New York’s Stemline Therapeutics Inc. has been bought by the Menarini Group, a privately held Italian pharma and diagnostics company, in a deal worth up to $677 million.

Stemline’s shareholders will be offered $12.50 per share, with $11.50 of it in cash up front along with one non-tradeable contingent value right for $1 in cash per share on the first sale of Elzonris (tagraxofusp) after EMA approval, which could come this year.

Elzonris is FDA approved for treating adults and pediatric patients age 2 and older for blastic plasmacytoid dendritic cell neoplasm (BPDCN), a rare and aggressive disease of the bone marrow and blood. Elzonris launched in the U.S. in January 2019 and brought Stemline $11.8 million in net revenue in the fourth quarter of 2019.

Stemline’s stock (NASDAQ:STML) was up 150% when the market opened this morning. On Friday, shares had dropped 9%, closing at $4.75 each.

J.P. Morgan’s Jessica Frye wrote Monday morning that Stemline’s stock is depressed at its current levels. She also expects Elzonris will launch in the EU in late 2020.

The transaction, expected to close in the second quarter of 2020, will be funded through Menarini’s existing cash resources. The company said it will support Elzonris’ further development by leveraging its commercial infrastructure in Europe and other ex-U.S. geographies

The FDA’s December 2018 approval of Elzonris, directed to the interleukin-3 (IL-3) receptor-α, made it the first drug ever approved for BPDCN. The green light, which covered both adult and pediatric patients ages 2 and older, arrived two months ahead of the date by which the regulator was expected to release its decision. Elzonris, which had orphan status in both the U.S. and Europe, was granted an FDA breakthrough designation in August 2016 and priority review in August 2018.

The acquisition puts Menarini in the U.S. oncology market. The global group is an active player in 136 counties and relies on international partners in research, manufacturing and diagnostics.

In late April, Menarini-Silicon Biosystems, part of the Menarini Group, which has a presence in Bologna, Italy, and Huntingdon Valley, Pa., said that it is exploring the possible use of its proprietary Cellsearch technology to study the progression of COVID-19 disease and potentially identify patients who may be at risk of developing the most severe complications of the disease.

In late January, Dublin-based Innovation Zed Ltd. and A. Menarini Diagnostics SA, a diagnostics company headquartered in Italy, and also part of the Menarini Group, reported an international partnership to commercialize the Insulcheck Connect device developed by Innovation Zed. Insulcheck Connect is an insulin pen add-on device that automatically collects essential usage data that informs insulin pen users of their injection history to assist them take control of their diabetes management.

A biological conjugate, Elzonris consists of human IL-3 linked to a truncated diphtheria toxin that targets ILR-3-alpha on cancer stem cells. Its efficacy was studied in two cohorts of patients in a single-arm trial. BPDCN is very rare, and accounts for just 0.44 percent of all hematologic malignancies and 0.7 percent of cutaneous lymphomas, according to epidemiological data compiled by Cortellis.