Pfizer scored a small but significant victory this week after being granted a reissue patent that will afford the company 18 additional months of market exclusivity for its blockbuster painkiller Celebrex.

"We are pleased with the reissuance of this patent protecting the invention of using [the active ingredient] celecoxib to treat osteoarthritis and other approved conditions, and have initiated legal proceedings to enforce our intellectual property rights through December 2, 2015," Pfizer general counsel Amy Shulman stated.

Those forthcoming enforcement efforts will be targeted at several generic drug manufacturers who had secured rights to sell their alternative products following Pfizer's former patent cliff of May 2014. According to The Wall Street Journal, this news has already created both upstream and downstream ripple effects.

Investors were encouraged to hear about the extension of Celebrex's market monopoly, and Pfizer's shares rose nearly 2 percent immediately following the announcement. But according to the Journal, both distributors and customers were disheartened by the realization that they must continue to pay premium prices with no alternative available until the end of 2015.