Global Blood Therapeutics’ GBT440 IPF trial endpoints challenging to record efficacy change; MOA elicits interest but dyspnea link not solid – experts

29 Aug 2017

Global Blood Therapeutics’ GBT440 IPF trial endpoints challenging to record efficacy change; MOA elicits interest but dyspnea link not solid – experts

Global Blood Therapeutics’ (NASDAQ:GBT) GBT440 has a mixed Phase II outlook in idiopathic pulmonary fibrosis (IPF) patients due to challenges in recording accurate improvements in oxygen saturation and clinical translation of such changes, expert said.

While some experts acknowledged GBT440’s concept of improving quality of life (QoL) by improving oxygen carrying capacity of hemoglobin (Hb), others pointed to the difficulties in consistent measurements of oxygen saturation levels with the pulse oximeter and inferring a clinically relevant measure from it. The drug is being studied in IPF patients who are on supplementary oxygen or not.

GBT440 is a small molecule Hb modulator that increases Hb’s oxygen affinity by enhancing oxygen tension or partial pressure of oxygen within red blood cells, and thus increases oxygen uptake in the lungs. GBT440 is designed to target hypoxemia, commonly found in IPF, according to Global Blood Therapeutics (GBT).

Analysts have noted increasing oxygen affinity may improve IPF dyspnea symptoms by increasing the oxygen carrying capacity of patients' blood. However, while dyspnea (difficulty in breathing) is a major challenge with IPF, it is not always associated with hypoxemia, said experts, calling into question the hypothesis that targeting hypoxemia would improve QoL by reducing breathing problems.

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