Safety and efficacy of autologous cell vaccines in solid tumors: a systematic review and meta-analysis of randomized control trials.

We conducted a systematic review and meta-analysis of randomized control trials to formally assess the safety and efficacy of autologous whole cell vaccines as immunotherapies for solid tumors. Our primary safety outcome was number, and grade of adverse events. Our primary efficacy outcome was clinical responses. Secondary outcomes included survival metrics and correlative immune assays. We searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials for studies published between 1946 and August 2020 using any autologous whole cell product in the treatment of any solid tumor. The Cochrane Randomized Controlled Trial risk of bias tool was used to assess risk of bias. Eighteen manuscripts were identified with a total of 714 patients enrolled in control and 808 in vaccine arms. In 698 patients receiving at least one dose of vaccine, treatment was well tolerated with a total of 5 grade III or higher adverse events. Clinical response was reported in a minority (n = 2, 14%) of studies. Autologous cell vaccines were associated with improved overall (HR 1.28, 95% CI 1.01-1.63) and disease-free survival (HR 1.33, 95% CI 1.05-1.67) over thirteen and ten trials respectively. Where reported, immune assays correlated well with clinical outcomes. Our results suggest that autologous whole cell vaccination is safe and efficacious in increasing survival in patients undergoing treatment for solid tumors.Registration: PROSPERO CRD42019140187.

A Translational Randomized Trial of Perioperative Arginine Immunonutrition on Natural Killer Cell Function in Colorectal Cancer Surgery Patients.

BACKGROUND: Surgery results in severe impairment of natural killer (NK) cell cytotoxicity (NKC) and activity (NKA, cytokine secretion), and a dramatic drop in arginine levels. Postoperative immunosuppression is associated with increased complications and recurrence. Perioperative arginine is reported to reduce postoperative complications. Because arginine modulates NK cell function, this study aimed to determine whether perioperative consumption of arginine-enriched supplements (AES) can improve NK cell function in colorectal cancer (CRC) surgery patients. METHODS: This study randomized 24 CRC patients to receive the AES or isocaloric/isonitrogenous control supplement three times a day for five days before and after surgery. The AES contained 4.2 g of arginine per dose (12.6 g/day). The primary objective was to determine whether AES improved NKC by 50 % compared with the control group after surgery. RESULTS: On surgery day (SD) 1, NKC was significantly reduced postoperatively in the control group by 50 % (interquartile range [IQR], 36-55 %; p = 0.02) but not in the AES group (25 % reduction; IQR, 28-75 %; p = 0.3). Furthermore, AES had no benefit in terms of NKA or NK cell number. Compliance was much greater preoperatively (>91 %) than postoperatively (<46 %). However, despite excellent preoperative compliance, arginine was rapidly cleared from the blood within 4 h after consumption and therefore, did not prevent the postoperative drop in arginine. CONCLUSIONS: Oral consumption of arginine immunonutrition resulted in a modest improvement in NKC after surgery but was unable to prevent postoperative arginine depletion or the suppression of NKA (ClinicalTrials.gov NCT02987296).

Perioperative arginine prevents metastases by accelerating natural killer cell recovery after surgery.

Profound natural killer (NK) cell suppression after cancer surgery is a main driver of metastases and recurrence, for which there is no clinically approved intervention available. Surgical stress is known to cause systemic postoperative changes that negatively modulate NK cell function including the expansion of surgery-induced myeloid-derived suppressor cells (Sx-MDSCs) and a marked reduction in arginine bioavailability. In this study, we determine that Sx-MDSCs regulate systemic arginine levels in the postoperative period and that restoring arginine imbalance after surgery by dietary intake alone was sufficient to significantly reduce surgery-induced metastases in our preclinical murine models. Importantly, the effects of perioperative arginine were dependent upon NK cells. Although perioperative arginine did not prevent immediate NK cell immunoparalysis after surgery, it did accelerate their return to preoperative cytotoxicity, interferon gamma secretion, and activating receptor expression. Finally, in a cohort of patients with colorectal cancer, postoperative arginine levels were shown to correlate with their Sx-MDSC levels. Therefore, this study lends further support for the use of perioperative arginine supplementation by improving NK cell recovery after surgery.

Safety and efficacy of autologous whole cell vaccines in hematologic malignancies: A systematic review and meta-analysis.

Autologous cell vaccines use a patient's tumor cells to stimulate a broad antitumor response in vivo. This approach shows promise for treating hematologic cancers in early phase clinical trials, but overall safety and efficacy remain poorly described. We conducted a systematic review assessing the use of autologous cell vaccination in treating hematologic cancers. Primary outcomes of interest were safety and clinical response, with secondary outcomes including survival, relapse rate, correlative immune assays and health-quality related metrics. We performed a search of MEDLINE, Embase and the Cochrane Register of Controlled Trials including any interventional trial employing an autologous, whole cell product in any hematologic malignancy. Risk of bias was assessed using a modified Institute of Health Economics tool. Across 20 single arm studies, only 341 of 592 enrolled participants received one or more vaccinations. Primary reasons for not receiving vaccination included rapid disease progression/death and manufacturing challenges. Overall, few high-grade adverse events were observed. One death was reported and attributed to a GM-CSF producing allogeneic cell line co-administered with the autologous vaccine. Of 58 evaluable patients, the complete response rate was 21.0% [95% CI, 10.4%-37.8%)] and overall response rate was 35.8% (95% CI, 24.4%-49.0%). Of 97 evaluable patients for survival, the 5-years overall survival rate was 64.9% (95% CI, 52.6%-77.2%) and disease-free survival was 59.7% (95% CI, 47.7%-71.7%). We conclude that, in hematologic malignancies, based on limited available data, autologous cell vaccines are safe and display a trend towards efficacy but that challenges exist in vaccine manufacture and administration.

Flattening the COVID-19 Curve With Natural Killer Cell Based Immunotherapies.

Natural Killer (NK) cells are innate immune responders critical for viral clearance and immunomodulation. Despite their vital role in viral infection, the contribution of NK cells in fighting SARS-CoV-2 has not yet been directly investigated. Insights into pathophysiology and therapeutic opportunities can therefore be inferred from studies assessing NK cell phenotype and function during SARS, MERS, and COVID-19. These studies suggest a reduction in circulating NK cell numbers and/or an exhausted phenotype following infection and hint toward the dampening of NK cell responses by coronaviruses. Reduced circulating NK cell levels and exhaustion may be directly responsible for the progression and severity of COVID-19. Conversely, in light of data linking inflammation with coronavirus disease severity, it is necessary to examine NK cell potential in mediating immunopathology. A common feature of coronavirus infections is that significant morbidity and mortality is associated with lung injury and acute respiratory distress syndrome resulting from an exaggerated immune response, of which NK cells are an important component. In this review, we summarize the current understanding of how NK cells respond in both early and late coronavirus infections, and the implication for ongoing COVID-19 clinical trials. Using this immunological lens, we outline recommendations for therapeutic strategies against COVID-19 in clearing the virus while preventing the harm of immunopathological responses.

Gender and academic promotion of Canadian general surgeons: a cross-sectional study.

BACKGROUND: Gender disparities in faculty rank have yet to be studied among Canadian physicians. The purpose of this study was to determine whether differences in region, training, research productivity and years in practice explain gender differences in academic promotion among Canadian general surgeons. METHODS: We developed a cross-sectional database of faculty-appointed general surgeons practising in the hospitals affiliated with the 17 universities within the Association of Faculties of Medicine of Canada in 2017 using publicly available directories, university and hospital websites, and direct communication. The data were collected between October and December 2018 and included gender, residency completion year, graduate education, fellowships, number of publications and Scopus h-index; faculty lists and professorship status were verified by program administrators or division heads of their respective divisions. The dependent variable was binary: full professor or not. A combined outcome of associate or full professor was also analyzed. We analyzed all variables in a multivariable logistic regression model. RESULTS: Of the 17 institutions contacted, all but 1 confirmed the faculty lists and professorship status. A total of 405 surgeons were included, of whom 111 (27.4%) were women. Sixty-eight women (61.3%) and 120 men (40.8%) were assistant professors, and 9 women (8.1%) and 75 men (25.5%) were full professors. Although on average women had completed residency more recently than men (15.2 yr v. 19.2 yr, p < 0.001), there was no difference between men and women in the mean number of publications as residents (2.98 v. 2.74, p = 0.7) or per year of practice (3.12 v. 2.09, p = 0.2), number of fellowships pursued (p = 0.7) or graduate education (p = 0.2). In the multivariable model (C-statistic = 0.88), gender remained significantly associated with full professorship (odds ratio 2.79, 95% confidence interval 1.13 to 6.92), along with years in practice (odds ratio 1.61, 95% confidence interval 1.13 to 2.30). INTERPRETATION: After controlling for years in practice, training and research productivity measures, we found that female surgeons with faculty appointments in Canada were less likely than their male counterparts to receive promotion to full professor. Pervasive inequities in systems of promotion must be addressed.

Natural Killer Cell IFNγ Secretion is Profoundly Suppressed Following Colorectal Cancer Surgery.

BACKGROUND: Surgical stress results in a significant reduction in natural killer (NK) cell cytotoxicity (NKC), which has been linked to postoperative cancer metastases. However, few studies have measured the impact of surgical stress upon NK cell IFNγ secretion (NKA), a cytokine with essential roles in controlling infection and metastases. The objective of this study was to investigate the impact of surgical stress on NKA in colorectal cancer (CRC) surgery patients. METHODS: Peripheral blood was collected from CRC surgery patients (n = 42) preoperatively and on postoperative day (POD) 1, 3, 5, 28, and 56. Healthy donor blood (n = 27) was collected for controls. We assessed NKA by production of IFNγ following whole blood cytokine stimulation, NKC by 51Cr-release assay, and immune cell profiling by flow cytometry. RESULTS: The mean reduction in NKA on POD1 compared with baseline was 83.1% (standard deviation 25.2%; confidence interval 75-91), and therefore the study met the primary endpoint of demonstrating a > 75% decrease in a cohort of CRC surgery patients (p < 0.0001). The profound and universal suppression of NKA persisted with 65.5% (19/29) and 33.3% (4/12) of patients with levels measuring < 75% of baseline on POD28 and POD56 respectively. The NKC was significantly reduced on POD1, but the degree was less pronounced (24.6%, p = 0.0024). Immune cell profiling did not reveal differences in the absolute number of NK cells (CD3-CD56+) or the ratio of CD56dim-to-CD56bright subsets. CONCLUSIONS: NKA is significantly suppressed for up to two months following surgery in CRC patients, a degree of surgery-induced immunosuppression far worse than previously reported.

Prognostic significance of a positive radial margin after esophageal cancer resection.

OBJECTIVE: The prognostic significance of an incomplete esophageal cancer resection due to a positive microscopic radial margin remains unclear. The aim of this study is to examine the relationship between radial margin status and oncologic outcomes. METHODS: We performed a retrospective review of esophageal cancer resections between 2004 and 2012. Radial margin status was defined according to the College of American Pathologists. Exclusion criteria were complete pathologic response (n = 12), positive proximal or distal margin (n = 11), R2 resection (n = 5), and carcinoma in situ (n = 2). RESULTS: Of 154 patients, 30 (19%) had a positive radial margin (RM+) and 124 (81%) had a complete resection (R0). The 2 groups were similar with respect to age, gender, proportion of squamous tumors, middle thoracic tumor location, rate of neoadjuvant chemoradiation and adjuvant radiation, transhiatal approach, number of examined lymph nodes, and length of proximal and distal margins. In patients with stage III, the locoregional recurrence-free interval was similar between groups; however, RM+ was associated with a 17-month decrease in the median time to distant recurrence (RM+ = 7 months [95% confidence interval, 4-14]; R0 = 24 months [median not reached]; P < .01). The median survival was also significantly decreased by 12 months in the RM+ group (RM+ = 13 months [95% confidence interval, 7-26]; R0 = 25 months [95% confidence interval, 20-30]; P = .04). CONCLUSIONS: An isolated, positive microscopic radial margin was associated with a greater risk for distant recurrence. There was no impact on locoregional disease control. The role of adjuvant, systemic therapy in patients with an isolated, microscopically RM+ merits further evaluation.