Pfizer has decided to terminate a brain cancer vaccine partnership with Celldex Therapeutics, news which has sent the latter's share price crashing to an all-time low before recovering.

Celldex revealed that it is regaining full worldwide rights to rindopepimut, also known as CDX-110, an experimental therapeutic cancer vaccine. It targets the tumour-specific molecule epidermal growth factor receptor variant III (EGFRvIII) in patients with glioblastoma multiforme and has completed Phase II trials.

However Pfizer has told Celldex that the rindopepimut programme "is no longer a strategic priority" and has terminated the agreement. The handover of rights will take place on November 1.

Celldex appears to be far from downbeat, however. Chief executive Anthony Marucci said "there is a significant need for new therapies for GBM and we are fully committed to developing rindopepimut".  He added that the programme has advanced significantly, with the completion of a multi-centre Phase II trial, "the development of a diagnostic companion product, the manufacture of drug supply for clinical studies and the execution of discussions with regulatory agencies on the design of a global controlled study".

As such, Mr Marucci claimed that the programme is "very well-positioned to advance into pivotal clinical studies and that the GBM market remains extremely attractive." This view was echoed by Celldex chief medical officer Tom Davis who claimed that rindopepimut is "widely perceived by clinicians as one of the most promising non-toxic drug candidates for a patient population that has very limited treatment options".

Some observers believe that Celldex' enthusiasm is not misplaced, seeing as how three Phase II studies in more than 110 patients with GBM "consistently demonstrated significant improvements in median-time-to-disease progression, progression free survival and overall survival, when compared to historical controls receiving the standard of care". Investors have been less enthusiastic and the company's stock sank 26.2% to $3.53.