Macropinocytosis promotes internalization of albumin into cells to serve as a nutrient supply and is constitutively driven by signaling pathways frequently hyperactivated in head and neck squamous-cell carcinoma (HNSCC). In this way, drugs bound to albumin may selectively target HNSCC. nab-paclitaxel is a nanoparticle albumin-bound formulation of paclitaxel that improves drug delivery into tumor compared to paclitaxel. The primary aim of this single-arm, multicenter, phase 2 trial was to determine if nab-paclitaxel, cetuximab, and carboplatin (CACTUX regimen) would result in longer progression-free survival (PFS) than the historical regimen (EXTREME: 5-fluorouracil, cetuximab, and a platinum).
Patients with untreated recurrent or metastatic HNSCC received six, three-week cycles of nab-paclitaxel, cetuximab, and carboplatin, followed by maintenance nab-paclitaxel and cetuximab until progression. We hypothesized the median PFS with CACTUX would be 35% longer than with EXTREME (corresponding to 7.6 vs 5.6 months; power 0.80, α = 0.05, one-sided test, n = 70). Secondary outcomes included objective response rate (ORR) and overall survival (OS).
Seventy-four patients enrolled into the trial; seventy were evaluable. The median PFS was 6.1 months (95% CI, 4.1-7.4). The ORR was 60%. Median follow-up was 18 months (IQR: 4.7-23). The median OS was 17.8 months (95% CI, 8.5-21.7) for all patients, and 19.8 months (95% CI, 10.9-22.0) for human papillomavirus (HPV)-related oropharynx SCC and 14.0 months (95% CI, 4.6-23.3) for HPV-unrelated HNSCC.
Among patients with recurrent or metastatic HNSCC, CACTUX did not result in a longer PFS than historical EXTREME. However, CACTUX did result in a more favorable ORR and OS.