Placebo-controlled, double-blind, prospective, randomized study on the effect of octreotide LAR in the control of tumor growth in patients with metastatic neuroendocrine midgut tumors: a report from the PROMID Study Group
Rinke A, Müller H-H, Schade-Brittinger C, Klose K-J, Barth P, Wied M, Mayer C, Aminossadati B, +6 more
Journal of Clinical Oncology (2009) · n=85
Octreotide LAR 30 mg every 28 days extended median time to tumor progression from 6.0 to 14.3 months in patients with well-differentiated metastatic midgut neuroendocrine tumors — the first randomized controlled trial to establish a somatostatin analog as a tumor-control rather than purely symptom-control intervention.
PROMID was the first placebo-controlled randomized trial to test whether a somatostatin analog slows tumor growth in neuroendocrine disease, rather than merely controlling the hormone-mediated symptoms of carcinoid syndrome. The PROMID Study Group, a multicenter German consortium led from Marburg, randomized 85 treatment-naive patients with histologically confirmed, well-differentiated, locally inoperable or metastatic midgut neuroendocrine tumors — carcinoid tumors arising in the ileum or jejunum, with the cecum and proximal colon included as midgut sites — to either octreotide LAR 30 mg intramuscularly every 28 days or matching placebo, continued until tumor progression or death. The primary endpoint was time to tumor progression (TTP) assessed by an independent radiology review committee blinded to treatment assignment. Both functionally active (carcinoid-syndrome-producing) and non-functional tumors were eligible, an enrollment choice that the design pre-specified for separate subgroup analysis.
Median time to tumor progression was 14.3 months on octreotide LAR versus 6.0 months on placebo, with a hazard ratio of 0.34 (95% CI, 0.20 to 0.59; p = 0.000072). At six months from randomization, 66.7% of octreotide-treated patients had stable disease compared with 37.2% of placebo-treated patients. The functionally active and functionally inactive carcinoid subgroups responded comparably, an observation that decoupled the antiproliferative effect from the carcinoid-syndrome biology that had previously framed somatostatin-analog prescribing. The most favorable treatment effect concentrated in patients with low hepatic tumor burden (≤10% liver involvement) and a resected primary tumor — a clinical phenotype consistent with the indolent natural history of well-differentiated midgut disease that remained the population where the trial-grade evidence was most secure. The overall survival comparison was not powered to reach statistical significance at the planned analysis (16 deaths total; HR 0.81, 95% CI 0.30 to 2.18). Adverse events were consistent with the established octreotide profile — diarrhea, abdominal pain, and the gallstone-formation signal that the chronic SST2 agonism produces through gallbladder hypomotility — and treatment discontinuation for toxicity was uncommon in both arms.
The Phase III result moved the somatostatin-analog class from a 1980s symptomatic-control role into the regulatory and clinical-practice category of antiproliferative therapy for well-differentiated gastroenteropancreatic neuroendocrine tumors. PROMID was the trial cited in the FDA labeling supplement that added the GEP-NET indication to the octreotide family, and it set the methodological template — placebo control, independent blinded radiology review, TTP primary endpoint — that the subsequent Caplin et al., New England Journal of Medicine 2014, 371:224-233 CLARINET trial of lanreotide extended to pancreatic and other GEP-NET primary sites at the 204-patient scale.
The 85-patient sample is small for a Phase III pivotal trial, and the planned analysis rested on a modest number of progression events. The hazard ratio is large and the p-value is small, but the confidence interval (0.20 to 0.59) reflects the limited event count, and the absolute survival comparison was uninformative at the planned analysis. PROMID enrolled only midgut primary sites, so the trial does not directly speak to pancreatic, hindgut, foregut-bronchopulmonary, or thymic neuroendocrine disease — the generalization of the somatostatin-analog antiproliferative effect to the broader GEP-NET population came from CLARINET rather than from PROMID itself. The trial enrolled treatment-naive patients, which excludes the question of octreotide activity in second-line or post-progression settings that the practice-pattern literature continues to debate. The fixed 30-mg LAR dose tested in PROMID is the standard labeled dose, but a dose-response literature has accumulated around 60-mg and 40-mg LAR regimens in patients who progress on the labeled dose, and the trial does not address whether dose escalation extends TTP in the post-progression setting. Industry sponsorship by Novartis is disclosed in the original report; the independent radiology review committee design partially insulates the primary endpoint from sponsor influence. The trial was conducted in Germany at a small number of academic centers, which constrains generalizability to community oncology practice patterns and to non-European populations that the original cohort underrepresented.
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