Amgen, AstraZeneca’s Tezepelumab Impresses in Phase 3 Asthma Trial

On November 9th, Amgen and AstraZeneca announced the Phase 3 clinical trial results of Tezepelumab, a novel monoclonal antibody for the treatment of severe asthma. Results demonstrated that the drug significantly reduced asthma exacerbations (asthma attacks) compared to placebo.

Globally, there are approximately 339 million people with asthma, and the rates of this disease have been increasing since the early 1980s. According to the Centers for Disease Control (CDC), more than 25 million people have asthma in the USA, which is 1 in 13 Americans. Although the exact cause of asthma is unknown, it is believed to be a combination of environmental and genetic factors. Asthma can range from a minor nuisance to a life-threatening and debilitating disease. It can have severe effects on the quality of life and result in a significant socio-economic burden.

Currently, there is no cure for asthma, although it can be managed with inhaled corticosteroids, leukotriene modifiers, combination inhalers, or Theophylline. However, many people with severe asthma present an inadequate response to these medications. There is a clear need for novel medication that can help people with severe asthma.

Tezepelumab

Tezepelumab is a monoclonal antibody that blocks a protein called Thymic stromal lymphopoietin (TSLP). TSLP is primarily located in the airway epithelium, the cells exposed to viruses, allergens, pollutants, and other environmental factors that can lead to inflammation. Upon reaction with allergens, TSPL is released from the cells and can lead to a severe inflammatory response, leading to an exacerbation. In 2012, Amgen and AstraZeneca signed an agreement to share cost and profits equally for the drug’s development and commercialization.

NAVIGATOR and SOURCE Clinical Trials

The efficacy of Tezepelumab was tested in two Phase 3 clinical trials, NAVIGATOR, and SOURCE.

NAVIGATOR is a randomized, double-blinded, placebo-controlled study that included adults and adolescents with severe, uncontrolled asthma. The trial consisted of 52 weeks of treatment, followed by a 12 week follow-up period. The results showed that Tezepelumab, combined with the standard of care, resulted in a statistically significant reduction in the annualized asthma exacerbation rate during the 52 weeks of the trial. Additionally, preliminary analysis showed no significant side effects of Tezepelumab when compared to the placebo group. These results are very encouraging and show for the first time that targeting TSLP can have a clinically meaningful benefit for asthma patients.

“We are absolutely thrilled with the topline results of the NAVIGATOR study in this broad population of patients with severe asthma, regardless of eosinophil count,” said David M. Reese, M.D., Executive Vice President of Research and Development at Amgen. “Tezepelumab represents a potential new class of biologics that could enable us to treat severe asthma at the top of the inflammatory cascade, addressing a high unmet need among the millions of patients living with severe asthma throughout the world. Tezepelumab has the potential to revolutionize care with efficacy demonstrated even in patients with a low eosinophil count”.

These results demonstrate the potential of targeting TSLP for asthma, which is also good news for Novartis. They are currently on Phase 2 clinical trials testing the efficacy of CSJ117, an antibody fragment targeting TSLP, in patients with severe uncontrolled asthma.

By Daniel Ojeda, Ph.D.

Related Article: GSK’s Trelegy Brings Relief to Millions Suffering from Asthma

References

1. https://www.amgen.com/media/news-releases/2020/11/tezepelumab-navigator-phase-3-trial-met-primary-endpoint-of-a-statistically-significant-and-clinically-meaningful-reduction-in-exacerbations-in-a-broad-population-of-patients-with-severe-asthma/
2. https://www.aafa.org/asthma-facts/#:~:text=According%20to%20the%20Centers%20for,in%2013%20people%20have%20asthma.&text=More%20than%2025%20million%20Americans,age%2C%20sex%20and%20racial%20groups.
3. https://www.mayoclinic.org/diseases-conditions/asthma/diagnosis-treatment/drc-20369660
4. https://respiratory-research.biomedcentral.com/articles/10.1186/s12931-020-01505-x
5. https://www.novartis.com/clinicaltrials/study/nct04410523

Author

Daniel Ojeda