The Menarini Group Announces ELZONRIS® (Tagraxofusp) Designated as an Orphan Drug for BPDCN by Japanese Ministry of Health, Labor and Welfare

• Japanese Ministry of Health, Labor and Welfare grants Orphan Drug Designation to tagraxofusp for blastic plasmacytoid dendritic cell neoplasm (BPDCN)

FLORENCE, Italy & NEW YORK–(BUSINESS WIRE)–The Menarini Group (“Menarini”), a leading international pharmaceutical and diagnostics company, and Stemline Therapeutics, Inc. (“Stemline”), a wholly-owned subsidiary of the Menarini Group, today announced that Nippon Shinyaku Co., Ltd. (Nippon Shinyaku), Stemline’s development partner in Japan, received Orphan Drug Designation for tagraxofusp, from the Japanese Ministry of Health, Labor and Welfare (MHLW) for the expected indication of blastic plasmacytoid dendritic cell neoplasm (BPDCN).

BPDCN is an aggressive orphan hematologic malignancy with historically poor clinical outcomes. Stemline’s ELZONRIS^® (tagraxofusp) is the only approved treatment for patients with BPDCN, and the first and only approved CD123-targeted therapy, in both the United States and Europe.

Orphan drugs are designated by Japan’s MHLW for treatments that are intended for use in fewer than 50,000 patients, where there is also a particularly high medical need. Orphan drug designation can potentially shorten the period required to obtain regulatory approval in Japan by several months, thereby enabling faster patient access.

In Japan, tagraxofusp is being developed by Nippon Shinyaku, which is currently conducting a Phase 1/2 clinical trial. In March 2021, Stemline and Nippon Shinyaku entered into an exclusive licensing agreement for the development and commercialization of tagraxofusp in Japan, including the possibility of co-promotion.

“The MHLW’s decision to grant Orphan Drug Designation recognizes the potential positive impact tagraxofusp could have on BPDCN patients in Japan, a patient population that currently has limited treatment options,” said Elcin Barker Ergun, CEO of the Menarini Group. “This achievement by our partner, Nippon Shinyaku, advances our commitment to bring transformative new therapeutic options to patients with difficult-to-treat cancers, and to deliver innovative medicines to people around the globe.”

About BPDCN

BPDCN, formerly blastic NK-cell lymphoma, is an aggressive hematologic malignancy, often with cutaneous manifestations, with historically poor outcomes. BPDCN typically presents in the bone marrow and/or skin and may also involve lymph nodes and viscera. The BPDCN cell of origin is the plasmacytoid dendritic cell (pDC) precursor. The diagnosis of BPDCN is based on the immunophenotypic diagnostic triad of CD123, CD4, and CD56, as well as other markers. The World Health Organization (WHO) termed this disease “BPDCN” in 2008; previous names included blastic NK cell lymphoma and agranular CD4+/CD56+ hematodermic neoplasm. For more information, please visit the BPDCN disease awareness website at www.bpdcninfo.com.

About The Menarini Group

The Menarini Group is a leading international pharmaceutical and diagnostics company, with a turnover of over $4.4 billion and over 17,000 employees. Menarini is focused on therapeutic areas with high unmet needs with products for cardiology, oncology, pneumology, gastroenterology, infectious diseases, diabetology, inflammation, and analgesia. With 18 production sites and 9 Research and Development centers, Menarini’s products are available in 140 countries worldwide. For further information, please visit www.menarini.com.

About Stemline Therapeutics Inc.

Stemline Therapeutics, Inc. (“Stemline”) a wholly-owned subsidiary of the Menarini Group, is a commercial-stage biopharmaceutical company focused on the development and commercialization of novel oncology therapeutics. Stemline commercializes ORSERDU^® (elacestrant) in the United States, an oral endocrine therapy indicated for the treatment of postmenopausal women or adult men with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy. Stemline also commercializes ELZONRIS^® (tagraxofusp-erzs), a novel targeted treatment directed to CD123 for patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN), an aggressive hematologic cancer, in the United States and Europe, which is the only approved treatment for BPDCN in the US and EU to date. Stemline also commercializes NEXPOVIO^® in Europe, an XPO1 inhibitor for multiple myeloma. Stemline also has an extensive clinical pipeline of small molecules and biologics in various stages of development for a host of solid and hematologic cancers.

About Nippon Shinyaku

Our mission is to help people lead healthier and happier lives. Through creating unique medicines that will bring hope to patients and families struggling with illness, we aim to be an organization trusted by the community. Please visit our website (https://www.nippon-shinyaku.co.jp/english/index.php) for products or detailed information.

Contacts

The Menarini Group

Valeria Speroni Cardi

Email: pressoffice@menarini.com

Stemline Therapeutics, Inc.

Cheya Pope

Email: cpope@stemline.com