Robert Spiera, MD, from Weill Cornell Medical College, New York, and principal investigator of the Phase 2 study, shared the data in a presentation titled, “Safety and Efficacy of Lenabasum in an Open-Label Extension of a Phase 2 study in Diffuse Cutaneous Systemic Sclerosis Subjects” at the 2019 European Congress of Rheumatology (EULAR 2019), June 12-15 in Madrid.
Lenabasum, developed by Corbus Pharmaceuticals, is an engineered small molecule designed to selectively activate the cannabinoid receptor type 2, or CB2, in immune cells and fibroblasts. Through activation of CB2, lenabasum triggers cellular signals that reduce inflammation, promote bacterial clearance, and prevent fibrosis.
Patients with dcSSc in the open-label extension study (NCT02465437) received 20 mg lenabasum twice a day after they had completed 12 weeks of treatment in Part A of the Phase 2 trial. Participants were allowed to continue their standard-of-care treatments in addition to lenabasum in Part B of the trial.
Previous data at one year after treatment with lenabasum showed that patients improved by 92% on their mean CRISS score (Combined Response Index in diffuse cutaneous Systemic Sclerosis) — a measure of disease state and organ damage — compared to the beginning of the extension study.
Also, skin thickness improved by 9.4 points, as determined by the modified Rodnan Skin Score, compared to the start of the trial. More than 77% of participants experienced at least a 5-point improvement, which is considered medically meaningful.
Now, data from 36 patients after 21 months of treatment showed that their CRISS scores remained above 95%, and skin thickness improved by more than 9.8 points. Skin symptoms, itch, and disability also improved or remained stable, according to patients and physicians.
Since the beginning of the study, however, the mean forced vital capacity percentage — a measure of lung function — declined -3.2 percent.
After 21 months, 81% of the patients were still enrolled in the open-label study.
During the study, no severe adverse effects linked with lenabasum treatment were reported. Almost all participants (97%) experienced one or more adverse effects during the 21 months of the study. However, only 11% of them had adverse effects directly linked with lenabasum. These included mild fatigue, skin ulcer, lymph node pain, and behavior disturbances such as attention deficit, mild lethargy, and abnormal feelings.
“These findings support the potential for lenabasum to be used as a chronic treatment,” Barbara White, MD, chief medical officer of Corbus, said in a press release.
The company is also testing lenabasum in a Phase 2 trial in patients with dermatomyositis, a rare inflammatory disease characterized by muscle weakness and a distinct skin rash.
“We are encouraged by the degree, durability, and consistency of improvement in multiple efficacy outcomes in subjects in both of these Phase 2 [systemic sclerosis] and [dermatomyositis] open-label extension studies,” White said.
Lenabasum is also being evaluated in the Phase 3 RESOLVE-1 trial (NCT03398837) in patients with dcSSc. Results are expected in the summer of 2020.