6009 Background: Induction chemotherapy (IC) with TPF isa standard regimen for patients (pts) with locally advanced head and neck squamous cell carcinoma (N Engl J Med. 2007;357:1705–1715). However, CRT alone is standard treatment for unresectable LAHNC. We designed a trial to compare two different regimens of IC followed by CRT versus CRT alone in pts with unresectable LAHNC. Methods: Pts with unresectable, measurable LAHNC, adequate organ function, and ECOG 0–1 were enrolled and stratified according to primary tumor site. (IC) regimens (3 cycles): PF (cisplatin 100 mg/m2 day [d] 1, then 5-FU 1,000 mg/m2 continuous infusion [CI], d1–5, q21d); TPF (docetaxel 75 mg/m2 d1, cisplatin 75 mg/m2 d1, 5-FU 750 mg/m2 CI, d1–5, q21d plus G-CSF and ciprofloxacin). All pts were to receive CRT, consisting of conventional radiotherapy up to 70 Gy plus cisplatin 100 mg/m2 d 1, 22, 43. The primary end point was time to treatment failure (TTF) for (IC) vs. no (IC); secondary endpoints included locoregional control (LRC) rate and safety; 438 pts were needed to demonstrate a 15% difference in treatment failure (death, progression, surgery, other treatments) with α = 0.05, β = 0.2. Results: From December 2002 to June 2007, 439 pts were enrolled: IC 311 pts (TPF 155, PF 156) and CRT 128 pts. The majority of pts were: ECOG 1 (70%); oropharynx and oral cavity (63%); T4 (75%); N2-N3 (61%). In evaluable pts (at least 1 cycle), the median TTF was 12.5 months with IC/CRT vs. 4.9 months with CRT alone (p < 0.001; HR 0.57; 95%CI 0.44–0.74); LRC rate was 60.9% IC/CRT vs. 44.5% CRT (p = 0.003; OR = 0.52; 95%CI 0.3–0.81). Grade 3–4 adverse events (IC/CRT vs. CRT) occurred in 83% vs. 69% of pts and included febrile neutropenia (10% vs 1%), and stomatitis (43.7% vs 37%). Conclusions: This is the first phase III trial to demonstrate that (IC) followed by CRT significantly increases TTF and LRC compared with CRT alone in pts with unresectable LAHNC. IC/CRT should now be considered standard treatment for these pts. No significant financial relationships to disclose.