Celldex Therapeutics (NYSE:CLDX) said Friday it will take full control of commercializing an experimental cancer vaccine used to treat patients with brain tumors after partner Pfizer (NYSE:{PFE) pulled out, stating the project was no longer a strategic priority.

Shares of Celldex hit a 52-week low on the news, plunging more than 39% to a low of $2.91.

The two entered into an agreement to develop and commercialize rindopepimut, an experimental therapeutic cancer vaccine that targets patients with Glioblastoma Multiforme, in April 2008.

Now that Pfizer has terminated the agreement, Needham, Massachusetts-based Celldex will gain full worldwide rights effective Nov. 1 for the drug.

The drug has undergone three clinical studies in more that 110 patients that have all yielded positive results, though it still needs to undergo late-stage studies, to be funded and conducted solely by Celldex, requiring the company to hire more people and acquire more resources, according to Celldex CEO Anthony Marucci.

“There is a significant need for new therapies for GBM and we are fully committed to developing rindopepimut for the patients who suffer from this fatal disease,” he said.