CLDN6-specific CAR-T cells plus amplifying RNA vaccine in relapsed or refractory solid tumors: the phase 1 BNT211-01 trial.

The oncofetal antigen Claudin 6 (CLDN6) is highly and specifically expressed in many solid tumors, and could be a promising treatment target. We report dose escalation results from the ongoing phase 1/2 BNT211-01 trial evaluating the safety and feasibility of chimeric antigen receptor (CAR) T cells targeting the CLDN6 with or without a CAR-T cell-amplifying RNA vaccine (CARVac) at two dose levels (DLs) in relapsed/refractory CLDN6-positive solid tumors. The primary endpoints were safety and tolerability, maximum tolerated dose and recommended phase 2 dose (RP2D). Secondary endpoints included objective response rate (ORR) and disease control rate. We observed manageable toxicity, with 10 out of 22 patients (46%) experiencing cytokine release syndrome including one grade 3 event and 1 out of 22 (5%) with grade 1 immune effector cell-associated neurotoxicity syndrome. Dose-limiting toxicities occurred in two patients at the higher DL, resolving without sequelae. CAR-T cell engraftment was robust, and the addition of CARVac was well tolerated. The unconfirmed ORR in 21 evaluable patients was 33% (7 of 21), including one complete response. The disease control rate was 67% (14 of 21), with stable disease in seven patients. Patients with germ cell tumors treated at the higher DL exhibited the highest response rate (ORR 57% (4 of 7)). The maximum tolerated dose and RP2D were not established as the trial has been amended to utilize an automated manufacturing process. A repeat of the dose escalation is ongoing and will identify a RP2D for pivotal trials. ClinicalTrials.gov Identifier: NCT04503278 .

Exposure to BA.4/5 S protein drives neutralization of Omicron BA.1, BA.2, BA.2.12.1, and BA.4/5 in vaccine-experienced humans and mice.

The SARS-CoV-2 Omicron variant and its sublineages show pronounced viral escape from neutralizing antibodies elicited by vaccination or prior SARS-CoV-2 variant infection owing to over 30-amino acid alterations within the spike (S) glycoprotein. Breakthrough infection of vaccinated individuals with Omicron sublineages BA.1 and BA.2 is associated with distinct patterns of cross-neutralizing activity against SARS-CoV-2 variants of concern (VOCs). In continuation of our previous work, we characterized the effect of Omicron BA.4/BA.5 S glycoprotein exposure on the neutralizing antibody response upon breakthrough infection in vaccinated individuals and upon variant-adapted booster vaccination in mice. We found that immune sera from triple mRNA-vaccinated individuals with subsequent breakthrough infection during the Omicron BA.4/BA.5 wave showed cross-neutralizing activity against previous Omicron variants BA.1, BA.2, BA.2.12.1, and BA.4/BA.5 itself. Administration of a prototypic BA.4/BA.5-adapted mRNA booster vaccine to mice after SARS-CoV-2 wild-type strain-based primary immunization is associated with broader cross-neutralizing activity than a BA.1-adapted booster. Whereas the Omicron BA.1-adapted mRNA vaccine in a bivalent format (wild-type + BA.1) broadens cross-neutralizing activity relative to the BA.1 monovalent booster, cross-neutralization of BA.2 and descendants is more effective in mice boosted with a bivalent wild-type + BA.4/BA.5 vaccine. In naïve mice, primary immunization with the bivalent wild-type + Omicron BA.4/BA.5 vaccine induces strong cross-neutralizing activity against Omicron VOCs and previous variants. These findings suggest that, when administered as boosters, mono- and bivalent Omicron BA.4/BA.5-adapted vaccines enhance neutralization breadth and that the bivalent version also has the potential to confer protection to individuals with no preexisting immunity against SARS-CoV-2.

Omicron BA.2 breakthrough infection enhances cross-neutralization of BA.2.12.1 and BA.4/BA.5.

BNT162b2-vaccinated individuals after Omicron BA.1 breakthrough infection have strong serum-neutralizing activity against Omicron BA.1, BA.2, and previous SARS-CoV-2 variants of concern (VOCs) yet less against the highly contagious Omicron sublineages BA.4 and BA.5 that have displaced previous variants. Because the latter sublineages are derived from Omicron BA.2, we characterized serum-neutralizing activity of COVID-19 mRNA vaccine triple-immunized individuals who experienced BA.2 breakthrough infection. We demonstrate that sera of these individuals have broadly neutralizing activity against previous VOCs and all tested Omicron sublineages, including BA.2-derived variants BA.2.12.1 and BA.4/BA.5. Furthermore, applying antibody depletion, we showed that neutralization of BA.2 and BA.4/BA.5 sublineages by BA.2 convalescent sera is driven to a considerable extent by antibodies targeting the N-terminal domain (NTD) of the spike glycoprotein. However, neutralization by Omicron BA.1 convalescent sera depends exclusively on antibodies targeting the receptor binding domain (RBD). These findings suggest that exposure to Omicron BA.2, in contrast to BA.1 spike glycoprotein, triggers substantial NTD-specific recall responses in vaccinated individuals and thereby enhances the neutralization of BA.4/BA.5 sublineages. Given the current epidemiology with a predominance of BA.2-derived sublineages such as BA.4/BA.5 and rapidly ongoing evolution, these findings helped to inform development of our Omicron BA.4/BA.5-adapted vaccine.

Cost analysis of a watch-and-wait approach in patients with a complete clinical response to chemoradiotherapy for rectal cancer.

BACKGROUND: There is increasing interest in the watch-and-wait approach for patients with rectal cancer who have had a complete clinical response following neoadjuvant long course chemoradiotherapy. This study is a cost analysis of expenditure on patients in the watch-and-wait program versus patients who underwent standard rectal resection followed by routine surveillance. METHODS: Data were prospectively collated and retrospectively analysed in all patients who presented with rectal cancer from January 2016 to January 2018 at Sir Charles Gairdner Hospital, Perth, Western Australia. Software developed by the North Metropolitan Health Service was used to capture comprehensive data to calculate the in-hospital expenditure for an individual patient throughout their treatment journey. RESULTS: For a patient enrolled in the watch-and-wait pathway, the total cost of surveillance over a 5-year period was $45 246. This was compared with the cost of an ultra-low anterior resection/loop ileostomy/closure of loop and routine postoperative surveillance which came to a total of $87 473. While a patient who had an abdominoperineal resection followed by routine 5-year surveillance had an expenditure of $82 290. CONCLUSION: There is growing evidence that the watch-and-wait strategy is a valid management option. In the cost-conscious environment of the current health care system, the watch-and-wait pathway is a cost-effective and economically advantage treatment.

Omicron BA.1 breakthrough infection drives cross-variant neutralization and memory B cell formation against conserved epitopes.

Omicron is the evolutionarily most distinct severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern (VOC) to date. We report that Omicron BA.1 breakthrough infection in BNT162b2-vaccinated individuals resulted in strong neutralizing activity against Omicron BA.1, BA.2, and previous SARS-CoV-2 VOCs but not against the Omicron sublineages BA.4 and BA.5. BA.1 breakthrough infection induced a robust recall response, primarily expanding memory B (BMEM) cells against epitopes shared broadly among variants, rather than inducing BA.1-specific B cells. The vaccination-imprinted BMEM cell pool had sufficient plasticity to be remodeled by heterologous SARS-CoV-2 spike glycoprotein exposure. Whereas selective amplification of BMEM cells recognizing shared epitopes allows for effective neutralization of most variants that evade previously established immunity, susceptibility to escape by variants that acquire alterations at hitherto conserved sites may be heightened.

Neutralization of SARS-CoV-2 Omicron by BNT162b2 mRNA vaccine-elicited human sera.

The globally circulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern Omicron (B.1.1.529) has a large number of mutations, especially in the spike protein, indicating that recognition by neutralizing antibodies may be compromised. We tested Wuhan (Wuhan-Hu-1 reference strain), Beta (B.1.351), Delta (B.1.617.2), or Omicron pseudoviruses with sera of 51 participants who received two or three doses of the messenger RNA (mRNA)-based COVID-19 vaccine BNT162b2. After two doses, Omicron-neutralizing titers were reduced >22-fold compared with Wuhan-neutralizing titers. One month after the third vaccine dose, Omicron-neutralizing titers were increased 23-fold relative to their levels after two doses and were similar to levels of Wuhan-neutralizing titers after two doses. The requirement of a third vaccine dose to effectively neutralize Omicron was confirmed with sera from a subset of participants using live SARS-CoV-2. These data suggest that three doses of the mRNA vaccine BNT162b2 may protect against Omicron-mediated COVID-19.

Nuclear hormone receptor DHR96 mediates the resistance to xenobiotics but not the increased lifespan of insulin-mutant Drosophila.

Lifespan of laboratory animals can be increased by genetic, pharmacological, and dietary interventions. Increased expression of genes involved in xenobiotic metabolism, together with resistance to xenobiotics, are frequent correlates of lifespan extension in the nematode worm Caenorhabditis elegans, the fruit fly Drosophila, and mice. The Green Theory of Aging suggests that this association is causal, with the ability of cells to rid themselves of lipophilic toxins limiting normal lifespan. To test this idea, we experimentally increased resistance of Drosophila to the xenobiotic dichlordiphenyltrichlorethan (DDT), by artificial selection or by transgenic expression of a gene encoding a cytochrome P450. Although both interventions increased DDT resistance, neither increased lifespan. Furthermore, dietary restriction increased lifespan without increasing xenobiotic resistance, confirming that the two traits can be uncoupled. Reduced activity of the insulin/Igf signaling (IIS) pathway increases resistance to xenobiotics and extends lifespan in Drosophila, and can also increase longevity in C. elegans, mice, and possibly humans. We identified a nuclear hormone receptor, DHR96, as an essential mediator of the increased xenobiotic resistance of IIS mutant flies. However, the IIS mutants remained long-lived in the absence of DHR96 and the xenobiotic resistance that it conferred. Thus, in Drosophila IIS mutants, increased xenobiotic resistance and enhanced longevity are not causally connected. The frequent co-occurrence of the two traits may instead have evolved because, in nature, lowered IIS can signal the presence of pathogens. It will be important to determine whether enhanced xenobiotic metabolism is also a correlated, rather than a causal, trait in long-lived mice.

Palliative colonic stenting: a safe alternative to surgery in stage IV colorectal cancer.

BACKGROUND: The morbidity associated with surgery for obstructing or near-obstructing stage IV colorectal cancer can be high including the frequent need for a stoma. Self-expandable metal stents (SEMS) offer an alternative to surgery. Our aim was to analyse our palliative SEMS outcomes and compare this with a palliative surgery group. METHODS: A retrospective study of a single institutions' experience with SEMS or surgery in the management of stage IV colorectal cancer was performed. RESULTS: Sixty-five patients treated with SEMS were included in the study. These were compared with an unmatched group of 63 patients who underwent surgery. Within the SEMS group was a 98.5% technical success and 100% clinical success of deployed SEMS. Overall complication rate was low at 23.1% (restenosis 7.7%, migration 7.7%, perforation 4.6% and bleeding 3.1%). Only 7.7% of patients in the SEMS group required an operation. SEMS insertion was associated with a shorter hospital stay (2.9 days versus 14.6 days; P < 0.001) and reduced requirement for a stoma (4.6% versus 44.4%; P < 0.001). There was no statistically significant difference in 30-day mortality (13.8% versus 11.1%; P = 0.640), 1-year survival (42.9% versus 41.4%; P = 0.949) or 2-year survival (24.5% versus 21.4%; P = 0.700). Overall survival was equivalent between the two groups (hazard ratio 1.27; 95% confidence interval 0.88-1.88; P = 0.212). CONCLUSION: SEMS is a safe alternative to surgery in obstructing or near-obstructing stage IV colorectal cancer. It offers high success rate, a shorter hospital stay and a reduced stoma rate while not impacting overall survival.

Triradiate caecal fold: Is it a useful landmark for caecal intubation in colonoscopy?

AIM: To determine the frequency of identification of the triradiate fold during colonoscopy and evaluate its reliability as a marker of caecal intubation. METHODS: One hundred consecutive patients undergoing colonoscopy in a tertiary hospital colorectal unit from May to September 2013 were studied. Video documentation of the caecum was recorded and shown to consultant colorectal surgeons on the unit. Each reviewer was asked through a series of questions to independently identify the triradiate fold. The main outcome was the frequency of visualisation of the triradiate fold in the caecum. RESULTS: The triradiate fold was seen on average in 18% of cases, but inter-observer agreement was poor. There were only four patients (4%) in which all reviewers agreed on the presence of a triradiate fold. In patients who had undergone previous appendicectomy, the appendiceal orifice was less frequently seen compared with patients who had not undergone appendicectomy. CONCLUSION: The triradiate fold is infrequently seen during colonoscopy and is therefore an unreliable landmark of caecal intubation.

Cell-specific inositol 1,4,5 trisphosphate 3-kinase mediates epithelial cell apoptosis in response to oxidative stress in Drosophila.

Organismal stress responses to oxidative stress are relevant to ageing and disease and involve key cell-/tissue-specific signal transduction mechanisms. Using Drosophila, an established in vivo model for stress studies, we show that cell-specific inositol phosphate signalling specifically via inositol 1,4,5 trisphosphate 3-kinase (InsP(3) 3-K, IP(3)K), negatively regulates organismal responses to oxidative stress. We demonstrate that the Drosophila Malpighian tubule (equivalent to vertebrate kidney and liver) is a key epithelial sensor for organismal oxidative stress responses: precise targeting of either gain-of-function constructs of Drosophila IP(3)Ks (IP(3)K-1 and IP(3)K-2), or loss-of-function (RNAi) constructs to only one cell type in tubule reversibly modulates survival of stress-challenged adult flies. In vivo, targeted IP(3)K-1 directly increases H(2)O(2) production, pro-apoptotic caspase-9 activity and mitochondrial membrane potential. The mitochondrial calcium load in tubule principal cells-assessed by luminescent and fluorescent genetically-encoded mitochondrial calcium reporters-is significantly increased by IP(3)K-1 under oxidative stress conditions, leading to apoptosis. The Drosophila orthologues of human apoptotic bcl-2 genes include debcl and buffy. Oxidative stress challenge does not modulate gene expression of either debcl or buffy in tubules; and altered debcl expression does not influence survival rates under oxidative stress challenge. Finally, targeted over-expression of either debcl or buffy to tubule principal cells does not impact on tubule caspase-9 activity. Thus, IP(3)K-1 modulates epithelial cell apoptosis without involvement of bcl-2-type proteins.

Outcomes of a contemporary amputation series.

BACKGROUND: The aim of this study was to determine the outcomes of a contemporary amputation series. METHODS: A retrospective audit of 87 cases of major lower limb amputation from January 2000 to December 2002 from the Department of Vascular Surgery, Royal Perth Hospital, was conducted. RESULTS: The mean age of the study population was 70.1 +/- 14.3 years; the male : female ratio was 3.35:1. Comorbid problems included diabetes (49.4%), smoking (81.6%), hypertension (77.0%), ischaemic heart disease (58.6%), stroke (25.3%), raised creatinine level (34.5%) and chronic airway limitation (25.3%). Preamputation vascular reconstructive procedures were common, 34.5% in a previous admission and 23.0% in the same admission. The main indication was critical limb ischaemia (75.9%) followed by diabetic infection (17.2%). There were 51 below-knee (58.6%), 5 through-knee (5.7%) and 31 above-knee (35.6%.) amputations. The below-knee amputation to above-knee amputation ratio was 1.65:1. The overall wound infection rate was 26.4%; the infection rates for below-knee (29.4%) and above-knee (22.6%) amputation did not differ significantly (P = 0.58). Revision rates were 17.6% for below-knee, 20% for through-knee and none for above-knee amputations. Twenty patients (23.0%) underwent subsequent contralateral amputation. Thirty-nine patients (44.8%) were selected as suitable for a prosthesis by a rehabilitation physician; 31 (79.5%) used the prosthesis both indoors and outdoors and 6 (15.4%) used it indoors only within 3 months. Cumulative mortality at 30 days, 6 months, 12 months and 24 months was 10.1, 28.7, 43.1 and 51.7%, respectively. CONCLUSION: This series agrees with the current published work in finding that patients undergoing major lower limb amputation are older, with a high prevalence of comorbid conditions. Successful prosthesis rehabilitation depends on patient selection and a multidisciplinary approach. Despite a low immediate mortality, the overall long-term results of lower limb amputation remain dismal.