(Reuters) – Nektar Therapeutics (NASDAQ:) Monday’s announcement by the company that it will lay off approximately 70% or 500 workers after having stopped the development of its main cancer drug in early March was made.

After the treatment failed to achieve its main objective in multiple studies, the company ended all clinical trials for bempegaldesleukin.

According to Nektar, the layoffs will result in an estimated charge between $150 million-$160 million. Most of this would be recorded during the second quarter. Nektar also announced that the chief medical officer, chief commissary officer, and chief financial officer would be retiring.

Extended trading saw a 3% drop in shares of the company.

Nektar claimed that restructuring would allow it to have sufficient capital to invest in drugs it considers to be the most “impactful” for its future.

These include NKTR-358 (an experimental treatment of autoimmune and inflammatory disorders that was developed with Eli Lilly, NYSE:) and NKTR-257, which are being evaluated in clinical trials for patients with head, neck, or colorectal cancer.

It expects that the company will end 2011 with approximately $440 to $450 millions in cash, investments, and no debt.