BARCELONA - Spanish drugmaker Almirall reported an unexpected first-half loss on Monday after it had written down the value of its anti-acne drug Seysara, sending its shares down as much as 9% despite an improved earnings outlook.

The group, which specialises in dermatology treatments, said the net loss of 42.8 million euros ($50.41 million) was mainly triggered by a 100 million euro write-down from the value of Seysara. Chief Financial Officer Mike McClellan told investors the group lowered its estimates for the drug's sales growth.

Almirall's shares were down 9% at 13.60 euros in midday trading.

The swing into the red from a 42.4 million euro net profit reported in the first half of 2020, was not expected by the consensus estimates while the upgraded forecast fell below market expectations, CM Capital Markets analysts said in a report.

The Barcelona-based company said it now expected its core annual earnings at between 195 million euros and 215 million euros, up 5 million euros from the previous target range.

Almirall's first half revenue dipped 1.2% compared with the same period of 2020, dented by lower sales in the United States, where it faces stiff competition from generic drug makers. Core earnings before interest, tax, depreciation and amortization (EBITDA) inched down to 136.6 million euros from 137.2 million euros.

However, second quarter EBITDA improved to 62.4 million euros from 48.9 million euros in the same period of 2020, coming above 57 million euros forecast in a Refinitiv poll.

Despite the first-half setback chief executive Gianfranco Nazzi offered a positive take on the rest of the year.

"The strength of our results confirms that we are progressing as expected, with an innovative pipeline," Nazzi said in a statement, adding the company was preparing significant launches in the second half and looking at more opportunities.

($1 = 0.8490 euros)

(Reporting by Joan Faus, Editing by Inti Landauro, Sherry Jacob-Phillips and Tomasz Janowski) ((joan.faus@thomsonreuters.com;))