Atara tanks after its kidney drug comes up short in Phase II

Atara CEO Isaac Ciechanover

Atara Biotherapeutics ($ATRA) is halting development of its lead drug after the kidney treatment flunked a mid-stage study, forcing management to regroup around some mid-stage oncology candidates in the pipeline.

The drug, PINTA 745, is designed to block the protein myostatin in order to fight protein energy wasting, an inflammatory ailment that afflicts patients with end-stage renal disease. In a Phase II trial, however, the treatment missed its primary endpoint of improving the disease's effect on body mass as measured by X-ray, Atara said, and PINTA 745 failed to improve physical function, glycemic control and inflammation.

The data are "unambiguous and contrast with prior clinical and preclinical results," Atara CEO Isaac Ciechanover said in a statement, and the company is now suspending all further development of PINTA 745.

The news sent Atara's shares down about 30% on Monday as investors reacted to the company's suddenly dwindled pipeline. With PINTA 745 on indefinite hold, Atara is working through Phase II trials on a pair of cell therapies for cancer related to Epstein-Barr virus and cytomegalovirus. Behind those assets is STM 434, a Phase I treatment for ovarian cancer, and WT1-CTL, a cell therapy in development for leukemia and multiple myeloma.

Atara, which spun out of Amgen ($AMGN) in 2012, raised $55 million in a below-the-range IPO last year but has since seen its share price increase roughly sixfold on positive results from its pipeline projects.

- read the statement

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