With that, I'd like to turn the call over to Gregory Frost, Halozyme's President and CEO.
Gregory I. Frost
Thank you, Anne, and good afternoon to everyone. We appreciate you participating in our second quarter call for 2012.
Today, I'll be elaborating on the announcement we made last week, as well as providing an update on the business. After that, Kurt Gustafson, Halozyme's CFO, will review the quarter's underlying financial results with you.
As you know, we confirmed last week that Baxter received the Complete Response Letter from FDA's Blood Products division for the HyQ BLA. And at this point in time, the subcutaneous plasma derivatives programs for the recombinant human hyaluronidase, or rHuPH20, are not dosing patients.
Upon receiving this information from Baxter and ViroPharma early last week, we contacted FDA's Drug division to ascertain whether this regulatory action would apply to other programs using rHuPH20. According to our most recent communications with the drug divisions last Wednesday, following submission of a data supplement to the Hylenex NDA, including detailed immunogenicity data from insulin and subcutaneous Herceptin programs, we were informed by the drug division that concerns appear to be related to potential interactions with certain biologics that generate an antibody response that is different from what we've seen in other development programs using rHuPH20.
Furthermore, the drug division confirmed that there is no need for actions against Hylenex or clinical programs under the Hylenex IND. As a reminder, the only open trial at this time under the Hylenex IND is the ongoing Hylenex insulin pump study.
For these reasons, we believe that the regulatory concerns raised by FDA's Blood Products division are specific to Baxter and ViroPharma's clinical programs.
It's not abnormal to see some form of antibodies to recombinant proteins with sufficient assays. In fact, approximately 10% of the general population test positive to anti-rHuPH20 antibodies prior to any exposure to the rHuPH20 enzyme. This is also not uncommon for other proteins.