Sample sizes per arm for a placebo-controlled trial using in vivo lesion magnetisation transfer ratio (MTR) recovery as a primary surrogate outcome marker of remyelination (80% power)
| Mean lesion MTR | Individual lesion MTR | |||||
|---|---|---|---|---|---|---|
| Gd lesions | ΔMTR lesions | |||||
| Effect size (%) | T2w lesions | Gd lesions | MTRRecovered | MTRDrop | MTRRecovered | MTRDrop |
| 30 | 38 | 68 | 22 | 12 | 19 | 21 |
| 40 | 21 | 38 | – | – | – | – |
| 50 | 14 | 24 | 10 | 6 | 8 | 8 |
| 60 | 10 | 18 | – | – | – | – |
| 70 | – | 14 | 6 | 6 | 5 | 5 |
Gd lesions, gadolinium-enhancing lesions.