Open label Extension of Study PB1046-PT-CL-0004

This is a research study involving an investigational drug called PB1046. The word “investigational” means this drug is still being tested in a research setting and is not approved by the U.S. Food and Drug Administration (FDA).  Throughout the remainder of this consent form the investigational drug, PB1046 will be referred to as the “study drug”.

The active ingredient in the study drug is a slightly changed form of a protein called vasoactive intestinal peptide (VIP).  The VIP protein is normally found in the body. The change made to the natural protein helps to protect the protein from breaking down too quickly. It has been reported in scientific sources that the amount of VIP may be lower in people with Pulmonary Arterial Hypertension (PAH).

This study is being done for multiple reasons.  One reason is to see how well participants with PAH tolerate the study drug long term by checking bloodwork periodically and checking for side effects.  The study will also see whether your body makes antibodies against the study drug. Antibodies are proteins produced by the body's immune system that are usually found in the blood that help protect our bodies from harm by finding and destroying invaders, like bacteria and viruses.  They can also cause harm when they find other proteins that are not normally in the body like the study drug, and these antibodies can make the study drug, or the natural VIP found in our bodies, not work as well or not at all.

Inclusion Criteria

• Completed Week 17 End of Study of PB1046-PT-CL-0004

Exclusion Criteria

Study Requirements

• Pregnant of lactating female subjects
• Recent history of substance abuse
• Significant liver dysfunction as measured by any one of the following during participation in PB1046-PT-CL-0004.
  • alanine aminotransferase (ALT) > 3.0 times ULN or
  • aspartate aminotransferase (AST) > 3.0 times ULN or
  • serum bilirubin ≥ 1.6 mg/dL