Lessons Learned From Translational Research in Neuromuscular Diseases: Impact on Study Design, Outcome Measures and Managing Expectation

Spinal Muscular Atrophy (SMA) and Duchenne Muscular Dystrophy (DMD), two of the most common, child onset, rare neuromuscular disorders, present a case study for the translation of preclinical research into clinical work. Over the past decade, well-designed clinical trials and innovative methods have led to the approval of several novel therapies for SMA and DMD, with many more in the pipeline. This review discusses several features that must be considered during trial design for neuromuscular diseases, as well as other rare diseases, to maximise the possibility of trial success using historic examples. These features include well-defined inclusion criteria, matching criteria, alternatives to placebo-controlled trials and the selection of trial endpoints. These features will be particularly important in the coming years as the investigation into innovative therapy approaches for neuromuscular diseases continues.

Translation of Pharmacodynamic Biomarkers of Antibiotic Efficacy in Specific Populations to Optimize Doses

Antibiotic efficacy determination in clinical trials often relies on non-inferiority designs because they afford smaller study sample sizes. These efficacy studies tend to exclude patients within specific populations or include too few patients to discern potential differences in their clinical outcomes. As a result, dosing guidance in patients with abnormal liver and kidney function, age across the lifespan, and other specific populations relies on drug exposure-matching. The underlying assumption for exposure-matching is that the disease course and the response to the antibiotic are similar in patients with and without the specific condition. While this may not be the case, clinical efficacy studies are underpowered to ensure this is true. The current paper provides an integrative review of the current approach to dose selection in specific populations. We review existing clinical trial endpoints that could be measured on a more continuous rather than a discrete scale to better inform exposure–response relationships. The inclusion of newer systemic biomarkers of efficacy can help overcome the current limitations. We use a modeling and simulation exercise to illustrate how an efficacy biomarker can inform dose selection better. Studies that inform response-matching rather than exposure-matching only are needed to improve dose selection in specific populations.

RAMucirumab in combination with TAS102 versus TAS102 monotherapy in metastatic colorectal cancer: Safety results from the phase IIb part of the RAMTAS phase II/III trial of the German AIO (AIO-KRK-0316).

3566 Background: Patients (pts) with mCRC progressing on standard chemotherapy have limited therapeutic options. Trifluridine/tipiracil (TAS102) significantly improved survival in patients with refractory mCRC. Ramucirumab (ram) is approved in combination with FOLFIRI for second-line treatment. There is a strong rationale to evaluate the efficacy and safety of ram in combination with TAS102 in pts with refractory mCRC. Methods: This is a randomized, open-label, multicenter, starting as phase IIb and extended to a phase III study in pts with advanced mCRC. Eligible pts were randomized to receive either ram (8 mg/kg on d1+15, q4w) and TAS102 (35 mg/m² on d1-5 and d8-12, q4w, arm A) or TAS102 alone (arm B). The primary endpoint is overall survival. A total of 145 pts were enrolled into phase IIb. Here, we present the data from an interim safety analysis comprising the first 80 treated pts. The trial was extended to phase III including a total of 426 pts. Enrolment of additional 281 pts started in Dec 2020. The trial endpoints remained unchanged. Results: Pts (40 arm A, 40 arm B) received a median of 2.5 treatment cycles in arm A and 2 cycles in arm B; 31 pts in treatment arm A and 32 pts in arm B discontinued participation prematurely, mainly due to cancer progression. Most patients developed adverse events (AEs): grade 3 AEs were observed in 28 pts (70%) in arm A (24 treatment-related) and 27 pts (67%, 17 treatment-related) in arm B. More grade 4 AEs were seen in arm A (13 pts, 32.5%) than in arm B (5 pts, 12.5%). In total, 46 Serious AEs (SAEs) occurred, 27 in arm A (10 treatment-related) and 19 in Arm B (2 treatment-related). Five SAEs (3 in arm A, 2 in arm B) had a fatal outcome (one in arm A treatment-related). Within the analyzed population, no SUSAR occurred. Conclusions: This safety analysis demonstrates a minor increase in AEs in the experimental arm but no unexpected events. There were no excessive toxicity or unacceptable risks. In summary, a favorable risk-benefit-profile was confirmed. Based on these safety results and the ongoing need for efficient treatment in the tested population, the trial was extended to phase III. Clinical trial information: NCT03520946.

Looking Ahead: Visual and Anatomical Endpoints in Future Trials of Diabetic Macular Ischemia

Diabetic macular ischemia (DMI) is a common complication of diabetic retinopathy that can lead to progressive and irreversible visual loss. Despite substantial clinical burden, there are no treatments for DMI, no validated clinical trial endpoints, and few clinical trials focusing on DMI. Therefore, generating consensus on validated endpoints that can be used in DMI for the development of effective interventions is vital. In this review, we discuss potential endpoints appropriate for use in clinical trials of DMI, and consider the data required to establish acceptable and meaningful endpoints. A combination of anatomical, functional, and patient-reported outcome measures will provide the most complete picture of changes that occur during the progression of DMI. Potential endpoint measures include change in size of the foveal avascular zone measured by optical coherence tomography angiography and change over time in best-corrected visual acuity. However, these endpoints must be supported by further research. We also recommend studies to investigate the natural history and progression of DMI. In addition to improving understanding of how patient demographics and comorbidities such as diabetic macular edema affect clinical trial endpoints, these studies would help to build the consensus definition of DMI that is currently missing from clinical practice and research.

Disease monitoring with quantitative serum IgA levels provides a more reliable response assessment in multiple myeloma patients

Unlike IgG monoclonal proteins (MCPs), IgA MCP quantification is unreliable due to beta-migration of IgA MCPs on serum protein electrophoresis (SPEP). The utility of nephelometric quantitative IgA (qIgA) to monitor IgA multiple myeloma (MM) is unclear. We retrospectively studied disease response kinetics using qIgA versus MCPs by SPEP, and developed and validated novel qIgA disease assessment criteria in 491 IgA MM patients. The SPEP MCP nadir occurred a median of 41 (IQR 0–102) days before the qIgA. The median time to achieve a partial response (PR) was shorter using standard IMWG versus qIgA response criteria (32 vs 58 days, p < 0.001). Stratification by qIgA criteria, unlike IMWG criteria, led to clear separation of the progression-free survival curves of patients achieving a PR or very good PR. There was a consistent trend toward earlier detection of disease progression using qIgA versus IMWG progression criteria. In conclusion, monitoring IgA MM using MCP-based IMWG criteria may be falsely reassuring, given that MCP levels on SPEP decrease faster than qIgA levels. The qIgA response criteria more accurately stratify patients based on the progression risk and may detect disease progression earlier, which may lead to more consistent measurement of trial endpoints and improved patient outcomes.

Clinical Perspectives and Trends: Microperimetry as a trial endpoint in retinal disease

Endpoint development trials are underway across the spectrum of retinal disease. New validated endpoints are urgently required for the assessment of emerging gene therapies and in preparation for the arrival of novel therapeutics targeting early stages of common sight-threatening conditions such as age-related macular degeneration. Visual function measures are likely to be key candidates in this search. Over the last two decades, microperimetry has been used extensively to characterize functional vision in a wide range of retinal conditions, detecting subtle defects in retinal sensitivity that precede visual acuity loss and tracking disease progression over relatively short periods. Given these appealing features, microperimetry has already been adopted as an endpoint in interventional studies, including multicenter trials, on a modest scale. A review of its use to date shows a concurrent lack of consensus in test strategy and a wealth of innovative disease and treatment-specific metrics which may show promise as clinical trial endpoints. There are practical issues to consider, but these have not held back its popularity and it remains a widely used psychophysical test in research. Endpoint development trials will undoubtedly be key in understanding the validity of microperimetry as a clinical trial endpoint, but existing signs are promising.