Disappointing clinical trial results have prompted Global Blood Therapeutics to scrap its program to develop GBT440 as a treatment for idiopathic pulmonary fibrosis.
GBT440 increased patients’ lung oxygen levels, but not enough to be considered an effective IPF therapy.
The company said it will continue developing GBT440 as a possible treatment for sickle-cell disease, however, holding additional clinical trials for that application. “We remain on track to announce top-line clinical trial results from our Phase 3 HOPE study [of GBT440 as a sickle-cell disease therapy] in the first half of 2019,” said Dr. Ted W. Love, the company’s president and chief executive officer.
Love said in a press release that his team is disappointed that GBT440 was unable to meet its IPF trial goals and thus help patients with the disease. He said the company was ”grateful to the patients, healthy volunteers and healthcare professionals who participated in the trials.”
“From the outset, we set a high bar for success in our IPF program,” Love said. Although the therapy candidate failed to alleviate the disease’s symptoms, the trials did “re-affirm our confidence in the mechanism of action of GBT440,” he said.
The three trials were the Phase 1 Basecamp study (NCT03051711), which involved healthy volunteers, and the Phase 2a GBT440-006 (NCT02846324) and ZEPHYR (NCT02989168) studies, which involved IPF patients.
Researchers said the trials met their safety objectives, and showed that both healthy volunteers and IPF patients tolerated GBT440 well.
The healthy volunteers in the Basecamp study received GBT440 under hypoxic conditions — or situations where the lungs were unable to obtain enough oxygen.
Researchers said the therapy significantly increased patients’ oxygen levels. In addition, GBT440 helped the red blood cell molecule hemoglobin do a better job of carrying oxygen.
GBT440 also increased patients’ oxygen levels in the GBT440-006 trial, although the improvement was more moderate than in the Basecamp trial. When researchers gave the therapy to adults with low oxygen levels during exercise, it significantly increased those levels.
But the highest dose that patients received failed to increase their oxygen levels to the point that researchers considered it an effective IPF therapy. They concluded that it offered no meaningful benefit to IPF patients, even when combined with exercise.
In the ZEPHYR trial, GBT440 failed to improve the oxygen levels of patients with more severe cases of IPF.
The trials showed that GBT440 did improve the oxygen levels of healthy volunteers and IPF patients, but not enough to make a difference.
Global Blood Therapeutics plans to present the findings at a conference.
The company said it “intends to make no further investments in additional clinical studies in hypoxemia [low-levels of oxygen in the blood] with GBT440 and intends to stop further enrollment in any ongoing studies.”