1000 Robotic-assisted lobectomies for primary lung cancer: 16 years single center experience.

OBJECTIVE: This study aimed at describing our high-volume single center experience in robotic-assisted thoracic surgery (RATS) to evaluate short outcome and feasibility of the technique, the adequacy of oncological results, and the learning curve. METHODS: We retrospectively analyzed data from 1000 consecutive patients who underwent lobectomy and systematic lymphadenectomy for primary lung cancer using RATS approach between May 2007 and May 2023. RESULTS: Nine-hundred ninety-seven patients (99.7 %) underwent lobectomy, whereas 3 (0.03 %) patients bilobectomy. Conversion rate to open surgery was 3.7 %. Minor complications occurred in 213 (21.3 %) patients, major complications in 29 patients (2.9 %). The 30-day and 90-day operative mortality was 0 % and 0.1 %, respectively. The median number of N1 + N2 stations resected was 5 (range 0-9), with a median number of 17 of N1 + N2 lymph nodes resected (range 0-55). The oncological outcome was evaluated only on the subgroup of patients (n = 895) with non-small cell lung cancer. Pathological lymph node upstaging from cN0 to pN1/pN2 was evident in 147 patients (17.3 %): 9 % from cN0 to pN1 and 7.1 % from cN0 to pN2. With a median follow-up of 3.9, 5-year OS and DFS were respectively 89.3 % and 83.6 % for stage I, 74 % and 66.5 % for stage II, and 61 % and 36.4 % for stage IIIA. CONCLUSIONS: Better vision and excellent instrument maneuverability of the robotic surgical system allowed excellent results in terms of early, adequate oncological outcome comparable to open surgery literature data, and acceptable learning curve. ULTRAMINI ABSTRACT: 1000 consecutive patients who underwent lobectomy and systematic lymphadenectomy for primary lung cancer using RATS approach have been analyzed with the aim to describe our high-volume single center experience, and to evaluate short outcome and feasibility of the technique, the adequacy of oncological results, and the learning curve.

The Role of Hyperthermic Intrathoracic Chemotherapy (HITHOC) in Thoracic Tumors.

Pleural mesothelioma (PM) is a rare but aggressive thoracic tumor with a poor prognosis. Multimodal treatment-including induction chemotherapy, aggressive surgical resection, radiotherapy and immunotherapy in selected cases-currently represents the best therapeutic option. Single-center studies advocate hyperthermic intrathoracic chemotherapy (HITHOC) during surgical resection as an additional therapeutic option, although its impact on post-operative morbidity and survival has not yet been evaluated on a larger scale. HITHOC can be applied not only in the case of mesothelioma, but also in the case of thymoma with pleural involvement or-in very selected cases-in patients with secondary pleural metastases. Despite favorable outcomes and reduced clinical risks, there is no uniform approach to HITHOC, and a wide variety of indications and technical applications are still reported. Based on available data, HITHOC seems to offer a clear benefit in regard to overall survival of all mesothelioma patients; however, multicenter randomized controlled trials are required to validate and standardize this approach. The aim of this review is to focus on the present role of HITHOC in thoracic tumors with pleural involvement as well as on future challenges, particularly in the light of possible combined therapy of thoracic tumors still presenting poor prognoses.

Multicentre retrospective analysis on pulmonary metastasectomy: an European perspective.

OBJECTIVES: To assess the current practice of pulmonary metastasectomy at 15 European Centres. Short- and long-term outcomes were analysed. METHODS: Retrospective analysis on patients ≥18 years who underwent curative-intent pulmonary metastasectomy (January 2010 to December 2018). Data were collected on a purpose-built database (REDCap). Exclusion criteria were: previous lung/extrapulmonary metastasectomy, pneumonectomy, non-curative intent and evidence of extrapulmonary recurrence at the time of lung surgery. RESULTS: A total of 1647 patients [mean age 59.5 (standard deviation; SD = 13.1) years; 56.8% males] were included. The most common primary tumour was colorectal adenocarcinoma. The mean disease-free interval was 3.4 (SD = 3.9) years. Relevant comorbidities were observed in 53.8% patients, with a higher prevalence of metabolic disorders (32.3%). Video-assisted thoracic surgery was the chosen approach in 54.9% cases. Wedge resections were the most common operation (67.1%). Lymph node dissection was carried out in 41.4% cases. The median number of resected lesions was 1 (interquartile range 25-75% = 1-2), ranging from 1 to 57. The mean size of the metastases was 18.2 (SD = 14.1) mm, with a mean negative resection margin of 8.9 (SD = 9.4) mm. A R0 resection of all lung metastases was achieved in 95.7% cases. Thirty-day postoperative morbidity was 14.5%, with the most frequent complication being respiratory failure (5.6%). Thirty-day mortality was 0.4%. Five-year overall survival and recurrence-free survival were 62.0% and 29.6%, respectively. CONCLUSIONS: Pulmonary metastasectomy is a low-risk procedure that provides satisfactory oncological outcomes and patient survival. Further research should aim at clarifying the many controversial aspects of its daily clinical practice.

Colorectal Cancer Pulmonary Metastasectomy: When, Why and How.

Colorectal cancer is the third-most-diagnosed cancer in males and in females, representing 8% of estimated new cases, and the third cause of cancer-related death in both sexes, accounting for 9% of cancer deaths in men and 8% in women. About 20% of patients diagnosed with CRC present metastatic disease. Although lung metachronous or synchronous metastatic spread without other involved sites has been reported in only a small proportion of patients, considering that this tumor is frequently diagnosed, the clinical approach to CRC pulmonary metastases represents a major issue for thoracic surgeons and CRC oncologists. Among patients diagnosed with pulmonary metastases from CRC, about 9-12% are eligible for local treatments with radical intent, including surgical resection, SBRT (stereotactic body radiation therapy) and ablation therapy. Due to the lack of randomized controlled trials among different local strategies, there is no definitive evidence about the optimal approach, although surgical resection is considered the most effective therapeutic option in this clinical scenario. Oncological achievement of primary radical resection, the biology of primary tumor and metastatic sites, disease free interval and or progression free survival are independent prognostic factors which make it possible to define a cohort of patients which might significantly benefit from pulmonary metastasectomy.

The role of the surgical volume for clinical outcomes in VATS lobectomy for lung cancer: a national large database multicenter analysis.

Improving the quality of lung cancer care at a cost that can be sustained is a hotly debated issue. High-risk, low-volume procedures (such as lung resections) are believed to improve significantly when centralised in high-volume centres. However, limited evidence exists to support volume requirements in lung cancer surgery. On the other hand, there was no evidence that the number of lung resections affected either the short-term perioperative results or the long-term cost. Using data from an extensive nationwide registry, this study investigated the correlations between surgical volumes and selected perioperative outcomes. A retrospective analysis of a prospectively filled national registry that follows stringent quality assurance and security procedures was conducted to ensure data accuracy and security. Patients who underwent VATS lobectomy from 2014 to 2019 at the participating centres were included. Selected perioperative outcomes were reported. Total direct hospital cost is measured at discharge for hospitalisations with a primary diagnosis of lung cancer, hospital stay costs, and postoperative length of hospital stay after lobectomy. After the propensity score matched, centres were divided into three groups according to the surgical volume of the unit where VATS lobectomies were performed (high-volume centre: > 500 lobectomies; medium-volume centre: 200-500 lobectomies; low-volume centre: < 200 lobectomies). 11,347 patients were included and matched (low-volume center = 2890; medium-volume center = 3147; high-volume center = 2907). The mean operative time density plot (Fig. 1A) showed no statistically significant difference (p = 0.67). In contrast, the density plot of the harvested lymph nodes (Fig. 1B) showed significantly higher values in the high-volume centres (p = 0.045), albeit without being clinically significant. The adjusted rates of any and significant complications were higher in the low-volume centre (p = 0.034) without significantly affecting the length of hospital stay (p = 0.57). VATS lobectomies for lung cancer in higher-volume centres seem associated with a statistically significantly higher number of harvested lymph nodes and lower perioperative complications, yet without any significant impact in terms of costs and resource consumption. These findings may advise the investigation of the learning curve effect in a complete economic evaluation of VATS lobectomy in lung cancer. Fig. 1 The mean operative time density plot showed no statistically significant difference (p = 0.67).

Anastomosis Complications after Bronchoplasty: Incidence, Risk Factors, and Treatment Options Reported by a Referral Cancer Center.

BACKGROUND: Sleeve lobectomy with bronchoplasty is a safe surgical technique for the management of lung cancer and endobronchial localization of extrapulmonary cancers. However, anastomotic complications can occur, and treatment strategies are not standardized. METHODS: Data from 280 patients subjected to bronchoplasty were retrospectively analyzed, focusing on surgical techniques, anastomotic complications, and their management. Multivariate analysis was performed, and Kaplan-Meier curves were used to determine survival. RESULTS: Ninety percent of 280 surgeries were for lung cancer. Anastomotic complications occurred in 6.42% of patients: late stenosis in 3.92% and broncho-pleural fistula in 1.78%. The median survival was 65.90 months (95% CI = 41.76-90.97), with no difference (p = 0.375) for patients with (51.28 months) or without (71.03 months) anastomotic complications. Mortality at 30 days was higher with anastomotic complications (16.7% vs. 3%, p = 0.014). Multivariable analysis confirmed pathological stage (N+) as a risk factor for anastomotic complications (p = 0.016). Our mortality (3.93%) and morbidity rate (41.78%) corresponded to recent series results. CONCLUSIONS: In our experience, surgery is preferred to avoid life-threatening complications in bronchopleural fistulas. Bronchoscopic balloon dilatation is preferred for benign strictures. The nodal stage is related to complications (p = 0.0014), reflecting the aggressiveness of surgery, which requires extended radical lymphadenectomy.

Differences in selected postoperative outcomes between simple and complex segmentectomies for lung cancer: A systematic review and meta-analysis.

BACKGROUND: This systematic review and meta-analysis aimed to synthesize the evidence on the preoperative characteristics, operative outcomes, and postoperative complications of simple and complex segmentectomy for lung cancer. METHODS: A systematic review of EMBASE (through Ovid), MEDLINE (via PubMed), and Cochrane CENTRAL (January 1990 - January 2023) was done. We included studies to compare simple versus complex segmentectomies for lung cancer in terms of characteristics and operative and postoperative outcomes. RESULTS: There was a statistically significant difference regarding higher operative time in favor of simple segmentectomies (Mean Difference, MD = 15.76, 95% Confidence Interval, CI: 2.46 - 29.07, p = 0.02). The incidence of postoperative complications did not change between the two groups (Risk Ratio, RR = 0.86, 95% CI: 0.66 - 1.13, p = 0.27). There were no significant differences regarding postoperative length of hospital stay between simple or complex segmentectomies (MD = -0.02, 95% CI: 0.56 - 0.51, p = 0.93). CONCLUSIONS: Simple and complex segmentectomies have comparable postoperative outcomes; in particular, postoperative complication rates and length of hospital stay were similar. Complex segmentectomies were associated with a longer operative time.

Real-world survival outcomes of wedge resection versus lobectomy for cT1a/b cN0 cM0 non-small cell lung cancer: a single center retrospective analysis.

Background: JCOG0802/WJOG4607L showed benefits in overall survival (OS) of segmentectomy. CALGB 140503 confirmed that sublobar resection was not inferior to lobectomy concerning recurrence-free survival (RFS) but did not provide specific OS and RFS according to the techniques of sublobar resections. Hence, we retrospectively analyze the survival differences between wedge resection and lobectomies for stage IA lung cancer. Methods: We reviewed the clinical records of patients with clinical stage IA NSCLC over 20 years. The inclusion criteria were: preoperative staging with CT scan and whole body CT/PET; tumor size <20 mm; wedge resections or lobectomies with or without lymph node dissection; NSCLC as the only primary tumor during the follow-up period. We excluded: multiple invasive lung cancer; positive resection margin; preoperative evidence of nodal disease; distant metastasis at presentation; follow-up time <5 years. The reverse Kaplan - Meier method estimated the median OS and PFS and compared them by the log-rank test. The stratified backward stepwise Cox regression model was employed for multivariable survival analyses. Results: 539 patients were identified: 476 (88.3%) lobectomies and 63 (11.7%) wedge resections. The median OS time for the whole cohort was 189.7 months (range: 173.7 - 213.9 months). The 5-year wedge resection and lobectomy OS were 82.2% and 87.0%. The 5-year RFS of wedge resection and lobectomy were 17.8% and 28.9%. The log-rank test showed no significant differences (p = 0.39) between wedge resections and lobectomies regarding OS and RFS (p = 0.23). Conclusions: Lobectomy and wedge resection are equivalent oncologic treatments for individuals with cN0/cM0 stage IA NSCLC <20 mm. Validating the current findings requires a prospective, randomized comparison between wedge resection and standard lobectomy to establish the prognostic significance of wedge resection.

How Much Stress Does a Surgeon Endure? The Effects of the Robotic Approach on the Autonomic Nervous System of a Surgeon in the Modern Era of Thoracic Surgery.

(1) Objective: the purpose of this study was to evaluate and quantify the stress to which a surgeon is subjected during his/her surgical activity; we compared the individual clinical and psychological responses to stress of two surgeons during their surgical activities via robotic and open approaches. (2) Materials and methods: This was a prospective observational study in which we progressively collected data concerning the surgical performances of two different thoracic surgeons (October 2021-June 2022). We evaluated 20 lung resections performed via robot-assisted surgery and 20 lung resections performed via an open approach by each surgeon; in particular, we evaluated a panel of pre-, peri-, and postoperative data concerning the interventions, the patients, and other outcomes concerning the autonomic nervous system (ANS) and psychological responses to stress of the surgeons during their surgical activities. (3) Results: When analyzing data concerning the ANS activity of two surgeons, during robotic activity we found lower maximum, minimum, and mean heart rates; lower mean respiratory frequencies; lower body temperatures; and lower mean desaturations compared to the open approach activity for both surgeons. The psychological monitoring showed that the open approach created more physical fatigue and frustration but higher levels of satisfaction and performance evaluation. The robot-assisted surgeries showed higher levels of anxiety. (4) Conclusions: for different reasons, the robotic approach stimulated the ANS to a lesser degree, causing less stress for surgeons and ensuring greater comfort.

Learning Curve of Robotic Lobectomy for the Treatment of Lung Cancer: How Does It Impact on the Autonomic Nervous System of the Surgeon?

OBJECTIVE: Our purpose is to define the learning curve for robot-assisted thoracoscopic surgery lobectomy by reporting the experience of a single surgeon. MATERIAL AND METHODS: We progressively collected the data concerning the surgical performance of a single male thoracic surgeon, from the beginning of his robotic activity as first operator from January 2021 to June 2022. We evaluated several pre-, intra- and postoperative parameters concerning patients and intraoperative cardiovascular and respiratory outcomes of the surgeon, recorded during surgical interventions, in order to evaluate his cardiovascular stress. We used cumulative sum control charts (CUSUM) to analyze the learning curve. RESULTS: A total of 72 lung lobectomies were performed by a single surgeon in this period. Analyzing the CUSUM of several parameters, the inflection point identifying the transition beyond the surgeon learning phase was reached at cases 28, 22, 27 and 33 when considering operating time, mean heart rate, max heart rate and mean respiratory rate, respectively. CONCLUSIONS: The learning curve for robotic lobectomy seems to be safe and feasible with a correct robotic training program. The analysis of a single surgeon from the beginning of his robotic activity demonstrates that confidence, competence, dexterity and security are achieved after about 20-30 procedures, without compromising efficiency and oncological radicality.

Artificial Neural Networks in Lung Cancer Research: A Narrative Review.

BACKGROUND: Artificial neural networks are statistical methods that mimic complex neural connections, simulating the learning dynamics of the human brain. They play a fundamental role in clinical decision-making, although their success depends on good integration with clinical protocols. When applied to lung cancer research, artificial neural networks do not aim to be biologically realistic, but rather to provide efficient models for nonlinear regression or classification. METHODS: We conducted a comprehensive search of EMBASE (via Ovid), MEDLINE (via PubMed), Cochrane CENTRAL, and Google Scholar from April 2018 to December 2022, using a combination of keywords and related terms for "artificial neural network", "lung cancer", "non-small cell lung cancer", "diagnosis", and "treatment". RESULTS: Artificial neural networks have shown excellent aptitude in learning the relationships between the input/output mapping from a given dataset, without any prior information or assumptions about the statistical distribution of the data. They can simultaneously process numerous variables, managing complexity; hence, they have found broad application in tasks requiring attention. CONCLUSIONS: Lung cancer is the most common and lethal form of tumor, with limited diagnostic and treatment methods. The advances in tailored medicine have led to the development of novel tools for diagnosis and treatment. Artificial neural networks can provide valuable support for both basic research and clinical decision-making. Therefore, tight cooperation among surgeons, oncologists, and biostatisticians appears mandatory.

Minimally Invasive Anatomical Segmentectomy versus Lobectomy in Stage IA Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis.

OBJECTIVE: A systematic review and meta-analysis was performed to assess potential differences in perioperative outcomes and disease-free survival (DFS) and overall survival (OS) of patients with pathological stage IA non-small cell lung cancer (NSCLC) who underwent minimally invasive anatomical segmentectomy or lobectomy. METHODS: This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic search of EMBASE (through Ovid), MEDLINE (via PubMed), and Cochrane CENTRAL was conducted. Two researchers independently reviewed each eligible study that included patients with stage IA NSCLC who underwent minimally invasive anatomical segmentectomy and lobectomy and compared perioperative and/or survival outcomes of patients. RESULTS: A total of 887 publications were identified. Of these, 10 articles met our eligibility criteria. A significantly higher number of lymph nodes were harvested in lobectomies. The two groups did not significantly differ in postoperative complication rates, DFS, and OS. Patients who underwent segmentectomy had shorter postoperative hospital stays. CONCLUSIONS: Minimally invasive lobectomy and segmentectomy showed comparable short-term and long-term outcomes in stage IA NSCLC patients. Postoperative complication rates were similar. Minimally invasive lobectomies are associated with a higher number of harvested lymph nodes, although this did not affect the final staging or the survival outcomes.

Unplanned Return to the Operating Room after Elective Oncologic Thoracic Surgery: A Further Quality Indicator in Surgical Oncology.

Background: An unplanned return to the operating room (UROR) is defined as a readmission to the operating room because of a complication or an untoward outcome related to the initial surgery. The aim of the present report is to evaluate the role of URORs after elective oncologic thoracic surgery. Methods: In the study, 4012 consecutive patients were enrolled; among them, 71 patients (1.76%) had an unplanned return to the operating room. Age, sex, Charlson comorbidity index, induction treatments, type of the first operation, indication to readmission to the operating room and type of second operation, length of stay, complication after reoperation and outcomes were collected. Results: The mean age was 63.3 (SD: 13.0); there were 53 male patients (74.6%); the type of the first procedure was: lower lobectomy (11.3%), middle lobectomy (1.4%), upper lobectomy (22.5%), metastasectomy (5.6%), extrapleural pneumonectomy (4.2%), pneumonectomy (40.9%), pleural biopsy (5.6%) and other procedures (8.5%). Patients presenting complications after UROR had undergone a significantly longer first procedure (p < 0.02), had a longer length of stay (p < 0.001) and had higher post-operative mortality (p < 0.001). Conclusions: The patients experiencing UROR after elective oncologic thoracic surgery have significantly higher morbidity and mortality rates when compared to standard thoracic surgery. Bronchopleural fistula remains the most lethal complication in patients undergoing UROR.

CT-Derived Body Composition Values and Complications After Pneumonectomy in Lung Cancer Patients: Time for a Sex-Related Analysis?

Purpose: This study aimed to assess if CT-derived body composition values and clinical characteristics are associated with the risk of postsurgical complications in men and women who underwent pneumonectomy for lung cancer. Materials and Methods: Patients who underwent pneumonectomy between 2004 and 2008 were selected. The ethics committee approved this retrospective study with waiver of informed content. Main clinical data collected were sex, age, weight and height to calculate body mass index (BMI), albumin, C-reactive protein, smoking status, side, sarcopenia, presurgical treatments, reoperation, and complications within 30 days after pneumonectomy, classified as: lung complications, cardiac complications, other complications, and any complication. From an axial CT image at the level of L3, automatic segmentations were performed to calculate skeletal muscle area (SMA), skeletal muscle density, subcutaneous adipose tissue, and visceral adipose tissue. Skeletal muscle index was calculated as SMA/square height. Univariate and multivariate logistic regression analyses were performed to estimate the risk of any complication, both on the total population and in a by sex subgroup analysis. All tests were two tailed and considered significant at 5% level. Results: A total of 107 patients (84 men and 23 women) were included. Despite no significant differences in BMI, there were significant differences of body composition values in muscle and adipose tissue parameters between men and women, with women being significantly more sarcopenic than men (p = 0.002). Separate analyses for men and women showed that age and SMA were significantly associated with postoperative complications in men (p = 0.03 and 0.02, respectively). Conclusions: Body composition measurements extracted from routine CT may help in predicting complications after pneumonectomy, with men and women being different in quantity and distribution of muscle and fat, and men significantly more prone to postpneumonectomy complications with the increase of age and the decrease of skeletal muscle area.

Protective mucosal immunity against SARS-CoV-2 after heterologous systemic prime-mucosal boost immunization.

Several effective SARS-CoV-2 vaccines are currently in use, but effective boosters are needed to maintain or increase immunity due to waning responses and the emergence of novel variants. Here we report that intranasal vaccinations with adenovirus 5 and 19a vectored vaccines following a systemic plasmid DNA or mRNA priming result in systemic and mucosal immunity in mice. In contrast to two intramuscular applications of an mRNA vaccine, intranasal boosts with adenoviral vectors induce high levels of mucosal IgA and lung-resident memory T cells (TRM); mucosal neutralization of virus variants of concern is also enhanced. The mRNA prime provokes a comprehensive T cell response consisting of circulating and lung TRM after the boost, while the plasmid DNA prime induces mostly mucosal T cells. Concomitantly, the intranasal boost strategies lead to complete protection against a SARS-CoV-2 infection in mice. Our data thus suggest that mucosal booster immunizations after mRNA priming is a promising approach to establish mucosal immunity in addition to systemic responses.

Isolation and Characterization of Mouse Monoclonal Antibodies That Neutralize SARS-CoV-2 and Its Variants of Concern Alpha, Beta, Gamma and Delta by Binding Conformational Epitopes of Glycosylated RBD With High Potency.

Antibodies targeting Receptor Binding Domain (RBD) of SARS-CoV-2 have been suggested to account for the majority of neutralizing activity in COVID-19 convalescent sera and several neutralizing antibodies (nAbs) have been isolated, characterized and proposed as emergency therapeutics in the form of monoclonal antibodies (mAbs). However, SARS-CoV-2 variants are rapidly spreading worldwide from the sites of initial identification. The variants of concern (VOC) B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma) and B.1.167.2 (Delta) showed mutations in the SARS-CoV-2 spike protein potentially able to cause escape from nAb responses with a consequent reduction of efficacy of vaccines and mAbs-based therapy. We produced the recombinant RBD (rRBD) of SARS-CoV-2 spike glycoprotein from the Wuhan-Hu 1 reference sequence in a mammalian system, for mice immunization to isolate new mAbs with neutralizing activity. Here we describe four mAbs that were able to bind the rRBD in Enzyme-Linked Immunosorbent Assay and the transmembrane full-length spike protein expressed in HEK293T cells by flow cytometry assay. Moreover, the mAbs recognized the RBD in supernatants of SARS-CoV-2 infected VERO E6 cells by Western Blot under non-reducing condition or in supernatants of cells infected with lentivirus pseudotyped for spike protein, by immunoprecipitation assay. Three out of four mAbs lost their binding efficiency to completely N-deglycosylated rRBD and none was able to bind the same recombinant protein expressed in Escherichia coli, suggesting that the epitopes recognized by three mAbs are generated by the conformational structure of the glycosylated native protein. Of particular relevance, three mAbs were able to inhibit Wuhan SARS-CoV-2 infection of VERO E6 cells in a plaque-reduction neutralization test and the Wuhan SARS-CoV-2 as well as the Alpha, Beta, Gamma and Delta VOC in a pseudoviruses-based neutralization test. These mAbs represent important additional tools for diagnosis and therapy of COVID-19 and may contribute to the understanding of the functional structure of SARS-CoV-2 RBD.

Safety and efficiency modifications of SIV-based integrase-defective lentiviral vectors for immunization.

Integrase-defective lentiviral vectors (IDLVs) represent an attractive platform for vaccine development as a result of the ability to induce persistent humoral- and cellular-mediated immune responses against the encoded transgene. Compared with the parental integrating vector, the main advantages for using IDLV are the reduced hazard of insertional mutagenesis and the decreased risk for vector mobilization by wild-type viruses. Here we report on the development and use in the mouse immunogenicity model of simian immunodeficiency virus (SIV)-based IDLV containing a long deletion in the U3 region and with the 3' polypurine tract (PPT) removed from the transfer vector for improving safety and/or efficacy. Results show that a safer extended deletion of U3 sequences did not modify integrase-mediated or -independent integration efficiency. Interestingly, 3' PPT deletion impaired integrase-mediated integration but did not reduce illegitimate, integrase-independent integration efficiency, contrary to what was previously reported in the HIV system. Importantly, although the extended deletion in the U3 did not affect expression or immunogenicity from IDLV, deletion of 3' PPT considerably reduced both expression and immunogenicity of IDLV.

Integrase-Defective Lentiviral Vector Is an Efficient Vaccine Platform for Cancer Immunotherapy.

Integrase-defective lentiviral vectors (IDLVs) have been used as a safe and efficient delivery system in several immunization protocols in murine and non-human primate preclinical models as well as in recent clinical trials. In this work, we validated in preclinical murine models our vaccine platform based on IDLVs as delivery system for cancer immunotherapy. To evaluate the anti-tumor activity of our vaccine strategy we generated IDLV delivering ovalbumin (OVA) as a non-self-model antigen and TRP2 as a self-tumor associated antigen (TAA) of melanoma. Results demonstrated the ability of IDLVs to eradicate and/or controlling tumor growth after a single immunization in preventive and therapeutic approaches, using lymphoma and melanoma expressing OVA. Importantly, LV-TRP2 but not IDLV-TRP2 was able to break tolerance efficiently and prevent tumor growth of B16F10 melanoma cells. In order to improve the IDLV efficacy, the human homologue of murine TRP2 was used, showing the ability to break tolerance and control the tumor growth. These results validate the use of IDLV for cancer therapy.