Practical considerations of utilizing propensity score methods in clinical development using real-world and historical data.

In recent years, with the rapid increase in the volume and accessibility of Real-World-Data (RWD) and Real-World-Evidence (RWE), we have seen the unprecedented opportunities for their use in drug clinical development and life-cycle management. RWD and RWE have demonstrated the significant potential to improve the design, planning, and execution of clinical development. Furthermore, they can feature in the designs as either a substitute or compliment to traditional clinical trials. However, to utilize RWD and RWE appropriately and wisely, it is critical to apply rigorous statistical methodologies that enable the robustness of results to be characterized and ascertained. Several statistical methodologies including exact matching, propensity score methods, matching-adjusted indirect comparisons and meta-analysis have been proposed for analyzing RWD. Among them, propensity score method is one of the most commonly used methods for non-randomized trials with indirect comparison. Although massive methodologies and examples have been published and discussed since propensity score methods were introduced, systematic review and discussion of how to rigorously use propensity score methods in the practical clinical development is still deficient. This paper introduces commonly used and emerging propensity score methods with detailed discussions of their pros and cons. Three different case studies are presented to illustrate the practical considerations of utilizing propensity score methods in the study design and evaluation using real-world and historical data. Additional considerations including selection of patient populations, endpoints, baseline covariates, propensity score methods, sensitivity analysis and practical implementation flow in clinical development will be discussed.

Panoptic clinical review of the current and future treatment of relapsed/refractory T-cell lymphomas: Peripheral T-cell lymphomas.

Peripheral T-cell lymphomas (PTCLs) tend to be aggressive and chemorefractory, with about 70% of patients developing relapsed/refractory disease. Prior to 2009, chemotherapies were the only options for relapsed/refractory PTCL, other than hematopoietic transplants. However, chemotherapy only improves survival by about 1 month compared with palliation. Four drugs are now approved in the US to treat relapsed/refractory PTCL: pralatrexate, romidepsin, belinostat, and brentuximab vedotin (for systemic anaplastic large cell lymphoma [sALCL]). Response rates with pralatrexate, romidepsin, and belinostat range from 25 to 54% in mixed relapsed/refractory PTCL populations, while 86% of sALCL patients respond to brentuximab vedotin. Here, we critically evaluate the evidence supporting the current drug treatment of relapsed/refractory PTCL, and look to the future to see how the treatment panorama may change with the advent of new targeted therapies, some of which (e.g., alisertib in PTCL and mogamulizumab in CCR4-positive adult T-cell leukemia/lymphoma) are already in phase 3 trials.

Panoptic clinical review of the current and future treatment of relapsed/refractory T-cell lymphomas: Cutaneous T-cell lymphomas.

Primary cutaneous T-cell lymphomas (CTCLs), such as mycosis fungoides and Sézary syndrome, are a rare group of non-Hodgkin lymphomas, usually treated using a multimodal approach. Unfortunately, many patients go on to develop relapsed/refractory disease. Systemic treatment for relapsed/refractory CTCL has historically relied on chemotherapies and interferons, and while active, responses are often short-lived. Three drugs are now approved in the US to treat relapsed/refractory CTCL including the oral retinoid, bexarotene, and histone deacetylase inhibitors, romidepsin and vorinostat. Although response rates are typically <35%, romidepsin and vorinostat can induce some durable responses in heavily pretreated patients and alleviate bothersome symptoms, such as pruritus. New studies indicate that the anti-CD30 antibody-drug conjugate brentuximab vedotin, anti-CCR4 antibody mogamulizumab, and fusion protein immunotoxin A-dmDT390-bisFv(UCHT1) may be particularly active in this setting. In this paper, we present an exhaustive review of the clinical data on current and possible future drug treatment options for relapsed/refractory CTCL.

Designing a Microfluidic Device with Integrated Ratiometric Oxygen Sensors for the Long-Term Control and Monitoring of Chronic and Cyclic Hypoxia.

Control of oxygen over cell cultures in vitro is a topic of considerable interest, as chronic and cyclic hypoxia can alter cell behaviour. Both static and transient hypoxic levels have been found to affect tumour cell behaviour; it is potentially valuable to include these effects in early, in vitro stages of drug screening. A barrier to their inclusion is that rates of transient hypoxia can be a few cycles/hour, which is difficult to reproduce in traditional in vitro cell culture environments due to long diffusion distances from control gases to the cells. We use a gas-permeable three-layer microfluidic device to achieve spatial and temporal oxygen control with biologically-relevant switching times. We measure the oxygen profiles with integrated, ratiometric optical oxygen sensors, demonstrate sensor and system stability over multi-day experiments, and characterize a pre-bleaching process to improve sensor stability. We show, with both finite-element modelling and experimental data, excellent control over the oxygen levels by the device, independent of fluid flow rate and oxygenation for the operating flow regime. We measure equilibration times of approximately 10 min, generate complex, time-varying oxygen profiles, and study the effects of oxygenated media flow rates on the measured oxygen levels. This device could form a useful tool for future long-term studies of cell behaviour under hypoxia.

Brentuximab vedotin compared with other therapies in relapsed/refractory Hodgkin lymphoma post autologous stem cell transplant: median overall survival meta-analysis.

OBJECTIVE: This meta-analysis compared the median overall survival (mOS) of brentuximab vedotin reported in the pivotal phase 2 study with published results of other therapies for the treatment of relapsed/refractory (R/R) Hodgkin lymphoma (HL) post autologous stem cell transplant (ASCT). RESEARCH DESIGN AND METHODS: A systematic literature review identified studies that reported survival outcomes following conventional/experimental therapies in R/R HL patients, with ≥50% having failed ≥1 ASCT. Kaplan-Meier curves were used to reconstruct individual patient level survival data. Patients were grouped by treatment type and reconstructed data were used to estimate the mOS. Censored median regression modeling was used to compare mOS in each group with the mOS in the pivotal brentuximab vedotin trial. All patients in the pivotal trial had undergone ASCT, therefore a sensitivity analysis was conducted among studies with a 100% post-ASCT patient population. RESULTS: The mOS reported for brentuximab vedotin was 40.5 (95% CI 30.8-NA) compared with 26.4 months (95% CI 23.5-28.5) across all 40 studies identified (n = 2518 excluding the brentuximab vedotin trial) (p < 0.0001). The difference in mOS between brentuximab vedotin and chemotherapy, allogeneic stem cell transplant (allo-SCT), and other therapies, was 17.7 (95% CI 10.6-24.7; p < 0.0001), 12.5 (95% CI 8.2-16.9; p < 0.0001), and 15.2 months (95% CI 4.9-25.5; p = 0.0037), respectively. For the 11 studies reporting a 100% prior-ASCT rate (n = 662 excluding the brentuximab vedotin trial), the mOS was 28.1 months (95% CI 23.9-34.5), and the difference in mOS between brentuximab vedotin, chemotherapy, allo-SCT, and other therapies was 19.0 (95% CI 12.9-25.1; p < 0.0001), 9.4 (p > 0.05), and 6.8 months (95% CI 1.2-12.5; p = 0.0018), respectively. CONCLUSIONS: While some selection bias may occur when comparing trials with heterogeneous eligibility criteria, in the absence of randomized controlled trial data these results suggest brentuximab vedotin improves long-term survival and is associated with longer mOS in R/R HL post-ASCT compared with other therapies.

Brentuximab vedotin in relapsed/refractory Hodgkin lymphoma post-autologous transplant: meta-analysis versus historical data.

OBJECTIVE: This meta-analysis evaluated the antitumor activity of brentuximab vedotin versus historical values in patients with relapsed/refractory Hodgkin lymphoma post-autologous stem cell transplantation (ASCT). METHODS: A systematic literature review identified studies (1993-February 2013) reporting complete remission (CR) rates in patients with relapsed/refractory Hodgkin lymphoma post-ASCT. Publications reporting CR rates, identified through interrogation of multiple electronic databases and manual searches (with search terms used to capture 'relapsed', 'refractory', 'HL', and 'ASCT'), were included if they reported: ≥20 relapsed/refractory Hodgkin lymphoma patients, where ≥80% were aged ≥12 years and ≥50% had failed prior ASCT. Overall CR rate was determined using a random-effect model, and compared with that reported for brentuximab vedotin in a pivotal phase 2 trial (SG035-0003). MAIN OUTCOME MEASURES: Across 17 evaluable studies of historical or experimental agents (n = 812), the estimated overall CR rate was 11.1% (95% confidence interval [CI] 7.0, 17.6; range, 0-38.5%) versus 33.3% (95% CI 25.3, 43.9) for brentuximab vedotin (p < 0.0001). In sensitivity analyses, the estimated overall CR rates for historical/experimental agents were 13.6% (95% CI 8.7, 21.4) when only HL trials that reported a CR rate of >0% were included (13 studies; n = 696; p = 0.0009 vs. brentuximab vedotin), and 9.0% (95% CI 4.9, 16.6) when only HL trials were included where CR definition was reported and was measured using the same criteria as in the SG035-0003 study (12 studies; n = 562; p = 0.0001 vs. brentuximab vedotin). CONCLUSIONS: Indirect comparisons against a heterogeneous historical sample population naturally limit our ability to draw comparisons, yet the results from this quantitative meta-analysis suggest that the antitumor activity of brentuximab vedotin may exceed that of other therapies used to treat patients with relapsed/refractory Hodgkin lymphoma post-ASCT.

Brentuximab vedotin as consolidation therapy after autologous stem-cell transplantation in patients with Hodgkin's lymphoma at risk of relapse or progression (AETHERA): a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: High-dose therapy followed by autologous stem-cell transplantation is standard of care for patients with relapsed or primary refractory Hodgkin's lymphoma. Roughly 50% of patients might be cured after autologous stem-cell transplantation; however, most patients with unfavourable risk factors progress after transplantation. We aimed to assess whether brentuximab vedotin improves progression-free survival when given as early consolidation after autologous stem-cell transplantation. METHODS: We did this randomised, double-blind, placebo-controlled, phase 3 trial at 78 sites in North America and Europe. Patients with unfavourable-risk relapsed or primary refractory classic Hodgkin's lymphoma who had undergone autologous stem-cell transplantation were randomly assigned, by fixed-block randomisation with a computer-generated random number sequence, to receive 16 cycles of 1·8 mg/kg brentuximab vedotin or placebo intravenously every 3 weeks, starting 30-45 days after transplantation. Randomisation was stratified by best clinical response after completion of salvage chemotherapy (complete response vs partial response vs stable disease) and primary refractory Hodgkin's lymphoma versus relapsed disease less than 12 months after completion of frontline therapy versus relapse 12 months or more after treatment completion. Patients and study investigators were masked to treatment assignment. The primary endpoint was progression-free survival by independent review, defined as the time from randomisation to the first documentation of tumour progression or death. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01100502. FINDINGS: Between April 6, 2010, and Sept 21, 2012, we randomly assigned 329 patients to the brentuximab vedotin group (n=165) or the placebo group (n=164). Progression-free survival by independent review was significantly improved in patients in the brentuximab vedotin group compared with those in the placebo group (hazard ratio [HR] 0·57, 95% CI 0·40-0·81; p=0·0013). Median progression-free survival by independent review was 42·9 months (95% CI 30·4-42·9) for patients in the brentuximab vedotin group compared with 24·1 months (11·5-not estimable) for those in the placebo group. We recorded consistent benefit (HR <1) of brentuximab vedotin consolidation across subgroups. The most frequent adverse events in the brentuximab vedotin group were peripheral sensory neuropathy (94 [56%] of 167 patients vs 25 [16%] of 160 patients in the placebo group) and neutropenia (58 [35%] vs 19 [12%] patients). At time of analysis, 28 (17%) of 167 patients had died in the brentuximab vedotin group compared with 25 (16%) of 160 patients in the placebo group. INTERPRETATION: Early consolidation with brentuximab vedotin after autologous stem-cell transplantation improved progression-free survival in patients with Hodgkin's lymphoma with risk factors for relapse or progression after transplantation. This treatment provides an important therapeutic option for patients undergoing autologous stem-cell transplantation. FUNDING: Seattle Genetics and Takeda Pharmaceuticals International.

Surgical reconstruction of severe forefoot derangement in a patient with traumatically acquired contralateral limb-length discrepancy: a case report.

Limb-length discrepancy is a very common condition. A severe debilitating forefoot deformity resulting from a post-traumatic limb length discrepancy is quite rare. This case study discusses the surgical reconstruction of a forefoot deformity of a 64-year-old male following a post-traumatic limb-length discrepancy from a motor vehicle accident that caused compensatory biomechanical changes in the unaffected lower extremity. These changes resulted in a severe hallux abducto valgus deformity with subluxated metatarsophalangeal joints of the second and third digits, leaving the patient with a severe symptomatic forefoot deformity that closely mimics the radiographic appearance of a rheumatoid forefoot. The forefoot deformity was corrected using the Mckeever and Hoffman procedures with Kirschner-wire fixation. Seven months following the corrective procedures, the patient was able to obtain an asymptomatic plantigrade foot and can now wear regular footwear.