In this episode of The Gut-Onc Lab, Drs. Nicholas Hornstein and Udhayvir Grewal welcome world-renowned neuroendocrine authority Dr. Simron Singh (Sunnybrook Health Sciences Centre / University of Toronto) to explore why radioligand therapies are undergoing an explosive transformation. Moving from historical nuclear medicine “vibes” into a rigorous oncological trial framework, the panel dissects how the frontline map of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is being entirely redrawn.

Key discussion points include:

  • The Frontline Shift: Dr. Singh explains the rationale behind the practice-changing NETTER-2 trial—the first randomized trial of radioligand therapy in the first-line metastatic setting for any solid tumor—and its striking 72% reduction in the risk of progression or death for high-grade G2 and G3 well-differentiated tumors.
  • The SSTR2 Landing Strip: Why PRRT relies entirely on stable somatostatin receptor expression (Krenning 3 or 4 score), and the operational necessity of integrating dual-PET imaging (SSTR-PET + FDG-PET) to calculate a comprehensive NetPET Score.
  • Sequencing vs. Small Molecules: Analyzing the comparative data from COMPETE and OCCLURANDOM that establishes the clear progression-free survival and health-related quality of life superiority of PRRT over traditional small molecule choices like everolimus or sunitinib.
  • The Alpha Frontier (ACTION-1): An exclusive preview of the highly anticipated Fall 2026 readout of the Phase III ACTION-1 trial evaluating Actinium-225 labeled dotatate (RYZ101) in patients who have progressed through Lutetium-177, contrasting heavy beta emissions against localized double-stranded DNA breaks.
  • Therapy-Related Myeloid Neoplasms (TMN): A direct, honest dialogue on the long-term risk of treatment-related MDS and AML, the role of clonal hematopoiesis of indeterminate potential (CHIP), and how sequential alkylating agents alter the marrow baseline.
  • The 5-Year Vision: Slicing past the limits of a simplistic, static pathology slice toward dynamic 3D tumor mapping, alongside the arrival of DLL3-targeted bispecifics and antibody-drug conjugates (ADCs) for aggressive neuroendocrine carcinomas.

From the hockey analogies of “skating your best player in the first period” to eliminating the logistical 6-hour amino acid chair-time infusion burden, this conversation captures the precision medicine revolution hitting the neuroendocrine landscape.

Chapters:

00:00 PRRT and NETTER-1 Basics

02:08 Why NETTER-2 Went Frontline

04:50 NETTER-2 Results and Impact

05:26 Choosing First Line PRRT

07:56 NETTER-3 for Bulky Low Grade

10:32 Sequencing PRRT vs Other Drugs

14:13 Repeat PRRT and Key Trials

16:53 Dual PET and NetPET Score

20:09 Alpha PRRT Next Wave

25:08 TMN Risk and CHIP Biomarkers

27:35 Toxicities and Mitigation Tips

29:54 Future Outlook and Wrap Up

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