Barclays analyst Gena Wang downgraded Puma Biotechnology (PBYI) to Equal Weight and lowered her price target for the shares to $70 from $90. The analyst's survey of U.S. oncologists showed a lower than expected growth rate for future Nerlynx penetration. She views Nerlynx as a key value driver for Puma shares. Further, changing treatment paradigm represents some risk to the company's Phase III NALA trial, which is investigating the use of neratinib in combination with Roche's (RHHBY) Xeloda for third line treatment of metastatic HER2-positive breast cancer, Wang tells investors in a research note.