Credit Suisse downgraded Pfizer (PFE) to Neutral from Outperform, saying that the company’s positive catalysts will become “more limited” over the next six to twelve months.

DRIVERS TO SLOW: In recent years, Pfizer has benefited from strong use of its Ibrance drug for breast cancer and its Prevnar drug for bacterial infections, wrote Credit Suisse analyst Vamil Divan. However, demand for both drugs is slowing, he stated. Furthermore, patents on two other key drugs, Viagra and Lyric, are due to expire over the next 18 months, he wrote.

ACQUIRED DRUGS FACE HURDLES: Pfizer has acquired prostate cancer treatment Xtandi and eczema treatment Eucrisa, but the former drug is “facing reimbursement challenges” and a key generic competitor, while the latter “is too small to move the needle in the near-term,” he wrote. Although Pfizer could pursue new M&A deals, only big deals will probably move the needle, and Pfizer doesn’t look ready to pursue such a transaction yet, he stated.

ALTERNATIVE STOCKS: Johnson & Johnson (JNJ) and Merck (MRK) are better investments at this point than Pfizer, according to Divan.

PRICE ACTION: In morning trading, Pfizer fell 0.3% to $33.51 per share.