable or progressive disease (SD or PD) on 1 on FC(rd)+G, and nil on Cbl+G. BM MRD-negativity rates were 3/17 (20.0%) FC(rd)+G vs 1/15 (7.7%) Cbl+G (Table 2).CONCLUSIONThis randomized trial of dose-reduced FC(rd)+G vs Cbl+G in elderly patients aged ≥65 and with co-morbidities (CIRS ≥6) was terminated early due to poor recruitment. Due to the dose-reduced FC, and early stopping rule, treatment was safe and tolerable and most patients completed all 6 cycles of planned therapy. Grade 3/4 toxicity was mainly hematological and manageable, with higher rates of neutropenia with the FC (60%) vs Cbl (35.7%) backbone. FC(rd)+G compared to Cbl+G resulted a higher CR rate of 86.6%% versus 53.9%, and higher MRD-negativity (20% vs 7.7%). Progression-free and overall survival are being evaluated. [Display omitted] DisclosuresBadoux:Roche: Research Funding. Cull:Takeda Australia: Other: Travel Expenses; Amgen Australia: Other: Travel Expenses; AbbVie (Australia): Membership on an entity's Board of Directors or advisory committees. Tam:Janssen: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BeiGene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Pembrolizumab for the Treatment of Disease Relapse Following Allogeneic Hematopoietic Cell Transplantation

Background: Disease relapse remains the primary cause of mortality following allogeneic hematopoietic cell transplantation (alloHCT). One important mechanism of disease relapse in this setting is failure of the graft-versus-tumor (GvT) effect, and the PD-1/PD-L1 axis may diminish GvT after alloSCT. We hypothesized that PD-1/PD-L1 interactions prevent donor-derived T cells from eliminating malignant cells expressing minor histocompatibility antigens, and that blocking PD-1/PD-L1 interactions with the anti-PD-1 antibody, pembrolizumab (pem), might restore GvT and induce clinical responses in patients (pts) with relapsed hematologic malignancies following alloHCT. However, PD-1 blockade therapy has been associated with severe graft-versus-host disease (GVHD) in murine models, and GVHD has been reported in humans treated with anti-PD-1 therapy after alloHCT. Thus, we developed a prospective clinical study to test the tolerability and preliminary efficacy of pembrolizumab in patients with relapsed leukemia/lymphoma after alloSCT.Methods: Pts with AML, MDS, or B cell lymphomas with biopsy-proven recurrence after alloSCT were eligible, as long as no active acute GVHD > grade 1 or chronic GVHD was present. Pts were treated with pem 200 mg IV q3 weeks for up to 2 years, provided that neither intolerable side-effects nor disease progression occurred. Pem could be delayed for treatment-limiting toxicities (TLT), defined as immune-related adverse events (irAEs) not meeting criteria for a dose-limiting toxicity (DLT). DLT was defined as the development of grade 3 or 4 acute GVHD/irAE, any unexpected grade > 2 toxicity related to pem, or development of > grade 2 vital organ dysfunction secondary to an irAE within 90 days of pem initiation. A two-stage mini-max design was chosen, with an early stopping rule for DLT after the first 11 patients were enrolled.Results: 11 pts (7 male, 4 female), mean age 49.5 yrs (range, 27-62 yrs) have been enrolled. 8 pts had AML and 3 had lymphoma (DLBCL - 2, cHL - 1). 6 pts had matched-related donors (MRD) and 5 pts had haploidentical/umbilical cord blood (haplo-cord) donors. Pts with MRD were conditioned with fludarabine, melphalan, and alemtuzumab, or fludarabine and busulfan. Pts with haplo-cord donors were conditioned with fludarabine, melphalan, and ATG. 5 pts had prior acute GVHD. Pts relapsed following alloHCT at a median of 453 days (range, 101-1021 days). A median of 2 cycles of pembrolizumab (range, 1-8) was administered. 3 pts are receiving ongoing treatment. 3 pts experienced a DLT due to an irAE (grade 3-4 pneumonitis 2 pts; grade 3 hyperthyroidism 1 pt), all of which occurred after 1-2 cycles of pem, and resolved after pem discontinuation and corticosteroid treatment. 1 pt experienced a TLT (grade 2 rash), but resumed pem treatment. Among all pts, irAEs of any grade occurred in 7 pts. 7 pts were evaluable for response. 3 pts (2 AML, 1 DLBCL) experienced progressive disease (PD), 2 pts (AML) had stable disease (SD), and 2 pts achieved CR (DLBCL, cHL). 1 pt with AML (myeloid sarcoma) in whom pem was discontinued for PD by PET/CT imaging had a concurrent tumor biopsy that revealed marked T cell infiltration and PD-L1 expression on a significant fraction of malignant myeloid cells, suggestive of possible inflammatory “pseudo-progression”. 1 pt in CR developed therapy-related AML unrelated to pem. Notably, both patients with CR following pem had PD-L1 gene-amplified lymphomas by FISH, and diffuse PD-L1 protein expression on pre-treatment biopsies. Currently, 4 pts have died, all due to disease progression, and 7 are alive. A total of 26 patients are expected to be enrolled.Conclusions: Treatment with pem in the post-alloHCT disease relapse setting is feasible, but can induce early and severe irAEs, requiring vigilant monitoring. To date, objective responses were seen in 2/3 lymphoma patients treated with pem. In AML, pem may be less effective, where a best response of SD was observed in 2 pts, and possible “pseudo-progression” in a patient with myeloid sarcoma. This study continues to accrue pts, and correlative analyses are underway. To our knowledge, these are the first prospective data of PD-1 blockade therapy in the post-alloHCT setting. DisclosuresKline:iTeos: Research Funding; Merck: Honoraria, Research Funding. Liu:BMS: Research Funding. Curran:Merck: Research Funding. Stock:Jazz Pharmaceuticals: Consultancy. Smith:BMS: Consultancy; Portola: Honoraria. Bishop:Juneau Therapeutics: Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees; United Healthcare: Employment; Novartis Pharmaceuticals Corporation: Speakers Bureau.

A Study of Tbo-Filgrastim (Granix) to Disrupt the Bone Marrow Microenvironment in Patients with Multiple Myeloma Undergoing Autologous Stem Cell Transplantation

Multiple myeloma is the second most common hematologic malignancy in the US. The current standard of care for transplant eligible patients is therapy with high-dose melphalan (HDM) followed by autologous stem cell transplant (ASCT). Although ASCT improves progression-free (PFS) and overall survival (OS), it is not curative and virtually all patients will relapse. Attempts to improve upon HDM by adding other agents to transplant protocols have largely resulted in unacceptable increases in toxicity.Preclinical studies performed by our group suggest that granulocyte-stimulating factor (G-CSF) disrupts the bone marrow microenvironment, resulting in a striking loss of plasmablasts, plasma cells, and decreased expression of chemokine/cytokines contributing to plasma cell maintenance. Tbo-filgrastim (Granix, Teva Pharmaceuticals) is a recombinant methionyl human granulocyte colony-stimulating factor. We hypothesized that tbo-filgrastim treatment may provide a potent and well-tolerated method to disrupt the ‘myeloma cell niche’, rendering patients more sensitive to HDM.Methods: Here, we report results from an open label, single center, phase II randomized study to test the efficacy and safety of tbo-filgrastim plus HDM (tbo-filgrastim arm) versus HDM alone (SOC arm) prior to ASCT (NCT02112045). Patients were randomized 1:1 to tbo-filgrastim on Day -7 through Day -2 (480 or 960 mcg/day, based on weight) and melphalan on Day -2 prior to ASCT (140 or 200 mg/m2, based on age) or melphalan alone. The primary objective was to compare CR rate at day 100. Secondary objectives included comparison of the toxicity, overall response rate, PFS, OS, and rate of neutrophil and platelet engraftment between the two arms. Eligible patients were ≥18 years with symptomatic multiple myeloma enrolled within 12 months of receiving at least 2 cycles of any systemic therapy, were undergoing their first ASCT, and had an adequate ASCT collection product (at least 2 million CD34+ cells/kg). Target enrollment was 176 patients, with an interim analysis of efficacy and futility planned after 88 patients reached Day 100 post-ASCT. Early stopping rules for unacceptable toxicity were in place. Responses were evaluated by IMWG criteria.Results: Ninety patients were enrolled (median age 59.5, range 33 to 77) and 89 were evaluable for response. The early stopping rules for toxicity were not met. The planned interim analysis showed that the proportion of patients in CR at Day 100 was similar between the arms and the study was halted for futility (39.5% on the tbo-filgrastim arm vs. 37.8% on SOC arm). The overall response rate (CR + VGPR + PR) between the tbo-filgrastim and the SOC arm was 95% vs 93%, respectively. At the interim analysis, with median follow-up time for the study of 21.7 months, (range 8.8 to 25.8), the median PFS and OS had not been reached for either arm. There was no difference in PFS between the tbo-filgrastim and the SOC arm (84% vs 80%, respectively, p=0.60). There was no difference in OS between the tbo-filgrastim and the SOC arm (90.9% vs 95.6%, respectively, p=0.43). All patients in the study achieved neutrophil (ANC > 0.5 K/cumm) and platelet (> 20 K/cumm) engraftment. The median time to neutrophil engraftment for the tbo-filgrastim arm was 5 days (range, 3-9) vs 4 days (range, 3-7) in the SOC arm, p<0.001. There was no difference in the median time to platelet engraftment between the arms (11 days in the tbo-filgrastim arm, range 2-23, and 10 days in the SOC arm, range 1-24, p=0.67). Adverse events for both arms were typical of those observed in the ASCT population.Conclusions: The administration of tbo-filgrastim in the setting of HDM prior to ASCT is feasible, without excess toxicity or loss of engraftment. There was no difference in Day +100 CR or ORR rates, PFS, or OS in patients treated with tbo-filgrastim plus HDM versus HDM alone with a median follow-up of 21.7 months. The lack of efficacy may be secondary to the high pre-ASCT response rates seen with modern agents. DisclosuresJacoby:Celgene: Speakers Bureau; NovoNordisk: Consultancy. Schroeder:Amgen Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees. Vij:Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Jansson: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.