Pfizer Inc. (PFE) - Get Report shares fell Tuesday after analysts at JPMorgan lowered their rating for the drugmaker amid concerns of the loss of exclusivity on one of its key pain treatments.

JPMorgan analyst Chris Schott maintained a $46 price target for Pfizer, but clipped his overall rating to "neutral" from "overweight" as he argued the need for further expansion of the group's product pipeline following the patent expiration of its blockbuster pain treatment Lyrica next year.

Pfizer shares fell 1.5% on Tuesday to $43.75. 

Lyrica, which generated around $5 billion in sales for Pfizer last year, was granted a six-month patent exclusivity extension by the U.S. Food & Drug Administration last month, but the branded treatment, known also as pregabalin, will face generic competition from June of next year. 

Schott said Pfizer faces another patent cycle risk in 2026/2027, but said he sees "an extended window to address the potential headwinds through internal R&D and bizdev".

Pfizer currently is bringing four new drugs to the market, focusing on breast and lung cancer treatments as well as drug used for patients with newly diagnosed elderly acute myeloid leukemia.

Pfizer said last month that it plans to boost prices on around 41 of its listed drugs by between 5% and 10%, starting next year, but noted that rebates from insurance companies and pharmacy benefit managers would offset some of the added costs to customers.

The move reverses an earlier decision by Pfizer in July to delay price increases following a Tweet from President Donald Trump that the drugmaker "should be ashamed that they have raised drug prices for no reason."

"We believe the best means to address affordability of medicines is to reduce the growing out-of-pocket costs that consumers are facing due to high deductibles and co-insurance, and ensure that patients receive the benefit of rebates at the pharmacy counter," outgoing CEO Ian Read said in a statement.