Objective To compare the efficacy of covid-19 vaccines between immunocompromised and immunocompetent people. Design Systematic review and meta-analysis. Data sources PubMed, Embase, Central Register of Controlled Trials, COVID-19 Open Research Dataset Challenge (CORD-19), and WHO covid-19 databases for studies published between 1 December 2020 and 5 November 2021. ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform were searched in November 2021 to identify registered but as yet unpublished or ongoing studies. Study selection Prospective observational studies comparing the efficacy of covid-19 vaccination in immunocompromised and immunocompetent participants. Methods A frequentist random effects meta-analysis was used to separately pool relative and absolute risks of seroconversion after the first and second doses of a covid-19 vaccine. Systematic review without meta-analysis of SARS-CoV-2 antibody titre levels was performed after first, second, and third vaccine doses and the seroconversion rate after a third dose. Risk of bias and certainty of evidence were assessed. Results 82 studies were included in the meta-analysis. Of these studies, 77 (94%) used mRNA vaccines, 16 (20%) viral vector vaccines, and 4 (5%) inactivated whole virus vaccines. 63 studies were assessed to be at low risk of bias and 19 at moderate risk of bias. After one vaccine dose, seroconversion was about half as likely in patients with haematological cancers (risk ratio 0.40, 95% confidence interval 0.32 to 0.50, I 2 =80%; absolute risk 0.29, 95% confidence interval 0.20 to 0.40, I 2 =89%), immune mediated inflammatory disorders (0.53, 0.39 to 0.71, I 2 =89%; 0.29, 0.11 to 0.58, I 2 =97%), and solid cancers (0.55, 0.46 to 0.65, I 2 =78%; 0.44, 0.36 to 0.53, I 2 =84%) compared with immunocompetent controls, whereas organ transplant recipients were 16 times less likely to seroconvert (0.06, 0.04 to 0.09, I 2 =0%; 0.06, 0.04 to 0.08, I 2 =0%). After a second dose, seroconversion remained least likely in transplant recipients (0.39, 0.32 to 0.46, I 2 =92%; 0.35, 0.26 to 0.46), with only a third achieving seroconversion. Seroconversion was increasingly likely in patients with haematological cancers (0.63, 0.57 to 0.69, I 2 =88%; 0.62, 0.54 to 0.70, I 2 =90%), immune mediated inflammatory disorders (0.75, 0.69 to 0.82, I 2 =92%; 0.77, 0.66 to 0.85, I 2 =93%), and solid cancers (0.90, 0.88 to 0.93, I 2 =51%; 0.89, 0.86 to 0.91, I 2 =49%). Seroconversion was similar between people with HIV and immunocompetent controls (1.00, 0.98 to 1.01, I 2 =0%; 0.97, 0.83 to 1.00, I 2 =89%). Systematic review of 11 studies showed that a third dose of a covid-19 mRNA vaccine was associated with seroconversion among vaccine non-responders with solid cancers, haematological cancers, and immune mediated inflammatory disorders, although response was variable in transplant recipients and inadequately studied in people with HIV and those receiving non-mRNA vaccines. Conclusion Seroconversion rates after covid-19 vaccination were significantly lower in immunocompromised patients, especially organ transplant recipients. A second dose was associated with consistently improved seroconversion across all patient groups, albeit at a lower magnitude for organ transplant recipients. Targeted interventions for immunocompromised patients, including a third (booster) dose, should be performed. Systematic review registration PROSPERO CRD42021272088.

Defective DNA repair is a common hallmark of cancer. Homologous recombination is a DNA repair pathway of clinical interest due to the sensitivity of homologous recombination-deficient cells to poly-ADP ribose polymerase (PARP) inhibitors. The measurement of homologous recombination deficiency (HRD) in cancer is therefore vital to the appropriate design of clinical trials incorporating PARP inhibitors. However, methods to identify HRD in tumors are varied and controversial. Understanding existing and new methods to measure HRD is important to their appropriate use in clinical trials and practice. The aim of this review is to summarize the biology and clinical validation of current methods to measure HRD, to aid decision-making for patient stratification and translational research in PARP inhibitor trials. We discuss the current clinical development of PARP inhibitors, along with established indicators for HRD such as germline BRCA1/2 mutation status and clinical response to platinum-based therapy. We then examine newer assays undergoing clinical validation, including 1) somatic mutations in homologous recombination genes, 2) "genomic scar" assays using array-based comparative genomic hybridization (aCGH), single nucleotide polymorphism (SNP) analysis or mutational signatures derived from next-generation sequencing, 3) transcriptional profiles of HRD, and 4) phenotypic or functional assays of protein expression and localization. We highlight the strengths and weaknesses of each of these assays, for consideration during the design of studies involving PARP inhibitors.

The idea that chemotherapy can be used in combination with immunotherapy may seem somewhat counterproductive, as it can theoretically eliminate the immune cells needed for antitumour immunity. However, much preclinical work has now demonstrated that in addition to direct cytotoxic effects on cancer cells, a proportion of DNA damaging agents may actually promote immunogenic cell death, alter the inflammatory milieu of the tumour microenvironment and/or stimulate neoantigen production, thereby activating an antitumour immune response. Some notable combinations have now moved forward into the clinic, showing promise in phase I–III trials, whereas others have proven toxic, and challenging to deliver. In this review, we discuss the emerging data of how DNA damaging agents can enhance the immunogenic properties of malignant cells, focussing especially on immunogenic cell death, and the expansion of neoantigen repertoires. We discuss how best to strategically combine DNA damaging therapeutics with immunotherapy, and the challenges of successfully delivering these combination regimens to patients. With an overwhelming number of chemotherapy/immunotherapy combination trials in process, clear hypothesis-driven trials are needed to refine the choice of combinations, and determine the timing and sequencing of agents in order to stimulate antitumour immunological memory and improve maintained durable response rates, with minimal toxicity.

New insight on the interaction between the immune system and tumor has identified the programmed death-1/programmed death-1 ligand pathway to be a key player in evading host immune response. The immune checkpoint modulator, nivolumab (BMS-936558/ONO-4538), is the first PD-1 inhibitor to gain regulatory approval, for the treatment of patients with unresectable melanoma. This review will discuss results from early phase studies of nivolumab in solid tumors including non-small cell lung cancer (NSCLC) as well as studies of nivolumab in combination with chemotherapy, other immune modulators and molecular targeted therapy in patients with NSCLC.

BackgroundThere are inconsistencies in the literature regarding the prevalence and assessment of chemotherapy-induced peripheral neuropathy (CIPN). This study explored CIPN natural history and its characteristics in patients receiving taxane- and platinum-based chemotherapy.Patients and methodsMulti-country multisite prospective longitudinal observational study. Patients were assessed before commencing and three weekly during chemotherapy for up to six cycles, and at 6,9, and 12 months using clinician-based scales (NCI-CTCAE; WHO-CIPN criterion), objective assessments (cotton wool test;10 g monofilament); patient-reported outcome measures (FACT/GOG-Ntx; EORTC-CIPN20), and Nerve Conduction Studies.ResultsIn total, 343 patients were recruited in the cohort, providing 2399 observations. There was wide variation in CIPN prevalence rates using different assessments (14.2–53.4%). Prevalence of sensory neuropathy (and associated symptom profile) was also different in each type of chemotherapy, with paclitaxel (up to 63%) and oxaliplatin (up to 71.4%) showing the highest CIPN rates in most assessments and a more complex symptom profile. Peak prevalence was around the 6-month assessment (up to 71.4%). Motor neurotoxicity was common, particularly in the docetaxel subgroup (up to 22.1%; detected by NCI-CTCAE). There were relatively moderately-to-low correlations between scales (rs = 0.15,p < 0.05-rs = 0.48 p < 0.001), suggesting that they measure different neurotoxicity aspects from each other. Cumulative chemotherapy dose was not associated with onset and course of CIPN.ConclusionThe historical variation reported in CIPN incidence and prevalence is possibly confounded by disagreement between assessment modalities. Clinical practice should consider assessment of motor neuropathy for neurotoxic chemotherapy. Current scales may not be all appropriate to measure CIPN in a valid way, and a combination of scales are needed.

Gastric cancer (GC) heterogeneity represents a barrier to disease management. We generated a comprehensive single-cell atlas of GC (>200,000 cells) comprising 48 samples from 31 patients across clinical stages and histological subtypes. We identified 34 distinct cell-lineage states including novel rare cell populations. Many lineage states exhibited distinct cancer-associated expression profiles, individually contributing to a combined tumor-wide molecular collage. We observed increased plasma cell proportions in diffuse-type tumors associated with epithelial-resident KLF2, and stage-wise accrual of cancer-associated fibroblast sub-populations marked by high INHBA and FAP co-expression. Single-cell comparisons between patient-derived organoids (PDOs) and primary tumors highlighted inter-and intralineage similarities and differences, demarcating molecular boundaries of PDOs as experimental models. We complemented these findings by spatial transcriptomics, orthogonal validation in independent bulk RNA-seq cohorts, and functional demonstration using in vitro and in vivo models. Our results provide a high-resolution molecular resource of intra-and inter-patient lineage-states across distinct GC subtypes.

BackgroundPeripheral neuropathy (PN) due to paclitaxel is a common dose-limiting toxicity with no effective prevention or treatment. We hypothesize that continuous-flow limb hypothermia can reduce paclitaxel-induced PN.Patients and methodsAn internally controlled pilot trial was conducted to investigate the neuroprotective effect of continuous-flow limb hypothermia in breast cancer patients receiving weekly paclitaxel. Patients underwent limb hypothermia of one limb for a duration of 3 h with every paclitaxel infusion, with the contralateral limb used as control. PN was primarily assessed using nerve conduction studies (NCSs) before the start of chemotherapy, and after 1, 3, and 6 months. Skin temperature and tolerability to hypothermia were monitored using validated scores.ResultsTwenty patients underwent a total of 218 cycles of continuous-flow limb hypothermia at a coolant temperature of 22°C. Continuous-flow limb hypothermia achieved mean skin temperature reduction of 1.5 ± 0.7°C and was well tolerated, with no premature termination of cooling due to intolerance. Grade 3 PN occurred in 2 patients (10%), grade 2 in 2 (10%), and grade 1 in 12 (60%). Significant correlation was observed between amount of skin cooling and motor nerve amplitude preservation at 6 months (p < 0.0005). Sensory velocity and amplitude in the cooled limbs were less preserved than in the control limbs, but the difference did not attain statistical significance. One patient with a history of diabetes mellitus had significant preservation of compound muscle action potential in the cooled limb on NCS analysis.ConclusionThis study suggests that continuous limb hypothermia accompanying paclitaxel infusion may reduce paclitaxel-induced PN and have therapeutic potential in select patients and warrants further investigation. The method is safe and well tolerated.

Advances in the understanding of the role of the immune system in tumor immunosurveillance have resulted in the recognition that tumors can evade immune destruction via the dysregulation of co-inhibitory or checkpoint signals. This has led to the development of a generation immunotherapeutic agents targeting the immune checkpoint pathway. Recent early phase studies of immune checkpoint modulators, such as CTLA-4, PD-1 and PD-L1 inhibitors in NSCLC have reported promising results with prolonged clinical responses and tolerable toxicity. This article provides an overview of co-stimulatory and inhibitory molecules that regulate the immune response to tumors, recent therapies that have been developed to exploit these interactions and the role of predictive biomarkers in treatment selection.