Tama, Elif

Abstract Disclosure: S. Fansa: None. W. Ghusn: None. E. Tama: None. B. Nicolalde: None. D. Anazco: None. S. D'Andre: None. S. Faubion: None. C. Shufelt: None. A. Acosta: None. M.D. Hurtado: None. Background: Aromatase inhibitors (AIs) block estrogen synthesis and are used as adjuvant treatment for breast cancer. AIs are associated with weight gain that can lead to increased cardiometabolic risk, thereby affecting health and survivorship quality in these patients. The role of anti-obesity medications (AOMs) in patients using AIs has not been studied. We sought to investigate weight loss outcomes to AOMs in patients taking AIs for breast cancer treatment. Methods: This is a matched case-control retrospective cohort study of breast cancer survivors on AI using FDA-approved AOMs (AI/AOM group). We compared their weight loss outcomes with a group of female patients with obesity, without a history of breast cancer or AI use, on AOMs (AOM group). We matched patients by age and body mass index (BMI). Exclusion criteria: AOM initiation prior to AI therapy, ≤3 months of AOM use, history of bariatric surgery, active malignancy, or pregnancy. Primary endpoint: total body weight loss % (TBWL%) at 12 months. Secondary endpoints: TBWL% at 3 and 6 months and % of patients achieving categorical TBWL ≥5%, ≥10% and ≥15% at 12 months. We used Pearson χ2 and unpaired t-test to compare baseline characteristics and outcomes between groups, and univariate analyses to estimate the contribution of variables to TBWL% in the AI/AOM group. We present results as mean ± standard deviation. Results: We included 99 patients: 63 in the AI/AOM group (63.5±10 years, BMI 34.4±7.0 kg/m2) and 36 in the AOM group (60.4±8.7 years, BMI 36.3±6.9 kg/m2). Liraglutide, semaglutide and phentermine were the only AOMs used. There was no difference in the frequency of use of these three AOMs among both groups (p= 0.1). AI/AOM group had a lower TBWL% compared to the AOM group during follow-up: 3.7± 4.3% vs. 5.6 ± 4.1% (p= 0.03) at 3 months, 3.9± 4.3% vs. 9.5± 4.7% (p< 0.0001) at 6 months, and 5.2± 5.3% vs. 10.5± 6.8% (p< 0.0001) at 12 months. Although the AI/AOM group was more likely to use lower doses of AOMs (p= 0.0004), TBWL% differences persisted among groups at 12 months after adjusting for AOM dosing (p< 0.0001). There was no difference in nutritional and behavioral modification sessions among groups (p=0.06 and p=0.9, respectively). At 12 months, the percentage of patients achieving ≥5%, ≥10%, and ≥15% TBWL was greater in the AOM group compared to the AI/AOM group: ≥5% TBWL, 85.7% vs. 50.0% (p< 0.0001); ≥10%, 57.1 vs. 20.0% (p< 0.0001); and ≥15%, 28.6 vs. 5.0% (p< 0.0001); respectively. We found no predictors of TBWL% at 12 months in the AI/AOM group. Conclusion: Weight loss outcomes in breast cancer survivors on AIs taking AOMs are poorer compared to patients without breast cancer history and not taking AIs. Studies are needed to assess the mechanisms behind the different weight loss response to AOMs in women taking AIs, which we hypothesize may relate to AIs’ anti-estrogenic effect on lean and fat mass. Presentation: Friday, June 16, 2023

Abstract Disclosure: S. Fansa: None. W. Ghusn: None. B. Nicolalde: None. D. Anazco: None. E. Tama: None. A. Acosta: None. M.D. Hurtado: None. Introduction: The increasing prevalences of obesity and type 2 diabetes (T2D), the “twin epidemics”, have led to the development of drugs targeting both diseases simultaneously. Liraglutide and semaglutide, GLP-1 receptor agonists used for T2DM, are also FDA-approved for weight loss. Tirzepatide, a novel dual GIP/GLP-1 receptor agonist approved for T2D, has shown promising weight loss outcomes in clinical trials. To date, no study has assessed weight loss outcomes of tirzepatide in a real-world setting. Our aim is to assess its efficacy and safety in patients with overweight or obesity. Methods: This is a retrospective cohort study of adults with overweight or obesity taking weekly subcutaneous tirzepatide for T2D or off-label for weight loss. We excluded patients taking tirzepatide for less than one month, prior bariatric procedure, use of any anti-obesity medications, and active malignancy or pregnancy. The primary outcome was total body weight loss percentage (TBWL%) at 3 months. Secondary outcomes included TBWL% at 1 and 2 months; TBWL% difference by T2D status (with and without) and by sex at 3 months; proportion of patients achieving ≥5%, ≥10%, and ≥15% of TBWL% at 3 months; predictors of TBWL% at 3 months; and reported side effects during follow up. We used paired t-test to assess TBWL% compared to baseline, non-paired t-test to compare TBWL% by T2D status and sex, and univariate analyses to estimate the contribution of other variables to TBWL%. Results are presented as mean ± standard deviation. Results: We included 175 participants (81% female, age 49.8±12.2, 91% white, BMI 38.8±7.3 kg/m2). One third of patients had T2D (n=59, 34%). Most patients were on 5mg (39%) or 7.5mg (22%) of tirzepatide weekly. TBWL% at 1, 2, and 3 months was 3.6±2.5% (n=87), 5.8±3.5% (n=100), and 8.4± 4.3% (n=60), respectively (p <0.0001 compared to baseline at all timepoints). Patients with T2D lost less weight at 3 months compared to patients without T2D: 6.9±4.0% vs. 9.1±4.4% (p= 0.03). At 3 months, TBWL% was greater in females, 9.2±4.3% vs. 5.0±2.5% for males, p<0.0001. Greater baseline weight was associated with greater TBWL% (R=0.32, p<0.0001). At 3 months, 60 patients had documented weights with 81.6% achieving ≥ 5%, 30% achieving ≥10%, and 10% achieving ≥15% TBWL. Forty participants (23%) reported side effects. The most frequent were nausea/vomiting (n=27, 15%), constipation (n=6, 3%), and abdominal pain (n=5, 3%). Eight patients (5%) had to either decrease dosage or discontinue the drug due to side effects. Conclusion: In this retrospective cohort study, tirzepatide led to substantial weight loss at 3 months. Patients with T2DM lost less weight than patients without. Further real-world studies with longer follow-up duration and higher tirzepatide doses are needed to establish the long-term efficacy, safety, and tolerability of this drug in this setting. Presentation: Friday, June 16, 2023

Abstract A false pituitary tumor describes pituitary enlargement due to intracranial hypotension. Reported previously primarily in the neurological literature, we present this case referred to endocrinology for evaluation of a pituitary mass. A 24-year-old male was referred to endocrinology for evaluation of pituitary enlargement without a hypo-enhancing lesion on magnetic resonance imaging (MRI). The main symptom reported was headache that was worse in the standing position and in the afternoon. He had no symptoms or signs of pituitary mass-effect, or hormone excess or deficiencies. Past medical history was relevant for a history of nerve schwannoma status post resection with subsequent spinal fusion. Biochemical evaluation of pituitary hormones was normal. Upon review of his pituitary MRI, other abnormalities seen were suggestive of intracranial hypotension. Based on his history and imaging findings, he was diagnosed with intracranial hypotension causing a “false pituitary tumor” rather than pituitary enlargement or abnormality. Further evaluation revealed multiple spinal leaks that were patched. His symptoms subsided within a few days of repair. Endocrinologists should be aware of the possible misdiagnosis of a pituitary mass due to intracranial hypotension.