FDA Rejects Edotreotide PET Imaging Kit Over Manufacturing Concerns

The US FDA has issued a complete response letter (CRL) for gallium Ga 68 edotreotide (LNTH-2501), a positron emission tomography (PET) diagnostic kit developed by Lantheus Holdings for localizing somatostatin receptor–positive (SSTR+) neuroendocrine tumors (NETs), the company announced June 26, 2026.¹

The FDA stated it could not approve the new drug application (NDA) by its June 29, 2026, action date because of unresolved manufacturing conditions at a third-party facility responsible for drug product production. The agency did not raise concerns about the data Lantheus submitted in support of the application and identified no issues related to the safety or efficacy of edotreotide, according to the company.

"The feedback received from the FDA relates solely to our third-party manufacturer, and not to the clinical performance of the product," Mary Anne Heino, executive chairperson and chief executive officer of Lantheus, said in a news release. "We are working closely with our partner and the Agency to address these facility manufacturing-related conditions and advance the program."

Edotreotide is supplied as a 2-vial kit distributed to radiopharmacies, where it is combined on-site with gallium eluate from a generator to prepare the final injectable PET tracer. This decentralized preparation model is intended to allow individual radiopharmacies to produce doses locally rather than rely on a centralized manufacturing and distribution network, an approach Lantheus has said could broaden access to SSTR-targeted PET imaging.²

Regulatory Timeline

Lantheus submitted the NDA for edotreotide under the FDA's 505(b)(2) pathway, which permits an applicant to rely in part on existing published data rather than generating an entirely new evidentiary package. The FDA initially set a Prescription Drug User Fee Act (PDUFA) target action date of March 29, 2026.³ In March 2026, the agency extended its review by 3 months to allow additional time to evaluate manufacturing-related information, setting the revised PDUFA date of June 29, 2026, that the CRL has now missed.⁵ The agency described that extension as unrelated to the efficacy or safety data supporting the application.

Clinical Evidence Base

The 505(b)(2) submission drew on 2 prospective trials evaluating the diagnostic accuracy of gallium Ga 68 edotreotide PET/CT for detecting SSTR+ NETs.¹

In the first trial (NCT01619865), 220 patients with known or suspected SSTR+ tumors underwent gallium Ga 68 edotreotide PET/CT, which investigators compared against indium In 111-pentetreotide (Octreoscan) SPECT combined with high-resolution, contrast-enhanced CT. Of the 220 patients enrolled, 177 had sufficient data to establish NET status against a composite reference standard. Positive percent agreement was 90% to 91% across 2 independent readers, and negative percent agreement ranged from 86% to 89%.

The second trial (NCT01869725) enrolled 62 patients with histologically confirmed NETs or other SSTR+ tumors undergoing disease evaluation before or after treatment; 59 patients had data sufficient for efficacy assessment. Gallium Ga 68 edotreotide PET/CT was compared against Octreoscan combined with contrast-enhanced CT or MRI. Positive percent agreement was 90% to 92%, and negative percent agreement was 75% for both readers.

Clinical Context

NETs are an uncommon and frequently slow-growing group of cancers that can arise throughout the body; more than 170,000 people in the United States are estimated to be living with the disease. Gastroenteropancreatic NETs, which originate in the digestive system and pancreas, account for an estimated 55% to 70% of cases. Because symptoms are often nonspecific, diagnosis is frequently delayed.

Accurate SSTR-targeted PET imaging informs several points along the NET care pathway, including initial diagnosis, staging, treatment response assessment, and selection of patients for peptide receptor radionuclide therapy (PRRT). A 505(b)(2) approval for gallium Ga 68 edotreotide would have added a generator-based, decentralized manufacturing option to existing SSTR PET agents that rely on centralized radiopharmaceutical production and distribution.

What Happens Next

Lantheus has not provided a timeline for resubmission. The company said it is working with its third-party manufacturing partner and the FDA to resolve the cited facility conditions, which it characterized as unrelated to the clinical data supporting the application. Edotreotide is not approved by the FDA and is not available for clinical use in the United States.

REFERENCES

1. Lantheus receives complete response letter from FDA for LNTH-2501 (Ga 68 edotreotide). News release. Lantheus Holdings, Inc; June 26, 2026. Accessed June 29, 2026. https://tinyurl.com/2na2bkpc

2. Lantheus announces FDA grants PDUFA date for LNTH-2501 (Ga 68 edotreotide), a PET diagnostic imaging kit targeting somatostatin receptor-positive (SSTR+) neuroendocrine tumors (NETs). News release. Lantheus Holdings, Inc; October 30, 2025. Accessed June 29, 2026. https://tinyurl.com/yc6xk5sh

3. Lantheus announces three-month extension of PDUFA date for LNTH-2501 (Ga 68 edotreotide), a PET diagnostic imaging kit targeting somatostatin receptor-positive (SSTR+) neuroendocrine tumors (NETs). News release. Lantheus Holdings, Inc. Accessed June 29, 2026. https://tinyurl.com/589dmtsb