1186P Impact of Temozolomide (TEM) and Capecitabine (CAP) Dose Reductions in Toxicity and Efficacy in Patients (pts) with Neuroendocrine Neoplasms (nens) Treated with CAPTEM Chemotherapy

The combination of CAP and TEM (CAPTEM) is a regimen with significant activity in pts with NENs. Although efficacy data has been reported, hematological and gastrointestinal toxicity could reduce compliance with the treatment, especially at standard doses of CAP (750mg/m2 bid) and especially TEM (200mg/m2 day). The aim of this retrospective study is to review safety, toxicity and efficacy in daily routine practice in patients with NENs. All patients with NENs treated with the CAPTEM regimen in our institution between 2015 and 2020 were reviewed. Data related to safety, efficacy, and compliance were recorded. 32 pts received CAPTEM (age 62, 56% female). The primary site was pancreas (46.9%), lung (15.6%), and unknown origin (12.5%). 90.6% were well-differentiated tumors (56.3% NET G1-G2 and 34.3% NET G3). The daily practice population was well represented, including 43% of pts with significant comorbidities and 28.1% of pts with ECOG 2. Most pts received CAPTEM beyond the second line (68.8%). Preferred dose for starting the CAPTEM regime was CAP 750mg/m2 bid (59.4%) or 1000mg/m2 bid (34.4%); and TEM 150mg/m2 (75%). For the whole cohort, response rate (RR) was 34.4%, progression-free survival (PFS) 10.4 months (m), and Overall survival 16.4m. RR was higher in pancreatic tumors compared with extrapancreatic (53.3 vs 17.6%, p0.03). The main condition related with a worse PFS was ECOG 2 vs 0-1 (3.7 vs 10.8 m, p 0.015) Most common grade 1-2 toxicities were Nausea/Vomiting (53.1%), fatigue (50%), anemia (25%), oral mucositis (18.7%) and thrombocytopenia (12.5%). Grade 3-4 toxicity was related to Thrombocytopenia (9.3%), diarrhea (9.3%), and neutropenia (9.3%). Dose reduction was needed in 34.4% of cases and 15.6% of pts withdrawal due to toxicity, mainly related to hematological G3 and vomiting G2. Lower doses of TMZ in the CAPTEM combination in NENs could reduce toxicity to improve compliance and efficacy, especially in ECOG 2 patients.