I will now turn the call over to Gustav Christensen, our President and CEO. Gustav?
Thank you, Nicole. Good morning and thank you for joining Dyax’s second quarter earnings conference call. Joining me today are George Migausky, EVP and Chief Financial Officer; Ivana Magovcevic-Liebisch, EVP Corporate Development and General Counsel; and Bill Pullman, EVP and Chief Development Officer.
We are pleased with the positive progress made during our first full quarter of US commercial launch of KALBITOR. And we’ll turn to those updates and other company news shortly. However, before doing so, George will go through the financial highlights of the second quarter. George?
Thank you, Gustav, and good morning to all. This morning’s press release contains the full financial results for the second quarter. So let me begin by highlighting some of the noteworthy financial events of the quarter. This was the first full quarter of the US commercial launch of KALBITOR and cumulative net sales have now reached $3.2 million, which reflects a 55% increase over Q1. Operating costs in the first half of 2010 were reduced by 25% to $32.9 million despite adding all of the new KALBITOR commercial launch expenses.
In the second quarter of 2010, our net operating cash burn was reduced to $11.4 million and our cash balance at June 30, 2010, which includes a cash equivalents and investments totaled $94.4 million. As reported earlier today, for the second quarter of 2010, total revenues increased to $15.1 million as compared to $4.8 million in the same quarter last year. And for the six-month period, revenues increased to $35.2 million from $10.8 million in the prior year. The higher revenue in the second quarter was primarily due to two factors. First, net product sales of KALBITOR, which were 1.9 million and second, $9.8 million of revenue recognized from the sale of our rights to royalties and other payments related to the commercialization of Xyntha by Pfizer.