Idera rose 17.92% to $3.35 at 1:04 p.m. The stock opened at $2.86.
The stock is trading in the middle of its 52-week range of 52 cents to $6.87. It had a range today of $2.86 to $3.48 as of 1:04 p.m.
Idera was one of the biggest gainers among healthcare stocks and helped lead the sector upward along with Allergan (AGN), which surged thanks to Pershing Square Capital Management, led by founder and CEO William Ackman, and Valeant Pharmaceuticals International's (VRX) joint effort to pursue a takeover of the company.