Biomarkers of disease progression in adolescents and adults with 5q spinal muscular atrophy: a systematic review and meta-analysis

Analysis of the efficacy and adverse effects of nusinersen in the treatment of children with spinal muscular atrophy in China

OBJECTIVE

This study was based on a retrospective clinical observational cohort study of a two-center application of nusinersen in China to evaluate the clinical efficacy and adverse effects of nusinersen in the treatment of SMA (spinal muscular atrophy) Types 1-3.

METHODS

Clinical data from children with clinically and genetically confirmed 5qSMA from a double center in western China (the Second Affiliated Hospital of Xi'an Jiaotong University and the Second Hospital of West China of Sichuan University). All children were younger than 18 years of age. Patients were assessed for motor function and underwent blood and fluid tests before each nusinersen injection.

RESULTS

At 14-month follow-up, 100% of children had improved their HFMSE (Hammersmith Functional Motor Scale Expanded) score, 83.6% had improved their CHOP INTEND (Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders) score, and 66.6% had improved their RULM (Revised Upper Limb Module) score by ≥3 points from baseline, and their 6MWT (6-min walk test) was 216.00 ± 52.08 m longer than at baseline. The age of the child at the start of treatment was negatively correlated with the clinical efficacy of nusinersen; the younger the child, the better the response to treatment. No significant adverse effects affecting the treatment and quality of life of the child were observed during the treatment of SMA with nusinersen.

CONCLUSION

This study concluded that nusinersen is clinically beneficial for children with SMA in western China, with mild adverse effects.

Therapeutic Biomarkers in Friedreich's Ataxia: a Systematic Review and Meta-analysis

Although a large array of biomarkers have been investigated in Friedreich's ataxia (FRDA) trials, the optimal biomarker for assessing disease progression or therapeutic benefit has yet to be identified. We searched PubMed, MEDLINE, and EMBASE databases up to June 2023 for any original study (with ≥ 5 participants and ≥ 2 months' follow-up) reporting the effect of therapeutic interventions on any clinical, cardiac, biochemical, patient-reported outcome measures, imaging, or neurophysiologic biomarker. We also explored the biomarkers' ability to detect subtle disease progression in untreated patients. The pooled standardized mean difference (SMD) was calculated using a random-effects model. The study's protocol was registered in PROSPERO (CRD42022319196). In total, 43 studies with 1409 FRDA patients were included in the qualitative synthesis. A statistically significant improvement was observed in Friedreich Ataxia Rating Scale scores [combining Friedreich Ataxia Rating Scale (FARS) and modified FARS (mFARS): SMD =  - 0.32 (- 0.62 to - 0.02)] following drugs that augment mitochondrial function in a sensitivity analysis. Left ventricular mass index (LVMI) was improved significantly [SMD =  - 0.34 (- 0.5 to - 0.18)] after 28.5 months of treatment with drugs that augment mitochondrial function. However, LVMI remained stable [SMD = 0.05 (- 0.3 to 0.41)] in untreated patients after 6-month follow-up. None of the remaining biomarkers changed significantly following any treatment intervention nor during the natural disease progression. Nevertheless, clinical implications of these results should be interpreted with caution because of low to very low quality of evidence. Further randomized controlled trials of at least 24 months' duration using a biomarker toolbox rather than a single biomarker are warranted.

Neurophysiological Characteristics in Type II and Type III 5q Spinal Muscular Atrophy Patients: Impact of Nusinersen Treatment

Objective

This study aimed to observe the neurophysiological characteristics of type II and type III 5q spinal muscular atrophy (SMA) patients and the changes in peripheral motor nerve electrophysiology after Nusinersen treatment, as well as the influencing factors.

Methods

This single-center retrospective case-control study collected clinical data and peripheral motor nerve CMAP parameters from 42 5qSMA patients and 42 healthy controls at the Second Affiliated Hospital of Xi'an Jiaotong University (January 2021 to December 2022). It evaluated changes in motor function and CMAP amplitude before and after Nusinersen treatment.

Results

Our investigation encompassed all symptomatic and genetically confirmed SMA patients, consisting of 32 type II and 10 type III cases, with a median age of 57 months (29.5 to 96 months). Comparative analysis with healthy controls revealed substantial reductions in CMAP amplitudes across various nerves in both type II and type III patients. Despite the administration of Nusinersen treatment for 6 or 14 months to the entire cohort, discernible alterations in motor nerve amplitudes were not observed, except for a significant improvement in younger patients (≤36 months) at the 14-month mark. Further scrutiny within the type II subgroup unveiled that individuals with a disease duration ≤12 months experienced a noteworthy upswing in femoral nerve amplitude, a statistically significant difference when compared to those with >12 months of disease duration.

Conclusion

Motor nerve amplitudes were significantly decreased in type II and type III 5q SMA patients compared to healthy controls. Nusinersen treatment showed better improvement in motor nerve amplitudes in younger age groups and those with shorter disease duration, indicating a treatment-time dependence.

Multidisciplinary team meetings in treatment of spinal muscular atrophy adult patients: a real-life observatory for innovative treatments

BACKGROUND

In 2017, a new treatment by nusinersen, an antisense oligonucleotide delivered by repeated intrathecal injections, became available for patients with spinal muscular atrophy (SMA), whereas clinical trials had mainly involved children. Since 2020, the oral, selective SMN2-splicing modifier risdiplam has been available with restrictions evolving with time. In this peculiar context of lack of data regarding adult patients, many questions were raised to define the indications of treatment and the appropriate follow-up in this population. To homogenize access to treatment in France, a national multidisciplinary team meeting dedicated to adult SMA patients, named SMA multidisciplinary team meeting, (SMDTs) was created in 2018. Our objective was to analyze the value of SMDTs in the decision-making process in SMA adult patients and to provide guidelines about treatment.

METHODS

From October 2020 to September 2021, data extracted from the SMDT reports were collected. The primary outcome was the percentage of cases in which recommendations on validating treatment plans were given. The secondary outcomes were type of treatment requested, description of expectations regarding treatment and description of recommendations or follow-up and discontinuation. Data were analyzed using descriptive statistics. Comparisons between the type of treatment requested were performed using Mann-Whitney test or the Student t test for quantitative data and the Fisher's exact test or the χ2 test for qualitative data.

RESULTS

Cases of 107 patients were discussed at the SMDTs with a mean age of 35.3 (16-62). Forty-seven were SMA type 2, and 57 SMA type 3. Twelve cases were presented twice. Out of 122 presentations to the SMDTs, most of requests related to the initiation of a treatment (nusinersen (n = 46), risdiplam (n = 54), treatment without mentioning preferred choice (n = 5)) or a switch of treatment (n = 12). Risdiplam requests concerned significantly older patients (p = 0.002), mostly SMA type 2 (p < 0.0001), with greater disease severity in terms of motor and respiratory function compared to requests for nusinersen. In the year prior to presentation to the SMDTs, most of the patients experienced worsening of motor weakness assessed by functional tests as MFM32 or other meaningful scales for the most severe patients. Only 12% of the patients discussed had a stable condition. Only 49/122 patients (40.1%) expressed clear expectations regarding treatment. The treatment requested was approved by the SMDTs in 72 patients (67.2%). The most common reasons to decline treatment were lack of objective data on the disease course prior discussion to the SMDTs or inappropriate patient's expectations. Treatment requests were more likely to be validated by the SMDTs if sufficient pre-therapeutic functional assessment had been performed to assess the natural history (55% vs. 32%) and if the patient had worsening rather than stable motor function (p = 0.029). In patients with approved treatment, a-priori criteria to define a further ineffectiveness of treatment (usually after 14 months of treatment) were proposed for 67/72 patients.

CONCLUSIONS

In the context of costly treatments with few controlled studies in adults with SMA, in whom assessment of efficacy can be complex, SMDTs are 'real-world observatories' of great interest to establish national recommendations about indications of treatment and follow-up.

[Experience with the use of risdiplam in a familial case of spinal muscular atrophy 5q in patients with a homozygous deletion of the SMN1 gene and the same copy number of the SMN2 gene]

Advances in the treatment of spinal muscular atrophy (SMA) have revolutionized the field. SMA is a rare autosomal recessive neurodegenerative motor neuron disease in which wide phenotypic variability has been described. The rate of increase in neurological deficit and the severity of the disease is mainly determined by the amount of functional SMN (Survival of Motor Neuron) protein. However, the clinical picture may differ significantly in patients carrying homozygous deletions of the SMN1 gene (Survival of Motor Neuron 1) and an identical number of copies of the SMN2 gene (Survival of Motor Neuron 2). A family clinical case of adult patients with spinal muscular atrophy 5q with a homozygous deletion of the SMN1 gene and the same number of copies of the SMN2 gene, having a different clinical picture of the disease, is presented, and the dynamics of the condition against the background of oral pathogenetic therapy is presented.

Biomarkers of therapeutic efficacy in adolescents and adults with 5q spinal muscular atrophy: a systematic review

BACKGROUND

The therapeutic landscape of spinal muscular atrophy (SMA) was dramatically transformed with the introduction of three disease-modifying therapies (DMTs). A systematic review was performed to assess available evidence regarding quantitative therapeutic biomarkers used in SMA patients older than 11 years under treatment with DMTs.

METHODS

Latest literature search in MEDLINE, EMBASE, Cochrane databases and gray literature resources was performed in June 2021. Studies reporting only motor function or muscle strength scales or pulmonary function tests were excluded. Primary outcome was the change from baseline score of any serum, cerebrospinal fluid (CSF) or neurophysiologic biomarker examined.

RESULTS

Database and gray literature search yielded a total of 8050 records. We identified 14 records published from 2019 until 2021 examining 18 putative serum, CSF or neurophysiologic biomarkers along with routine CSF parameters in 295 SMA nusinersen-treated type 2-4 patients older than 11 years of age. There is evidence based on real-world observational studies suggesting that serum creatinine, creatine kinase activity levels along with CSF Αβ42, glial fibrillary acidic protein concentration as well as ulnar compound motor action potential amplitude and single motor unit potential amplitude changes may depict therapeutic response in this population.

CONCLUSION

This systematic review explored for the first-time biomarkers used to monitor therapeutic efficacy in SMA adolescents and adults treated with DMTs. Research in this area is in its early stages, and our systematic review can facilitate selection of quantitative therapeutic biomarkers that may be used as surrogate measures of treatment efficacy in future trials.

PROTOCOL REGISTRATION

PROSPERO CRD42021245516.

Multi-omics profiling of CSF from spinal muscular atrophy type 3 patients after nusinersen treatment: a 2-year follow-up multicenter retrospective study

Spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by mutations in the SMN1 gene resulting in reduced levels of the SMN protein. Nusinersen, the first antisense oligonucleotide (ASO) approved for SMA treatment, binds to the SMN2 gene, paralogue to SMN1, and mediates the translation of a functional SMN protein. Here, we used longitudinal high-resolution mass spectrometry (MS) to assess both global proteome and metabolome in cerebrospinal fluid (CSF) from ten SMA type 3 patients, with the aim of identifying novel readouts of pharmacodynamic/response to treatment and predictive markers of treatment response. Patients had a median age of 33.5 [29.5; 38.25] years, and 80% of them were ambulant at time of the enrolment, with a median HFMSE score of 37.5 [25.75; 50.75]. Untargeted CSF proteome and metabolome were measured using high-resolution MS (nLC-HRMS) on CSF samples obtained before treatment (T0) and after 2 years of follow-up (T22). A total of 26 proteins were found to be differentially expressed between T0 and T22 upon VSN normalization and LIMMA differential analysis, accounting for paired replica. Notably, key markers of the insulin-growth factor signaling pathway were upregulated after treatment together with selective modulation of key transcription regulators. Using CombiROC multimarker signature analysis, we suggest that detecting a reduction of SEMA6A and an increase of COL1A2 and GRIA4 might reflect therapeutic efficacy of nusinersen. Longitudinal metabolome profiling, analyzed with paired t-Test, showed a significant shift for some aminoacid utilization induced by treatment, whereas other metabolites were largely unchanged. Together, these data suggest perturbation upon nusinersen treatment still sustained after 22 months of follow-up and confirm the utility of CSF multi-omic profiling as pharmacodynamic biomarker for SMA type 3. Nonetheless, validation studies are needed to confirm this evidence in a larger sample size and to further dissect combined markers of response to treatment.

Identification of Novel Biomarkers of Spinal Muscular Atrophy and Therapeutic Response by Proteomic and Metabolomic Profiling of Human Biological Fluid Samples

Spinal muscular atrophy (SMA) is a neuromuscular disease resulting from mutations or deletions in SMN1 that lead to progressive death of alpha motor neurons, ultimately leading to severe muscle weakness and atrophy, as well as premature death in the absence of treatment. Recent approval of SMN-increasing medications as SMA therapy has altered the natural course of the disease. Thus, accurate biomarkers are needed to predict SMA severity, prognosis, drug response, and overall treatment efficacy. This article reviews novel non-targeted omics strategies that could become useful clinical tools for patients with SMA. Proteomics and metabolomics can provide insights into molecular events underlying disease progression and treatment response. High-throughput omics data have shown that untreated SMA patients have different profiles than controls. In addition, patients who clinically improved after treatment have a different profile than those who did not. These results provide a glimpse on potential markers that could assist in identifying therapy responders, in tracing the course of the disease, and in predicting its outcome. These studies have been restricted by the limited number of patients, but the approaches are feasible and can unravel severity-specific neuro-proteomic and metabolic SMA signatures.

Prospective Analysis of Functional and Structural Changes in Patients with Spinal Muscular Atrophy-A Pilot Study

Spinal muscular atrophy (SMA) is a rare, autosomal recessive neuromuscular disease. Recent years have seen a significant development of therapeutic options for SMA patients. With the development of treatment methods, it has become necessary to adapt a physiotherapeutic approach to the evolving clinical picture of SMA patients. We presented an analysis of 40 SMA patients undergoing pharmacological treatment, examined twice in an average interval of 5 months. Twelve patients (non-sitters) were evaluated using CHOP-INTEND, while 28 (sitters) were tested using the Hammersmith scale. The research protocol consisted of measurements of upper and lower limb ranges of motion, and four tests for early detection of musculoskeletal changes. Both non-sitters and sitters patients showed motor improvement between the first and second examinations. Favorable changes in range of motion parameters were noted in most children, except for hip extension (HE) range, which deteriorated. An association was also observed between scale scores and the presence of contractures in the hip and knee joints depending on the group studied. Our findings showed that the presence of contractures at the hip and knee joint negatively affected functional improvement as measured by the scale scores.

Experimental and Clinical Biomarkers for Progressive Evaluation of Neuropathology and Therapeutic Interventions for Acute and Chronic Neurological Disorders

This article describes commonly used experimental and clinical biomarkers of neuronal injury and neurodegeneration for the evaluation of neuropathology and monitoring of therapeutic interventions. Biomarkers are vital for diagnostics of brain disease and therapeutic monitoring. A biomarker can be objectively measured and evaluated as a proxy indicator for the pathophysiological process or response to therapeutic interventions. There are complex hurdles in understanding the molecular pathophysiology of neurological disorders and the ability to diagnose them at initial stages. Novel biomarkers for neurological diseases may surpass these issues, especially for early identification of disease risk. Validated biomarkers can measure the severity and progression of both acute neuronal injury and chronic neurological diseases such as epilepsy, migraine, Alzheimer's disease, Parkinson's disease, Huntington's disease, traumatic brain injury, amyotrophic lateral sclerosis, multiple sclerosis, and other brain diseases. Biomarkers are deployed to study progression and response to treatment, including noninvasive imaging tools for both acute and chronic brain conditions. Neuronal biomarkers are classified into four core subtypes: blood-based, immunohistochemical-based, neuroimaging-based, and electrophysiological biomarkers. Neuronal conditions have progressive stages, such as acute injury, inflammation, neurodegeneration, and neurogenesis, which can serve as indices of pathological status. Biomarkers are critical for the targeted identification of specific molecules, cells, tissues, or proteins that dramatically alter throughout the progression of brain conditions. There has been tremendous progress with biomarkers in acute conditions and chronic diseases affecting the central nervous system.

Biochemical and clinical biomarkers in adult SMA 3-4 patients treated with nusinersen for 22 months

Objective

To investigate biomarkers of disease progression in cerebrospinal fluid (CSF) and serum in adult patients with spinal muscular atrophy (SMA). Furthermore, we assess the clinical response to nusinersen treatment in adults with SMA over a longer follow‐up period than the previously reported 6–14 months.

Methods

We included 16 adults with SMA type 3–4 for nusinersen treatment over 22 months in this prospective study. We evaluated chitotriosidase‐1 (CHIT1) and chitinase‐3‐like protein 1 (YKL‐40) as neuroinflammatory biomarkers in CSF, and neurofilament light chain (NfL) and heavy chain (pNfH) as neurodegenerative markers in CSF and serum at baseline, month 6, 14 and 22, together with a wide range of clinical outcome measures.

Results

Levels of CHIT1 increased significantly (p = 0.048) throughout the 22‐month treatment period and pNfH decreased significantly (p = 0.022) in CSF, but both did not correlate with clinical outcome measures. YKL‐40 correlated strongly with neurofilaments in CSF (rho = 0.76) and decreased significantly (p = 0.037) in patients with improvements in the revised upper limb module (RULM). Finally, patients showed significant improvements in hand grip strength, hand motor function, medical research council (MRC) sum score, and peak expiratory flow (PEF) after 22 months of treatment.

Interpretation

YKL‐40 in CSF correlated with clinical improvements during nusinersen treatment. In contrast, CHIT1 and pNfH in CSF changed significantly during treatment but did not correlate with clinical outcomes. Finally, we demonstrated a sustained clinical effect of nusinersen treatment in adults after 22 months.

Nusinersen in Adults with 5q Spinal Muscular Atrophy: a Systematic Review and Meta-analysis

Evidence for nusinersen administration in adult 5q spinal muscular atrophy (5q-SMA) patients is scarce and based on real-world observational data. The present systematic review and meta-analysis aimed to explore the efficacy and safety of nusinersen in patients older than 12 years of age with 5q-SMA. We searched MEDLINE, EMBASE, the Cochrane Library, and grey literature through April 2021. Cross-sectional studies, case reports, review articles, and studies with follow-up less than 6 months were excluded. We included 12 records (seven case-series, five cohorts) representing 11 population cohorts and enrolling 428 SMA patients. We observed statistically significant improvements on motor function Hammersmith Functional Motor Scale Expanded (HFMSE) and Revised Upper Limb Module (RULM) scores at the longest follow-up assessments [SMD = 0.17(95% CI 0.01-0.33), SMD = 0.22(95% CI 0.06-0.38), respectively]. HFMSE and RULM significant improvements were also detected at the subgroup analysis during 10 and 14 months. HFMSE and RULM amelioration occurred earlier in patients with SMA type 3 or 4 during short-term analysis (≤ 6 months). 6-min walk tests (6MWT) and pulmonary function tests did not change. Minimal clinically important differences in HFMSE and RULM were observed in 43.3% (95% CI 34.5-52.3) and 38.9% (95% CI 27.7-50.7), respectively. Severe adverse events were reported in 2% (95% CI 0-5.8). Treatment withdrawal rate was 3% (95% CI 0.5-6.6). Despite the low quality of evidence and the unmet need for randomized data to establish the safety and efficacy of nusinersen in adults, our meta-analysis confirms that nusinersen is a valuable treatment option for older patients with longer-disease duration.Trial registration: PROSPERO database CRD42020223109.