Phase 2

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We believe that by blocking GM-CSF signaling, mavrilimumab may be able to reverse the course of GCA by upstream targeting of the cell types driving the inflammatory process, a mechanism that is different from currently available therapies.

  • The GM-CSF signaling pathway has been shown to be upregulated in GCA biopsies versus control at both the messenger ribonucleic acid (mRNA) and protein level.
  • Mavrilimumab reduced inflammatory molecules characteristic of GCA pathophysiology in an ex vivo GCA artery culture model.
  • Mavrilimumab reduced arterial inflammation compared to control in an in vivo model of vasculitis.
  • In previous Phase 2b trials in rheumatoid arthritis, mavrilimumab demonstrated rapid and prolonged reductions in interleukin-6 (IL-6) production, which is indicative of suppression of tissue inflammation upstream.

Status: Phase 2

We are conducting a randomized, double-blind, placebo-controlled, global Phase 2 proof-of-concept clinical trial of mavrilimumab in patients with GCA.

The Phase 2 clinical trial is expected to enroll subjects with new-onset and refractory disease. Subjects will be randomized 3:2 to 150 mg of mavrilimumab or placebo injected subcutaneously once every 2 weeks and coadministered with a corticosteroid taper. Treatment duration is 26 weeks, and the primary efficacy endpoint is time to first flare. Data are expected in the fourth quarter of 2020.

COVID-19 Pneumonia and Hyperinflammation

Kiniksa is enrolling and dosing the global, randomized, double-blind, placebo-controlled Phase 2 portion of an adaptive design Phase 2/3 clinical trial of mavrilimumab in severe COVID-19 pneumonia and hyperinflammation. Additionally, a randomized, double-blind, placebo-controlled investigator-initiated study in the U.S. is enrolling and dosing patients.

In an open-label treatment protocol in Italy, 13 non-mechanically ventilated patients with severe COVID-19 pneumonia and hyperinflammation were treated with a single intravenous dose of mavrilimumab. Twenty-six contemporaneous non-mechanically ventilated patients with severe COVID-19 pneumonia and hyperinflammation and with similar characteristics upon admission, including comorbidities, baseline inflammatory markers and respiratory dysfunction, were evaluated as a control-group. All patients received standard of care therapy, including antivirals and antibiotics.

Over the course of a 28-day follow-up period, mavrilimumab-treated patients experienced earlier and improved clinical outcomes than control-group patients, including earlier weaning from supplemental oxygen, shorter hospitalizations, and no deaths. Mavrilimumab was well-tolerated in all patients, without infusion reactions.


Unmet Need

Corticosteroids are the mainstay for the treatment of GCA, but approximately 50% to 70% of patients are corticosteroid refractory or corticosteroid dependent. Long-term administration of corticosteroids carries significant morbidity, especially in an elderly population such as in those with GCA. The FDA recently approved an inhibitor of IL-6 activity as an adjunct to a corticosteroid taper for the treatment of GCA; however, IL-6 production is downstream of GM-CSF and does not address all of the underlying causes of inflammation.

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We are intent on developing an array of innovative therapies that answer the many and varied needs of patients.