Erlotinib, erlotinib-sulindac versus placebo: a randomized, double-blind, placebo-controlled window trial in operable head and neck cancer

Abstract

Purpose: The EGF receptor (EGFR) and COX2 pathways are upregulated in head and neck squamous cell carcinoma (HNSCC). Preclinical models indicate synergistic antitumor activity from dual blockade. We conducted a randomized, double-blind, placebo-controlled window trial of erlotinib, an EGFR inhibitor; erlotinib plus sulindac, a nonselective COX inhibitor; versus placebo.

Experimental design: Patients with untreated, operable stage II-IVb HNSCC were randomized 5:5:3 to erlotinib, erlotinib-sulindac, or placebo. Tumor specimens were collected before and after seven to 14 days of treatment. The primary endpoint was change in Ki67 proliferation index. We hypothesized an ordering effect in Ki67 reduction: erlotinib-sulindac > erlotinib > placebo. We evaluated tissue microarrays by immunohistochemistry for pharmacodynamic modulation of EGFR and COX2 signaling intermediates.

Results: From 2005-2009, 47 patients were randomized for the target 39 evaluable patients. Thirty-four tumor pairs were of sufficient quality to assess biomarker modulation. Ki67 was significantly decreased by erlotinib or erlotinib-sulindac (omnibus comparison, two-sided Kruskal-Wallis, P = 0.04). Wilcoxon pairwise contrasts confirmed greater Ki67 effect in both erlotinib groups (erlotinib-sulindac vs. placebo, P = 0.043; erlotinib vs. placebo, P = 0.027). There was a significant trend in ordering of Ki67 reduction: erlotinib-sulindac > erlotinib > placebo (two-sided exact Jonckheere-Terpstra, P = 0.0185). Low baseline pSrc correlated with greater Ki67 reduction (R(2) = 0.312, P = 0.024).

Conclusions: Brief treatment with erlotinib significantly decreased proliferation in HNSCC, with additive effect from sulindac. Efficacy studies of dual EGFR-COX inhibition are justified. pSrc is a potential resistance biomarker for anti-EGFR therapy, and warrants investigation as a molecular target.

Trial registration: ClinicalTrials.gov NCT00779389 NCT01488318.

Figure 1

CONSORT diagram. This flow chart depicts the number of patients who signed consent, were randomized and treated, and ultimately provided paired tumor specimens of sufficient quality for biomarker analysis.

Figure 2

The Primary Endpoint, Ki-67 Proliferation Index. (A) The primary omnibus hypothesis demonstrated a significant difference in Ki-67 modulation among groups (two-sided Kruskal-Wallis, p=0.04). Depicted in this box and whisker plot are the Wilcoxon pairwise contrasts confirming a significant decrease in Ki-67 for patients treated with either erlotinib or erlotinib-sulindac vs. placebo. Box and whisker plots consist of the median (white line), the inter-quartile range (box) and the distance to observed values within 1.5 times the inter-quartile range (whiskers). (B) A waterfall plot depicts the intra- patient change in tumoral Ki-67 expression, pre and post-treatment. Bars are color-coded according to treatment arm.

Figure 3

Biomarker Intermediates and ΔKi-67. We hypothesized that constituents of the EGFR or COX-2 signaling pathways may mediate the observed change in proliferation. The line represents restricted cubic-spline fit for the relationship between Δanalyte and ΔKi-67. No significant correlation was identified between ΔKi-67 and the priority analytes, ΔpSTAT3, ΔpSrc, or ΔpAkt (A) or 21 other candidate biomarkers (B).

Figure 4

Baseline pSrc and ΔKi-67. (A) Four priority baseline analytes (pSrc, pAkt, pSTAT3 and COX-2) were evaluated for association with Ki-67 modulation, with the line representing restricted cubic-spline fit. Higher pre-treatment pSrc was associated with a smaller decrease in Ki-67 following neoadjuvant treatment. (B) Baseline pSrc was plotted against ΔKi-67 for each color-coded treatment group. A significant association was noted only in the active treatment groups (tests that slopes differ from 0: placebo, p=0.8775; erlotinib, p=0 .0024; erlotinib-sulindac, p=0.0150), forwarding baseline pSrc as a candidate biomarker of erlotinib resistance.