Depending on your level of fitness nothing is unattainable and camping groups have done it several times setting up an advance camp before the Larke pass yet we don't recommend doing the trek the other way around. If you are doing a tea house trek then from Bhimthang (the base camp before pass) to Larke La you are ascending 1400 m / 4,593 feet in one go which obviously means you are undertaking great physical risk. A very well acclimatization approach for trekking in the Manaslu region is anti-clockwise.