ASCO spotlight burns Puma shares

Sometimes biotechs bask in the limelight of ASCO. And sometimes they get burned. Puma Biotechnology ($PBYI) is in the "burned" category. Its stock plunged 25% on Monday after investors soured on its "positive" news about neratinib, or PB272, with only three of 40 breast cancer patients in a study demonstrating a partial response. Also, there was a significant rate of Grade 3 diarrhea that had to be treated. And then GSK ($GSK) reported that its Tykerb/Herceptin combo study for breast cancer failed, flagging potential problems ahead for Puma as well. That's not what backers had been expecting, though there is plenty more data ahead for this company. Story