Why has kidney disease been left behind in the past and how has the landscape changed in recent years?
Kidney disease is often treated as a symptom of another disease indication (most often diabetes), with dialysis and transplantation as a common fallback for treatment, and thus it has not been viewed as a dire disorder. Patients tend to be treated with blood pressure lowering medication or steroids until their disease progresses and they need dialysis or kidney transplants. Our goal is to change the way kidney disease is treated and provide new therapeutics so that patients can live longer.
Traditionally, kidney disease trials had to be done using hard kidney outcomes conducted on thousands of patients over a decade. However, the FDA has recently started to allow surrogate endpoints so now we can do a trial in IgA nephropathy based only on 300 patients and over a span of a couple of years. Luckily, this improvement has encouraged a lot of small companies to get into this area and develop new drugs.
What do you hope to achieve with the three medications that you now have in clinical trials?
We have two drugs in development for IgA nephropathy - which is an autoimmune disease that affects young people, of which half progress towards kidney failure within 10 to 20 years. Atrasentan is in a Phase 3 clinical trial which is going to read out topline data in Q3 of next year, the same period when BION-1301 will start its Phase 3 that is going to span over the next three years. Our plan with both these drugs is to reduce protein in the urine (called proteinuria) by at least 20% to 30%. We have seen really unprecedented data in small, uncontrolled trials both for atrasentan which has registered 55% reduction in proteinuria and BION-1301 where we have seen up to 70% reduction. If we can translate these results into Phase 3 trials, we are going to have two incredibly strong medications on the market.
Our third drug, CHK-336, is for a rare kidney stone disease, more precisely oxalate stones that can be both genetic and idiopathic. The most severe form of this disease is called primary hyperoxaluria type 1 (PH1) and is a genetic disease where patients have rapid accumulation of stones from birth and often have kidney failure by the time they are 20 years old. Traditionally, they would do a kidney-liver transplant since it is caused by a liver enzyme deficiency, but there also is a new siRNA drug that has been approved in the last couple of years that is only used for severe forms. Beyond PH1, there are other variations (PH2, Ph3, etc.), and patients with stones associated with diabetes or obesity do not have a particular medication available.
As a result, we plan to develop an oral, small molecule drug that can be taken once a day to reduce oxalate levels across a wide range of these kidney stone diseases.
How challenging it is for a biotech company to attract capital nowadays, and what was the rationale behind your merger with Aduro Biotech?
In particular, small- and mid- CAP biotech companies are down 50% to 80% from where they were at the height of the market in early 2021 and there are about 200 players that are trading below their cash value. Thankfully, Chinook is an outlier, driven by fantastic clinical data we had on our first two programs out of the gate. Atrasentan was in-licensed from AbbVie, meaning we managed to go from research only to R&D with a Phase 3 ready asset. Our merger with Aduro Biotech helped boost our status as well. They were developing BION-1301 for multiple myeloma, but as it was not having the desired results, they pivoted to IgA nephropathy and we assumed development of the BION-1301 program upon the close of the merger. All these collaborations helped us a great deal and we managed to expand our market cap from $30 million to $1.5 billion.
Do you expect the Inflation Reduction Act to impact your ongoing effort to bring your drugs to market, and how do you believe we can ensure fair pricing for new drugs?
An age-old question is how to price medicines, but I believe there is too much focus on it since drugs take up only 10% of the healthcare spending in the U.S. Value-based pricing is already used in Europe and it is slowly winning more ground in the United States, as well. The Inflation Reduction Act is mostly going to affect small molecule drugs for larger patient populations who are older since it only applies to government care (primarily Medicare).
What are the most exciting milestones for Chinook in the upcoming two or three years?
Our next focus is the commercialization of atrasentan in North America, Asia and Europe, either through our own commercial infrastructure or through strategic partnerships. Kidney disease tends to disproportionally affect people of color in the United States and it is much more common in Asia, where there are several million patients. That being the case, we strive to make our clinical trials as inclusive as possible.
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