Heidelberg Pharma Partner Telix Pharmaceuticals Provides Regulatory Update on Imaging Agent TLX250-CDx

Heidelberg Pharma AG announced that its licensing partner, Telix Pharmaceuticals, has received a Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) regarding the Biologics License Application (BLA) for its imaging agent TLX250-CDx. The CRL identifies deficiencies related to the Chemistry, Manufacturing, and Controls (CMC) package.

Telix submitted the BLA in December 2024 and was granted Priority Review with a target FDA decision date of August 27, 2025. However, the FDA has requested additional data to demonstrate comparability between the drug product used in the Phase 3 ZIRCON trial and the scaled-up manufacturing process for commercial use. The agency also flagged issues with two third-party manufacturing partners that require remediation.

Telix stated it believes these issues are readily addressable and plans to begin corrective actions immediately, with updated timelines to be shared soon.

Under the licensing deal, Heidelberg Pharma stands to receive milestone payments and double-digit royalties upon market approval of TLX250-CDx. The company had sold a portion of future royalties to HealthCare Royalty (HCRx) and is eligible to receive $70 million upon FDA approval, a milestone now delayed due to the CRL. As a result, Heidelberg Pharma’s current cash runway remains stable through Q1 2026.

The company’s management and supervisory boards are currently exploring alternative financing and cost-saving measures in response to the update.