Johnson & Johnson said Thursday its partnership with Hanmi Pharmaceutical over a novel diabetes drug licensed out by the South Korean drugmaker “remains strong,” seeking to ease concerns over the drug’s halted clinical trials in the US.

According to the US National Institutes of Health’s ClinicalTrials.gov, J&J’s subsidiary Janssen Pharmaceutical had “suspended participant recruitment” for phase 1 clinical trials of JNJ-64565111.

The news had ignited alarm among Hanmi shareholders, who feared there may be new problems with the drug as well as J&J’s partnership with Hanmi. Shares of Hanmi Pharmaceutical plunged 10.76 percent Wednesday.

A spokesperson for J&J told biopharma media outlet Endpoint News that the move was prompted by a “manufacturing-related delay” from Hanmi.

“Our partnership with Hanmi remains strong regarding this drug candidate and we look forward to restarting the study,” she said.

A Hanmi spokesperson declined to further comment on the details of this manufacturing issue, citing a nondisclosure agreement with J&J.

Even after Janssen’s announcement, Hanmi Pharmaceutical shares further dropped 2.09 percent to a close of 304,500 won ($263) on Thursday.

JNJ-64565111, also known as HM12525A, is a biologic drug for the treatment of diabetes, originally developed by Hanmi. It was licensed out by Hanmi to Janssen in November 2015 in a deal valued at $915 million.

Janssen had begun phase 1 clinical trials in the US from July, testing the drug’s efficacy in treating patients with Type 2 diabetes mellitus. Given the recent delay, the first-stage trials are expected to continue beyond their estimated completion period in April 2017.

By Sohn Ji-young (jys@heraldcorp.com)