Today Atara Biotherapeutics (ATRA) shares plunged by 37% after the company reported that its phase 2 trial failed to produce statistically significant results. The trial was a proof of concept phase 2 study to test the effects of the PINTA 745 molecule. More specifically the trial enrolled protein energy wasting -- PEW -- patients that had End-stage renal disease -- kidney disease. 

The primary endpoint of the trial was defined as a percent change from baseline in Lean Body Mass -- LBM. The LBM was measured using a Dual Energy X-Ray Absorptiometry at week 12. This test was done after patients had taken weekly treatments with PINTA 745. The conclusion of the phase 2 proof of concept study was that the drug failed to meet on the primary endpoint of the study. 

In addition, on failing the primary endpoint, the study also failed to improve upon other measures in the study such as: physical function, glycemic control, and markers of inflammation. The only positive that came out of this trial was that the drug produced no safety issues. With $334 million in cash the company had decided to end this PINTA 745 program, and allocate all resources to its other pipeline drug candidates. These other candidates deal with oncology and immunotherapy products.