Chinook Therapeutics to Present Updated Data from Zigakibart (BION-1301) Phase 1/2 Trial in Patients with IgA Nephropathy (IgAN) at the 60th European Renal Association (ERA) Congress

• Zigakibart treatment continues to demonstrate rapid and sustained reductions in mechanistic biomarkers, including IgA and Gd-IgA1 levels, which correspond to clinically meaningful proteinuria reductions in patients with IgAN across Cohorts 1 and 2
  
  
• Zigakibart is well-tolerated, with no ADAs observed or treatment discontinuations due to adverse events (AEs) in patients with IgAN across Cohorts 1 and 2
  
  
• In all patients combined from both Cohorts 1 and 2, zigakibart demonstrated mean proteinuria reductions of 20% at 12 weeks of treatment, 39% at 24 weeks of treatment and 67% at 52 weeks of treatment
  
  
• Extended treatment with zigakibart resulted in sustained clinical benefit, with 67% mean proteinuria reduction in seven patients at 76 weeks of treatment and 72% in five patients at 100 weeks of treatment
  
  
• Additional presentations on the phase 2 ASSIST and phase 3 BEYOND study designs, initial data from the phase 1 study of CHK-336 in healthy volunteers, as well as research on the impact of maladaptive tubular epithelial cells on disease progression in chronic kidney diseases will also be presented at the 60^th ERA Congress
  
  
• Due to the pending acquisition of Chinook by Novartis AG, the investor conference call and webcast previously scheduled for Friday, June 16, 2023 at 8:15 am EDT (2:15 pm CEST) has been cancelled
  

SEATTLE, June 12, 2023 (GLOBE NEWSWIRE) -- Chinook Therapeutics, Inc. (Nasdaq: KDNY), a biopharmaceutical company focused on the discovery, development and commercialization of precision medicines for kidney diseases, today announced a focused oral presentation on zigakibart (BION-1301) will be presented on Friday, June 16, 2023 at the 60^th ERA Congress being held virtually and live in Milan, Italy.

“The strong data we will be presenting at the ERA Congress from the ongoing phase 1/2 study of zigakibart continue to demonstrate its disease-modifying potential in patients with IgAN,” said Eric Dobmeier, president and chief executive officer of Chinook Therapeutics. “In addition to sustained reductions in mechanistic biomarkers and correlating clinically meaningful proteinuria reductions observed in patients with IgAN with a wide range of baseline proteinuria levels, the phase 1/2 study has provided us additional key learnings that we look forward to implementing in the phase 3 BEYOND trial, including dose, schedule and route of administration and patient selection.”

Updated Interim Results of a Phase 1/2 Study of Zigakibart (BION-1301) in Patients with IgA Nephropathy

Zigakibart is a novel anti-APRIL monoclonal antibody currently in phase 2 clinical development for patients with IgAN. Blocking APRIL is a potentially disease-modifying approach to treating IgAN by reducing circulating levels of galactose-deficient IgA1 (Gd-IgA1).

Updated data from both Cohorts 1 and Cohort 2 will be presented from Part 3 of the ongoing phase 1/2 multi-center trial (see www.clinicaltrials.gov, identifier NCT03945318) evaluating the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD) and clinical responses of open-label zigakibart treatment in patients with IgAN.

Key highlights from the presentation include the following:

Patients in Cohort 1 initially received a 450mg intravenous (IV) dose of zigakibart every two weeks. After at least 24 weeks of IV dosing, patients in Cohort 1 transitioned to a 600 mg subcutaneous (SC) dose every two weeks for a total treatment duration of up to two years. Cohort 1 enrolled 10 patients, of which two patients withdrew from the study for reasons unrelated to study drug, and eight patients continued receiving treatment.

Patients in Cohort 2 are receiving a SC dose of 600 mg of zigakibart every two weeks for a total treatment duration of up to two years. Cohort 2 enrolled 30 patients, of which three patients were discontinued for not meeting the eligibility criterion of having biopsy-confirmed IgAN, and 27 patients continued receiving treatment.

Baseline 24-hour Urine Protein Excretion (g/day)

• The median baseline 24-hour urine protein excretion for patients enrolled in Cohort 1 was 1.2 g/day, with a range of 0.7 – 6.5 g/day, and the median baseline 24-hour urine protein excretion for patients enrolled in Cohort 2 was 1.1 g/day, with a range of 0.3 – 7.0 g/day. With a median baseline 24-hour urine protein excretion for patients enrolled in both Cohorts 1 and 2 of 1.1 g/day, this population represents patients with IgAN at high risk of kidney disease progression.
  
  

Safety and Tolerability

• As of the May 8, 2023 data cutoff, zigakibart has been well tolerated, with no deaths or treatment discontinuations due to adverse events. Of all 40 patients enrolled in both Cohorts 1 and 2:
  
  
  • All infections have been Grade 1 or 2 in severity and only one subject had infections deemed treatment-related (Grade 1 viral upper respiratory tract infection and influenza).
    
    
  • There were no anti-drug antibodies observed in any patients.
    
    
  • Two patients had IgG levels that fell below 3 g/L. One patient in Cohort 1 required protocol-mandated withholding of study drug. The patient reached end-of-treatment prior to re-initiation of study drug. One patient in Cohort 2 had IgG levels below 3g/L at their week 12 follow-up after permanent discontinuation due to not meeting eligibility criteria for having biopsy-confirmed IgAN. No infections were reported in either patient while their IgG levels were below 3g/L.
    
    
  • There were 16 injection site reactions (ISRs) reported from a total of 875 SC doses administered (<2%). All ISRs were Grade 1 or Grade 2.
    
    
  • One serious adverse event occurred (amnesia) that was not treatment-related and did not result in interruption of study drug.
    

Mechanistic Biomarkers

• Zigakibart treatment resulted in rapid and sustained reductions in IgA, pathogenic Gd-IgA1, IgM and to a lesser extent IgG, in patients with IgAN. Zigakibart’s effects on mechanistic biomarkers were highly consistent between Cohorts 1 and 2 (see figures below).
  
  

https://www.globenewswire.com/NewsRoom/AttachmentNg/6608e190-53ad-4117-b6da-e521a2f9acef

https://www.globenewswire.com/NewsRoom/AttachmentNg/baac3459-0bf7-4b0d-8ffe-36e05158951f

24-hour UPCR

• Zigakibart treatment resulted in sustained, clinically meaningful proteinuria reductions in patients with IgAN across a wide range of baseline proteinuria levels.
  
  
• In the combined Cohorts 1 and 2, zigakibart demonstrated mean reductions in 24-hour urine protein creatinine ratio (UPCR) of 20% in 33 patients at 12 weeks of treatment, 39% in 33 patients at 24 weeks of treatment, 67% in 17 patients at 52 weeks of treatment, 67% in seven patients at 76 weeks of treatment and 72% in five patients at 100 weeks of treatment (see figure below).
  
  

https://www.globenewswire.com/NewsRoom/AttachmentNg/dca0b8df-b710-4f2c-b410-33f8aeafaf01

Overviews of the phase 3 BEYOND and phase 2 ASSIST trials are also being presented as focused oral presentations (digital poster with 3-minute presentation) on Friday, June 16, 2023. A moderated oral presentation (6-slide presentation) on research regarding the impact of maladaptive tubular epithelial cells on disease progression in chronic kidney diseases will be presented on Friday, and a free communication presentation (10-minute live oral presentation) on initial data from the phase 1 study of CHK-336 in healthy volunteers will be presented Saturday, June 17, 2023.

Focused Orals:

Free Communication:

Moderated Oral:

Once presented, all five presentations can be found in the Scientific Publications section of Chinook’s website. For more information on these and other abstracts, please visit the 60^th ERA Congress website.

Due to the pending acquisition of Chinook by Novartis AG, the investor conference call and webcast previously scheduled for Friday, June 16, 2023 at 8:15 am EDT (2:15 pm CEST) during the ERA Congress has been cancelled.

About Chinook Therapeutics, Inc.
Chinook Therapeutics, Inc. is a clinical-stage biopharmaceutical company developing precision medicines for kidney diseases. Chinook’s product candidates are being investigated in rare, severe chronic kidney disorders with opportunities for well-defined clinical pathways. Chinook’s lead program is atrasentan, a phase 3 endothelin receptor antagonist for the treatment of IgA nephropathy and proteinuric glomerular diseases. Zigakibart (BION-1301), an anti-APRIL monoclonal antibody, is being evaluated in a phase 1/2 trial for IgA nephropathy. CHK-336, an oral small molecule LDHA inhibitor for the treatment of hyperoxalurias, is in phase 1 development. In addition, Chinook’s research and discovery efforts are focused on building a pipeline of precision medicines for rare, severe chronic kidney diseases with defined genetic and molecular drivers. Chinook is leveraging insights from kidney single cell RNA sequencing and large CKD patient cohorts that have been comprehensively panomically phenotyped, with retained biosamples and prospective clinical follow-up, to discover and develop therapeutic candidates with mechanisms of action targeted against key kidney disease pathways. To learn more, visit www.chinooktx.com.

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