FDA Approves Lutathera for GEP-NETs

Jonathan Strosberg, MD

The FDA has approved Lutathera (lutetium Lu 177 dotatate) for the treatment of patients with somatostatin receptor—positive gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

The approval is based on the phase III NETTER-1 trial, which compared Lutathera with high-dose octreotide LAR for patients with grade 1 or 2 metastatic midgut NETs. In this trial, there was a 79% reduction in the risk of progression or death with Lutathera compared with octreotide.

"There are very few effective treatment options for patients with inoperable, advanced GEP-NETs who are progressive on somatostatin analogues. As a medical oncologist seeing more than 500 patients with NETs each year, I am grateful to have another tool in my arsenal," NETTER-1 lead investigator Jonathan Strosberg, MD, associate professor, section Head, Neuroendocrine Tumor Program at Moffitt Cancer Center, said in a statement.

In NETTER-1, 229 patients with midgut NETs who progressed on standard-dose octreotide (30 mg) were randomized to Lutathera (n = 116) or high-dose octreotide (n = 113). Four doses of Lutathera were administered at 7.4 GBq every 8 weeks in combination with octreotide at 30 mg for symptom control. In the control arm, patients received octreotide LAR at 60 mg every 4 weeks.

Baseline characteristics were well balanced between the two arms. The mean age of patients in the investigational arm was 63 years (±9) and the mean BMI was 25 (±5). The primary tumor site was the ileum (74%) and the most common sites of metastasis were the liver (84%), lymph nodes (66%), and other locations (35%). All patients had somatostatin receptor-positive tumors, the majority of which were grade 4 on the Krenning scale (60%).

The primary endpoint of the study was progression-free survival (PFS). Secondary endpoints focused on objective response rates (ORR), overall survival (OS), and safety.

Median PFS had not been reached in the Lutathera arm compared with 8.5 months in the high-dose octreotide arm (HR, 0.21; 95% CI, 0.13-0.32; P <.0001).

The ORR with Lutathera was 13% versus 4% with octreotide (P <.0148). At the interim analysis of OS there was a 48% reduction in the risk of death seen with Lutathera versus octreotide (HR, 0.52; 95% CI, 0.32-0.84).

An adverse event (AE) of any grade was experienced by 96% of those in the Lutathera arm versus 86% of those in the octreotide group. Eighty-six percent and 31% of patients, in the Lutathera and octreotide groups, experienced treatment-related AEs, respectively. Treatment related serious AEs were experienced by 9% of patients treated with Lutathera versus 1% in the octreotide arm. Five patients discontinued the study due to Lutathera-related AEs.

The rates of the most common grade 3/4 AEs occuring at a higher frequency in the Lutathera group versus the high-dose octreotide arm were lymphopenia (44%); increased gamma-glutamyl transferase (20%); vomiting (7%); nausea and elevated AST (5% each); and increased ALT, hyperglycemia, and hypokalemia (4% each).

Lutathera consists of the somatostatin analog octreotide connected with the beta and gamma emitting radiopharmaceutical 177Lutetium (¹⁷⁷Lu). The 2 components are connected using the chelator DOTA. Lutathera represents a new generation of PRRT, and has been tested in several single-arm studies. In these trials, the median PFS ranged from 1 to 3 years.

The FDA had granted a priority review designation to a new drug application (NDA) for Lutathera in June 2016, and had been scheduled to make its final decision by December 28, 2016. However, on December 21, 2016, Novartis subsidiary Advanced Accelerator Applications, the manufacturer of Lutathera, reported that the FDA had issued a complete response letter (CRL) informing the company that the NDA for Lutathera would need to be resubmitted.

The CRL, which followed a discipline review letter issued in November 2016, requested new subgroup data, a safety update, and that revisions be made to the previously submitted data. The letter did not request the initiation of additional studies of Lutathera.

Strosberg JR, Wolin EM, Chasen B, et al. NETTER-1 phase III: Efficacy and safety results in patients with midgut neuroendocrine tumors treated with 177Lu-DOTATATE. J Clin Oncol. 2016;34 (suppl; abstr 4005).