Avalanche Biotechnologies Inc.'s IPO closed July with a bang, but the U.S. IPO waters hit a rough patch last week, with at least one company postponing its deal and two others taking significant haircuts to get out. It remains to be seen whether the market for new biotech paper has simply hit a summer lull or if this is a sign of the window beginning to close for companies that are early stage or don't have inflection points in the near term.

Avalanche raised $103 million through the sale of 6 million shares at $17 on July 31, after originally planning to sell 5.4 million shares at $13-$15. The ophthalmic gene therapy play closed last week at $23.54, up $6.54 (38%) since listing.