To Evaluate Stem Cell Therapies, Think Unilaterally?

Testing stem cell therapies unilaterally? A side-by-side comparison of strength of key muscles may enable scientists to evaluate stem cell therapies for the disease. The approach aims to control for the variability of the disease “internally”, without historical cohorts and/or the use of a placebo (see Donofrio and Bedlack, 2011; Glass et al., 2016).The biceps and triceps appear to be most reliable muscles to monitor progression in people with ALS according to this analysis (Rushton et al., 2017). [Neural progenitor cells. Courtesy of Nature Cell Biology. Reproduced with permission.]

Motor neurons degenerate in ALS. Why these cells are destroyed remains unclear. Therefore, how to slow or stop this destruction of motor neurons in ALS remains an open question.

In the meantime, a growing number of scientists are turning to stem cells in hopes to promote motor neuron survival in people with ALS and/or reduce their toxicity (see December 2015 conference news). But how to evaluate these strategies in the clinic remains hotly debated.

Now, a research team at Cedar Sinai Medical Center in Los Angeles, California reports that an emerging outcome measure, which involves monitoring muscle strength, may facilitate the evaluation of stem cell therapies for the disease (Rushton et al., 2017). The study, led by Clive Svendsen, found that functional decline of key muscles on the left and right side of people with ALS progressed at a similar rate. The results suggest that at least some stem cell therapies could be evaluated unilaterally by comparing the strength of muscles on the treated and untreated side for each of these muscle groups.

This side-by-side comparison, according to a subsequent power analysis, may enable clinicians to evaluate stem cell therapies for ALS in a smaller sample size without the need for sham surgeries and/or placebo injections.

This unilateral approach is emerging as an alternative to evaluate a growing number of potential neuroprotective strategies for neurodegenerative diseases including ALS (see NCT02943850, NCT02478450; Glass et al., 2016).

The study is published on June 9 in Neurology.

The retrospective analysis, performed in collaboration with Cedar Sinai’s Robert Baloh, studied the rates of decline of 6 upper and lower muscle groups in nearly 750 people with ALS determined by fixed dynamometry. These longitudinal datasets, previously collected by physical therapist Pat Andres and colleagues, now at Massachusetts General Hospital, capture the decline in strength of key muscles in people with ALS during at least a 16-month period measured by either the TUFTS Quantitative Neuromuscular Exam (TQNE) or more recently, the Accurate Test of Limb Isometric Strength (ATLIS) system (Andres et al., 1986; Shields et al., 1998; Andres et al., 2012.

Analyzing therapies by hand. Meanwhile, Biogen scientists in Cambridge, Massachusetts are turning to hand-held dynamometry to evaluate potential therapies for ALS. The emerging strength-based measure highly correlates with the progressive loss of motor function (ALS-FRS-R) and breathing capacity (FVC) according to a retrospective analysis of 924 people with ALS presented at the 2017 meeting of the American Academy of Neurology (see May 2017 news). And, according to a subsequent side-by-side comparison, these muscles decline at similar rates. [Image: Douma et al., 2014 under CC BY 2.0 license.]

The study builds on previous work, led by Barrow Institute’s Jeremy Shefner in Phoenix, Arizona and Biogen’s Toby Ferguson in Cambridge, Massachusetts, which found that monitoring the strength of key muscles using hand-held dynamometry is a reliable and reproducible approach to measure progression of ALS in a clinical setting and thereby, may facilitate the evaluation of potential therapies (see May 2017 conference news; Shefner et al., 2014).

Now, Svendsen’s team is gearing up to evaluate their potential stem cell therapy for ALS. The strategy uses genetically engineered neural progenitor cells (NPCs) to deliver GDNF into the CNS in hopes to protect motor neurons in people with the disease (see April 2017 news; Gowing et al., 2014). The approach is at the phase 1 stage. Stay tuned.

Featured Paper

Rushton DJ, Andres PL, Allred P, Baloh RH, Svendsen CN. Patients with ALS show highly correlated progression rates in left and right limb muscles. Neurology. 2017 Jun 9. [PubMed].

References

Shefner JM, Liu D, Leitner ML, Schoenfeld D, Johns DR, Ferguson T, Cudkowicz M. Quantitative strength testing in ALS clinical trials. Neurology. 2016 Aug 9;87(6):617-24. [PubMed].

Andres PL, Skerry LM, Munsat TL, Thornell BJ, Szymonifka J, Schoenfeld DA, Cudkowicz ME. Validation of a new strength measurement device for amyotrophic lateral sclerosis clinical trials. Muscle Nerve. 2012 Jan;45(1):81-5. [PubMed].

Andres PL, Hedlund W, Finison L, Conlon T, Felmus M, Munsat TL.Quantitative motor assessment in amyotrophic lateral sclerosis. Neurology. 1986 Jul;36(7):937-41.[PubMed].

Glass JD, Hertzberg VS, Boulis NM, Riley J, Federici T, Polak M, Bordeau J, Fournier C, Johe K, Hazel T, Cudkowicz M, Atassi N, Borges LF, Rutkove SB, Duell J, Patil PG, Goutman SA, Feldman EL. Transplantation of spinal cord-derived neural stem cells for ALS: Analysis of phase 1 and 2 trials. Neurology. 2016 Jul 26;87(4):392-400. [PubMed].

Gowing G, Shelley B, Staggenborg K, Hurley A, Avalos P, Victoroff J, Latter J, Garcia L, Svendsen CN. Glial cell line-derived neurotrophic factor-secreting human neural progenitors show long-term survival, maturation into astrocytes, and no tumor formation following transplantation into the spinal cord of immunocompromised rats. Neuroreport. 2014 Apr 16;25(6):367-72. [PubMed].

Further Reading

Atassi N, Beghi E, Blanquer M, Boulis NM, Cantello R, Caponnetto C, Chiò A, Dunnett SB, Feldman EL, Vescovi A1, Mazzini L; attendees of the International Workshop on Progress in Stem Cells Research for ALS/MND. Intraspinal stem cell transplantation for amyotrophic lateral sclerosis: Ready for efficacy clinical trials? Cytotherapy. 2016 Dec;18(12):1471-1475.  [PubMed].

Donofrio PD, Bedlack R. Historical controls in ALS trials: a high seas rescue? Neurology. 2011 Sep 6;77(10):936-7. [PubMed].

clinical trial clinical trial design disease-als gdnf neuralstem neuroprotection stem cell topic-clinical topic-randd
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