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Introduction: The INGE-B trial (NCT02894398) aimed to confirm the efficacy and safety data from the PALOMA trials for patients treated first line (1L) with palbociclib (PAL) and letrozole or 1L and later line with PAL and fulvestrant. In addition, so far lacking evidence for efficacy and safety on the combination of PAL with anastrozole, exemestane (1L), or letrozole (later line) was investigated., Methods: The prospective, multicenter, multicohort phase 2 trial INGE-B enrolled adult patients with locally advanced, inoperable, or metastatic HR+/HER2- breast cancer in Germany. The primary endpoint was the clinical benefit rate (CBR) in patients with measurable disease according to RECIST v1.1. Secondary endpoints were overall response rate, progression-free survival (PFS), overall survival (OS), safety, and quality of life. Data were analyzed with descriptive statistics., Results: Between 2016 and 2018, 388 patients were enrolled at 64 German sites. Among patients with measurable disease treated with PAL in 1L (n = 157), the CBR was 63.7% (100/157). Among all patients treated with PAL 1L (n = 219), PFS was 20.1 months (95% CI 14.6-24.0), and OS was 40.9 months (95% CI 35.1-49.2). The most common grade 3/4 adverse event was neutropenia (33.4% n = 77). There were no treatment-related deaths., Conclusion: The INGE-B trial demonstrated good efficacy and tolerability of PAL with letrozole (1L) or fulvestrant (first and later line) in accordance with the PALOMA trials. In addition, the so far lacking proof of efficacy and safety of PAL in combination with anastrozole or exemestane in 1L and with letrozole in later line was provided by INGE-B., (© 2024 The Author(s). Published by S. Karger AG, Basel.)

Background: The role of immune checkpoint inhibitor (ICI) maintenance therapy in metastatic renal cell carcinoma (mRCC) is undefined., Objective: To determine whether switch maintenance therapy with nivolumab improves clinical outcomes in patients with mRCC with tyrosine kinase inhibitor (TKI) sensitivity., Design, Setting, and Participants: This open-label phase 2 trial randomized patients with a partial response or stable disease after 10-12-wk TKI induction therapy to either TKI or nivolumab maintenance. Key inclusion criteria were measurable disease, clear cell histology, Eastern Cooperative Oncology Group performance status (ECOG PS) 0-2, and adequate organ function., Intervention: Intravenous nivolumab 8 × 240 mg every 2 wk, followed by 480 mg every 4 wk or sunitinib 50 mg (4-2 regimen) or pazopanib 800 mg once daily orally., Outcome Measurements and Statistical Analyses: The primary endpoint was overall survival (OS). Secondary endpoints were the objective response rate (ORR; Response Evaluation Criteria in Solid Tumors v1.1), progression-free survival (PFS), safety (Common Terminology Criteria for Adverse Events v4.03), and patient-reported outcomes (Functional Assessment of Cancer Therapy Kidney Symptom Index). The Kaplan-Meier method, two-sided log-rank tests, and Cox regression models were used for statistical analysis., Results and Limitations: Maintenance therapy was nivolumab for 25 patients (51.0%) and TKI for 24 (48.9%). The median age was 65 yr (range 35-79). Nine patients (18.4%) were female, 31 (63.3%) had ECOG PS of 0, and 15 (30.6%) had favorable risk. OS data are immature (17 deaths, 34.7%). The ORR was 20.0% (n = 5) for nivolumab and 52.2% (n = 12) for TKI. PFS was worse with nivolumab (hazard ratio 2.57, 95% confidence interval 1.36-4.89; p = 0.003). Grade ≥3 adverse events occurred in 14 patients (56.0%) with nivolumab and 17 (70.8%) with TKI. A major limitation is early termination of our study., Conclusions: TKI treatment achieved superior ORR and PFS in comparison to nivolumab maintenance therapy. Our data do not indicate a role for nivolumab switch maintenance in mRCC., Patient Summary: Patients with metastatic kidney cancer who experienced a tumor response or disease stabilization after a short period of targeted treatment with a tyrosine kinase inhibitor did not benefit from a switch to the immunotherapy drug nivolumab. Patients who continued their original treatment achieved better responses and a longer time without disease progression. This trial is registered on EudraCT as 2016-002170-13 and on ClinicalTrials.gov as NCT02959554., (Copyright © 2023 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

Importance: The increasing use of neoadjuvant systemic therapy (NST) has led to substantial pathological complete response rates in patients with initially node-positive, early breast cancer, thereby questioning the need for axillary lymph node dissection (ALND). Targeted axillary dissection (TAD) is feasible for axillary staging; however, data on oncological safety are scarce., Objective: To assess 3-year clinical outcomes in patients with node-positive breast cancer who underwent TAD alone or TAD with ALND., Design, Setting, and Participants: The SenTa study is a prospective registry study and was conducted between January 2017 and October 2018. The registry includes 50 study centers in Germany. Patients with clinically node-positive breast cancer underwent clipping of the most suspicious lymph node (LN) before NST. After NST, the marked LNs and sentinel LNs were excised (TAD) followed by ALND according to the clinician's choice. Patients who did not undergo TAD were excluded. Data analysis was performed in April 2022 after 43 months of follow-up., Exposure: TAD alone vs TAD with ALND., Main Outcomes and Measures: Three-year clinical outcomes were evaluated., Results: Of 199 female patients, the median (IQR) age was 52 (45-60) years. A total of 182 patients (91.5%) had 1 to 3 suspicious LNs; 119 received TAD alone and 80 received TAD with ALND. Unadjusted invasive disease-free survival was 82.4% (95% CI, 71.5-89.4) in the TAD with ALND group and 91.2% (95% CI, 84.2-95.1) in the TAD alone group (P = .04); axillary recurrence rates were 1.4% (95% CI, 0-54.8) and 1.8% (95% CI, 0-36.4), respectively (P = .56). Adjusted multivariate Cox regression indicated that TAD alone was not associated with an increased risk of recurrence (hazard ratio [HR], 0.83; 95% CI, 0.34-2.05; P = .69) or death (HR, 1.07; 95% CI, 0.31-3.70; P = .91). Similar results were obtained for 152 patients with clinically node-negative breast cancer after NST (invasive disease-free survival: HR, 1.26; 95% CI, 0.27-5.87; P = .77; overall survival: HR, 0.81; 95% CI, 0.15-3.83; P = .74)., Conclusions and Relevance: These results suggest that TAD alone in patients with mostly good clinical response to NST and at least 3 TAD LNs may confer survival outcomes and recurrence rates similar to TAD with ALND.

Introduction: Inhibition of neo-angiogenesis is a cornerstone of medical treatment in metastatic renal cell carcinoma (mRCC). While 1st line therapies were previously dominated by inhibitors of the vascular endothelial growth factor axis, 2nd line options were less clearly defined. We investigated the role of everolimus (EVE) or a tyrosine kinase inhibitor (TKI) in 2nd line treatment of mRCC patients., Methods: Key inclusion criteria were measurable mRCC, ECOG 0-1, IMDC risk: good or intermediate and adequate organ function. Patients who progressed on or were intolerant to bevacizumab + interferon were subject for randomization between TKI and EVE treatment. Cross-over occurred at time of progression during 2nd line treatment. Improvement of 2nd line progression-free survival (PFS) rate (PFR) at 6 months from 50% to 65% was the primary endpoint. Secondary endpoints were PFS, total PFS, objective response rate (ORR), overall survival (OS), safety, and patient reported outcomes., Results: In 2012-2015, a total of 22 patients were included. The study was stopped for poor accrual. Ten patients (46%) were randomized to receive 2nd line treatment with EVE (n = 5) or axitinib (n = 4)/sunitinib (n = 1). ECOG 0 was recorded in 20% (EVE) and 60% (TKI). Severe adverse events occurred in approx. 60% in each arm. ORR was 1/5 (20%) for TKI and 0/5 (0%) for EVE. PFR at 6 months was 20% in each arm. Median PFS was 3.7 months (EVE) and 2.2 months (TKI) (hazard ratio [HR] 1.0 [95% confidence interval [CI]: 0.26-3.85]). The OS was comparable between arms HR 1.12 (95% CI: 0.27-4.61)., Conclusion: The rapid change of the treatment landscape, the limited use of bevacizumab and interferon in 1st line and the duration of 1st line treatment jeopardized BERAT trial recruitment. The small number of patients is a major limitation of our trial. Our observation indicated the poor prognosis in progressive patients and the limited efficacy of TKI or mTOR inhibitors in 2nd line treatment., (© 2022 S. Karger AG, Basel.)

Background: The multicenter, single-arm, phase II study CEBIFOX evaluated the efficacy of a biweekly cetuximab administration in combination with FOLFOX6 as first-line therapy in KRAS (exon 2) wild-type (wt) metastatic colorectal cancer (mCRC)., Patients and Methods: Patients received FOLFOX6 with cetuximab (500 mg/m 2 ) every second week. Primary endpoint was objective response rate (ORR), among others secondary endpoints were safety, progression-free survival (PFS), overall survival (OS), and patient-reported outcome (PRO). The impact on the treatment efficacy was evaluated in explorative subgroup analyses, including extended molecular profiling and primary tumor location., Results: In total, 57 were included in the intention-to-treat (ITT) analyses. New RAS mutations were detected in 14.0% by post hoc next-generation sequencing analysis in 43 patients. The ORR in the all RASwt population was 70.3% with a median PFS and OS of 10.9 (95% confidence interval [CI], 9.0-12.9) and 33.8 (95% CI, 21.1-45.5) months. Grade 3-5 adverse events occurred in 66.7% of the ITT, without significant impact on the PRO. Patients with right-sided primary tumors had a reduced ORR (54.5%), and median PFS and OS (10.1 and 23.8 months). BRAF mutations were detected in 11.3%. These patients had a significantly lower ORR, and median PFS and OS. Patients with RASwt/BRAFwt tumors had a notably high median PFS and OS of 14.3 and 38.9 months., Conclusions: This study supports the efficacy and safety of biweekly cetuximab given in combination with FOLFOX6 in patients with RASwt/BRAFwt mCRC with left-sided primary tumor. CEBIFOX is the first trial reporting the complete dataset, including extended molecular profiling and tumor location of a biweekly administered cetuximab/FOLFOX6 in mCRC. Clinical trial number: NCT01051167., (Copyright © 2020 Elsevier Inc. All rights reserved.)

CAP7.1 is a novel topoisomerase II inhibitor, converted to active etoposide via carboxylesterase 2 (CES2), with signals of efficacy in treatment-refractory solid tumours. In a Phase II trial, 27 patients with advanced biliary tract cancers (BTC) were randomised 1:1 to CAP7.1 plus best supportive care (BSC), or BSC alone, with crossover to CAP7.1 upon disease progression. The primary objective was disease control rate (DCR) following 28-day cycles of CAP7.1 (200/150 mg/m 2 ; iv), or BSC until progression. Secondary objectives included progression-free survival (PFS), time-to-treatment failure (TTF), overall survival (OS) and safety. Fourteen patients received CAP7.1 and 13 BSC. DCR favoured CAP7.1 vs. BSC (50% vs. 20%; treatment difference: 30%, 95%CI -18.44, 69.22, full analysis set [FAS]), with disease progression in 40% vs. 70%, respectively. Significantly longer median PFS was achieved for CAP7.1 vs. BSC: 66 vs. 39 days, respectively (hazard ratio [HR] 0.31; 95%CI 0.11, 0.86; p = 0.009; FAS). Similar trends were observed for TTF and OS. CES2-positive patients had longer median PFS (158 vs. 56 days) and OS (228 vs. 82 days) vs. CES2-negative patients. Adverse events were predictable, dose-dependent and consistent with those previously observed with etoposide. These efficacy and safety findings in second-line BTC warrant further clinical investigation of CAP7.1.

Background: Docetaxel-based chemotherapy is effective in metastatic gastric and gastro-oesophageal junction adenocarcinoma. This study reports on the safety and efficacy of the docetaxel-based triplet FLOT (fluorouracil plus leucovorin, oxaliplatin and docetaxel) as a perioperative therapy for patients with locally advanced, resectable tumours., Methods: In this controlled, open-label, phase 2/3 trial, we randomly assigned 716 patients with histologically-confirmed advanced clinical stage cT2 or higher or nodal positive stage (cN+), or both, resectable tumours, with no evidence of distant metastases, via central interactive web-based-response system, to receive either three pre-operative and three postoperative 3-week cycles of 50 mg/m 2 epirubicin and 60 mg/m 2 cisplatin on day 1 plus either 200 mg/m 2 fluorouracil as continuous intravenous infusion or 1250 mg/m 2 capecitabine orally on days 1 to 21 (ECF/ECX; control group) or four preoperative and four postoperative 2-week cycles of 50 mg/m 2 docetaxel, 85 mg/m 2 oxaliplatin, 200 mg/m 2 leucovorin and 2600 mg/m 2 fluorouracil as 24-h infusion on day 1 (FLOT; experimental group). The primary outcome of the trial was overall survival (superiority) analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01216644., Findings: Between Aug 8, 2010, and Feb 10, 2015, 716 patients were randomly assigned to treatment in 38 German hospitals or with practice-based oncologists. 360 patients were assigned to ECF/ECX and 356 patients to FLOT. Overall survival was increased in the FLOT group compared with the ECF/ECX group (hazard ratio [HR] 0·77; 95% confidence interval [CI; 0.63 to 0·94]; median overall survival, 50 months [38·33 to not reached] vs 35 months [27·35 to 46·26]). The number of patients with related serious adverse events (including those occurring during hospital stay for surgery) was similar in the two groups (96 [27%] in the ECF/ECX group vs 97 [27%] in the FLOT group), as was the number of toxic deaths (two [<1%] in both groups). Hospitalisation for toxicity occurred in 94 patients (26%) in the ECF/ECX group and 89 patients (25%) in the FLOT group., Interpretation: In locally advanced, resectable gastric or gastro-oesophageal junction adenocarcinoma, perioperative FLOT improved overall survival compared with perioperative ECF/ECX., Funding: The German Cancer Aid (Deutsche Krebshilfe), Sanofi-Aventis, Chugai, and Stiftung Leben mit Krebs Foundation., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Monoclonal antibodies targeting the epidermal growth factor receptor (EGFR), cetuximab and panitumumab, are a mainstay of metastatic colorectal cancer (mCRC) treatment. However, a significant number of patients suffer from primary or acquired resistance. RAS mutations are negative predictors of clinical efficacy of anti-EGFR antibodies in patients with mCRC. Oncogenic RAS activates the MAPK and PI3K/AKT pathways, which are considered the main effectors of resistance. However, the relative impact of these pathways in RAS-mutant CRC is less defined. A better mechanistic understanding of RAS-mediated resistance may guide development of rational intervention strategies. To this end we developed cancer models for functional dissection of resistance to anti-EGFR therapy in vitro and in vivo. To selectively activate MAPK- or AKT-signaling we expressed conditionally activatable RAF-1 and AKT in cancer cells. We found that either pathway independently protected sensitive cancer models against anti-EGFR antibody treatment in vitro and in vivo. RAF-1- and AKT-mediated resistance was associated with increased expression of anti-apoptotic BCL-2 proteins. Biomarkers of MAPK and PI3K/AKT pathway activation correlated with inferior outcome in a cohort of mCRC patients receiving cetuximab-based therapy. Dual pharmacologic inhibition of PI3K and MEK successfully sensitized primary resistant CRC models to anti-EGFR therapy. In conclusion, combined targeting of MAPK and PI3K/AKT signaling, but not single pathways, may be required to enhance the efficacy of anti-EGFR antibody therapy in patients with RAS-mutated CRC as well as in RAS wild type tumors with clinical resistance.

Objectives: Chromosomal rearrangements involving ROS1 define a rare entity of lung adenocarcinomas with exquisite sensitivity to molecularly targeted therapy. We report clinical outcomes and genomic findings of patients with ROS1-positive lung cancer who were prospectively identified within a multiplex biomarker profiling program at the West German Cancer Center., Methods: Standardized immunohistochemical (IHC) analysis, fluorescence in situ hybridization (FISH), and hotspot mutation analyses were performed in 1345 patients with advanced cancer, including 805 patients with metastatic lung adenocarcinoma. Clinical and epidemiological data were retrieved from the institutional database., Results: ROS1 positivity by IHC analysis was detected in 25 patients with lung cancer (4.8% of lung adenocarcinomas), including 13 patients (2.5%) with ROS1 FISH positivity with a cutoff of at least 15% of events. Of the ROS1 IHC analysis-positive cases, 36% presented with concomitant oncogenic driver mutations involving EGFR (six cases, five of which were clinically validated by response to EGFR-targeting agents), KRAS (two cases), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha gene (PIK3CA), and BRAF. Three cases initially classified as ROS1 FISH-negative passed the threshold of 15% positive events when repeat biopsies were analyzed at progression. The median overall survival of the ROS1-positive patients (104 months) was significantly superior to that of the 261 patients with EGFR/anaplastic lymphoma kinase/ROS1-negative lung adenocarcinoma (24.4 months, p = 0.044). Interestingly, the overall survival of the 13 ROS1-positive patients with lung cancer from initiation of pemetrexed-based chemotherapy was significantly prolonged when compared with that of 169 pemetrexed-treated patients with EGFR/anaplastic lymphoma kinase/ROS1-negative adenocarcinoma (p = 0.01)., Conclusions: ROS1-positive metastatic lung adenocarcinomas frequently harbor concomitant oncogenic driver mutations. Levels of ROS1 FISH-positive events are variable over time. This heterogeneity provides additional therapeutic options if discovered by multiplex biomarker testing and repeat biopsies., (Copyright © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Background: Docetaxel-based chemotherapy is effective in metastatic gastric and gastro-oesophageal junction adenocarcinoma, but has not yet been evaluated in the context of resectable patients. Here we report findings from the phase 2 part of the phase 2/3 FLOT4 trial, which compared histopathological regression in patients treated with a docetaxel-based triplet chemotherapy versus an anthracycline-based triplet chemotherapy before surgical resection., Methods: In this randomised, open-label, phase 2/3 study, eligible participants were recruited from 28 German oncology centres. Patients with resectable gastric or gastro-oesophageal junction cancer who had clinical stage cT2 or higher, nodal positive (cN+) disease, or both were randomly assigned (1:1) to either three preoperative and three postoperative 3-week cycles of intravenous epirubicin 50 mg/m 2 on day 1, intravenous cisplatin 60 mg/m 2 on day 1, and either fluorouracil 200 mg/m 2 as continuous intravenous infusion or capecitabine 1250 mg/m 2 orally (two doses of 625 mg/m 2 per day) on days 1 to 21 (ECF/ECX group) or four preoperative and four postoperative 2-week cycles of docetaxel 50 mg/m 2 , intravenous oxaliplatin 85 mg/m 2 , intravenous leucovorin 200 mg/m 2 , and fluorouracil 2600 mg/m 2 as a 24 h infusion, all on day 1 (FLOT group). Randomisation was done centrally with an interactive web-response system based on a sequence generated with blocks (block size 2) stratified by Eastern Cooperative Oncology Group performance status, location of primary tumour, age, and nodal status. No masking was done. Central assessment of pathological regression was done according to the Becker criteria. The primary endpoint was pathological complete regression (tumour regression grade TRG1a) and was analysed in the modified intention-to-treat population, defined as all patients who were randomly assigned to treatment excluding patients who had surgery but did not provide resection specimens for central evaluation. The study (including the phase 3 part) has completed enrolment, but follow-up is ongoing and this is an interim analysis. The trial is registered with ClinicalTrials.gov, number NCT01216644., Findings: Between Aug 18, 2010, and Aug 10, 2012, 300 patients (152 patients in the ECF/ECX group; 148 patients in the FLOT group) were enrolled into the phase 2 part of the study, 265 of whom (137 in the ECF/ECX group; 128 in the FLOT group) were assessable on a modified intention-to-treat basis. 119 (93%) of 128 patients in the FLOT group and 126 (92%) of 137 patients in the ECF/ECX group were given all planned preoperative cycles of treatment. FLOT was associated with significantly higher proportions of patients achieving pathological complete regression than was ECF/ECX (20 [16%; 95% CI 10-23] of 128 patients vs eight [6%; 3-11] of 137 patients; p=0·02). 44 (40%) of 111 patients in the ECF/ECX group and 30 (25%) of 119 patients in the FLOT group had at least one serious adverse event involving a perioperative medical or surgical complication. The most common non-surgical grade 3-4 adverse events were neutropenia (52 [38%] of 137 patients in the ECF/ECX group vs 67 [52%] of 128 patients in the FLOT group), leucopenia (28 [20%] vs 36 [28%]), nausea (23 [17%] vs 12 [9%]), infection (16 [12%] vs 15 [12%]), fatigue (19 [14%] vs 11 [9%]), and vomiting (13 [10%] vs four [3%])., Interpretation: Perioperative FLOT was active and feasible to administer, and might represent an option for patients with locally advanced, resectable gastric or gastro-eosophageal junction adenocarcinoma., Funding: None., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Chemotherapy (CTX) with gemcitabine, oxaliplatin, and paclitaxel (GOP) has demonstrated efficacy with an overall response rate (ORR) of approximately 50% in patients with multiply relapsed or cisplatin-refractory germ cell cancer (GCC) or both within a phase II study. We analyzed the efficacy and safety of GOP in routine clinical practice within a registry of the German Testicular Cancer Study Group., Methods: Overall, 63 patients with refractory GCC, who received GOP because of progression under cisplatin-based treatment or relapse after high-dose CTX, were included in this database. Patient characteristics, response rate, toxicity, progression-free and overall survival (OS) were analyzed. For further risk stratification, univariate and multivariate analyses were performed., Results: GOP was applied as second to eighth treatment line (median fourth) after cisplatin-based CTX. The ORR was 44% with complete remissions achieved in 8 patients (4 patients with CTX plus additional residual tumor resections and 4 patients with CTX alone) and partial remissions achieved in 19 of all for best response evaluable patients. The median progression-free survival and OS were 4.0 months (95% CI: 3.08-4.94) and 13.3 months (95% CI: 9.50-17.06), respectively. Long-term OS of>2 years was achieved in 13 (21%), and grade III and IV toxicities, mainly thrombocytopenia and leukopenia, occurred in 29 patients., Conclusion: Our results were similar compared with the previous results from the phase II study with a distinct activity with an ORR of 44%, and a long-term OS in 21% of the patients. Our data support the recommendation to use GOP ± secondary surgery in patients with multiply refractory metastatic GCC., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: Multiple investigational drugs are currently explored in cancer patient populations defined by specific biomarkers. This demands a new process of patient selection for clinical trials., Patients and Methods: Starting January 1, 2012, preemptive biomarker profiling was offered at the West German Cancer Center to all patients with advanced non-small-cell lung (NSCLC) or colorectal cancer (CRC), who met generic study inclusion criteria. Tumour specimens were subjected to prespecified profiling algorithms to detect 'actionable biomarkers' by amplicon sequencing, in situ hybridisation and immunohistochemistry. The clinical course was closely monitored to offer trial participation whenever applicable., Results: Within 12 months, 267 patients (188 NSCLC, 79 CRC) were profiled. Estimated additional cost for biomarker profiling was 219615.51 EUR excluding histopathology workup and administration. The most prevalent biomarkers in pulmonary adenocarcinoma were KRAS mutations (29%), loss of PTEN expression (18%), EGFR mutations (9%), HER2 amplification (5%) and BRAF mutations (3%), while the prevalence of ALK translocations and PIK3CA mutations was extremely low. In pulmonary squamous cell carcinoma FGFR1 amplifications were found in 15%, PTEN expression was lost in 20% and DDR2 was mutated in a single case. KRAS mutations (41%) predominated in CRC, followed by loss of PTEN expression (16%), PIK3CA (5%) and BRAF (5%) mutations. So far 13 patients (5%) have entered biomarker-stratified clinical trials. Therapeutic decisions for approved drugs were guided in another 45 patients (17%)., Conclusion: Preemptive biomarker profiling can be implemented into the diagnostic algorithm of a large Comprehensive Cancer Center. Substantial investments in diagnostics and administration are required., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Purpose: To investigate the combination of conventional cytotoxic anticancer agents and a small molecule kinase inhibitor in preclinical models of non-small-cell lung cancer (NSCLC)., Methods: We compared the induction of apoptosis by DNA-damaging anticancer drugs and PKC412, a predominantly protein kinase C (PKC)-specific small molecule inhibitor, in six NSCLC cell lines of different histologic and genetic backgrounds. The outcome of various combinations and schedules of DNA-damaging agents and PKC412 was studied, and isobolograms were calculated. Conditional expression of pro-apoptotic BAK was applied to specifically target apoptotic signal transduction in combination with drug therapy., Results: Resistance of NSCLC cells to DNA damage-induced apoptosis was mainly determined at the mitochondrial step of the intrinsic pathway of caspase activation. PKC412 effectively inhibited the growth factor signal transduction, but failed to induce apoptosis in NSCLC cells resistant to DNA-damaging agents. Combining conventional anticancer drugs with PKC412 at different doses and schedules resulted in unpredictable outcomes, including synergistic, additive, and antagonistic interactions. In contrast, conditional expression of BAK reliably sensitized drug-resistant NSCLC cells to apoptosis induced by cytotoxic agents or PKC412., Conclusions: Combining DNA-damaging anticancer drugs with a pharmacologic inhibitor of growth and survival factor signaling in NSCLC may result in unpredictable treatment outcomes. In contrast, targeting specific death effector mechanisms, such as apoptotic signal transduction, is a promising strategy to sensitize NSCLC to cytotoxic agents or kinase inhibitors.

Programmed cell death (apoptosis) is a key tumor suppressor mechanism. Consequently, most if not all cancers develop mechanisms to abolish or circumvent this genetic program. Besides enabling malignant transformation and tumor progression, defects in apoptosis can result in resistance to cytotoxic cancer therapies. Much progress has been made in the delineation of the molecular pathways leading to apoptosis. This allows the identification of target molecules and lead compounds to develop novel therapies, which make use of this intrinsic death program for the treatment of cancer. Here, we review the current understanding of apoptotic signal transduction pathways, and strategies of their therapeutic modulation in relation to lymphoma and other cancers.