Trial Search Results

FK506 (Tacrolimus) in Pulmonary Arterial Hypertension

Mutations in bone morphogenetic protein receptor 2 (BMPR2) are present in >80% of familial and ~20% of sporadic pulmonary arterial hypertension (PAH) patients. Furthermore dysfunctional BMP signaling is a general feature of pulmonary hypertension even in non-familial PAH.

We therefore hypothesized that increasing BMP signaling might prevent and reverse the disease. We screened > 3500 FDA approved drugs for their propensity to increase BMP signaling and found FK506 (Tacrolimus) to be a strong activator of BMP signaling. Tacrolimus restored normal function of pulmonary artery endothelial cells, prevented and reversed experimental PAH in mice and rats.

Given that Tacrolimus is already FDA approved with a known side-effect profile, it is an ideal candidate drug to use in patients with pulmonary arterial hypertension.

The aims of our trial are:

1. Establish the Safety of FK506 in patients with PAH.

2. Evaluate the Efficacy of FK506 in PAH

3. Identify ideal candidates for future FK506 phase III clinical trial.

Stanford is currently accepting patients for this trial.

Lead Sponsor:

Edda Spiekerkoetter

Collaborator: Stanford University

Stanford Investigator(s):


  • Drug: Placebo
  • Drug: FK506 level < 2 ng/ml
  • Drug: FK506 level 2-3 ng/ml
  • Drug: FK506 level 3-5 ng/ml


Phase 2


Inclusion Criteria:

   1. Age ≥ 18 and < 70 years

   2. Diagnosis of WHO Group I Pulmonary Arterial Hypertension (PAH) (Idiopathic (I)PAH,
   Heritable PAH (including Hereditary Hemorrhagic Telangiectasia), Associated (A)PAH
   (including collagen vascular disorders, drugs+toxins exposure, congenital heart
   disease, and portopulmonary disease).

   3. Stable on active PAH treatment including any prostacycline or phosphodiesterase
   inhibitors and the endothelin antagonist Ambrisentan alone or in combination
   (stability defined as: <10% change in 6MWD, no change in NYHA class, no
   hospitalization or addition of PAH therapy for at least 3 months).

   4. Previous Right Heart Catheterization that documented:

      1. Mean PAP ≥ 25 mmHg.

      2. Pulmonary capillary wedge pressure < 15 mmHg.

      3. Pulmonary Vascular Resistance ≥ 3.0 Wood units or 240 dynes/sec/cm5

   5. WHO functional class I to IV as judged by the investigator.

Exclusion Criteria:

   1. WHO Group II - V Pulmonary Hypertension.

   2. Current or prior experimental PAH treatments within the last 6 months (including but
   not limited to tyrosine kinase inhibitors, rho-kinase inhibitors, or cGMP modulators).

   3. Current active treatment with the dual endothelin receptor antagonist bosentan.

   4. TLC < 60% predicted; if TLC b/w 60 and 70% predicted, high resolution computed
   tomography must be available to exclude significant interstitial lung disease.

   5. FEV1 / FVC < 70% predicted and FEV1 < 60% predicted

   6. Significant left-sided heart disease (based on screening Echocardiogram):

      1. Significant aortic or mitral valve disease

      2. Diastolic dysfunction ≥ Grade II

      3. LV systolic function < 45%

      4. Pericardial constriction

      5. Restrictive cardiomyopathy

      6. Significant coronary disease with demonstrable ischemia.

   7. Chronic renal insufficiency defined as an estimated creatinine clearance < 30 ml/min
   (by MDRD equation).

   8. Current atrial arrhythmias not under optimal control.

   9. Uncontrolled systemic hypertension: SBP > 160 mm or DBP > 100mm

10. Severe hypotension: SBP < 80 mmHg.

11. Pregnant or breast-feeding.

12. Psychiatric, addictive, or other disorder that compromises patient's ability to
   provide informed consent, follow study protocol, and adhere to treatment instructions.

13. Active cyclosporine use.

14. Known allergy or hypersensitivity to FK-506.

15. Planned initiation of cardiac or pulmonary rehabilitation during period of study.

16. Human Immunodeficiency Virus infection.

17. Moderate to severe hepatic dysfunction with a Pugh score >10.

18. Hyperkalemia defined as Potassium > 5.1 mEq/L at screening .

19. Known active infection requiring antibiotic, antifungal, or antiviral therapies.

20. Co-morbid conditions that would impair a patient's exercise performance and ability to
   assess WHO functional class, including but not limited to chronic low-back pain or
   peripheral musculoskeletal problems.

Ages Eligible for Study

18 Years - 70 Years

Genders Eligible for Study


Now accepting new patients

Contact Information

Stanford University
School of Medicine
300 Pasteur Drive
Stanford, CA 94305
Edda Spiekerkoetter, MD