Cara Therapeutics’ prospects got a boost today with positive pivotal data on its lead project, the injectable itching candidate Korsuva.
The win in the US Kalm-1 trial not only bodes well for the asset’s chances of approval, but could also be good news for an oral version of Korsuva, which is in phase II trials.
Both candidates are being tested for pruritus, painful itching that is a side effect of kidney failure, liver disease and certain cancers. Kalm-1 specifically evaluated patients with chronic kidney disease who were receiving dialysis.
The study tested Korsuva dosed at 0.5µg/kg versus placebo over 12 weeks; its primary endpoint was reduction in itching intensity, measured by the proportion of patients with a three-point or greater improvement from baseline in the weekly mean of the daily worst itch numerical rating scale (WI-NRS).
51% Korsuva-treated patients achieved this, compared with 28% in the placebo group. Statistical significance was strong at a p value of 0.000019.
Cara also pointed to a significant difference in the WI-NRS score between Korsuva and placebo as early as one week into the trial.
The company played down an increased incidence of diarrhoea with Korsuva, with its chief medical officer, Jo Goncalves, saying this side effect was manageable and generally only lasted a couple of days. She added that no patients discontinued owing to diarrhoea.
The most common reasons for discontinuations were dizziness and paresthesia. Reassuringly, Cara did not see any cases of hallucinations or dysphoria, known side effects of the kappa opioid pathway that Korsuva aims to hit.
Next up for Cara will be data from its second pivotal trial, Kalm-2, which is similar to Kalm-1 but with an international scope. Results are due in the second half of the year. The phase III programme will be rounded out by two open-label safety studies.
Topline data with oral Korsuva are also expected later this year. The phase II trial in non-dialysis moderate to severe chronic kidney disease is testing three doses – 0.25mg, 0.5mg and 1mg – versus placebo. It is also designed to show a benefit on the WI-NRS at 12 weeks.
Cara also plans to start phase II trials this year of oral Korsuva in chronic liver disease-associated pruritus, and atopic dermatitis.
Of course, the latest data do not mean that these trials are without risk, but today's 18% share price climb, and resulting $850m market cap, suggest that investor jitters are being calmed.