I am going to KTM in late April and ended up going to DOH with CO/UA/LH and then Qatar Airlines DOH-KTM in deeply discounted business class.
On the way to DOH is IAH-EWR-FRA-DOH, the last leg in LH.
On the way back, DOH-IAD-IAH all UA/CO. The flight from DOH to IAD stops in Dubai for about an hour.
Hope this helps,
TMT