const arr = str.split(/(?<=[A-Z]), /);
// или
const arr = str.match(/[^,\s][^,]*, [^,]+/g) ?? [];
// или
const arr = str
.split(', ')
.reduce((acc, n, i) => (
(i & 1) || acc.push([]),
acc[acc.length - 1].push(n),
acc
), [])
.map(n => n.join(', '));