We report the impact of 177Lu DOTATATE treatment on
abdominal pain,
diarrhea, and
flushing, symptoms that patients with advanced midgut
neuroendocrine tumors (NETs) often find burdensome. Methods: All patients enrolled in the international randomized phase 3
Neuroendocrine Tumors Therapy (NETTER-1) trial (177Lu-DOTATATE plus standard-dose
octreotide long-acting repeatable [LAR], n = 117; high-dose
octreotide LAR, n = 114) were asked to record the occurrence of predefined symptoms in a daily diary. Change from baseline in symptom scores (mean number of days with a symptom) was analyzed using a mixed model for repeated measures. Results: Patients (intent-to-treat) who received
177Lu-DOTATATE experienced a significantly greater decline from baseline in symptom scores than patients who received high-dose
octreotide LAR. For
177Lu-DOTATATE, the mean decline in days with
abdominal pain,
diarrhea, and
flushing was 4.10, 4.55, and 4.52 days per 4 weeks, respectively, compared with 0.99, 1.44, and 2.54 days for high-dose
octreotide LAR. The mean differences were 3.11 days (95% confidence interval, 1.35-4.88; P = 0.0007) for
abdominal pain, 3.11 days (1.18-5.04; P = 0.0017) for
diarrhea, and 1.98 days (0.08-3.88; P = 0.0413) for
flushing, favoring
177Lu-DOTATATE. A positive repeated measures correlation was found between diary-recorded symptom scores and questionnaire-recorded
pain,
diarrhea, and
flushing. Conclusion: In addition to efficacy and quality of life benefits, symptom diaries from NETTER-1 demonstrated that treatment with 177Lu DOTATATE was associated with statistically significant reductions in
abdominal pain,
diarrhea, and
flushing, constituting the core symptoms of patients with progressive midgut NETs, compared with high-dose
octreotide LAR, supporting a beneficial effect of 177Lu DOTATATE on HRQoL.