This is a multi-center, Phase 2 Long-Term, Open Label Extension (OLE) Study to assess the safety and tolerability of pemziviptadil (PB1046) at an optimally titrated dose. This is a Long-Term, Open label Extension (OLE) Study for subjects with (PAH), having participated in double-blind Study PB1046-PT-CL-0004. The study will include adult subjects previously diagnosed with symptomatic PAH, who are receiving background clinician-directed therapy for PAH. During this period, subjects will continue to be followed for safety and tolerability, as well as for periodic efficacy, quality of life data and immunogenicity. The study will continue per the schedule of events until such time when pemziviptadil (PB1046) is able to be self-administered, becomes commercially available to the subjects in a particular country or region, or the sponsor terminates the study due to lack of efficacy, safety or other reasons.



Eligible Ages
Between 18 Years and 79 Years
Eligible Genders
Accepts Healthy Volunteers

Inclusion Criteria

  • Subjects must have completed Week 17 / End of Study of PB1046-PT-CL-0004;
  • Willing and able to sign a written Informed Consent (IC) prior to all study-related procedures;
  • Agrees to use a medically acceptable method of contraception (both male and female patients) throughout the entire study period and continuing for 30 days after their last dose of study drug. if the possibility of conception exists. Medically acceptable methods of contraception include the following: abstinence (not having sex), vasectomy (with confirmed negative sperm counts), condoms and partner using vaginal spermicide and/or cervical cap with spermicide or sponge; oral, implantable, or injectable contraceptives (starting ˃2 months before dosing), diaphragm with vaginal spermicide, intrauterine device, surgical sterilization (˃6 months after surgery). Female subjects ˂45 years of age of non-childbearing potential are defined as being surgically sterile by bilateral tubal ligation, bilateral oophorectomy, or hysterectomy. Female subjects 45to-60 years of age, inclusive, who are post-menopausal for at least 1 year, and have a follicle-stimulating hormone (FSH) level confirmation indicating post-menopausal status, will be considered to be of non-childbearing potential. Female subjects > 60 years of age are considered post-menopausal and of non-childbearing potential;
  • Willing and able to understand and follow instructions, return to the study unit for specified study visits; and, be able to participate in the study through the Stable Dose Maintenance Period, at a minimum.

Exclusion Criteria

  • Concomitant medical disorder, condition, or history, that in the opinion of the Investigator, would impair the subject's ability to participate in or complete the requirements of the study;
  • Pregnant or lactating female subjects;
  • Significant liver dysfunction as measured by any one of the following during participation in PB1046-PT-CL-0004. (If exclusionary laboratory results become available after the subject has enrolled in PB1046-PT-CL-0006 they should be discontinued. a. alanine aminotransferase (ALT) > 3.0 times upper limit of normal (ULN) or; b. aspartate aminotransferase (AST) > 3.0 times ULN or; c. serum bilirubin ≥ 1.6 mg/dL.
  • Recent history of substance abuse that, in the opinion of the Investigator, would impair the subject's ability to participate in or complete the requirements of the study;
  • In the opinion of the principal investigator (PI), any major surgical procedure within 90 days, or a planned surgical procedure during the study period; which would impact participation in PB1046-PT-CL-0006.
  • Other new medical or psychiatric conditions which, in the opinion of the Investigator, would place the subject at increased risk, would preclude obtaining voluntary consent, or would confound the objectives of the study;
  • Known hypersensitivity to study drug or any of the excipients of the drug formulation.

Study Design

Phase 2
Study Type
Intervention Model
Sequential Assignment
Intervention Model Description
To protect the blind of the parent study (PB1046-PT-CL-0004), all subjects entering PB1046-PT-CL-0006 will commence dosing at Week 1 on 0.4 mg/kg and will be up-titrated in 0.2 mg/kg increments in an open label fashion for 9 weeks.
Primary Purpose
None (Open Label)
Masking Description
Subjects entering the 0006 trial prior to the implementation of this protocol amendment will remain blinded until such time that open label dosing will not unblind the 0004 study.

Arm Groups

ArmDescriptionAssigned Intervention
Pemziviptadil (PB1046) Injection-OL Active Drug-Up-Titration to Stable Dose
Pemziviptadil (PB1046) Injection: Regardless of dose assignment, all subjects will be up-titrated in 0.2 mg/kg weekly increments, beginning with 0.4 mg/kg at Week 1, to the target dose of 1.2 mg/kg or higher depending on safety and tolerability.
  • Drug: Pemziviptadil (PB1046) Injection
    Once-weekly subcutaneous injection

Recruiting Locations

University of Kansas Medical Center
Kansas City, Kansas 66160
Luigi Boccardi

More Details

PhaseBio Pharmaceuticals Inc.

Study Contact

Detailed Description

Subjects entering this study will enter from the double-blind Study PB1046-PT-CL-0004. The starting dose level of pemziviptadil (PB1046) for all subjects in this parent study was a sub-therapeutic or minimally effective dose (MED) of 0.2 mg/kg, administered by SC injection.

Subjects were randomized into the MED) Group or a dose-titration group. In the dose-titration group, individual subjects were titrated up to their maximum tolerated dose (MTD) in a blinded fashion, with the objective of titrating subjects up to a dose of at least 1.2 mg/kg or higher in the MTD Group, while subjects in the MED Group remained at the MED level of 0.2 mg/kg, and underwent "sham dose-titration" to maintain the blind.

Subjects entering the 0006 trial prior to implementation of this protocol amendment will remain blinded until such time that open label dosing will not unblind the 0004 study.


Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.