Halozyme went down 20% yesterday.
The reason was an abstract published at ASCO Gastro which apparently had doubtful trial results.
Was this justified?
Halozyme (HALO) went down 20% yesterday after data from the so-called SWOG trial was published at ASCO Gastro which seemed to show poor data for PEGPH20. This study compared mFOLFIRINOX (’mFFOX)+ pegylated recombinant human hyaluronidase (PEGPH20) versus mFFOX alone in patients with good performance status metastatic pancreatic adenocarcinoma (’mPC). FFOX is a recently developed chemotherapy regimen that has shown good OS in mPC, even compared to standard gemcitabine treatment as an article in NEJM tells us. mFFOX is modified FFOX, and this trial aimed to show that adding Halozyme’s promising PEGPH20, which helps anti-cancer drugs better penetrate the tumor microenvironment in cancers where Hyaluronic acid or HA is obtained in higher levels, can improve OS even further than by using FFOX alone.
The MoA or mechanism of action of PEGPH20 is best stated from the company’s Annual Report:
We believe that depleting the HA component of the tumor microenvironment with PEGPH20 remodels the tumor microenvironment, resulting in tumor growth inhibition in animal models. Removal of HA from the tumor microenvironment results in expansion of previously constricted blood vessels allowing increased blood flow, potentially increasing the access of activated immune cells and factors in the blood into the tumor microenvironment. If PEGPH20 is administered in conjunction with other anti-cancer therapies, the increase in blood flow may allow anti-cancer therapies to have greater access to the tumor, which may enhance the treatment effect of therapeutic modalities like chemotherapies, monoclonal antibodies and other agents.
Now, the trial in question was conducted by an outside agency, SWOG. This is a cancer research cooperative group of more than 4,000 researchers in over 500 institutions around the world. In October 2013, they initiated this 144 patient Phase 1b/2 study. The trial was temporarily halted along with study 109-202, but was later resumed. 109-202 has gone on to yield strong efficacy results, as we will presently see.