TROPION-Breast01: Datopotamab deruxtecan vs chemotherapy in pre-treated inoperable or metastatic HR+/HER2- breast cancer.

Improving the prognosis for patients with metastatic HR+/HER2- breast cancer remains an unmet need. Patients with tumors that have progressed on endocrine therapy and/or are not eligible for endocrine therapy had limited treatment options beyond chemotherapy. Antibody-drug conjugates are a novel and promising treatment class in this setting. Datopotamab deruxtecan (Dato-DXd) consists of a TROP2-directed humanized IgG1 monoclonal antibody attached via a serum-stable cleavable linker to a topoisomerase I inhibitor payload. TROPION-Breast01 is an ongoing phase III study that is evaluating the efficacy and safety of Dato-DXd compared with investigator's choice of standard-of-care chemotherapy in patients with inoperable or metastatic HR+/HER2- breast cancer who have received one or two prior lines of systemic chemotherapy in the inoperable or metastatic setting. Clinical Trial Registration: NCT05104866 (ClinicalTrials.gov).

Antibody-drug conjugates are a type of drug with two parts: an antibody that directs the drug to the cancer cells and a cancer-cell killing toxic payload. By binding to cancer cells before releasing the payload, treatment is directed to the site of action so there are fewer side effects in the rest of the body. Datopotamab deruxtecan (Dato-DXd) is an antibody-drug conjugates made up of datopotamab (antibody) and DXd (payload) which are joined together via a stable linker. Datopotamab binds to a protein found on cancer cells called TROP2; it then goes inside and releases the DXd payload to kill the tumor cells. DXd may leak out to surrounding cancer cells and kill those as well. The TROPION-Breast01 study is comparing Dato-DXd with standard-of-care chemotherapy. Around 700 patients will take part, who have: Tumors that cannot be surgically removed. Tumors that are hormone receptor-positive and do not have HER2 overexpression. Had one or two lines of previous chemotherapy (after the tumor could not be surgically removed, or had spread). Had tumor growth despite hormonal therapy or are ineligible for hormonal therapy. Patients who meet the entry criteria will be randomly assigned to a treatment group in equal numbers to either Dato-DXd or an appropriate chemotherapy, out of four options chosen by the treating doctor. At the end of the study, researchers will look at whether the patients who receive Dato-DXd live longer without their breast cancer getting worse, compared with patients who receive chemotherapy. This study is also looking at how the treatment affects patients' quality of life.

Estimands for overall survival in clinical trials with treatment switching in oncology.

An addendum of the ICH E9 guideline on Statistical Principles for Clinical Trials was released in November 2019 introducing the estimand framework. This new framework aims to align trial objectives and statistical analyses by requiring a precise definition of the inferential quantity of interest, that is, the estimand. This definition explicitly accounts for intercurrent events, such as switching to new anticancer therapies for the analysis of overall survival (OS), the gold standard in oncology. Traditionally, OS in confirmatory studies is analyzed using the intention-to-treat (ITT) approach comparing treatment groups as they were initially randomized regardless of whether treatment switching occurred and regardless of any subsequent therapy (treatment-policy strategy). Regulatory authorities and other stakeholders often consider ITT results as most relevant. However, the respective estimand only yields a clinically meaningful comparison of two treatment arms if subsequent therapies are already approved and reflect clinical practice. We illustrate different scenarios where subsequent therapies are not yet approved drugs and thus do not reflect clinical practice. In such situations the hypothetical strategy could be more meaningful from patient's and prescriber's perspective. The cross-industry Oncology Estimand Working Group (www.oncoestimand.org) was initiated to foster a common understanding and consistent implementation of the estimand framework in oncology clinical trials. This paper summarizes the group's recommendations for appropriate estimands in the presence of treatment switching, one of the key intercurrent events in oncology clinical trials. We also discuss how different choices of estimands may impact study design, data collection, trial conduct, analysis, and interpretation.

Blinatumomab for minimal residual disease in adults with B-cell precursor acute lymphoblastic leukemia.

Approximately 30% to 50% of adults with acute lymphoblastic leukemia (ALL) in hematologic complete remission after multiagent therapy exhibit minimal residual disease (MRD) by reverse transcriptase-polymerase chain reaction or flow cytometry. MRD is the strongest predictor of relapse in ALL. In this open-label, single-arm study, adults with B-cell precursor ALL in hematologic complete remission with MRD (≥10-3) received blinatumomab 15 µg/m2 per day by continuous IV infusion for up to 4 cycles. Patients could undergo allogeneic hematopoietic stem-cell transplantation any time after cycle 1. The primary end point was complete MRD response status after 1 cycle of blinatumomab. One hundred sixteen patients received blinatumomab. Eighty-eight (78%) of 113 evaluable patients achieved a complete MRD response. In the subgroup of 110 patients with Ph-negative ALL in hematologic remission, the Kaplan-Meier estimate of relapse-free survival (RFS) at 18 months was 54%. Median overall survival (OS) was 36.5 months. In landmark analyses, complete MRD responders had longer RFS (23.6 vs 5.7 months; P = .002) and OS (38.9 vs 12.5 months; P = .002) compared with MRD nonresponders. Adverse events were consistent with previous studies of blinatumomab. Twelve (10%) and 3 patients (3%) had grade 3 or 4 neurologic events, respectively. Four patients (3%) had cytokine release syndrome grade 1, n = 2; grade 3, n = 2), all during cycle 1. After treatment with blinatumomab in a population of patients with MRD-positive B-cell precursor ALL, a majority achieved a complete MRD response, which was associated with significantly longer RFS and OS compared with MRD nonresponders. This study is registered at www.clinicaltrials.gov as #NCT01207388.

TRAIL receptor agonist conatumumab with modified FOLFOX6 plus bevacizumab for first-line treatment of metastatic colorectal cancer: A randomized phase 1b/2 trial.

BACKGROUND: In patients with previously untreated metastatic colorectal cancer (mCRC), we conducted a phase 1b/randomized phase 2 trial to define the safety, tolerability, and efficacy of mFOLFOX6 plus bevacizumab (mFOLFOX6/bev) with conatumumab, an investigational, fully human monoclonal IgG1 antibody that specifically activates death receptor 5 (DR5). METHODS: Twelve patients were enrolled in a phase 1b open-label dose-escalation trial of conatumumab with mFOLFOX6/bev; thereafter, 190 patients were randomized 1:1:1 to receive mFOLFOX6/bev in combination with 2 mg/kg conatumumab, 10 mg/kg conatumumab, or placebo. Therapy cycles were repeated every 2 weeks until disease progression or the occurrence of unacceptable toxicity. RESULTS: In phase 1b, conatumumab with mFOLFOX6/bev was tolerated without apparent added toxicity over mFOLFOX6/bev alone. In phase 2, conatumumab with mFOLFOX6/bev did not confer a benefit in progression-free survival when compared with placebo with mFOLFOX6/bev. Toxicity was similar in all treatment arms. Following treatment, similar increases in circulating caspase-3 levels were observed in all arms. CONCLUSIONS: Conatumumab with mFOLFOX6/bev did not offer improved efficacy over the same chemotherapy with placebo in first-line treatment of patients with mCRC. These data do not support further development of conatumumab in advanced CRC.

DNA repair by ERCC1 in non-small-cell lung cancer and cisplatin-based adjuvant chemotherapy.

BACKGROUND: Adjuvant cisplatin-based chemotherapy improves survival among patients with completely resected non-small-cell lung cancer, but there is no validated clinical or biologic predictor of the benefit of chemotherapy. METHODS: We used immunohistochemical analysis to determine the expression of the excision repair cross-complementation group 1 (ERCC1) protein in operative specimens of non-small-cell lung cancer. The patients had been enrolled in the International Adjuvant Lung Cancer Trial, thereby allowing a comparison of the effect of adjuvant cisplatin-based chemotherapy on survival, according to ERCC1 expression. Overall survival was analyzed with a Cox model adjusted for clinical and pathological factors. RESULTS: Among 761 tumors, ERCC1 expression was positive in 335 (44%) and negative in 426 (56%). A benefit from cisplatin-based adjuvant chemotherapy was associated with the absence of ERCC1 (test for interaction, P=0.009). Adjuvant chemotherapy, as compared with observation, significantly prolonged survival among patients with ERCC1-negative tumors (adjusted hazard ratio for death, 0.65; 95% confidence interval [CI], 0.50 to 0.86; P=0.002) but not among patients with ERCC1-positive tumors (adjusted hazard ratio for death, 1.14; 95% CI, 0.84 to 1.55; P=0.40). Among patients who did not receive adjuvant chemotherapy, those with ERCC1-positive tumors survived longer than those with ERCC1-negative tumors (adjusted hazard ratio for death, 0.66; 95% CI, 0.49 to 0.90; P=0.009). CONCLUSIONS: Patients with completely resected non-small-cell lung cancer and ERCC1-negative tumors appear to benefit from adjuvant cisplatin-based chemotherapy, whereas patients with ERCC1-positive tumors do not.

Importance of contact surface between electrodes and treated tissue in electrochemotherapy.

Electrochemotherapy is an effective antitumor treatment employing locally applied high voltage electric pulses delivered through conductive electrodes to the tumor in combination with chemotherapeutic drugs. The efficiency of electrochemotherapy strongly depends on the local electric field distribution inside the target tissue. For successful therapy the entire target tissue has to be exposed to the local electric field strength above the reversible threshold. The aim of this study is to demonstrate the influence of the contact surface between electrode and treated tissue on the coverage of the tumor tissue by sufficiently high local electric field. The electric field distribution is calculated by means of numerical modeling using finite element method. Numerical results are confirmed with in vivo experiments. We demonstrated that the placement of electrodes giving larger electrode-tissue contact surface leads to improved electrochemotherapy outcome. Our results provide guidance on electrochemotherapy for treatment of protruding cutaneous tumors using parallel plate electrodes.

Multidrug resistance proteins do not predict benefit of adjuvant chemotherapy in patients with completely resected non-small cell lung cancer: International Adjuvant Lung Cancer Trial Biologic Program.

PURPOSE: The purpose of our study was to determine whether multidrug resistance proteins (MRP) are of prognostic and/or predictive value in patients who were enrolled into the International Adjuvant Lung Cancer Trial (IALT). EXPERIMENTAL DESIGN: Expression of MRP1 and MRP2 was immunohistochemically assessed in tumor specimens obtained from 782 IALT patients. Prognostic and predictive analyses were based on Cox models adjusted for clinical and pathologic variables. RESULTS: MRP1 expression was considered positive in 364 (47%) patients and MRP2 expression in 313 (40%) patients. MRP2-positive patients had a significantly shorter overall survival than MRP2-negative patients in the total patient population [adjusted hazard ratio for death, 1.37; 95% confidence interval (95% CI), 1.09-1.72; P = 0.007]. There was no significant association between MRP1 expression and overall survival. Neither MRP1 nor MRP2 predicted response to adjuvant cisplatin-based chemotherapy. CONCLUSIONS: MRP2 expression is an independent prognostic factor in patients with completely resected non-small cell lung cancer but neither MRP1 nor MRP2 was of predictive value in patients enrolled into the IALT.

Efficacy according to blind independent central review: Post-hoc analyses from the phase III, randomized, multicenter, IPASS study of first-line gefitinib versus carboplatin/paclitaxel in Asian patients with EGFR mutation-positive advanced NSCLC.

OBJECTIVE: The Phase III, randomized, open-label IPASS study (NCT00322452) of first-line epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) gefitinib versus carboplatin/paclitaxel for Asian patients with advanced non-small-cell lung cancer (NSCLC) showed that investigator-assessed progression-free survival (PFS) and objective response rate (ORR) were significantly prolonged in patients with EGFR mutation-positive NSCLC who received gefitinib versus patients with EGFR mutation-negative NSCLC. We report post-hoc analyses of IPASS data by blind independent central review (BICR), performed at the request of the US FDA, in a subset of patients with EGFR mutation-positive NSCLC. PATIENTS AND METHODS: Eligible patients (aged ≥18 years; histologically/cytologically confirmed Stage IIB/IV adenocarcinoma NSCLC; non- or former light-smokers; treatment-naïve) were randomly assigned 1:1 to gefitinib (250mg/day) or carboplatin (dose calculated to produce an area under the curve of 5 or 6 mg/mL/minute)/paclitaxel (200mg/m2). Primary endpoint: PFS. BICR analyses included PFS, ORR, and duration of response (DoR). RESULTS: Scans from 186 IPASS patients (gefitinib n=88, carboplatin/paclitaxel n=98) with EGFR mutation-positive NSCLC were available for BICR. Consistent with investigator-assessed results, in patients with EGFR mutation-positive NSCLC: PFS (hazard ratio 0.54; 95% confidence interval [CI] 0.38, 0.79; p=0.0012) and ORR (odds ratio 3.00; 95% CI 1.63, 5.54; p=0.0004) were significantly longer with gefitinib versus carboplatin/paclitaxel. The median DoR by BICR was 9.6 months with gefitinib and 5.5 months with carboplatin/paclitaxel. CONCLUSION: BICR analysis of IPASS data support the original, investigator-assessed results. EGFR mutation-positive status remains a significant predictor of response to first-line TKI therapy.

Gefitinib Plus Chemotherapy Versus Chemotherapy in Epidermal Growth Factor Receptor Mutation-Positive Non-Small-Cell Lung Cancer Resistant to First-Line Gefitinib (IMPRESS): Overall Survival and Biomarker Analyses.

Purpose The Iressa Mutation-Positive Multicentre Treatment Beyond ProgRESsion Study (IMPRESS) compared the continuation of gefitinib plus chemotherapy with placebo plus chemotherapy in patients with epidermal growth factor receptor ( EGFR) mutation-positive advanced non-small-cell lung cancer with progression (Response Evaluation Criteria in Solid Tumors 1.1) after first-line gefitinib. Primary results indicated no difference between treatments in terms of progression-free survival (PFS). The current analysis presents final, mature, overall survival (OS) data, together with exploratory analyses that examined whether specific biomarkers, including T790M mutation status, were able to differentiate a relative treatment effect. Patients and Methods Patients were randomly assigned to gefitinib 250 mg or placebo, in addition to cisplatin 75 mg/m2 plus pemetrexed 500 mg/m2 (maximum of six cycles of chemotherapy). EGFR mutation status was determined from plasma-derived circulating free tumor-derived DNA samples (beads, emulsification, amplification, and magnetics digital polymerase chain reaction assay, allelic fraction analysis). Results A total of 265 patients with non-small-cell lung cancer were randomly assigned, and overall data maturity was 66%. Continuation of gefitinib plus cisplatin and pemetrexed was detrimental to OS when compared with placebo plus cisplatin and pemetrexed (hazard ratio [HR], 1.44; 95% CI, 1.07 to 1.94; P = .016; median OS, 13.4 v 19.5 months). The detriment was statistically significant in patients with T790M mutation-positive plasma samples (HR, 1.49; 95% CI, 1.02 to 2.21), whereas statistical significance was not reached in T790M mutation-negative patients (HR, 1.15; 95% CI, 0.68 to 1.94). PFS in T790M mutation-positive patients was similar between treatments, and the difference observed in T790M mutation-negative patients did not reach statistical significance (HR, 0.67; 95% CI, 0.43 to 1.03; P = .0745). Conclusion Final OS data from IMPRESS are supportive of earlier PFS results and are sufficient to warn physicians against the continuation of treatment with first-generation EGFR tyrosine kinase inhibitors beyond radiologic disease progression when chemotherapy is initiated. Plasma biomarker analyses suggest that this effect may be driven by T790M-positive status.

The HGF/c-MET Pathway Is a Driver and Biomarker of VEGFR-inhibitor Resistance and Vascular Remodeling in Non-Small Cell Lung Cancer.

Purpose: Resistance to VEGFR inhibitors is a major obstacle in the treatment of non-small cell lung cancer (NSCLC). We investigated the cellular mechanisms mediating resistance of NSCLCs to VEGFR tyrosine kinase inhibitors.Experimental Design: We generated murine models of human NSCLC and performed targeted inhibition studies with the VEGFR TKIs cediranib and vandetanib. We used species-specific hybridization of microarrays to compare cancer (human) and stromal (mouse) cell transcriptomes of TKI-sensitive and -resistant tumors. We measured tumor microvascular density and vessel tortuosity to characterize the effects of therapy on the tumor vascular bed. Circulating cytokine and angiogenic factor levels in patients enrolled in VEGFR TKI trials were correlated with clinical outcomes.Results: Murine xenograft models of human lung adenocarcinoma were initially sensitive to VEGFR TKIs, but developed resistance to treatment. Species-specific microarray analysis identified increased expression of stromal-derived hepatocyte growth factor (HGF) as a candidate mediator of TKI resistance and its receptor, c-MET, was activated in cancer cells and tumor-associated stroma. A transient increase in hypoxia-regulated molecules in the initial response phase was followed by adaptive changes resulting in a more tortuous vasculature. Forced HGF expression in cancer cells reduced tumor sensitivity to VEGFR TKIs and produced tumors with tortuous blood vessels. Dual VEGFR/c-MET signaling inhibition delayed the onset of the resistant phenotype and prevented the vascular morphology alterations. In patients with cancer receiving VEGFR TKIs, high pretreatment HGF plasma levels correlated with poorer survival.Conclusions: HGF/c-MET pathway mediates VEGFR inhibitor resistance and vascular remodeling in NSCLC. Clin Cancer Res; 23(18); 5489-501. ©2017 AACR.

Stress hormones promote EGFR inhibitor resistance in NSCLC: Implications for combinations with ß-blockers.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) resistance mediated by T790M-independent mechanisms remains a major challenge in the treatment of non-small cell lung cancer (NSCLC). We identified a targetable mechanism of EGFR inhibitor resistance whereby stress hormones activate ß2-adrenergic receptors (ß2-ARs) on NSCLC cells, which cooperatively signal with mutant EGFR, resulting in the inactivation of the tumor suppressor, liver kinase B1 (LKB1), and subsequently induce interleukin-6 (IL-6) expression. We show that stress and ß2-AR activation promote tumor growth and EGFR inhibitor resistance, which can be abrogated with ß-blockers or IL-6 inhibition. IL-6 was associated with a worse outcome in EGFR TKI-treated NSCLC patients, and ß-blocker use was associated with lower IL-6 concentrations and improved benefit from EGFR inhibitors. These findings provide evidence that chronic stress hormones promote EGFR TKI resistance via ß2-AR signaling by an LKB1/CREB (cyclic adenosine 3',5'-monophosphate response element-binding protein)/IL-6-dependent mechanism and suggest that combinations of ß-blockers with EGFR TKIs merit further investigation as a strategy to abrogate resistance.

A randomized phase 2 study of paclitaxel and carboplatin with or without conatumumab for first-line treatment of advanced non-small-cell lung cancer.

INTRODUCTION: This study evaluated the efficacy, safety, and pharmacokinetics of conatumumab combined with paclitaxel-carboplatin (PC) as first-line treatment for advanced non-small-cell lung cancer (NSCLC). METHODS: Patients (aged >18 years) with previously untreated advanced or recurrent NSCLC were randomized 1:1:1 (stratified by Eastern Cooperative Oncology Group performance status and disease stage) to receive up to six 3-week cycles of PC combined with conatumumab (arm 1, 3 mg/kg; arm 2, 15 mg/kg) or placebo (arm 3) every 3 weeks. The primary endpoint was progression-free survival (PFS). This study is registered with ClinicalTrials.gov (NCT00534027). RESULTS: Between August 8, 2007 and April 9, 2009, 172 patients were randomized (arm 1, n = 57; arm 2, n = 56; arm 3, n = 59). Median PFS was 5.4 months (95% confidence interval [CI] 4.1-6.3) in arm 1 (hazard ratio [HR] 0.84 [95% CI 0.57-1.24]; p = 0.41), 4.8 months (95% CI 3.2-6.5) in arm 2 (HR 0.93 [0.64-1.35]; p = 0.57), and 5.5 months (95% CI 4.3-5.7) in arm 3. There was an interaction between tumor histology and the effect of conatumumab on PFS (squamous HR 0.47 [0.23-0.94]; nonsquamous HR 1.08 [0.74-1.57]; interaction p = 0.039).The most common grade of three or more adverse events were neutropenia, anemia, and thrombocytopenia. There was no evidence of pharmacokinetic interactions between conatumumab and PC. Of 158 patients assessable for FCGR3A polymorphisms, conatumumab treatment was associated with a trend toward longer overall survival (HR 0.72 [0.43-1.23]) among V-allele carriers (V/V or F/V; n = 54) but not among F-allele homozygotes (n = 34; HR 1.37 [0.66-2.86]). CONCLUSION: Although well tolerated, the addition of conatumumab to PC did not improve outcomes in unselected patients with previously untreated advanced NSCLC.

Use of adjuvant chemotherapy in non-small cell lung cancer in routine practice.

BACKGROUND: For many years, surgery has been the standard treatment for patients with early-stage non-small cell lung cancer (NSCLC). Recent randomized trials demonstrated that cisplatin-based adjuvant chemotherapy increases overall survival. The aim of this study was to analyze the precise use of adjuvant chemotherapy in patients with resected NSCLC in routine practice. PATIENTS AND METHODS: Between January 2004 and May 2005, we retrospectively analyzed 219 patients with early-stage NSCLC who had undergone surgery at one major surgical center in Paris, Institut Mutualiste Montsouris. Patient characteristics, the type of surgery, and indications for adjuvant chemotherapy were analyzed. RESULTS: Eighty-seven of the 219 patients (40%) in this study had been treated with adjuvant chemotherapy. Different factors were associated with doctors not prescribing this treatment: age, comorbidity, tumor, node, metastasis stage, and postoperative complications. More than eight different cisplatin-based regimens were used, highlighting considerable heterogeneity in the use of adjuvant chemotherapy in daily practice. There is an increase of adjuvant chemotherapy during the study period. CONCLUSION: Cisplatin-based chemotherapy is the standard treatment for patients with resected stage II and IIIA NSCLC. However, such therapy is used quite heterogeneously in daily practice and specific regimens, and the percentage of patients receiving adjuvant chemotherapy vary from standard recommendations. A prospective follow-up of daily practice regarding the use of adjuvant chemotherapy is warranted.

Phase II trial of consolidation docetaxel and samarium-153 in patients with bone metastases from castration-resistant prostate cancer.

PURPOSE: To assess docetaxel combined with samarium-153-ethylene diamine tetramethylene phosphonic acid (EDTMP), a radiopharmaceutical with a high affinity for bone, in patients with castration-resistant prostate cancer (CRPC). PATIENTS AND METHODS: Patients with bone metastases from CRPC who achieved a response or stabilization after four cycles of docetaxel and estramustine were given consolidation docetaxel 20 mg/m(2)/wk for 6 weeks and samarium-153-EDTMP (37 MBq/kg) during week 1. Prostate-specific antigen (PSA) response was assessed by using consensus criteria, and pain was assessed by using a visual analog scale (VAS). This study used a Simon two-step design with PSA-progression-free survival (PFS) as the primary end point. RESULTS: Forty-three patients were included in the trial. A PSA response was obtained in 77% (95% CI, 61% to 82%). The pain response rate was 69% (95% CI, 49% to 85%). At least five of the six planned weekly injections of docetaxel were administered to 34 patients (81%). The consolidation docetaxel-samarium-153-EDTMP regimen was well tolerated; there was no febrile neutropenia, and only two episodes (5%) of rapidly reversible grade 3 thrombocytopenia occurred. Although a serum PSA relapse eventually occurred in all patient cases, this regimen resulted in pain control in the long-term. The median PSA-PFS was 6.4 months (95% CI, 6 to 7 months). The median survival was 29 months (95% CI, 22 to 31); the 1-year survival rate was 77% (62% to 87%); and the 2-year survival rate was 56% (41% to 70%). CONCLUSION: Combining docetaxel and samarium-153-EDTMP in patients with bone metastases from CRPC is well tolerated, and it yields major pain relief that persists long after treatment. Overall survival compares favorably with that expected in this population of patients, most of whom exhibit symptoms.

Cell cycle regulators and outcome of adjuvant cisplatin-based chemotherapy in completely resected non-small-cell lung cancer: the International Adjuvant Lung Cancer Trial Biologic Program.

PURPOSE: The International Adjuvant Lung Cancer Trial (IALT) demonstrated that adjuvant cisplatin-based chemotherapy improves the survival of patients with completely resected non-small-cell lung cancer (NSCLC). The purpose of our study was to determine whether cell cycle regulators are of prognostic and/or predictive value in patients who were enrolled onto the IALT. PATIENTS AND METHODS: Expression of p27Kip1, p16INK4A, cyclin D1, cyclin D3, cyclin E, and Ki-67 was immunohistochemically assessed in tumor specimens obtained from 778 IALT patients. Prognostic and predictive analyses were based on Cox models adjusted for clinical and pathologic parameters. RESULTS: There was a relationship between p27Kip1 status and benefit of cisplatin-based chemotherapy (test for interaction, P = .02). Among patients with p27Kip1-negative tumors, cisplatin-based chemotherapy resulted in longer overall survival compared with controls (adjusted hazard ratio [HR] for death = 0.66; 95% CI, 0.50 to 0.88; P = .006). In patients with p27Kip1-positive tumors, overall survival was not different between patients treated with cisplatin-based chemotherapy and controls (adjusted HR for death = 1.09; 95% CI, 0.82 to 1.45; P = .54). The other cell cycle regulators and Ki-67 did not predict benefit of adjuvant cisplatin-based chemotherapy. None of these biomarkers was significantly associated with overall survival of the patients in the total study population. CONCLUSION: NSCLC patients with p27Kip1-negative tumors benefit from adjuvant cisplatin-based chemotherapy after complete tumor resection. Before establishing p27Kip1 as a routine marker for selection of patients for adjuvant chemotherapy, the predictive value of p27Kip1 has to be confirmed in patients from other trials.