A stable pharmaceutical formulation comprising a protein of interest, sorbitol and polyethylene glycol (PEG). The sorbitol and protein is present in a molar ratio of 550 to 700 mole of sorbitol:1 mole of protein and the PEG to protein is present in the molar ratio of 2-50:1. The formulation optionally comprising buffer. The formulation in lyophilised form is stable for at least 4 years at 2-8° C. Also provided is a process for preparing the composition and a pharmaceutical kit comprising the same.