Serum Cardiac Troponin T Levels as a Therapy Response Marker in Tofersen-Treated ALS.

Introduction/aims: Cardiac troponin T (cTnT) levels are elevated in the majority of persons with amyotrophic lateral sclerosis (ALS) and increase over time. Neurofilament light chain (NfL) is an established therapy response biomarker in ALS as superoxide dismutase1 (SOD1)-ALS patients treated with the antisense oligonucleotide tofersen show a decrease in NfL. In this study, we assess cTnT levels in SOD1-ALS at baseline and during tofersen treatment.

Methods: cTnT was analyzed at baseline and during tofersen treatment in 23 SOD1-ALS patients at two specialized ALS centers in Germany and compared to a control cohort of 74 ALS patients without SOD1 variants.

Results: cTnT levels increased in the control ALS cohort over time (p < 0.0001) but not in the tofersen group (p = 0.36). Creatine kinase (CK) and CK-MB levels did not show significant changes over time. The median monthly increase of cTnT was 0.045 points (IQR 0.02-0.08) in the control ALS cohort and 0.01 points (IQR -0.01-0.03) in the tofersen group (p = 0.0013). A significantly lower fold change in cTnT levels was observed in the tofersen-treated cohort (median 1.2; IQR 0.77-1.59) relative to the control group (median 1.89; IQR 1.35-2.75) (p = 0.0003). Nine (39%) patients treated with tofersen experienced a reduction in cTnT levels.

Discussion: In this study, we describe a response signal of cTnT to tofersen treatment, which supports the value of cTnT as an independent biomarker in ALS. These results contribute to the notion that cTnT may provide additional value as a progression and treatment response biomarker in ALS complementary to NfL and warrant further investigation.