6041 Background: Patients (pt) with advanced inoperable squamous cell carcinoma of the head and neck (SCCHN) have poor radiotherapy alone (RT) outcome. EGFR is over-expressed in >90% SCCHN. h-R3mAb (BIOMAb/nimotuzumab/TheraCIM) is a humanized monoclonal antibody, a validated oncotherapeutic-targeting EGFR. Objective: To investigate the safety and efficacy of concurrent h-R3mAb in combination with chemoradiotherapy of SCCHN. Methods: September 2004–2005, pt 18–70 yrs, SCCHN stageIII-IVA, 113 screened, 92 enrolled and randomly asssigned to, Group A: radical radiotherapy (pt) and Group B: chemoradiotherapy (pt). Randomization within Group A: [RT]v/s[RT+h-R3mAb] and within Group B: [RT+CT]v/s[RT+CT+ h-R3mAb] (n = 23 in each arm). Protocol: Radiotherapy: TD: 66 Gy,2Gy/Fr,5Fr/w,6.5wks. Radiation sensitizer (chemotherapy): CDDP-50mg/wk x 6wks. Study Drug (h-R3mAb): 200 mg/wk I.V.60min x 6weeks. Results: Evaluable (n = 76) in Group A-36 and Group B-40. F/u Analysis at 30 months after end of RT. Survival rate ITT: Group B: CT+RT+hR3- 69.5% v/s CT+RT-21.7% (p - 0.0011), Group A: RT alone - 21.7% v/s RT+ hR3–39.1% (ns). Progression-free survival: RT alone - 3(13.04 %) v/s RT+hR3mAb-8 (34.78 %), RT+CT-5 (21.74 %) v/s RT+CT+hR3mAb-13 (56.52%). Median overall survival (OS): CT+RT+hR3 - NR* v/s CT+RT- 21.96 months (hazard ratio [HR]-0.337, p - 0.0018) and RT alone - 25.02 v/s RT+hR3 - NR*(HR-0.678, p - 0.39). Disease-free survival: CT+RT+hR3- NR*v/sCT+RT-21.30 mths (HR-0.344, p - 0.0052) and RT alone-25.02 v/s RT+hR3- NA* (HR-0.599, p - 0.32). (NR*- median OS is yet to be reached). Safety: few grade - 1/2AE, no HAMA observed. OS per protocol - adding h-R3mAb to chemoradiation resulted in a reduction in risk of death (rrd) by 85% (HR 0.15, p - 0.0006) and to RT a 36 % rrd (HR0.64, p - 0.33). Conclusions: Concurrent use of h-R3mAb with RT or RT+CT is safe and efficacious. It enhances radiation and chemotherapy responses. Concurrent use of h-R3mAb with chemoradiotherapy enhances long-term loco-regional control and survival. Adding biological agents to physically targeted modality improves long-term therapeutic outcome of SCCHN. No significant financial relationships to disclose.