Global Blood Therapeutics has enrolled its first patient in the ZEPHYR Phase 2a clinical study assessing the safety and effectiveness of GBT440 in treating hypoxemia (low levels of oxygen in the blood) in patients with idiopathic pulmonary fibrosis (IPF) who are on supplemental oxygen at rest.
GBT440 is an oral, once-daily hemoglobin modifier, originally developed for sickle cell disease, now being tested in patients with hypoxemia associated with lung diseases like IPF. GBT440 works by increasing hemoglobin’s affinity for oxygen.
The effects of GBT440 analogs have been established in three different animal models of hypoxia, with the results supporting the beneficial therapeutic effects of hemoglobin modifiers in the treatment of hypoxemia associated with chronic fibrotic lung diseases, including IPF.
The company now has two clinical trials underway assessing GBT440 for hypoxemia in a broad range of IPF patients, including those who are on supplemental oxygen at rest and patients who become hypoxemic with exercise.
“Although supplemental oxygen is an important treatment for IPF patients with hypoxemia, it’s also a burden due to the mobility restrictions posed by oxygen delivery devices and, as a result, adherence to therapy may be limited,” Ted W. Love, MD, president and CEO of GBT, said in a press release.
Allowing these patients to become oxygen-independent or reduce their need for oxygen would be very helpful, he said.
“This Phase 2a study will provide further important evidence to validate GBT440’s unique hypoxemia-targeting mechanism of action,” Love added. “We believe that GBT440 has the potential to be a promising therapeutic option for IPF patients. Together with the data from our other ongoing Phase 2a study (GBT440-006) in IPF patients who do not use oxygen at rest but become hypoxemic with exercise, we intend to utilize findings from ZEPHYR to further inform our strategy in this indication.”
ZEPHYR is a randomized, double-blind, placebo-controlled Phase 2a trial (NCT02846324) evaluating the safety, tolerability, pharmacokinetics and effect of a daily oral dose of GBT440 (900 mg) on hypoxemia in 16 IPF patients, ages 45 to 80, who are receiving supplemental oxygen at rest.
The trial will assess the effect of the drug on oxygen saturation at rest for 90 days as its primary endpoint. The trial will also evaluate the effect of GBT440 on the requirement for supplemental oxygen, symptoms related to IPF, and patients’ quality of life. These secondary endpoints will be measured using patient-reported outcomes and the six-minute walk distance (6MWD) test.