The future of ALS diagnosis and staging: where do we go from here?

Diagnostic criteria for amyotrophic lateral sclerosis

PURPOSE OF REVIEW

The present review will discuss the evolution of diagnostic criteria for amyotrophic lateral sclerosis (ALS) and biomarker considerations.

RECENT FINDINGS

To address the limitations of existing ALS diagnostic criteria, a consortium of key stakeholders developed the Gold Coast consensus criteria (GCC). The GCC has similar or greater sensitivity compared with the revised El Escorial (rEEC) and Awaji criteria (AC), particularly for atypical phenotypes, maintained across disease duration, severity, and site of onset. In addition to improving diagnostic sensitivity, using the GCC in clinical trials may promote an increased enrolment of up to 50% of ALS patients who do not currently meet the full diagnostic eligibility requirements of the rEEC. Future inclusion of genetic biomarkers may mitigate some limitations of the GCC, to further improve diagnostic utility. In advance of such a process, validation of these biomarkers will be required before inclusion as additional criteria.

SUMMARY

The GCC are simpler to use than previous consensus criteria, with demonstrated greater sensitivity and, enabling an earlier and more definitive ALS diagnosis, thereby facilitating wider enrolment into clinical trials. Broader implementation of the GCC in clinical trial settings is currently underway, globally.

Neural Differentiation and spinal cord organoid generation from induced pluripotent stem cells (iPSCs) for ALS modelling and inflammatory screening

C9orf72 genetic mutation is the most common genetic cause of ALS/FTD accompanied by abnormal protein insufficiency. Induced pluripotent stem cell (iPSC)-derived two-dimensional (2D) and three-dimensional (3D) cultures are providing new approaches. Therefore, this study established neuronal cell types and generated spinal cord organoids (SCOs) derived from C9orf72 knockdown human iPSCs to model ALS disease and screen the unrevealed phenotype. Wild-type (WT) iPSC lines from three healthy donor fibroblasts were established, and pluripotency and differentiation ability were identified by RT-PCR, immunofluorescence and flow cytometry. After infection by the lentivirus with C9orf72-targeting shRNA, stable C9-knockdown iPSC colonies were selected and differentiated into astrocytes, motor neurons and SCOs. Finally, we analyzed the extracted RNA-seq data of human C9 mutant/knockout iPSC-derived motor neurons and astrocytes from the GEO database and the inflammatory regulation-related genes in function and pathways. The expression of inflammatory factors was measured by qRT-PCR. The results showed that both WT-iPSCs and edited C9-iPSCs maintained a similar ability to differentiate into the three germ layers, astrocytes and motor neurons, forming SCOs in a 3D culture system. The constructed C9-SCOs have features of spinal cord development and multiple neuronal cell types, including sensory neurons, motor neurons, and other neurons. Based on the bioinformatics analysis, proinflammatory factors were confirmed to be upregulated in C9-iPSC-derived 2D cells and 3D cultured SCOs. The above differentiated models exhibited low C9orf72 expression and the pathological characteristics of ALS, especially neuroinflammation.

The ALSFRS-R Summit: a global call to action on the use of the ALSFRS-R in ALS clinical trials

The Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) was developed more than 25 years ago as an instrument to monitor functional change over time in patients with ALS. It has since been revised and extended to meet the needs of high data quality in ALS trials (ALSFRS-R), however a full re-validation of the scale was not completed. Despite this, the scale has remained a primary outcome measure in clinical trials. We convened a group of clinical trialists to discuss and explore opportunities to improve the scale and propose alternative measures. In this meeting report, we present a call to action on the use of the ALSFRS-Revised scale in clinical trials, focusing on the need for (1) harmonization of the ALSFRS-R administration globally, (2) alignment on a set of recommendations for clinical trial design and statistical analysis plans (SAPs), and (3) use of additional outcome measures.

Feasibility assessment of using the MiToS staging system for conducting economic evaluation in amyotrophic lateral sclerosis

OBJECTIVES

This study assessed the feasibility of using the Milano-Torino staging (MiToS) system for conducting economic evaluation to measure health outcomes in amyotrophic lateral sclerosis (ALS).

METHODS

A Markov model was developed using the MiToS system and evaluated with a hypothetical treatment versus standard of care. Health utilities and transition probabilities were derived from the literature. Four-time horizons (1, 5, 10, and 20 years) were examined. Treatment effects of 20-35% relative risk reduction (RRR) of progressing to the next MiToS stage were assessed. Three patient distribution scenarios were tested: (1) all patients began in stage 0; (2) patient distribution based on real-world TONiC study; (3) distribution based on the PRO-ACT database. Health outcomes (quality-adjusted life-years [QALYs], life-years [LYs]) were reported with a 3% discount rate.

RESULTS

A time horizon of 10 years fully captured treatment benefits: incremental QALYs were 0.28-0.60, 0.21-0.45, and 0.26-0.55 for scenarios 1-3, respectively; incremental LYs were 0.56-1.17, 0.46-0.97, and 0.53-1.11, respectively.

CONCLUSION

MiToS-based staging can be used for conducting economic analyses in ALS. Estimated incremental QALY and LY gains were meaningful within the context of ALS, for hypothetical treatments with RRR of 20-35%.

Misdiagnosis of amyotrophic lateral sclerosis in clinical practice in Europe and the USA: a patient chart review and physician survey

OBJECTIVE

Delays in amyotrophic lateral sclerosis (ALS) diagnosis can result in compromised disease management and unnecessary costs. We examined the extent of ALS misdiagnosis in the US and Europe.

METHODS

Data were collected via the Adelphi ALS Disease Specific Programme™, a cross-sectional survey of physicians and a medical chart review of their consulting patients with ALS in France, Germany, Italy, Spain, the UK (EU5), and the US. Between July 2020 and March 2021, eligible physicians (primary speciality neurology, active involvement in managing patients with ALS) abstracted data from patients (≥18 years old) with confirmed ALS.

RESULTS

Overall, 138 physicians completed the survey (EU5 107, US 31), with data reviewed from 795 patient medical charts (EU5 568, US 227); 278 (35.0%) patients (EU5 183 [32.2%], US 95 [41.9%]) had received ≥1 initial misdiagnosis based on symptoms later attributed to ALS. Mean (SD) time from symptom onset to first healthcare professional consultation was 3.8 (5.2) months (EU5 4.3 [4.8] months, US 2.6 [5.8] months). Mean (SD) time from symptom onset to ALS diagnosis was 8.2 (12.5) months (EU5 9.6 [14.0] months, US 5.0 [6.8] months) and increased to 10.4 (17.9) for patients with a misdiagnosis (compared with 6.9 [7.2] for patients with no misdiagnosis). Physician-identified barriers to timely ALS diagnosis included the similarity of symptoms to other conditions and delayed referral to neurologists.

CONCLUSIONS

Misdiagnosis of ALS is frequent, with a protracted diagnostic pathway. Targeted education of patients and physicians about signs and symptoms and benefits of prompt referral to multidisciplinary care are needed.

Urinary biomarkers for amyotrophic lateral sclerosis: candidates, opportunities and considerations

Amyotrophic lateral sclerosis is a relentless neurodegenerative disease that is mostly fatal within 3-5 years and is diagnosed on evidence of progressive upper and lower motor neuron degeneration. Around 15% of those with amyotrophic lateral sclerosis also have frontotemporal degeneration, and gene mutations account for ∼10%. Amyotrophic lateral sclerosis is a variable heterogeneous disease, and it is becoming increasingly clear that numerous different disease processes culminate in the final degeneration of motor neurons. There is a profound need to clearly articulate and measure pathological process that occurs. Such information is needed to tailor treatments to individuals with amyotrophic lateral sclerosis according to an individual's pathological fingerprint. For new candidate therapies, there is also a need for methods to select patients according to expected treatment outcomes and measure the success, or not, of treatments. Biomarkers are essential tools to fulfil these needs, and urine is a rich source for candidate biofluid biomarkers. This review will describe promising candidate urinary biomarkers of amyotrophic lateral sclerosis and other possible urinary candidates in future areas of investigation as well as the limitations of urinary biomarkers.

Creatine Kinase MB Isoenzyme Is a Complementary Biomarker in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is an invariably fatal neurodegenerative disease with limited therapeutic options. There is an urgent need for novel biomarkers to be used as surrogates for new therapeutic trials and disease monitoring. In this study, we sought to systematically study creatine kinase isoenzyme MB (CK-MB) in a real-world cohort of ALS patients, assess the diagnostic performance, and evaluate its association with other laboratory and clinical parameters. We reviewed data from 194 consecutive patients that included 130 ALS patients and 64 disease control patients (primary lateral sclerosis [PLS], benign fasciculations syndrome [BFS], Huntington's disease [HD] and Alzheimer's disease [AD]). CK-MB was elevated in the sera of more than half of all patients with ALS. In patients with spinal-onset ALS, CK-MB levels were significantly higher than in patients with other neurodegenerative diseases. Patients with slower rates of functional decline had a significantly higher baseline CK-MB. Furthermore, CK-MB elevations correlated with cardiac troponin T (cTnT) and with revised ALS Functional Rating Scale (ALSFRS-R) bulbar subcategory. We posit that measuring CK-MB in ALS patients in a complimentary fashion could potentially aid in the diagnostic workup of ALS and help discriminate the disease from some ALS mimics and other neurodegenerative diseases. CK-MB levels also may provide valuable prognostic information regarding disease aggressiveness as well as correlations with specific phenotypic presentations.