Siklos® now available in retail pharmacies

ROSEMONT, PA, August 21, 2018 – Medunik USA, a company dedicated to improving the health and quality of life of Americans with rare diseases by making orphan drugs available in the U.S., announced today that Siklos® (hydroxyurea), an FDA-approved orphan drug, is now available in 100 mg tablets for pharmacies to order.

Siklos® is indicated to reduce the frequency of painful crises and the need for blood transfusions in pediatric patients, two years of age and older, with sickle cell anemia with recurrent moderate to severe painful crises. It is the first and only FDA-approved hydroxyurea-based treatment for use in pediatric patients with sickle cell anemia.

Medunik USA holds the exclusive rights to market and distribute Siklos® in the United States, through an agreement with ADDMEDICA, a French pharmaceutical company specializing in hematology.

“We are pleased to partner with ADDMEDICA to provide access to an orphan drug therapy that can contribute to reducing painful crises, specifically for children with sickle cell anemia,” said Éric Gervais, Executive Vice President of Medunik. “The addition of Siklos® to the Medunik portfolio establishes our footprint in the United States in the area of orphan drug therapies and is the latest in a series of significant advances for our company.”

“Medunik USA is well positioned to ensure both the marketing and distribution of Siklos® in the United States, thanks to their knowledge of the orphan drug commercialization process. We are pleased to count them as a partner,” said Bernard Dauvergne, Executive Director of ADDMEDICA.

Sickle cell anemia (SCA) is the most common inherited blood disorder, resulting in the production of abnormal hemoglobin, known as hemoglobin-S (HbS), responsible for the sickling of red blood cells. This disease affects nearly 100,000 Americans, decreases life expectancy by 25 to 30 years, induces significant morbidity, and therefore, reduces quality of life1,2. Most of those affected are of African ancestry; a minority are of Hispanic or southern European, Middle Eastern or Asian Indian descent3.

“This approval is a major milestone in treatment for all children who suffer from devastating pain and disability associated with sickle cell anemia,” said Abbey Meyers, Founder and past-president of the National Organization for Rare Disorders (NORD) and member of Medunik’s Advisory Board.

FDA approval was granted based on tolerability and effectiveness data collected in a European sickle cell disease cohort (Escort-HU) study, which included 405 pediatric patients. Data showed that treatment with Siklos® increased the concentration of fetal hemoglobin (hemoglobin F or HbF), which prevents the sickling process within red blood cells. In the clinical trial, the number of pediatric patients experiencing at least one painful crisis in the 12 months prior to treatment with Siklos® was significantly reduced after 12 months of treatment4.

Siklos® offers flexible dosing to facilitate adjustment based on patient’s weight and maximum tolerated dose. This is particularly important in pediatric populations, where patient weight is constantly changing.

About SIKLOS® (hydroxyurea)

Siklos® is a prescription medicine that is used to reduce the frequency of painful crises and reduce the need for blood transfusions in children, 2 years of age and older, with sickle cell anemia with recurrent moderate to severe painful crises. It is not known if Siklos® is safe and effective in children less than 2 years of age.

See full prescribing information for complete Boxed Warning.

  • Low blood cell counts are common with Siklos®, including low red blood cells, white blood cells, and platelets, and can be severe and life threatening. If your white blood cell count becomes very low, you are at increased risk for infection. Your healthcare provider will check your blood cell counts before and during treatment with Siklos®. Your healthcare provider may change your dose or tell you to stop taking Siklos® if you have low blood cell counts. Tell your healthcare provider right away if you get any of the following symptoms: fever or chills; shortness of breath; body aches; unusual headache; feeling very tired; bleeding or unexplained bruising.
  • Cancer. Some people have developed cancer, such as leukemia and skin cancer, after taking Siklos® for a long time. Your healthcare provider will check you for cancer. You should protect your skin from the sun using sunblock, hats, and sun-protective clothing.


  • Siklos® can harm your unborn baby.
  • For females taking Siklos® who can become pregnant:
    • You should talk with your healthcare provider about the risks of Siklos® to your unborn baby.
    • You should use effective birth control during treatment with Siklos® and for at least 6 months after treatment with Siklos®.
    • Your healthcare provider will perform a pregnancy test before you start treatment with Siklos®. Tell your healthcare provider right away if you become pregnant or think you may be pregnant.
    • For males taking Siklos®. Siklos® can affect your sperm. If you have a female sexual partner who can become pregnant, you should use effective birth control during treatment with Siklos® and for at least 6 months after treatment.
  • Siklos® may cause fertility problems in males. Talk to your healthcare provider if this is a concern for you.


Do not take Siklos® if you are allergic to hydroxyurea or any of the ingredients in Siklos®. See the Medication Guide for a list of the ingredients in Siklos®.

Siklos® may cause serious side effects, including skin ulcers (including leg ulcers) and enlarged red blood cells (macrocytosis).

The most common side effects of Siklos® include: infections, headache, fever, skin problems, stomach and intestine problems, decrease in vitamin D and weight gain. These are not all the possible side effects of Siklos®.

Please consult full Prescribing Information, including Boxed Warning.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit or call 1-800-FDA-1088.

For more information about Siklos®, we invite you to contact our Medical Information Service at 1 844-884-5520 or

About Medunik USA

Based in Pennsylvania, Medunik USA works to improve the health and quality of life of Americans living with rare diseases by making orphan drug therapies available in the United States. With strategic partnerships at the global level, the company has critical experience in approval and market access processes as well as the marketing of orphan drug therapies. Medunik USA makes critical medications to treat rare diseases available to American patients who might not otherwise have access to these medications. For more information, visit:


ADDMEDICA is a fast-growing European company focused on developing and marketing medical products for rare diseases and unmet medical needs. By developing, registering and/or marketing a range of medical products in several rare and debilitating diseases ADDMEDICA provides high medical value solutions to physicians, patients and managed care organizations. For more information:

Amy Feldman
Lazar Partners
1 212-867-1779: This email address is being protected from spambots. You need JavaScript enabled to view it.

  1. Platt, O. S. et al. Mortality in sickle cell disease. Life expectancy and risk factors for early death. The New England journal of medicine 330, 1639-1644, doi:10.1056/NEJM199406093302303 (1994).
  2. McGann, P. T. & Ware, R. E. Hydroxyurea therapy for sickle cell anemia. Expert opinion on drug safety 14, 1749-1758, doi:10.1517/14740338.2015.1088827 (2015).
  3. Sickle Cell Disease, <>
  4. Siklos® (hydroxyurea) tablets, for oral use [Prescribing Information]. Addmedica, May 2018. 

Print Press Release (PDF)