Pemetrexed plus platinum with or without pembrolizumab in patients with previously untreated metastatic nonsquamous NSCLC: protocol-specified final analysis from KEYNOTE-189.

BACKGROUND: In the phase III KEYNOTE-189 study (NCT02578680), pembrolizumab plus pemetrexed and platinum-based chemotherapy (pemetrexed-platinum) significantly improved overall survival (OS) and progression-free survival (PFS) in patients with previously untreated metastatic nonsquamous non-small-cell lung cancer (NSCLC) versus placebo plus pemetrexed-platinum. We report updated efficacy outcomes from the protocol-specified final analysis, including outcomes in patients who crossed over to pembrolizumab from pemetrexed-platinum and in patients who completed 35 cycles (∼2 years) of pembrolizumab. PATIENTS AND METHODS: Eligible patients were randomized 2 : 1 to receive pembrolizumab 200 mg (n = 410) or placebo (n = 206) every 3 weeks (for up to 35 cycles, ∼2 years) plus four cycles of pemetrexed (500 mg/m2) and investigators' choice of cisplatin (75 mg/m2) or carboplatin (area under the curve 5 mg·min/ml) every 3 weeks, followed by pemetrexed until progression. Patients assigned to placebo plus pemetrexed-platinum could cross over to pembrolizumab upon progression if eligibility criteria were met. The primary endpoints were OS and PFS. RESULTS: After a median follow-up of 31.0 months, pembrolizumab plus pemetrexed-platinum continued to improve OS [hazard ratio (HR), 0.56; 95% confidence interval (CI), 0.46-0.69] and PFS (HR, 0.49; 95% CI, 0.41-0.59) over placebo plus pemetrexed-platinum regardless of programmed death-ligand 1 expression. Objective response rate (ORR) (48.3% versus 19.9%) and time to second/subsequent tumor progression on next-line treatment (PFS2; HR, 0.50; 95% CI, 0.41-0.61) were improved in patients who received pembrolizumab plus pemetrexed-platinum. Eighty-four patients (40.8%) from the placebo plus pemetrexed-platinum group crossed over to pembrolizumab on-study. Grade 3-5 adverse events occurred in 72.1% of patients receiving pembrolizumab plus pemetrexed-platinum and 66.8% of patients receiving placebo plus pemetrexed-platinum. Fifty-six patients completed 35 cycles (∼2 years) of pembrolizumab; ORR was 85.7% and 53 (94.6%) were alive at data cut-off. CONCLUSIONS: Pembrolizumab plus pemetrexed-platinum continued to show improved efficacy outcomes compared with placebo plus pemetrexed-platinum, with manageable toxicity. These findings support first-line pembrolizumab plus pemetrexed-platinum in patients with previously untreated metastatic nonsquamous NSCLC.

Association of clinical factors and recent anticancer therapy with COVID-19 severity among patients with cancer: a report from the COVID-19 and Cancer Consortium.

BACKGROUND: Patients with cancer may be at high risk of adverse outcomes from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We analyzed a cohort of patients with cancer and coronavirus 2019 (COVID-19) reported to the COVID-19 and Cancer Consortium (CCC19) to identify prognostic clinical factors, including laboratory measurements and anticancer therapies. PATIENTS AND METHODS: Patients with active or historical cancer and a laboratory-confirmed SARS-CoV-2 diagnosis recorded between 17 March and 18 November 2020 were included. The primary outcome was COVID-19 severity measured on an ordinal scale (uncomplicated, hospitalized, admitted to intensive care unit, mechanically ventilated, died within 30 days). Multivariable regression models included demographics, cancer status, anticancer therapy and timing, COVID-19-directed therapies, and laboratory measurements (among hospitalized patients). RESULTS: A total of 4966 patients were included (median age 66 years, 51% female, 50% non-Hispanic white); 2872 (58%) were hospitalized and 695 (14%) died; 61% had cancer that was present, diagnosed, or treated within the year prior to COVID-19 diagnosis. Older age, male sex, obesity, cardiovascular and pulmonary comorbidities, renal disease, diabetes mellitus, non-Hispanic black race, Hispanic ethnicity, worse Eastern Cooperative Oncology Group performance status, recent cytotoxic chemotherapy, and hematologic malignancy were associated with higher COVID-19 severity. Among hospitalized patients, low or high absolute lymphocyte count; high absolute neutrophil count; low platelet count; abnormal creatinine; troponin; lactate dehydrogenase; and C-reactive protein were associated with higher COVID-19 severity. Patients diagnosed early in the COVID-19 pandemic (January-April 2020) had worse outcomes than those diagnosed later. Specific anticancer therapies (e.g. R-CHOP, platinum combined with etoposide, and DNA methyltransferase inhibitors) were associated with high 30-day all-cause mortality. CONCLUSIONS: Clinical factors (e.g. older age, hematological malignancy, recent chemotherapy) and laboratory measurements were associated with poor outcomes among patients with cancer and COVID-19. Although further studies are needed, caution may be required in utilizing particular anticancer therapies. CLINICAL TRIAL IDENTIFIER: NCT04354701.

Updated overall survival and final progression-free survival data for patients with treatment-naive advanced ALK-positive non-small-cell lung cancer in the ALEX study.

BACKGROUND: The ALEX study demonstrated significantly improved progression-free survival (PFS) with alectinib versus crizotinib in treatment-naive ALK-positive non-small-cell lung cancer (NSCLC) at the primary data cut-off (9 February 2017). We report mature PFS (cut-off: 30 November 2018) and overall survival (OS) data up to 5 years (cut-off: 29 November 2019). PATIENTS AND METHODS: Patients with stage III/IV ALK-positive NSCLC were randomized to receive twice-daily alectinib 600 mg (n = 152) or crizotinib 250 mg (n = 151) until disease progression, toxicity, withdrawal or death. Primary end point: investigator-assessed PFS. Secondary end points included objective response rate, OS and safety. RESULTS: Mature PFS data showed significantly prolonged investigator-assessed PFS with alectinib [hazard ratio (HR) 0.43, 95% confidence interval (CI) 0.32-0.58; median PFS 34.8 versus 10.9 months crizotinib]. Median duration of OS follow-up: 48.2 months alectinib, 23.3 months crizotinib. OS data remain immature (37% of events). Median OS was not reached with alectinib versus 57.4 months with crizotinib (stratified HR 0.67, 95% CI 0.46-0.98). The 5-year OS rate was 62.5% (95% CI 54.3-70.8) with alectinib and 45.5% (95% CI 33.6-57.4) with crizotinib, with 34.9% and 8.6% of patients still on study treatment, respectively. The OS benefit of alectinib was seen in patients with central nervous system metastases at baseline [HR 0.58 (95% CI 0.34-1.00)] and those without [HR 0.76 (95% CI 0.45-1.26)]. Median treatment duration was longer with alectinib (28.1 versus 10.8 months), and no new safety signals were observed. CONCLUSIONS: Mature PFS data from ALEX confirmed significant improvement in PFS for alectinib over crizotinib in ALK-positive NSCLC. OS data remain immature, with a higher 5-year OS rate with alectinib versus crizotinib. This is the first global randomized study to show clinically meaningful improvement in OS for a next-generation tyrosine kinase inhibitor versus crizotinib in treatment-naive ALK-positive NSCLC. CLINICAL TRIALS NUMBER: NCT02075840.

Severe immune-related adverse events are common with sequential PD-(L)1 blockade and osimertinib.

BACKGROUND: Concurrent programmed death-ligand-1 (PD-(L)1) plus osimertinib is associated with severe immune related adverse events (irAE) in epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer (NSCLC). Now that PD-(L)1 inhibitors are routinely used as adjuvant and first-line treatments, sequential PD-(L)1 inhibition followed by osimertinib use may become more frequent and have unforeseen serious toxicity. METHODS: We identified patients with EGFR-mutant NSCLC who were treated with PD-(L)1 blockade and EGFR- tyrosine kinase inhibitors (TKIs), irrespective of drug or sequence of administration (total n = 126). Patient records were reviewed to identify severe (NCI-CTCAE v5.0 grades 3-4) toxicity. RESULTS: Fifteen percent [6 of 41, 95% confidence interval (CI) 7% to 29%] of all patients treated with sequential PD-(L)1 blockade followed later by osimertinib developed a severe irAE. Severe irAEs were most common among those who began osimertinib within 3 months of prior PD-(L)1 blockade (5 of 21, 24%, 95% CI 10% to 45%), as compared with >3-12 months (1 of 8, 13%, 95% CI 0% to 50%), >12 months (0 of 12, 0%, 95% CI 0% to 28%). By contrast, no severe irAEs were identified among patients treated with osimertinib followed by PD-(L)1 (0 of 29, 95% CI 0% to 14%) or PD-(L)1 followed by other EGFR-TKIs (afatinib or erlotinib, 0 of 27, 95% CI 0% to 15%). IrAEs occurred at a median onset of 20 days after osimertinib (range 14-167 days). All patients with irAEs required steroids and most required hospitalization. CONCLUSION: PD-(L)1 blockade followed by osimertinib is associated with severe irAE and is most frequent among patients who recently received PD-(L)1 blockade. No irAEs were observed when osimertinib preceded PD-(L)1 blockade or when PD-(L)1 was followed by other EGFR-TKIs. This association appears to be specific to osimertinib, as no severe irAEs occurred with administration of other EGFR-TKIs.

Alectinib versus crizotinib in treatment-naive anaplastic lymphoma kinase-positive (ALK+) non-small-cell lung cancer: CNS efficacy results from the ALEX study.

Background: The phase III ALEX study in patients with treatment-naive advanced anaplastic lymphoma kinase mutation-positive (ALK+) non-small-cell lung cancer (NSCLC) met its primary end point of improved progression-free survival (PFS) with alectinib versus crizotinib. Here, we present detailed central nervous system (CNS) efficacy data from ALEX. Patients and methods: Overall, 303 patients aged ≥18 years underwent 1:1 randomization to receive twice-daily doses of alectinib 600 mg or crizotinib 250 mg. Brain imaging was conducted in all patients at baseline and every subsequent 8 weeks. End points (analyzed by subgroup: patients with/without baseline CNS metastases; patients with/without prior radiotherapy) included PFS, CNS objective response rate (ORR), and time to CNS progression. Results: In total, 122 patients had Independent Review Committee-assessed baseline CNS metastases (alectinib, n = 64; crizotinib, n = 58), 43 had measurable lesions (alectinib, n = 21; crizotinib, n = 22), and 46 had received prior radiotherapy (alectinib, n = 25; crizotinib, n = 21). Investigator-assessed PFS with alectinib was consistent between patients with baseline CNS metastases [hazard ratio (HR) 0.40, 95% confidence interval (CI): 0.25-0.64] and those without (HR 0.51, 95% CI: 0.33-0.80, P interaction = 0.36). Similar results were seen in patients regardless of prior radiotherapy. Time to CNS progression was significantly longer with alectinib versus crizotinib and comparable between patients with and without baseline CNS metastases (P < 0.0001). CNS ORR was 85.7% with alectinib versus 71.4% with crizotinib in patients who received prior radiotherapy and 78.6% versus 40.0%, respectively, in those who had not. Conclusion: Alectinib demonstrated superior CNS activity and significantly delayed CNS progression versus crizotinib in patients with previously untreated, advanced ALK+ NSCLC, irrespective of prior CNS disease or radiotherapy. Clinical trial registration: ClinicalTrials.gov NCT02075840.

Improved EGFR mutation detection using combined exosomal RNA and circulating tumor DNA in NSCLC patient plasma.

Background: A major limitation of circulating tumor DNA (ctDNA) for somatic mutation detection has been the low level of ctDNA found in a subset of cancer patients. We investigated whether using a combined isolation of exosomal RNA (exoRNA) and cell-free DNA (cfDNA) could improve blood-based liquid biopsy for EGFR mutation detection in non-small-cell lung cancer (NSCLC) patients. Patients and methods: Matched pretreatment tumor and plasma were collected from 84 patients enrolled in TIGER-X (NCT01526928), a phase 1/2 study of rociletinib in mutant EGFR NSCLC patients. The combined isolated exoRNA and cfDNA (exoNA) was analyzed blinded for mutations using a targeted next-generation sequencing panel (EXO1000) and compared with existing data from the same samples using analysis of ctDNA by BEAMing. Results: For exoNA, the sensitivity was 98% for detection of activating EGFR mutations and 90% for EGFR T790M. The corresponding sensitivities for ctDNA by BEAMing were 82% for activating mutations and 84% for T790M. In a subgroup of patients with intrathoracic metastatic disease (M0/M1a; n = 21), the sensitivity increased from 26% to 74% for activating mutations (P = 0.003) and from 19% to 31% for T790M (P = 0.5) when using exoNA for detection. Conclusions: Combining exoRNA and ctDNA increased the sensitivity for EGFR mutation detection in plasma, with the largest improvement seen in the subgroup of M0/M1a disease patients known to have low levels of ctDNA and poses challenges for mutation detection on ctDNA alone. Clinical Trials: NCT01526928.

A randomized phase II study of the telomerase inhibitor imetelstat as maintenance therapy for advanced non-small-cell lung cancer.

BACKGROUND: Continuation or 'switch' maintenance therapy is commonly used in patients with advancd non-small-cell lung cancer (NSCLC). Here, we evaluated the efficacy of the telomerase inhibitor, imetelstat, as switch maintenance therapy in patients with advanced NSCLC. PATIENTS AND METHODS: The primary end point of this open-label, randomized phase II study was progression-free survival (PFS). Patients with non-progressive, advanced NSCLC after platinum-based doublet (first-line) chemotherapy (with or without bevacizumab), any histology, with Eastern Cooperative Oncology Group performance status 0-1 were eligible. Randomization was 2 : 1 in favor of imetelstat, administered at 9.4 mg/kg on days 1 and 8 of a 21-day cycle, or observation. Telomere length (TL) biomarker exploratory analysis was carried out in tumor tissue by quantitative PCR (qPCR) and telomerase fluorescence in situ hybridization. RESULTS: Of 116 patients enrolled, 114 were evaluable. Grade 3/4 neutropenia and thrombocytopenia were more frequent with imetelstat. Median PFS was 2.8 and 2.6 months for imetelstat-treated versus control [hazard ratio (HR) = 0.844; 95% CI 0.54-1.31; P = 0.446]. Median survival time favored imetelstat (14.3 versus 11.5 months), although not significantly (HR = 0.68; 95% CI 0.41-1.12; P = 0.129). Exploratory analysis demonstrated a trend toward longer median PFS (HR = 0.43; 95% CI 0.14-1.3; P = 0.124) and overall survival (OS; HR = 0.41; 95% CI 0.11-1.46; P = 0.155) in imetelstat-treated patients with short TL, but no improvement in median PFS and OS in patients with long TL (HR = 0.86; 95% CI 0.39-1.88; and HR = 0.51; 95% CI 0.2-1.28; P = 0.145). CONCLUSIONS: Maintenance imetelstat failed to improve PFS in advanced NSCLC patients responding to first-line therapy. There was a trend toward a improvement in median PFS and OS in patients with short TL. Short TL as a predictive biomarker will require further investigation for the clinical development of imetelstat.

A phase I clinical trial of spicamycin derivative KRN5500 (NSC 650426) using a phase I accelerated titration "2B" design.

The spicamycin derivative KRN5500 was considered as a potential anti-cancer agent based on in vitro and preclinical studies. A Phase I study involving 24 cancer patients in whom tumors were refractory to all other conventional therapies was conducted to determine the dose limiting toxicity, maximum tolerated dose, effectiveness, and pharmacokinetic parameters of this drug administered by 1-h IV infusion daily for five consecutive days every 3 weeks. Using an accelerated dose titration strategy, 8.4 mg/m2/d x 5 days was the maximum administered dose. Severe gastrointestinal and hepatic toxicities were observed at doses at or above 4.3 mg/m2/d x 5. The recommended Phase II dose i s 4.3mg/m2/d x 5. The distribution of KRN5500 followed a two-compartment model, and clearance did not decrease significantly over the dose range 0.8-8.4 mg/m2/d x 5. No significant correlation was observed between plasma levels and toxicity. No tumor responses were observed among the 14 patients evaluable for response.

Impact of race in lung cancer: analysis of temporal trends from a surveillance, epidemiology, and end results database.

STUDY OBJECTIVES: We analyzed data from a community-based cancer database over a 26-year period in order to characterize clinicopathologic differences between black and white patients with lung cancer, and to identify relevant temporal trends in incidence and survival. DESIGN, SETTING, AND PATIENTS: Data on demographics, stage, histology, and survival were obtained on all black and white patients with primary bronchogenic carcinoma registered in the community-based metropolitan Detroit Surveillance, Epidemiology, and End Results database from 1973 to 1998. RESULTS: Of 48,318 eligible patients, 23% were black. Lung cancer incidence rates decreased for men of both races from 1985 to 1998, with a greater decline occurring in black men (p < 0.0001). Although incidence rates declined over time for men of both races < 50 years of age, this decrease was greater in white men, resulting in an increase in the racial differential in younger men. Temporal trends in incidence rates were similar for women of both races. The incidence of distant-stage disease was higher among blacks throughout the study period. The incidence of local-stage disease decreased for both races, though this decline was greater in blacks. A significant racial difference in 2-year and 5-year survival rates developed during the study period, due to a distinct lack of improvement in black patients. In a multivariate model, the relative risks of death for black patients, relative to white patients, were 1.24 (p < 0.0001) for local stage, 1.14 (p < 0.0001) for regional stage, and 1.03 (p = 0.045) for distant stage. CONCLUSION: Significant racial differences exist in the incidence and survival rates for lung cancer in metropolitan Detroit. Since 1973, several disturbing trends have developed, particularly with regard to the lack of improvement in overall survival in black patients. Further study is required to determine the factors responsible for these temporal trends.

Paclitaxel, cisplatin, and 5-fluorouracil for patients with advanced or recurrent squamous cell carcinoma of the head and neck.

BACKGROUND: The combination of cisplatin and 5-fluorouracil (5-FU) is considered standard therapy for patients with recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN). Paclitaxel has exhibited single-agent activity in patients with this disease. The authors conducted this study to evaluate the feasibility and efficacy of combining paclitaxel with cisplatin and 5-FU for patients with advanced or recurrent SCCHN. METHODS: Patients with recurrent, metastatic, or locally advanced SCCHN who had measurable or evaluable disease and no prior chemotherapy were eligible. The starting dose level consisted of paclitaxel 135 mg/m(2) on Day 1, cisplatin 75 mg/m(2) on Day 2, and 5-FU 1 gm/m(2)/day on Days 2-6. Due to Grade 4 mucositis, dose level 1 of 5-FU was reduced to 800 mg/m(2)/day on Days 2-6 (for 7 patients), and subsequently the 5-FU dose was adjusted to 1 gm/m(2)/day on Days 2-5 (for 17 patients). RESULTS: Twenty-five patients were enrolled, with a median age of 60 years and a median Southwest Oncology Group performance status of 1. Of the 25 patients, 16 had recurrent disease, 3 had metastatic disease at diagnosis, and 6 had untreated locally advanced SCCHN. Ninety-nine courses of therapy were administered, with a median of 5 courses. Major toxicities were neutropenia and mucositis. Significant neurotoxicity or nephrotoxicity were not observed. There were two treatment-related deaths (one each due to mucositis and neutropenic pneumonia), and these precluded further dose escalation. Fifteen of the 25 patients (60%) achieved a major response. Of significance is the response rate of 58% (11 of 19 patients) in those with recurrent or metastatic disease who had a duration of response ranging from 3 to 19+ months. Two of these 19 patients continue to be in remission of 19+ and 15+ months' duration, respectively. The median survival for patients with recurrent or metastatic disease was 6 months (range, 1-26 months), with a 1-year survival rate of 37%. CONCLUSIONS: The dose and schedule for the combination of paclitaxel, 5-FU, and cisplatin as determined in this study are feasible, with encouraging outcomes and activity in patients with recurrent or metastatic SCCHN. The results of this trial warrant larger-scale evaluation to determine the role of this combination in the management of patients with this disease.

Lung cancer in patients < 50 years of age: the experience of an academic multidisciplinary program.

OBJECTIVE: To determine if the clinicopathologic features and survival of lung cancer patients < 50 years of age differ from those of older patients. DESIGN: Retrospective review of patients with primary bronchogenic carcinoma diagnosed at a single, multidisciplinary cancer center. SETTING: A National Cancer Institute-designated comprehensive cancer center in urban Detroit, MI. PATIENTS: All patients with primary bronchogenic carcinoma evaluated in the Multidisciplinary Lung Cancer Clinic at the Barbara Ann Karmanos Cancer Institute between 1990 and 1993. RESULTS: Of 1,012 patients with lung cancer, 126 (12.5%) were < 50 years old at diagnosis, with a median age of 44 years. The median age of the 886 patients > or = 50 years of age was 65 years. The gender (p = 0.08) and racial (p = 0.12) characteristics of the younger and older patient groups were not significantly different. More than 90% of patients in both groups were smokers. The incidence of adenocarcinoma was significantly higher in younger patients (48.4% vs 36.0%, p < 0.001), and early-stage disease was less frequently diagnosed in younger patients (4.8% vs 19.7%, p < 0.001). Younger patients were more likely than older patients to undergo treatment, including surgery and combined-modality therapy (p < 0.001). Median survival was 13 months in younger and 9 months in older patients, while overall survival was similar in younger and older patients (p = 0.13). CONCLUSIONS: Although younger patients with lung cancer present with more advanced-stage disease, their overall survival is similar to that of older patients, suggesting that lung cancer is not an inherently more aggressive disease in patients < 50 years of age.

Lung cancer in young patients: analysis of a Surveillance, Epidemiology, and End Results database.

PURPOSE: A large community-based cancer registry was analyzed to determine if the clinicopathologic characteristics and/or survival rates of lung cancer patients under 50 years of age at diagnosis differ from those of patients 50 years of age or greater at diagnosis. PATIENTS AND METHODS: Data regarding demographics, stage, histology, initial therapy, and survival were obtained on all patients with primary bronchogenic carcinoma registered in the metropolitan Detroit Surveillance, Epidemiology and End Results (SEER) registry from 1973 to 1992. RESULTS: Of 31,266 patients, 9.0% were under 50 years of age at diagnosis. Females (40.1% v 31.2%; P < .001) and blacks (28.7% v 21.9%, P < .001) were overrepresented in the younger group compared with the older group. Younger patients had a significantly higher incidence of adenocarcinoma and were less likely to present with local-stage disease (18.6% v 25.2%; P < .001). Younger patients were significantly more likely to undergo surgery and/or combined-modality therapy. Relative survival at 5 years was significantly better in the younger group (16.1% v 13.4%; P < .001), mainly because of better survival in patients with local-stage disease (48.7% v 35.4%; P < .001). In a multivariate analysis, advanced-stage, nonsurgical initial therapy, age 50 years or greater at diagnosis, and male gender were independent negative prognostic factors. CONCLUSION: The overrepresentation of females and blacks in the group of younger patients with lung cancer suggests an increased susceptibility to lung carcinogens in these populations. Overall, this study suggests that lung cancer is not a more aggressive disease in younger patients and that all patients with lung cancer should be managed along the same therapeutic guidelines.

A phase II study of carboplatin and paclitaxel in the treatment of patients with advanced esophageal and gastric cancer.

We initiated a phase II study to determine the efficacy of carboplatin and paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in patients with advanced esophageal or gastric cancer. Objective tumor responses, duration of response, time to disease progression, overall survival, and toxicity profile are the end points evaluated in this study. The study includes patients with locally advanced metastatic or recurrent esophageal or gastric cancer with no history of prior chemotherapy or radiation treatment. Patients are required to have a performance status of 0 to 2 and no organ failure. Staging diagnostics include computed tomography scans and endoscopic ultrasound when appropriate. Starting dose of paclitaxel is 200 mg/m2, and carboplatin is given to achieve an area under the concentration-time curve of 5.0. Dose escalation is attempted if nadir counts permit. Seventeen patients have registered so far. Of those, three are not evaluable for efficacy analysis: one has not been on study long enough to be assessed for response and the other two are not assessable for objective tumor response. Three patients with gastric cancer have achieved partial responses. Two of five patients with esophageal cancer responded (partial response) to this treatment. Dose escalation by one step was feasible in approximately half the patients. There were no episodes of neutropenic fever. Carboplatin and paclitaxel given on an outpatient basis is well tolerated and an interesting regimen for the treatment of patients with advanced gastric or esophageal cancer.

Growth inhibition and induction of apoptosis by fenretinide in small-cell lung cancer cell lines.

BACKGROUND: Lung cancer is the major cause of cancer-related death in the United States, with small-cell lung cancer (SCLC) constituting approximately 20% of all cases of lung cancer. Numerous epidemiologic and molecular studies have suggested that alterations in retinoid-signaling pathways play a role in the pathogenesis of lung cancer. Fenretinide [N-(4-hydroxyphenyl)retinamide; HPR] is a synthetic retinoid with minimal toxicity and favorable pharmacokinetics during long-term administration to patients in clinical trials. PURPOSE: The aim of this investigation was to study the effect of HPR on the growth of SCLC cells in vitro. METHODS: Seven SCLC cell lines (NCI-H69, NCI-H82, NCI-H146, NCI-H209, NCI-H345, NCI-H446, and NCI-H510A) were exposed continuously to a broad range of concentrations of HPR or all-trans-retinoic acid (RA), and cell viability was determined on day 3 and day 7 by the trypan blue dye exclusion assay. The growth of these cells was compared with that of control vehicle-treated cells to determine survival fraction and the dose resulting in a 50% inhibition of growth when compared with growth of control cells (IC50). The induction of apoptosis was evaluated by fluorescent microscopy, DNA content analysis, and a terminal deoxyribonucleotidyl transferase-based assay that labels 3'-hydroxyl ends of DNA fragments (TUNEL assay) combined with flow cytometric analysis. RESULTS: HPR inhibited growth of a panel of SCLC cell lines at IC50 values that ranged from 0.1 to 3.0 microM (concentrations that are clinically achievable). In all cell lines tested, HPR was a more potent growth inhibitor than RA. By use of fluorescent microscopy, HPR was found to induce morphologic changes consistent with apoptosis in NCI-H82 SCLC cells, including cellular shrinkage, chromatin condensation, and nuclear fragmentation. Flow cytometric analysis revealed decreased DNA content, and TUNEL assay showed increased digoxigenin-uridine triphosphate incorporation in HPR-treated NCI-H82 SCLC cells; these findings are consistent with the induction of apoptosis. CONCLUSIONS: HPR inhibited the in vitro growth of SCLC cells. In NCI-H82 cells, HPR inhibited growth via the induction of apoptosis.