Tokuda Hospital Sofia


Principal Investigators

Prof. Ivan Staikov, Head of Neurology Department


Prof. Staikov has an experience over 20 years. He has taken part in over 80 clinical trials – 20 as sub-investigator and the rest as Principal Investigator. 

  • The site has been №1 in the world in the recruitment of patients in a clinical trial for acute ischemic stroke.
  • The site has been nominated twice as №1 for Europe.
  • The site has been nominated many times as №1 for Bulgaria.
  • During the last years the Neurology Clinic of “Acibadem City Clinic Tokuda Hospital” is an explicit leader regarding the number of conducted clinical trials and overachievement of the targeted number of randomized patients.
  • 178% Achievement rate.
  • The site has been audited many times and always with positive outcome.
  • Prof. Staikov has received several awards “Investigator of the year” for “Acibadem City Clinic Tokuda Hospital” EAD.


• MS
• Epilepsy
• Alzheimer’s disease
• Acute ischemic stroke
• Parkinson’s disease
• Sleep Disorders
• Diabetic polyneuropathy
• Post herpetic neuralgia
• Peripheral neuropathic pain
• Migraine

Prof. Simeon Stoinov, Head of Gastroenterology Clinic


  • Ulcerative Colitis
  • Crohn’s Disease
  • Gastro Esophageal Reflux

Great experience with clinical trials as Principal Investigator

Successfully passed a FDA audit.

Dr. Rozalina Balabanska, gastroenterologist, internal medicine


Dr. Balabanska has an experience  over 20 years. She has taken part in over 30 clinical trials. Most of them as Principal Investigator.


  • Hepatitis C
  • Hepatitis B
  • Cirrhosis
  • Nonalcoholic steatohepatitis

Dr. Balabanska is one of the top Principal Investigators of “Acibadem City Clinic Tokuda Hospital”.

90% Achievement rate.

Very fast recruitment and great planning. Perfect communication with the patients.

Great experience with phase I clinical trials.

The site has been audited many times and always with positive outcome.

Dr. Balabanska has received two awards “Investigator of the year” for “Acibadem City Clinic Tokuda Hospital” EAD.

Valeri Gelev, MD, Cardiology Clinic Chief

Over the last 15 years dr Gelev has participated as a sub-investigator and a Principal Investigator in a large number of clinical trials Phase II, III, IV


  • Acute Coronary Syndrome
  • Chronic Coronary Occlusions
  • myocardial infarction
  • heart failure
  • Atrial Fibrillation

The greatest advantage of Dr Gelev is that he is realistic about the number of patients. He always randomizes as much patients as he has promised.

Great interest in clinical trials with devices. 

The site has been audited few times and always with positive outcome.

Two angiographic laboratories are available.

Vasil Traikov, MD, Invasive Electrophysiology and Cardiac Stimulation Dept. Chief

Dr. Traykov is specialized in invasive cardiac electrophysiology procedures for the treatment of cardiac rhythm and conduction disorders.

  • Electrophysiology studies
  • Catheter ablation in the treatment of arrhythmias
  • Implantable electronic device therapy
    • Pacemakers
    • Cardioverter-defibrillators
    • Cardiac resynchronization therapy
  • 85% achievement rate
  • Member of EHRA scientific documents committee
  • Interests in:
    • Atrial fibrillation ablation
    • Catheter ablation of ventricular tachyarrhythmias
    • Cardiac resynchronization therapy 

Zhelyazko Arabadzhiev, MD, Medical Oncology Dept. Chief

Dr. Arabadjiev has a great interest in clinical trials. He was a Sub-investigator in more than 15 clinical trials and now he is a Principal Investigator.

Specific scientific interests and clinical focus on:

  • Breast cancer (early BC, ABC, tumor infiltrating lymphocytes as predictive and prognostic factor for TNBC)
  • CRC
  • Glioblastoma
  • Ovarian cancer
  • Head and neck cancer
  • Urogenital cancers (prostate, testicular, renal)
  • IO
  • American Association for Clinical Research (AACR)
  • Member of Bulgarian Cancer Scientific Society (BCSS)
  • Member of European Society of Medical Oncology (ESMO)
  • Member of American Society of Clinical Oncology 

Krasimir Oreshkov, MD, Oncologist, Internist

Dr. Oreshkov is an experienced Principal Investigator.


  • Non-Small Cell Lung Cancer
  • Small Cell Lung Cancer
  • Ovarian Cancer
  • Hepatocellular carcinoma
  • Breast Cancer
  • Pancreatic Cancer
  • Very precise Principal Investigator with great attitude toward patients.
  • Excellent achievement rate.
  • Audits with positive outcomes. 


Prof. Galina Kirova, Head of Medical Imaging Department 

Prof. Kirova is a remarkable specialist in Medical Imaging. She has vast experience in Clinical Trials as a sub-investigator and now she is a PI of 2 Clinical Trials.

  • Thanks to her huge experience in the National Oncology Center, she is very knowledgeable of the biology of cancer, its special features and peculiarities, diagnostic methods, and the monitoring of cancerous diseases. Her areas of special professional interest include lung diseases and she has worked long years as a consultant of Pulmonology, Thoracic Surgery and Rheumatology Clinics. In the last years her clinical and scientific interest is oriented towards the medical imaging diagnostics of the heart and the blood vessels.
  • She has interest and great experience in research activities.
  • She is author of over 150 scientific publications in national and worldwide national journals.
  • Prof. Kirova is a vice president of Bulgarian Radiology Association.
  • She is the deputy chief editor of the scientific journal “Roentgenology and radiology”.
  • She is a member of the editors’ boards of the magazines Rheumatology and Oncologus.
  • She is founder and chairman of the Bulgarian Society of Cardiothoracic Roentgenology for the period of 2010-2014 and a board member of the European Society for Cardiac Roentgenology.
  • Prof. Kirova was a board member of the Bulgarian Endovascular Society for the period of 2010-2014, as well as regular member of numerous of European and national associations and organizations.

She is a chairman of the Scientific Ethics Commission of Acibadem City Clinic Tokuda Hospital.

More about the Medical Imaging and the equipment it can be found here: 

Assoc. Prof. Natalia Stoeva, MD, PhD, Pneumology Clinic Chief

Assoc. Prof. Stoeva has an experience  with clinical trials since 2001. At the beginning she was sub-PI and from 2007 she is a Principal Investigator. She has proven herself as an excellent Investigator with perfect attitude toward patients and great attention to details.


  • COPD
  • Asthma
  • Pneumonia
  • Pulmonary Thromboembolism
  • Bronchoalveolic Cancer
  • Idiopathic Pulmonary Fibrosis
  • Other Interstitial Diseases
  • Flu

The site is fast recruiter  and many times is №1 in the world.

185% Achievement rate.

The site has been audited many times and always with positive outcome.

Many times our Pulmonology Department is chosen for external services for other sites for:

  • DLCO
  • Spirometry 

Radka Maslarska, MD, Neonatology Dept. Chief

Dr. Maslarska has been a Principal Investigator since 2004.


  • RSV infection
  • Influenza
  • Venous thromboembolism (VTE)
  • New food formula for babies
  • Bacterial pneumonia
  • Influenza Vaccines
  • Excellent achievement rate.
  • Dr. Maslarska’s scientific interests are focused upon intensive therapies, cardio-pulmonary adaptation and continuous monitoring of risky and high risk newborns. She has numerous scientific publications in national and international medical journals, and regularly participates in neonatology forums locally and abroad. 

Assoc. Prof. Kaloyan Davidoff, MD, PhD, Urology Dept. Chief

Assoc. Prof. Davidoff has an experience with clinical trials about 10 years. He has taken part in about 10 clinical trials as Principal Investigator.

The Urology Department has the most motivated young team that is highly qualified in oncourology, conventional, endoscopic, reconstructive and pediatric urology.

  • He has an experience in the following therapeutic areas:
    • Cystitis
    • Urinary Tract Infections
    • Bladder Cancer
    • Kidney Cancer
    • Prostate Cancer
    • During the last years the assoc. prof. Davidoff has achieved very good results in the clinical trials.
  • The site has been audited few times and the results were positive.
  • Modern treatment of urology diseases
    • Endoscopic treatment methods, Oncourology, Pediatric and Reconstructive Urology
    • Ultrasonic Lithotripsy
    • Laser treatment of prostatic adenoma
    • Diagnosis and treatment of sterility and erectile dysfunctions
    • Reproductive medicine
    • Da Vinci  Surgeries 

Prof. Vassil Chervenkoff, MD, PhD, Vascular Surgery Clinic Chief

Prof. Chervenkoff has been a Principal Investigator since 2010.

  • Therapeutic areas:
  • Diabetic foot ulcers
  • Peripheral Artery Disease
  • Critical Limb Ischemia
  • Prof. Chervenkoff is a National Lead Principal Investigator and a National Consultant, who acts as an International Steering Committee Member,  of a clinical trial.
  • Prof. Chervenkoff is a chairman of the Bulgarian National Society of Endovascular Therapy 

Prof. Milena Staneva, MD, PhD, Angiology Clinic Chief, National Angiology Consultant

Experience as PI:

  • Venous thromboembolism (VTE)

Luchezar Lozanov, MD, PhD, Endocrinology and Metabolic Diseases Dept. Chief

Assoc. Prof. Lozanov has been a Principal Investigator since 2012.

  • Therapeutic areas:
    • Type II Diabetes
    • Диабетна нефропатия тип  II

Assoc. Prof. Vassil Yablanski, MD, PhD, Orthopedic and Traumatology Clinic Chief

Dr. Yablanski has been a Principal Investigator since 2013.

  • Experience:
    • Pain relief treatment
    • Factor XIa Inhibitors

Good achievement rate.

Dr. Yablanski took further qualification courses in primary and revision endoprosthesis in Germany, Austria, Japan, France and Sweden, spine surgery in Spain, Turkey and Israel, as well as many others in world leading centers.

He has also passed additional post-graduate medical training for bone-joint surgery received in Salzburg, Austria and in the surgical department of Duke University Hospital in North Carolina, USA.

Prof. Kiril Draganov, MD, PhD, DSc, Hepatobiliary, Pancreatic and General Surgery Clinic Chief

Prof. Draganov has been a Principal Investigator since 2008 at Acibadem City Clinic Tokuda Hospital Sofia.

  • Main activities:
    • Open and mini-invasive (laparoscopic and robot-assisted) surgical treatment of:
      • benign and malignant diseases of the stomach and intestinal tract (mainly gastric and colorectal cancer)
      • pancreas (chronic pancreatitis, pancreatic cancer, NET, Pancreatic Cystic Neoplasms)
      • liver (primary and metastatic tumors, hydatid liver disease, abscesses)
      • gall bladder and bile ducts (cholecystitis, Klatskin tumors, reconstruction surgery after bile duct lesions caused by laparoscopic cholecystectomy);
      • Proctology (hemorrhoides, fistulas);
      • Hernia repairs (hiatal hernia, umbilical and inguinal hernias, postoperative ventral hernias);
      • Breast surgery (Benign and malignant diseases, Plastic reconstruction); Thyroid gland surgery.
      • Experience with Clinical Trials’ Therapeutic areas:
        • Prevention of venous thromboembolism after a surgery in patients who have undergone huge abdominal operation
        • Restoring gastrointestinal motility in patients who have undergone partial abdominal resection
        • Intra-Abdominal Infections
        • Administrаtion of medicine post-operatively in patients who have undergone partial bowel resection
        • Great achievement rate - based on target patients and recruited.

Kalin Lisichki, MD, Pediatric Clinic Chief


  • Acute Respiratory Tract Infection 

Galina Popova, MD, Pediatrician, Pediatric Endocrinologist


  • Type 1 Diabetes 

Zlatko Dimitrov, MD, Pediatrician, Allergist, Pediatric Allergist


  • HDM allergic asthma

Galina Stoycheva, MD, Pediatrician, Pediatric Pneumologist, Outpatient Room


  • Influenza
  • Asthma

Prof. Dr. George Hristov, MD, Allergologist


  • HDM-associated allergic rhinitis 

Prof. Nikolai Tzankov, MD, PhD, DSc, Dermatology and Venereology Clinic Consultant

Prof. Tzankov has an experience with clinical trials since 2010 as a Principal Investigator. 

  • Experience in clinical trials with the following therapeutic areas:
    • Plaque Psoriasis
  • The site has been audited few times and always with positive outcome.
  • Prof. Tzankov has over 350 publications in Bulgarian and international scientific editions
  • He is a member in the following scientific organizations:

    Chairman of the Bulgarian Dermatologic Society
    Member of the managing board of the European Academy for Dermatology and Venereology
    Foreign assistant of the Medical Faculty of Lariboisier Hospital Saint Louis - Paris
    Corresponfing member of the French Dermatologic Society
    Honorary member of the Czech, Yugoslavian, Macedonian, Polish, Romanian, Swiss and Serbian Dermatologic Societies
    Since 12 October 2016 honorable member of the French Dermatologic Society
    Member of the Specialized scientific council for dermatology, venereology, infectious diseases, epidemiology, parasitology and Helminthology of the Higher Attestation Commission
    Chairman of Prof. Bogomil Beron Foundation
    Member of the Managing Board of University Hospital Alexandrovska
    National consultant for Dermatology and Venearology
    Doctor of the year for 2005

    On April 11th 2014 during the 20th Congress of the Czech Academy of Dermatology, at a celebration ceremony in the Charles University Aula, prof. Tzankov was awarded honorary membership to the Czech Academy of Dermatology. This is the 14th honorary membership in a row for Prof. Nikolai Tzankov in Dermatologic Societies and Academies in Europe and USA.

Assoc. Prof. Zdravka Demerdjieva, Head of Dermatology Department and Venerology

Assoc. Prof. Demerdjieva has an experience with clinical trials since 2012. She took part in 9 clinical trials as Principal Investigator. 

  • Experience in clinical trials with the following therapeutic areas:
    • Plaque Psoriasis
    • Atopic Dermatitis
    • Lupus Erythematosus 
  • The site has been audited few times and always with positive outcome.
  • Assoc. Prof. Demerdjieva has specialized child dermatology in Manchester, UK 
  • Consultations:
    • Serious and worsening cases of psoriasis 
    • Bacterial skin infections
    • Bullous dermatoses
    • Toxic-Allergic reactions
    • Erythrodermia
    • Skin conditions resultant of other health issues and others

Dr. Alek Topov, Head of Ophtalmology Department

Dr. Topov has been a Principal Investigator since 2013.

  • Experience:
    • Diabetic Macular Edema
    • Age-Related Macular Degeneration (AMD)
  • Great achievement rate - based on target patients and recruited. 

Dr. Ismail Amine, Head of Hematology Department

Dr. Amine is an experienced investigator.  He took part in over 10 clinical trials. 

  • Experience in the following therapeutic areas:
    • Hematologic malignancy :
      • Hodgkin’s Lymphomas
      • Non-Hodgkin’s Lymphomas (T-cell and B-cell)
      • Multiple Myeloma, Amyloidosis and heavy and light -chain disorders
      • Chronic Myeloproliferative Diseases (CML, PV, AV, ET, MF)
      • Acute Leukemia (all types)
      • Hematologic benign
      • All types of Anemias
      • PNH
      • Auto-immune Hemolytic Anemias
      • Thrombocyte disorders (thrombocytopenias, all types)
      • 84% achievement rate.
  • Audits with positive outcomes.
  • Investigational team with experience and accuracy.

Dr. Irena Galabova, clinical hematologist, internist


  • Low Tumor Burden Follicular Lymphoma

Assoc. Prof. Alexander Osichenko, Head of Hemodialysis Department

Dr. Osichenko is an experienced investigator in the area of nephrology and dialysis.

  • 9 successfully finished clinical trials.
  •  92% achievement rate (based on target patients and recruited patients).

Dr. Osichenko is a member of the European Dialysis and Transplant Association, the Bulgarian Society of Nephrology and the National Association of Dialysis professionals in Bulgaria.

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Hospital location

51B Nikola Y. Vaptsarov Blvd., Sofia, 1407 (if you drive, the entrance is from Atanas Dukov str.)

The hospital has a parking lot for patients and visitors. The first 30 min. are free of charge, every next hour is 3BGN/hrs.
IMPORTANT! Have in mind that the parking lot is very busy Monday to Friday between 10.00 and 14.00. The hospital team will appreciate if those whose health condition allow, take the drop off option without parking or use other transport means or alternative parking lots in the area.

Public transport:
Buses: №88, 120

Metro lines: You can get off at James Bourchier or Vitosha metro station and walk to the hospital.


From the Central Railway Station

Bus: take bus #305 and get off at Romanian Embassy stop, then transfer to bus #120 to Tokuda Hospital stop.

Metro: Take metro line Nadezda-Lozenetz and get off either at James Bourchier or Vitosha metro station, then walk to the hospital.