Nektar falls on short seller report

Nektar Therapeutics Inc. (NASDAQ:NKTR) fell $4.31 to $56.65 on Oct. 1 after short seller Plainview LLC released a report calling the value of the biotech's NKTR-214 zero. Nektar lost more than $740 million in market cap during the session.

The report cited data from the Phase I EXCEL trial of NKTR-214, which showed the compound as monotherapy led to an overall response rate (ORR) of 0% in 28 patients with locally advanced or metastatic solid tumors. NKTR-214 monotherapy did lead to 15 cases of stable disease, including four renal cell carcinoma patients who went on to receive sequential therapy with anti-PD-1 mAb Opdivo nivolumab. Of those four RCC patients, three achieved confirmed partial responses while on Opdivo...