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What: Shares of Advaxis (ADXS 36.36%), a clinical-stage immunotherapy company, dropped by more than 14% last month, according to data from S&P Global Market Intelligence. The biotech's poor showing in June appears to be the result of the marketwide sell-off following the Brexit vote combined with its hefty short ratio of 10.12 as of the middle of last month.   

ADXS Chart

ADXS data by YCharts

So what: Advaxis remains a top target among short sellers presumably because of the novelty of its lead product candidate, axalimogene filolisbac, a genetically modified bacterium (Listeria monocytogenes) that targets HPV-associated cancers. In a nutshell, Advaxis' approach to fighting cancer is far less popular in the pharma world than the headline-grabbing checkpoint inhibitors being developed by AstraZeneca (AZN 0.27%)Merck (MRK -0.15%), or many others, as just one example. Making matters worse, Advaxis has proved to be its own worst enemy by taking over a decade to develop its lead product candidate.  

Now what: The good news is that Advaxis appears to be on the cusp of breaking out of this funk after signing agreements to explore the use of its modified bacterium platform in conjunction with Astra and Merck's lead checkpoint inhibitors across a variety of solid tumors. The core issue is that Astra and Merck are both known for rapidly advancing their immuno-oncology pipelines, meaning that it shouldn't take yet another decade to figure out if this particular form of immunotherapy actually works. Having said that, Advaxis is nearing the launch of a late-stage study for axalimogene filolisbac in advanced cervical cancer that's to be conducted with the Gynecologic Oncology Group Foundation, Inc.. 

Turning to the question of whether Advaxis is a bargain, my take is that, despite its tiny market cap of around $300 million, this stock is probably currently fairly valued in light of the unproven nature of its platform. As its clinical efforts mature, this situation could of course change in a heartbeat -- which is why this speculative biotech perhaps merits a place on your watch watchlist instead of on your buy list.