AstraZeneca Reveals Mulberry and Chestnut Data on Children’s Bone Health

AstraZeneca presented Phase 3 data from its Mulberry and Chestnut clinical trials on June 28, 2026, at the International Conference on Children’s Bone Health. The data provides the clinical foundation for a $5 billion revenue forecast associated with a successor to the company’s bone disease treatment, Strensiq.

The disclosure follows an April 2026 earnings call where the company outlined financial expectations for its rare disease pipeline. The Mulberry and Chestnut trials focused on pediatric patients with bone disease, targeting improvements over existing therapeutic options.

Why is there a $5 billion forecast for the Strensiq successor?

The $5 billion projection is based on the potential market capture of a more efficient treatment for hypophosphatasia, the rare genetic bone disease Strensiq currently treats. According to company data shared during the June 28 conference, the Phase 3 results from the Mulberry and Chestnut trials are the primary drivers behind this valuation.

Pharmaceutical successors typically target higher efficacy or reduced dosing frequency to displace earlier versions of a drug. Strensiq, an enzyme replacement therapy, requires frequent administration, creating a business opportunity for a long-acting or more potent alternative.

The financial forecast mentioned in April 2026 suggests AstraZeneca expects the new asset to significantly expand its footprint in the pediatric bone health market by addressing the unmet needs of patients who struggle with the current Strensiq regimen.

How do the Mulberry and Chestnut trials compare to Strensiq?

While AstraZeneca did not release the full dataset to the public, the company presented the findings specifically to the International Conference on Children’s Bone Health. The Mulberry and Chestnut trials represent the final stage of clinical testing required before regulatory submission.

Strensiq’s current market position relies on its status as a critical treatment for preventing rickets and skeletal deformities in children. The successor’s value proposition, as indicated by the $5 billion forecast, likely hinges on superior clinical outcomes or a more manageable delivery mechanism than the original enzyme therapy.

This transition from Strensiq to a next-generation product is a standard industry strategy to protect revenue streams as patents age and to improve patient adherence through better drug delivery.

What was disclosed during the April earnings call?

During the April 2026 earnings call, AstraZeneca executives discussed the trajectory of their rare disease portfolio. Dunoyer mentioned the strategic importance of the bone disease pipeline during the call, linking the upcoming trial data to the company’s long-term financial goals.

The April call established the $5 billion figure as a key benchmark for the company’s growth in the pediatric sector. The subsequent release of the Mulberry and Chestnut data on June 28 serves as the clinical verification for the financial claims made during that call.

The company’s focus on these trials indicates a shift toward consolidating its dominance in the hypophosphatasia market before competitors can introduce alternative modalities.

What happens next for the bone disease drug?

AstraZeneca will likely move toward regulatory filings using the Phase 3 data from the Mulberry and Chestnut trials. The company’s ability to hit the $5 billion forecast depends on the speed of regulatory approval and the adoption rate among pediatric specialists.

The presentation at the International Conference on Children’s Bone Health is the final step in socializing the data with the medical community before the drug enters the formal approval process.