Shares of Cara Therapeutics Inc., a biotech developing treatments for itchiness, rose 12.6% in premarket trade Wednesday after the company reported that dialysis patients experiencing itchiness who were given its Korsuva injection showed statistically significant improvement compared with those on placebo. Itchiness is a common issue among patients on dialysis. Cara's Phase 3 study, which enrolled 350 patients, evaluated itchiness using a scale called the Worst Itching Intensity Numeric Rating Scale, which subjects used to report the severity of their itchiness symptoms in the past 24 hours. Fifty-one percent of patients given Korsuva showed a three-point or greater improvement in itchiness after 12 weeks, while only 28% showed improvement on placebo, the company said. On top of that, 39% percent of patients on the drug were able to show a four-point or greater improvement in itchiness, compared with 18% of patients on placebo. Researchers also looked at how patients' quality of life changed while on the injection -- a greater proportion of patients on Korsuva showed improvement in quality of life measures compared with those on placebo, the company said. "We are extremely pleased with the robust topline results from our first pivotal Phase 3 trial of KORSUVA Injection and are particularly encouraged by the early anti-pruritic response with Korsuva Injection, which resulted in statistically significant separation from placebo after only one week of treatment and a sustained significant benefit through 12 weeks," said Derek Chalmers, Cara's president and chief executive officer. "We look forward to reporting topline data from our second global Phase 3 trial, KALM-2, in the second half of this year and, assuming positive results, moving towards an NDA submission as quickly as possible thereafter." Shares of Cara have gained 38% in the year to date through Tuesday, while the S&P 500 has gained 11.8%.