LBA6053 Background: Advanced HNSCC has poor outcomes and limited treatment options, especially in resource-constrained settings. Immunotherapy is affordable for less than 5% of patients in lower-middle-income countries (LMICs). Triple OMCT, employing low-dose continuous chemotherapy, shows promise, but its safety and efficacy along with chemotherapy remain unproven. We aimed to assess whether the addition of OMCT to first-line chemotherapy can improve overall survival (OS) as compared to chemotherapy alone. Methods: This phase 3 randomized, prospective, open-label, superiority design study enrolled patients with advanced HNSCC who were planned for palliative intent platinum-based chemotherapy. The patients were stratified for the site of the tumor and ECOG PS, and were randomly assigned 1:1 to receive either triple OMCT (Erlotinib 150 mg OD, Celecoxib 200 mg BD and Methotrexate 9mg/m2 once weekly) in addition to 3-weekly paclitaxel carboplatin (PC) chemotherapy (Arm A) or, PC chemotherapy alone (Arm B). Sample size calculation assumed no OS improvement with OMCT+PC (5% type I error, 80% type II error). The primary endpoint was OS, while secondary endpoints included PFS, quality of life (QoL) assessments, and safety. OS and PFS were analyzed via Kaplan-Meier and log-rank test; HR estimated via Cox proportional hazard models. QoL was assessed using EORTC QLQ-C30. The study was approved by Institutional Ethics Committee and registered with the Clinical Trials Registry India (CTRI/2022/10/046520). Results: Between Nov 02, 2022, and Dec 20, 2023, 238 patients were randomly assigned with 119 in each arm. Median age was 47 years, with 97.8% being males, and 78% of patients had ECOG PS 0-1. The median OS for patients in Arm A was 8.3 months (95% CI, 6.3-10.4) while it was 6.1 months (95% CI, 4.7-7.4), in Arm B (HR 0.63; 95% CI, 0.47–0.83; p=0.00011). The corresponding median PFS was 7.6 months (95% CI, 6.3-8.8) and 3.5 months (95% CI, 2.2-4.7) (HR, 2.79; 95% CI, 1.98-3.93; P<0.000). Significant differences in EORTC-C30 were found for the physical functioning domain between baseline and 1-month follow-up visit. PC chemotherapy combined with triple OMCT showed good tolerability, with common toxicities including fatigue (40.3%), and hyponatremia (25.4%), similar to the incidence observed with PC chemotherapy alone. Conclusions: This study demonstrates that the addition of triple OMCT to paclitaxel and carboplatin chemotherapy is an effective and safe treatment option for patients with advanced HNSCC in platinum-sensitive settings. This treatment option is particularly valuable in LMICs, where cetuximab and pembrolizumab are not feasible. Clinical trial information: CTRI/2022/10/046520 . [Table: see text]