Background: Chemoradiation (CRT) with cis or anti-EGFR Ab has been shown to improve survival of patients with stage III-IV HNC. Since Lap, a dual EGFR and HER2 inhibitor, has shown effectiveness with CRT in a pilot non-HPV HNC cohort, the RTOG Foundation launched a phase II trial to test the hypothesis that adding Lap to the RT-cis for frontline therapy of stage III-IV Non-HPV HNC improves progression-free survival (PFS). Methods: Patients with stage III-IV carcinoma of the oropharynx (p16-negative), larynx, and hypopharynx, having Zubrod performance of 0-1, and meeting predefined blood chemistry criteria were enrolled after providing consent. Patients were randomized (1:1) to 70 Gy (6 weeks) + 2 cycles of CDDP (q3 weeks) plus either Lap (1500 mg daily, Arm A) or placebo (Arm B) starting 1 week prior to RT and concurrent with RT and for 3 months post RT. PFS was the primary endpoint. The protocol specified 69 PFS events (142 patients) for the final analysis based on HR = 0.65, 80% power, 1-sided alpha 0.20, and one interim efficacy and futility analysis at 50% information. PFS rates between arms for all randomized patients were compared by 1-sided log-rank test (1-sided alpha 0.1803). Overall survival (OS) was a secondary endpoint. Results: From 10/’12 to 04/’17, 142 patients were enrolled, of whom 127 were randomized, 63 to Arm A and 64 to Arm B. Arms A vs B, respectively, were similar in baseline patient characteristics, radiation delivery, completing ≥ 70 Gy (85.7% vs. 82.8%) and cisplatin delivery, completing 200 (±5%) mg/m² (65.1% vs 70.3%), but dissimilar in Lap/placebo delivery (median dose, 87000 mg vs. 125250 mg). Median follow-up was 4.1 years for surviving patients. The final analysis suggests no improvement in PFS of adding Lap to CRT (HR [A/B]: 0.91, 95% confidence interval CI 0.56-1.46; P= 0.34; 2-year rates: 50.6%, CI 37.5-63.7% vs. 56.2% CI 43.0-69.4%), or in OS (HR: 1.06, CI 0.61-1.86; P = 0.58; 2-year rates: 71.8% CI 60.1-83.5% vs. 76% CI 64.5-87.4%), death within 30 days of therapy (3.3% vs. 3.4%), and overall treatment-related grade 3-5 adverse event rate (86.7% vs. 84.7%). Grade 3-4 mucositis rates on Arm A and Arm B were 21.7% vs. 23.7%, all grade dysphagia and rash rates were 43.3% vs. 59.3%, and 13.3% vs. 6.8%, respectively. Conclusions: The addition of Lap to the radiation-cisplatin platform did not improve progression-free or overall survival in unselected non-HPV HN. Thus, dual EGFR, HER-2 inhibition does not appear to enhance the effects of chemoradiation. Although we showed that accrual to a non-HPV HN specific trial is feasible, new strategies must be investigated to improve the outcome for this poor prognosis HN population.