Reata’s Bardoxolone Methyl Benefits Patients with Chronic Kidney Disease, TSUBAKI Trial Shows

Kyowa Hakko Kirin, a partner company of Reata Pharmaceuticals, presented positive results from its TSUBAKI study showing that Reata’s investigational therapy bardoxolone methyl significantly improved kidney function in patients with chronic kidney disease (CKD) and type 2 diabetes.

The presentation, “Bardoxolone Methyl Improved GFR Measured by Standard Inulin Clearance: The TSUBAKI Study,” was delivered as a late-breaking oral presentation at the American Society of Nephrology Kidney Week 2017.

Data released on the TSUBAKI (NCT02316821) Phase 2 trial, which concluded in September, follows Reata’s release of preliminary data of its ongoing Phase 2/3 CARDINAL study (NCT03019185) that is investigating bardoxolone methyl in patients with CKD as a result of Alport syndrome.

CARDINAL, which is currently recruiting patients, showed to date that bardoxolone methyl improved kidney function in patients with Alport syndrome.

Underway at some 35 centers across the U.S., the CARDINAL Phase 3 study is evaluating the safety and efficacy of bardoxolone methyl in Alport syndrome patients  randomly assigned to either bardoxolone methyl treatment or a placebo control.

In the TSUBAKI study, patients were randomized to bardoxolone methyl in escalating doses — from 5 to 15 mg — delivered once-a-day for 16 weeks or a placebo.

Its primary efficacy endpoint was the change in glomerular filtration rate (GFR) — a test of kidney function —measured by inulin clearance from baseline through to the study’s end. The rate of inulin clearance is the gold-standard approach for measuring GFR.

At baseline, patients with CKD stage G3 — meaning they already had impaired kidney function — had a GFR of 48.5 mL/min/1.73 m2. After 16 weeks of treatment, the study reported significant improvement — a GFR of 6.6 mL/min/1.73 m2 — in these people versus those given placebo.

“The data from TSUBAKI are very encouraging and indicate that bardoxolone methyl clearly shows true improvements in GFR,” Mitsuo Satoh, vice president and head of R&D Division of Kyowa Hakko Kirin said in a press release.

“On the basis of the data, we are excited to plan a phase 3 study of bardoxolone methyl in diabetic kidney disease patients,” he added.

Kyowa Hakko Kirin has the rights to develop and commercialize bardoxolone methyl in renal and certain other indications in Japan, China, Taiwan, South Korea and Southeast Asia under a license agreement with Reata signed in 2009.

These results and preliminary data on Reata’s CARDINAL study support bardoxolone methyl as aiding kidney function in patients with various forms of CKD, including Alport syndrome.