Argos tanks as its HIV immunotherapy flunks Phase II

Argos Therapeutics' ($ARGS) HIV treatment failed to meet its main goal in a midstage trial, raising concerns about the company's platform technology and sending its shares spiraling downward.

The treatment, AGS-004, is a personalized immunotherapy designed to train patients' T cells to better attack HIV. In a placebo-controlled Phase IIb trial, AGS-004 missed its primary endpoint of significantly lowering viral load among chronically infected patients, the company said, news that spurred a 27% drop in Argos' share value on Friday morning.

The study, paid for by the National Institutes of Health, enrolled 54 patients, giving them four doses of either AGS-004 or placebo every month while maintaining baseline treatment with standard antiretroviral therapy (ART), the company said. After the fourth dose, Argos interrupted ART dosing for both groups, measuring viral load after 12 weeks to see how AGS-004 stacked up versus placebo.

Despite the miss on efficacy, the Durham, NC, biotech is looking on the bright side. AGS-004 led to memory T cell responses in the 70% of the patients who completed the trial, Argos said, a sign that the immunotherapy has potential as a treatment for persistent HIV infection rather than the chronic variety. And that's an encouraging development for Argos' ongoing HIV eradication study and its soon-to-begin pediatric trial, Chief Scientific Officer Charles Nicolette said.

Charles Nicolette

"These data support our plans to continue testing AGS-004 in the studies aimed at decreasing or eliminating the latent HIV reservoir," Nicolette said in a statement. "In addition, based on these data we believe that more frequent dosing of AGS-004 during ART may provide further benefit, but also highlight the need to better understand the mechanisms of immune evasion employed by the HIV virus in the absence of ART."

Argos squeaked out a $45 million IPO last year, taking a sizable discount but raising the cash it needed to launch a Phase III trial for AGS-003, its lead candidate. Using the same technology as its HIV treatment, AGS-003 is an immunotherapy that uses a patient's own dendritic cells to fight cancer growth, and it's now in the midst of a Phase III trial in patients with renal cell carcinoma.

- read the statement