NEW YORK (TheStreet) -- Avalanche Biotechnologies (AAVL) shares are down 50.21% to $19.18 in early market trading on Tuesday after the company released results from the Phase IIa trial of its gene therapy treatment for wet age-related macular degeneration.

The Menlo Park, CA-based company is a clinical stage biotech company that went public last year.

Investors are selling after the company said that the study was not designed to show significant statistical differences between the active and control groups.

Analysts at William Blair reduced the company's rating to "market perform" from "outperform" following the results while maintaining its $24 price target.

"The Phase IIa trial, which was powered for safety and tolerability, met the primary endpoint with no serious adverse events related to therapy observed," wrote analyst Tim Lugo.

However, investors and industry watchers were more concerned with efficacy endpoints related to visual acuity among other factors which showed mixed results.

"However, we believe the performance of Lucentis in the control arm raises more questions than answers," said Lugo.

TheStreet's Adam Feuerstein has further coverage of the trial here.

AAVL data by YCharts

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