Eli Lilly is reportedly planning significant changes to its US salesforce - including a large chunk of job cuts across the country - by the summer.

The Indianapolis-based drugmaker is keeping specific details under wraps, but did say that the number up for cull won't overshoot 1,000, according to the Associated Press.

A spokesperson for the company also told the AP that its Bio-Medicines salesforce will be reduced to better fit with "business realities" and customer needs.

On the other hand, its diabetes team will be expanded to pave the way for market entry and uptake of two new therapies currently in late-stage development. 

The cuts will reportedly be made by July 1, in order to place the company in better stead for coping with the looming loss of US patent protection for another two of its big sellers - the antidepressant Cymbalta (duloxetine) and the osteoporosis drug Evista (raloxifene).

This follows the loss of US protection for the antipsychotic Zyprexa (olanzapine) in 2011, slashing sales by more than 80% last year.