After turning down a $2.6 billion offer from long-time partner GlaxoSmithKline plc, Human Genome Sciences Inc. has three options: try to get more from GSK, look for a white knight, or essentially reinvent itself yet again in an attempt to remain independent.

Reinvention has allowed the biotech to survive as one of the last independent genomics pioneers. However, door number one seems the most likely scenario given GSK and HGS's 20-year relationship and the slow sales ramp of their lupus drug Benlysta belimumab.