Nov 7 (Reuters) - Investment fund Oaktree Capital

Management has urged British drugmaker Indivior ( INDV ) to

cooperate with the fund in refreshing its board of directors, it

said in a letter dated Nov. 6 and published in a filing on

Thursday.

The request from the fund, which became the company's second

largest shareholder in July, comes weeks after Indivior ( INDV ) issued

its second profit and revenue warnings in a span of three

months, citing lower than expected sales from its opioid

addiction treatment.

The company's opioid addiction treatment Sublocade has been

losing market share due to the rapid adoption of Brixadi, a

competing drug developed by Swedish pharmaceutical firm Camurus

.

"The Company essentially disregarded Brixadi's entrance into

the market by failing to take basic steps to protect Sublocade's

competitive position," Oaktree said in the letter.

Shares in the British drugmaker have slumped about 40% so

far this year.

Oaktree, which specialises in providing rescue funding to

struggling firms, had a 7.37% stake in the drugmaker, according

to LSEG data.

Investment manager Two Seas Capital is the top shareholder

with a 10.25% ownership.

Indivior ( INDV ) did not immediately respond to a Reuters request

for comment.

In July, the drugmaker had taken a $86 million hit in a

settlement over its alleged role in spreading opioid addiction

across the United States.

(Reporting by Yamini Kalia and Aby Jose Koilparambil in

Bengaluru; Editing by Mrigank Dhaniwala)