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Mielcarek
Marco Mielcarek, MD, PhD

Marco Mielcarek, MD, PhD

Medical Oncology

  • Medical Director, Adult Blood and Marrow Transplant Program, Fred Hutch
  • Professor, Clinical Research Division, Fred Hutch
  • Affiliate Investigator, Translational Science and Therapeutics Division, Fred Hutch
  • Professor, Division of Hematology and Oncology, University of Washington School of Medicine
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About

Dr. Marco Mielcarek is a board‑certified medical oncologist and research at Fred Hutch with more than 20 years of experience in adult blood and marrow transplantation. He focuses on improving transplant outcomes and preventing graft‑versus‑host disease.

Background

Dr. Mielcarek oversees care delivery as medical director of Fred Hutch’s Blood and Marrow Transplant Program. He specializes in caring for patients with blood cancers undergoing blood and marrow transplant (BMT) and supports patients through treatment and recovery.

Dr. Mielcarek’s research is focused on preventing and treating graft‑versus‑host disease (GVHD), a complication where transplanted immune cells attack a patient’s healthy tissues and organs. His work aims to reduce GVHD while minimizing treatment‑related side effects. In one study, he showed that patients with GVHD could be effectively treated with lower doses of prednisone, a steroid that can have more negative effects at higher doses.

He and his colleagues also conduct clinical trials testing new strategies to prevent GVHD, including studies evaluating whether treating stem cell donors with statins (drugs commonly used to lower cholesterol) can reduce GVHD risk in BMT recipients. Additional work from him and his colleagues has demonstrated that carefully timed infusions of high doses of cyclophosphamide, a widely used chemotherapy drug, can safely and effectively prevent GVHD after BMT. Across his research, Dr. Mielcarek is focused on improving survival, safety and quality of life for BMT patients.

Area of Clinical Practice
Adult blood and marrow transplantation

“Research is the backbone for improving patient care.”

— Dr. Mielcarek

How do you care for patients?

I believe there are two key ingredients to providing excellent care. The first is tailoring treatment according to your needs and philosophy. An approach that is a good fit for someone else may not be ideal for you, and I never want to make assumptions about what you prefer. The second ingredient is incorporating up-to-date research so that you’re receiving the very best treatment that medicine has to offer, which can sometimes be clinical trials. Participating in trials helps us increase our understanding of diseases and achieve better cure rates.

What do you love about your job?

I arrived in Seattle in 1994 for a research fellowship at the Fred Hutchinson Cancer Center. My plan was to stay for two years and then return to my home in Germany. As you can see, I’m still here. I learned a lot during my fellowship — it was a good collaboration — but I didn’t want the kind of career where I was restricted to the lab. I wanted the privilege of taking care of patients, too. So I decided to stay in the U.S. to pursue those two passions. At Fred Hutch, I get the best of both worlds — working closely with patients and conducting research to make treatment for blood cancers more tolerable.

Diseases Treated

Graft Versus Host Disease

Research Interests

Preventing and more effectively treating graft-versus-host disease (GVHD) after allogeneic stem cell transplantation.

Languages

English
German

Education and Experience

Fellowship, Medical Oncology, University of Washington/Fred Hutch

Residency, Internal Medicine, University of Washington; Internal Medicine, Freie Universität Berlin

PhD, Freie Universität Berlin

MD, Freie Universität Berlin

Board Certifications

Medical Oncology, 2003, 2013; American Board of Internal Medicine

Clinical Trials

We make promising new treatments available to you through studies called clinical trials led by Fred Hutch physicians and researchers. Many of these trials at Fred Hutch have led to FDA-approved treatments and have improved standards of care globally. Together, you and your physician can decide if a study is right for you.

Find a Clinical Trial Led by Dr. Mielcarek

Publications

Many of our Fred Hutch physicians and researchers conduct ongoing research to improve standards of patient care. Their work is evaluated by others in their field and selected for publication to the United States National Library of Medicine, the largest medical library in the world. See scientific papers this Fred Hutch physician has written.

View Dr. Mielcarek's Publications

Your Care Team

At Fred Hutch, you receive care from a team of providers with extensive experience in your disease. Your team includes physicians, a patient care coordinator, a registered nurse, an advanced practice provider and others, based on your needs. You also have access to experts like registered dietitians, social workers, acupuncturists, psychiatrists and more who specialize in supporting people with cancer or blood disorders. 

Meet Other Providers

Insurance

Fred Hutch accepts most national private health insurance plans as well as Medicare. We also accept Medicaid for people from Washington, Alaska, Montana and Idaho. We are working to ensure that everyone, no matter what their financial situation, has access to the care they need.

More About Insurance

Stories

All news
Oncology Insights with Dr. Petros Grivas - Episode 16
Oncology Insights with Dr. Petros Grivas - Episode 16 Dr. Marco Mielcarek on making blood and marrow transplants safer and more accessible June 16, 2026
Two lifetimes’ worth of bone marrow transplant breakthroughs
Two lifetimes’ worth of bone marrow transplant breakthroughs Bone marrow transplant pioneer Dr. Rainer Storb retires and reflects on six decades of science and mentorship August 14, 2025
Innovative approaches to lymphoma: clinical trials including CAR T-cell therapy, transplant, bispecific antibodies, novel kinase and checkpoint inhibitors
Innovative approaches to lymphoma: clinical trials including CAR T-cell therapy, transplant, bispecific antibodies, novel kinase and checkpoint inhibitors July 17, 2020

Contact Information

206.667.2827

206.667.6124