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Mergers & Acquisitions

Novartis enters multibillion-dollar agreement to buy Chinook

The deal broadens the Swiss pharma’s portfolio of renal disease treatments

by Shi En Kim
June 16, 2023

Swiss pharma giant Novartis has announced that it will acquire Chinook Therapeutics, a Seattle-based biopharmaceutical company that specializes in renal diseases for $3.2 billion upfront and potentially another $300 million or so in milestones. Two clinical assets for treating the kidney condition Immunoglobin A nephropathy (IgAN) are included in the deal.

Chemical structure for atrasentan

IgAN, or Berger’s disease, is an autoimmune condition that occurs when immunoglobin A antibodies clog the kidneys. The abnormal gunk sets off tissue inflammation, which causes the kidneys to leak blood and protein into urine. Over time, the condition can lead to organ failure. People with IgAN are commonly young adults who often need to undergo dialysis later in life.

No cure exists for IgAN, since the kidney’s blood-filtering units do not regenerate. Most treatments so far are aimed toward slowing disease progression.

Chinook hastwo promising late-stage clinical drugs for IgAN: atrasentan and zigakibart. Atrasentan is an endothelin A receptor antagonist that prevents the constriction of blood vessels to the kidneys, and so keeps the blood filtration rate low. Whereas, zigakibart is a monoclonal antibody that tamps down B-cell function to reduce the levels of the pathogenic IgA protein. Early-stage clinical trials demonstrated that both drugs suppressed the protein concentration in urine of trial participants. The two treatment candidates are now entering Phase 3 clinical studies.

Jonathan Barratt, a professor in renal medicine at the University of Leicester and a nephrologist at the Leicester General Hospital, was a clinical investigator for both treatments, which he personally observed to show promise, he says.

Novartis’s billion-dollar purchase echoes the flurry of hefty acquisitions by pharma companies in recent months, such as Merck’s purchase of Prometheus and Pfizer’s Seagen snag. Like these earlier deals, this one, too, is strategic. “Large pharmaceuticals have substantial funds to invest and are looking for growth drivers, especially due to patent expirations and other pressures,” says Peter Chang, a principal scientific analyst at Citeline.

With the acquisition of Chinook, Novartis now has three IgAN drugs on hand: the two Chinook assets plus an existing Phase 3 drug candidate, iptacopan, that reins in the complement immune pathway to suppress inflammation. Each of these drugs addresses different aspects of renal biology, and they represent the major drug classes that could become the standard of care for immune-mediated kidney diseases, Barratt says. No other company has such a broad drug portfolio for IgAN; the closest is Travere Thereapeutics’s endothelin receptor agonist that is a direct competitor to atrasentan. With this acquisition, the Swiss pharma giant could easily become a dominant player in the renal disease market.

The deal speaks to the long-standing belief among the scientific community that treating IgAN and other renal diseases requires combination therapy. No single treatment can plug the progression of IgAN on its own, and “Novartis has got [covered] the big three,” Barratt says. The hope is that a multipronged strategy can halt the disease in its tracks and maintain partial kidney function when the condition is first diagnosed. For people in their prime of their youth, that would mean “you don’t need any dialysis in your lifetime and you’ll have a normal life,” Barratt says.


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