Too little is known by this time about possible side-effects of the drug.

Too little is known by this time about possible side-effects of the drug.

1. presently
2. in the end
3. before hand
4. No improvement

Explanation:

. (a) presently (Adv.) : now ; currently; at the time you are speaking
by this time : a particular allotted time
Here, presently is the right usage.