Cara Therapeutics recently announced the conclusion of patient enrollment in the three-dose part of its Phase 2/3 clinical trial evaluating the effectiveness and safety of intravenous CR845 in dialysis patients with moderate to severe uremic pruritus.

The condition is also called chronic kidney disease (CKD)-associated pruritus, and it is considered the most common internal cause of itching.

There are currently no approved medications in the U.S. for uremic pruritus, an intractable type of itch that is generally resistant to conventional treatments and which diminishes the quality of life for nearly half of all CKD patients on dialysis.

“We’re very pleased to have completed enrollment as planned for Part A of the Phase 2/3 trial in pruritus associated with chronic kidney disease, as these eight-week data will determine the optimal dosing to carry forward into planned registration trials,” Derek Chalmers, PhD, president and CEO of Connecticut-based Cara Therapeutics, said in a press release.

“In our previous Phase 2 trial, IV CR845 significantly reduced itch and improved the quality of life for dialysis patients with this condition over a two-week treatment period,” he said.

Chambers said the company anticipates reporting top-line data from Part A of the trial in the first quarter of 2017 “and, based on the results, initiating the planned registration phase later in the year.”

Part A of the two-part clinical trial (NCT02858726) will assess three different dosing levels of IV CR845  (0.5 mcg per kg body weight, 1.0 mcg/kg, and 1.5 mcg/kg) compared to a placebo after each dialysis session for eight weeks in 160 patients. The safety and efficacy of CR845 will be monitored throughout the study.

Part B will assess one dose of IV CR845 versus a placebo administered for 12 weeks three times per week after dialysis in up to 240 patients on dialysis who have moderate to severe itching. The dose of CR845 used in Part B will be based on results from Part A.

Part B may be enrolling participants, according to information in clinicaltrials.gov. First read the eligibility requirements, then scroll down to the contact name, phone number and email address under Contacts and Locations. A list of the 23 U.S. study locations is also available.

Primary and secondary endpoints include assessments of three dose levels of CR845 and a placebo in reducing the intensity of itch; patient-reported intensity of itch using the Worst Itching Intensity Numerical Rating Scale; and quality of life measures associated with pruritus.

A previous Phase 2 clinical trial evaluated the effectiveness of IV CR845 (1.0 mcg per kg body weight) compared to a placebo in reducing the intensity of itch in 65 dialysis patients over a two-week dosing period.

The results showed that compared to placebo-treated patients, those who received IV CR845 experienced a 54 percent reduction in worst itch scores, as well as statistically significant reductions in both daytime (minus 51 percent) and nighttime (minus 75 percent) worst itch scores.

In addition, compared to the placebo, patients on IV CR845 also showed statistically significant improvements in quality of life measures.

CR845 is a peripherally-selective molecule that interacts with kappa opioid receptors on peripheral pain-sensing nerves, and has potent analgesic and anti-inflammatory properties.