Antibody-Drug Conjugates and Their Potential in the Treatment of Patients with Biliary Tract Cancer.

Background: Biliary tract cancers (BTCs) are aggressive in nature, often presenting asymptomatically until they are diagnosed at an advanced stage. Surgical resection or liver transplantation are potential curative options. However, a large proportion of patients present with incurable locally advanced or metastatic disease and most of these patients are only eligible for palliative chemotherapy or best supportive care. More recently, targeted therapies have proven beneficial in a molecularly selected subgroup of patients with cholangiocarcinoma who have progressed on previous lines of systemic treatment. However, only a minority of patients with BTCs whose tumours harbour specific molecular alterations can access these therapies. Methods: In relation to ADCs, studies regarding use of antibody-drug conjugates in cancer, particularly in BTCs, were searched in Embase (1974 to 2024) and Ovid MEDLINE(R) (1946 to 2024) to obtain relevant articles. Examples of current clinical trials utilising ADC treatment in BTCs were extracted from the ClinicalTrials.gov trial registry. Conclusions: Overall, this review has highlighted that ADCs have shown encouraging outcomes in cancer therapy, and this should lead to further research including in BTCs, where treatment options are often limited. The promising results observed with ADCs in various cancers underscore their potential as a transformative approach in oncology, warranting continued exploration and development and the need for education on the management of their specific toxicities. By addressing current challenges and optimising ADC design and application, future studies could potentially improve treatment outcomes for patients with BTCs and beyond, potentially in both early and advanced stage settings.

Promoting penicillin allergy de-labeling for children attending a hematology clinic.

BACKGROUND: Up to 10% of children are reported to be allergic to penicillin, but many allergy labels are unverified and may require formal testing. Inaccurate drug allergy labels are associated with a range of adverse clinical outcomes. Patients with hematological disorders may experience frequent and severe infections; those who have been incorrectly labeled penicillin allergic may benefit from allergy de-labeling (ADL) efforts to facilitate access to beta-lactam antibiotics. We developed a multidisciplinary, pharmacist-driven process that enabled non-allergist trained providers to assess and de-label penicillin allergies in a pediatric hematology center. METHODS: Volunteers, including physicians, advanced practice providers, nurses, and pharmacists, were trained in skin testing and oral challenge procedures. Patients were identified by review of electronic medical records for penicillin or penicillin-derivative allergy. Patient and family interviews were conducted in cases where a true penicillin allergy was deemed uncertain based on chart review. If allergy could not be de-labeled by chart review or interview alone, patients were offered skin and/or oral challenge testing. RESULTS: Fifty-nine patients were initially labeled as penicillin allergic. Allergy labels of 11 (19%) were removed by chart review only, and 15 (25%) after conducting interviews. A total of two (3%) patients were ineligible due to contraindications, and five (9%) declined participation. Twenty-six patients (44%) underwent allergy testing (50% skin testing, 50% oral challenge) of which 23 (88%) were negative. CONCLUSIONS: ADL was possible in most patients previously identified as penicillin allergic. Testing was well tolerated with no serious adverse effects.

Pharmacist Effect on Discharge Follow-Up Education in Pediatric Oncology Outpatient Clinics: A Quality Improvement Study.

OBJECTIVE: We aimed to describe the effect of education provided by a clinical pharmacy specialist at a patient's follow-up appointment after discharge, and to assess caregiver satisfaction. METHODS: A single-center, quality improvement study was conducted. A standardized data collection tool was created to characterize interventions made by clinical pharmacy specialists during an outpatient clinic appointment scheduled shortly after discharge. Pediatric patients with cancer who met the following criteria were included: 1) initial diagnosis without receiving chemotherapy, 2) first course of chemotherapy after initial diagnosis or relapsed disease, and 3) post-hematopoietic stem cell transplantation or cellular therapy. A survey was provided to families after the follow-up discharge appointment to assess the caregiver's satisfaction of the new process. RESULTS: From January to May 2021, a total of 78 first-time discharge appointments were completed. The most common reason for follow-up was discharge after first course of chemotherapy (77%). The average duration of each appointment was 20 minutes (range, 5-65). The clinical pharmacy specialist made an intervention during 85% of appointments. The most common intervention made during the visit was reinforcement of medications (31%). Thirteen surveys were completed by caregivers; 100% of the caregivers reported the follow-up appointment was helpful. Additionally, they reported the most useful resource provided at discharge was the medication calendar (85%). CONCLUSIONS: Investing clinical pharmacy specialist time with patients and caregiver after discharge appears to have a meaningful effect on patient care. Caregivers report this process is helpful in better understanding their child's medications.

Triple-Negative Apocrine Carcinomas: Toward a Unified Group With Shared Molecular Features and Clinical Behavior.

Triple-negative apocrine carcinomas (TNACs) are rare breast tumors with limited studies evaluating their molecular characteristics and clinical behavior. We performed a histologic, immunohistochemical, genetic, and clinicopathologic assessment of 42 invasive TNACs (1 with a focal spindle cell component) from 41 patients, 2 pure apocrine ductal carcinomas in situ (A-DCIS), and 1 A-DCIS associated with spindle cell metaplastic carcinoma (SCMBC). All TNACs had characteristic apocrine morphology and expressed androgen receptor (42/42), gross cystic disease fluid protein 15 (24/24), and CK5/6 (16/16). GATA3 was positive in most cases (16/18, 89%), and SOX10 was negative (0/22). TRPS1 was weakly expressed in a minority of tumors (3/14, 21%). Most TNACs had low Ki67 proliferation (≤10% in 67%, 26/39), with a median index of 10%. Levels of tumor infiltrating lymphocytes were low (≤10% in 93%, 39/42, and 15% in 7%, 3/42). Eighteen percent of TNACs presented with axillary nodal metastasis (7/38). No patients treated with neoadjuvant chemotherapy achieved pathologic complete response (0%, 0/10). Nearly all patients with TNAC (97%, n = 32) were without evidence of disease at the time of study (mean follow-up of 62 months). Seventeen invasive TNACs and 10 A-DCIS (7 with paired invasive TNAC) were profiled by targeted capture-based next-generation DNA sequencing. Pathogenic mutations in phosphatidylinositol 3-kinase pathway genes PIK3CA (53%) and/or PIK3R1 (53%) were identified in all TNACs (100%), including 4 (24%) with comutated PTEN. Ras-MAPK pathway genes, including NF1 (24%), and TP53 were mutated in 6 tumors each (35%). All A-DCIS shared mutations, such as phosphatidylinositol 3-kinase aberrations and copy number alterations with paired invasive TNACs or SCMBC, and a subset of invasive carcinomas showed additional mutations in tumor suppressors (NF1, TP53, ARID2, and CDKN2A). Divergent genetic profiles between A-DCIS and invasive carcinoma were identified in 1 case. In summary, our findings support TNAC as a morphologically, immunohistochemically, and genetically homogeneous subgroup of triple-negative breast carcinomas and suggest overall favorable clinical behavior.

What is the gender representation in authorship in later phase systemic clinical trials in biliary tract cancer (BTC)? - a retrospective review of the published literature.

OBJECTIVES: Female physicians in medicine are increasing, but disparities in female authorship exist. The aim of this study was to characterise factors associated with female first (FF) and female senior (SF) authorship in later phase systemic oncological clinical trials in biliary tract cancer (BTC) and identify any changes over time. SETTING: Embase/Medline identified trial publications in BTC (2000-2020) were included. χ2 tests and log regression were used (assessed factors associated with FF and SF authorship, including changes over time (STATA V.16)). PRIMARY OUTCOME MEASURE: FF and SF authorship in later phase systemic oncological clinical trials in BTC. SECONDARY OUTCOME MEASURE: Any changes over time? RESULTS: Of 501 publications, 163 met inclusion criteria. The median percentage of female author representation in publications was 25%; there were no female authors in 13% of publications. Geographic location of the home institution of the first and senior authors was Asia (42%/42%), Europe (29%/29%), USA (24%/22%) and other (4%/6%), respectively. Overall, FF and SF author representation was 20% and 10%, respectively. The median position of the first female author was second in all the publication author lists. The phase of trial, journal-impact factor, industry funding or whether the study met its primary endpoint did not impact FF/SF author representation. More SF authors had home institutions in 'other' geographic locations (40% in 10 trials) (p=0.02) versus Asia (6%), Europe (8%) and USA (14%). There were no significant changes in FF/SF representation over time (p=0.61 and p=0.33 respectively). CONCLUSIONS: FF and SF author representation in later phase systemic clinical trial publications in BTC is low and has not changed significantly over time. The underlying reasons for this imbalance need to be better understood and addressed.

Potential influence of the microbiome environment in patients with biliary tract cancer and implications for therapy.

Biliary tract cancers, including intra- and extra-hepatic cholangiocarcinoma as well as gallbladder cancer, are associated with poor prognosis and the majority of patients present with advanced-stage, non-resectable disease at diagnosis. Biliary tract cancer may develop through an accumulation of genetic and epigenetic alterations and can be influenced by microbial exposure. Furthermore, the liver and biliary tract are exposed to the gastrointestinal microbiome through the gut-liver axis. The availability of next-generation sequencing technology has led to an increase in studies investigating the relationship between microbiota and human disease. In particular, the interplay between the microbiome, the tumour micro-environment and response to systemic therapy is a prospering area of interest. Given the poor outcomes for patients with biliary tract cancer, this emerging field of research, through which new biomarkers may be identified, offers potential as a tool for early diagnosis, prognostication or even as a future therapeutic target. This review summarises the available evidence on the microbiome environment in patients with biliary tract cancer, including a discussion around confounding factors, implications for therapy and proposed future directions.

Prognostic factors for relapse in resected gastroenteropancreatic neuroendocrine neoplasms: A systematic review and meta-analysis.

BACKGROUND: Gastroenteropancreatic neoplasms (GEP-NENs)can potentially be cured through surgical resection, but only 42-57% achieve 5-year disease-free survival.There is a lack of consensus regarding the factorsassociated withrelapse followingresection ofGEP-NENs. METHODS: Asystematic review identified studies reporting factors associated with relapse in patients with GEP-NENs following resection of a primary tumour. Meta-analysis was performed to identify the factors prognostic for relapse-free survival (RFS)oroverall survival (OS). RESULTS: 63 studies comprising 13,715 patients were included; 56 studies reported on pancreatic NENs (12,418 patients), 24 reported on patients with grade 1-2 tumours (4,735 patients). Median follow-up was 44.2 months, median RFS was 32 months. Pooling of multivariable analyses of GEP-NENs (all sites and grades) found the following factors predicted worse RFS (all p values < 0.05): vascular resection performed, metastatic disease resected, grade 2 disease, grade 3 disease, tumour size > 20 mm, R1 resection, microvascular invasion, perineural invasion, Ki-67 > 5% and any lymph node positivity. In a subgroup of studies comprising exclusively of grade 1-2 GEP-NENs, R1 resection, perineural invasion, grade 2 disease, any lymph node positivity and tumour size > 20 mm predicted worse RFS (all p values < 0.05). Few OSdata were available for pooling; in univariableanalysis(entire cohort), grade 2 predicted worse OS (p = 0.007), whileR1 resectiondid not (p = 0.14). CONCLUSIONS: The factors prognostic for worse RFS following resection of a GEP-NEN identified in this meta-analysis could be included in post-curative treatment surveillance clinical guidelines and inform the stratification and inclusion criteria of future adjuvant trials.

Bispecific binder redirected lentiviral vector enables in vivo engineering of CAR-T cells.

BACKGROUND: Chimeric antigen receptor (CAR) T cells have shown considerable promise as a personalized cellular immunotherapy against B cell malignancies. However, the complex and lengthy manufacturing processes involved in generating CAR T cell products ex vivo result in substantial production time delays and high costs. Furthermore, ex vivo expansion of T cells promotes cell differentiation that reduces their in vivo replicative capacity and longevity. METHODS: Here, to overcome these limitations, CAR-T cells are engineered directly in vivo by administering a lentivirus expressing a mutant Sindbis envelope, coupled with a bispecific antibody binder that redirects the virus to CD3+ human T cells. RESULTS: This redirected lentiviral system offers exceptional specificity and efficiency; a single dose of the virus delivered to immunodeficient mice engrafted with human peripheral blood mononuclear cells generates CD19-specific CAR-T cells that markedly control the growth of an aggressive pre-established xenograft B cell tumor. CONCLUSIONS: These findings underscore in vivo engineering of CAR-T cells as a promising approach for personalized cancer immunotherapy.

Engineering sperm-binding IgG antibodies for the development of an effective nonhormonal female contraception.

Many women risk unintended pregnancy because of medical contraindications or dissatisfaction with contraceptive methods, including real and perceived side effects associated with the use of exogenous hormones. We pursued direct vaginal delivery of sperm-binding monoclonal antibodies (mAbs) that can limit progressive sperm motility in the female reproductive tract as a strategy for effective nonhormonal contraception. Here, motivated by the greater agglutination potencies of polyvalent immunoglobulins but the bioprocessing ease and stability of immunoglobulin G (IgG), we engineered a panel of sperm-binding IgGs with 6 to 10 antigen-binding fragments (Fabs), isolated from a healthy immune-infertile woman against a unique surface antigen universally present on human sperm. These highly multivalent IgGs (HM-IgGs) were at least 10- to 16-fold more potent and faster at agglutinating sperm than the parent IgG while preserving the crystallizable fragment (Fc) of IgG that mediates trapping of individual spermatozoa in mucus. The increased potencies translated into effective (>99.9%) reduction of progressively motile sperm in the sheep vagina using as little as 33 µg of the 10-Fab HM-IgG. HM-IgGs were produced at comparable yields and had identical thermal stability to the parent IgG, with greater homogeneity. HM-IgGs represent not only promising biologics for nonhormonal contraception but also a promising platform for engineering potent multivalent mAbs for other biomedical applications.

Locoregional therapies in patients with intrahepatic cholangiocarcinoma: A systematic review and pooled analysis.

BACKGROUND: Locoregional treatments (LRT) including radioembolisation (SIRT), transarterial chemo-embolisation (TACE), hepatic arterial infusion (HAI) of chemotherapy, external beam radiotherapy (EBRT) and ablation have been studied for the management of intrahepatic cholangiocarcinoma (iCC). The aim of this systematic review was to provide outcome benchmarks for clinical trial design. METHODS: Identification of studies reporting outcomes of patients treated with LRT for iCC was performed using PubMed and Embase. Pooled weighted means were calculated for progression-free survival (PFS) and overall survival (OS); meta-analysis of proportions was used for estimation of pooled response rate. RESULTS: 6325 entries were reviewed; 93 studies were eligible, representing 101 cohorts and 3990 patients: 15 cohorts (645 patients) for ablation, 18 cohorts (541 patients) for EBRT, 27 cohorts (1232 patients) for SIRT, 22 cohorts (1145 patients) for TACE, 16 cohorts (331 patients) for HAI and 3 cohorts (96 patients) not pooled. 74% of the studies were retrospective, 99% non-randomised. The pooled mean weighted OS was 30.2 months (95% confidence interval (CI): 21.8-38.6) for ablation, 18.9 (14.2-23.5) for EBRT, 14.1 (12.1-16.0) for SIRT, 15.9 (12.9-19.0) for TACE and 21.3 (15.4-27.1) for HAI. The pooled complete response rate was 93.9% for ablation. When analysed together, SIRT, TACE and HAI had a pooled mean weighted OS of 15.7 months, and 25.2 months for patients treated in first-line with concomitant systemic chemotherapy. CONCLUSIONS: Available literature on LRT for iCC was heterogeneous and of insufficient quality to make strong recommendations. Ablation achieved satisfactory outcomes, and may be recommended when surgery is not feasible.

Eltrombopag in children with severe aplastic anemia.

BACKGROUND: Immunosuppressive therapy with horse antithymocyte globulin and cyclosporine currently remains the standard therapy for children with severe aplastic anemia (SAA) who lack human leukocyte antigen (HLA)-identical sibling. The thrombopoietin receptor agonist eltrombopag has been recently approved for SAA patients 2 years and older. However, there are limited data on its safety and efficacy in pediatric cohorts. METHODS: We conducted a retrospective study of patients ≤18 years old consecutively diagnosed with SAA between 2000 and 2018. Patients received either standard immunosuppressive therapy (IST-Std) or IST with eltrombopag (IST-Epag). The primary outcome was the objective response (OR), including partial and complete response (CR), at 6 and 12 months after starting therapy. RESULTS: We identified 16 patients receiving IST-Std and nine IST-Epag treatment (seven of nine as upfront therapy and two of seven after previously failed IST). The OR at 6 and 12 months in IST-Std arm was 71% and 100%, with CR in 29% and 58%, respectively. Seven patients receiving upfront IST-Epag had OR at 6 and 12 months, with two of seven (29%) achieving CR at 6 and 12 months. Two patients who previously failed standard IST did not respond to eltrombopag. No significant differences were observed in both cohorts with regard to infections. One IST-Epag-treated patient developed transient grade 3 transaminitis. Finally, no changes in paroxysmal nocturnal hemoglobinuria (PNH) clone size and cytogenetic abnormalities were seen in either cohort. CONCLUSION: The addition of eltrombopag to standard IST was well tolerated and resulted in satisfactory hematological response at 6 and 12 months in this single-institution experience. A larger cohort with longer follow-up is required to assess response durability.

The cost-effectiveness of gene therapy for severe hemophilia B: a microsimulation study from the United States perspective.

Adeno-associated virus (AAV)-mediated gene therapy is a novel treatment promising to reduce morbidity associated with hemophilia. Although multiple clinical trials continue to evaluate efficacy and safety, limited cost-effectiveness data have been published. This study compared the potential cost-effectiveness of AAV-mediated factor IX (FIX)-Padua gene therapy for patients with severe hemophilia B in the United States vs on-demand FIX replacement and primary FIX prophylaxis, using either standard or extended half-life FIX products. A microsimulation Markov model was constructed, and transition probabilities between health states and utilities were informed by using published data. Costs were aggregated by using a microcosting approach. A time horizon from 18 years old until death, from the perspective of a third-party payer in the United States, was conducted. Gene therapy was more cost-effective than both alternatives considering a $150 000/quality-adjusted life-year threshold. The price for gene therapy was assumed to be $2 000 000 in the base case scenario; however, one of the 1-way sensitivity analyses was conducted by using observed manufacturing, administration, and 5-year follow-up costs of $87 198 for AAV-mediated gene therapy vector as derived from the manufacturing facility and clinical practice at St Jude Children's Research Hospital. One-way sensitivity analyses revealed 10 of 102 scenarios in which gene therapy was not cost-effective compared with alternative treatments. Notably, gene therapy remained cost-effective in a hypothetical scenario in which we estimated that the discounted factor concentrate price was 20% of the wholesale acquisition cost in the United States. Probabilistic sensitivity analysis estimated gene therapy to be cost-effective at 92% of simulations considering a $150 000/quality-adjusted life-year threshold. In conclusion, based on detailed simulation inputs and assumptions, gene therapy was more cost-effective than on-demand treatment and prophylaxis for patients with severe hemophilia B.

Limited sampling strategies for accurate determination of extended half-life factor VIII pharmacokinetics in severe haemophilia A patients.

BACKGROUND: Extended half-life (EHL) factor VIII (FVIII) products may decrease the burden of prophylactic treatment in haemophilia A by reducing infusion frequency. However, these products still exhibit wide inter-patient variability and benefit from pharmacokinetic (PK) tailoring. OBJECTIVE: Identify limited sampling strategies for rFVIIIFc, an EHL FVIII product, that produce accurate estimates of PK parameters and relevant troughs. METHODS: We performed a limited sampling analysis on simulated populations of adults, adolescents, and children based on published population PK data. Sampling strategies were evaluated by comparing the error in estimates of half-life, clearance, and trough levels, to a full 6-sample design. Furthermore, we assessed the impact of incorporating knowledge about prior doses, and the day of the PK study within the regimen. We also evaluated the potential inappropriate dose adjustment rate (IDAR) among the modelled sampling strategies. RESULTS: Many sampling strategies, including several 2-sample designs, accurately predicted the PK and exposure measures (median absolute error <10%). When samples are only collected during a single visit (i.e., predose + peak), inclusion of prior dose information reduces median half-life error from >20% to ~5% for adults/adolescents. In this same scenario, appropriate scheduling of the PK study decreases likelihood of unmeasurable predose samples, reducing median error on the 72-h trough from 25% to <12% in the youngest population. CONCLUSIONS: The PK of rFVIIIFc can be accurately estimated using only peak and trough samples, provided that knowledge of prior doses is incorporated and the PK study is planned on an appropriate day within the dosing regimen.

Knowns and unknowns of bone metastases in patients with neuroendocrine neoplasms: A systematic review and meta-analysis.

OBJECTIVE: This systematic review and meta-analysis aimed to develop an evidence-based summary of current knowledge of bone metastases (BMs) in neuroendocrine neoplasms (NENs), inform diagnosis and treatment and standardise management between institutions. METHODS: PubMed, Medline, EMBASE and meeting proceedings were searched for eligible studies reporting data on patients with BMs and NENs of any grade of differentiation and site; poorly-differentiated large/small cell lung cancer were excluded. Data were extracted and analysed using STATA v.12. Meta-analysis of proportions for calculation of estimated pooled prevalence of BM and calculation of weighted pooled frequency and weighted pooled mean for other variables of interest was performed . RESULTS: A total of 149 studies met the eligibility criteria. Pooled prevalence of BMs was 18.4% (95% CI 15.4-21.5). BMs were mainly metachronous with initial diagnosis of NEN (61.2%) and predominantly osteoblastic; around 61% were multifocal, with a predisposition in axial skeleton. PET/CT seemed to provide (together with MRI) the highest sensitivity and specificity for BM detection. Almost half of patients (46.4%) reported BM-related symptoms: pain (66%) and skeletal-related events (SREs, fracture/spinal cord compression) (26.2%; weightedweighted mean time-to-SRE 9.9 months). Management of BMs was multimodal [bisphosphonates and bone-modifying agents (45.2%), external beam radiotherapy (34.9%), surgery (14.8%)] and supported by little evidence. Overall survival (OS) from the time of diagnosis of BMs was long [weighted mean 50.9 months (95% CI 40.0-61.9)]. Patients with BMs had shorter OS [48.8 months (95% CI 37.9-59.6)] compared to patients without BMs [87.4 months (95% CI 74.9-100.0); p = 0.001]. Poor performance status and BM-related symptoms were also associated with worse OS. CONCLUSIONS: BMs in patients with NENs remain underdiagnosed and undertreated. Recommendations for management of BMs derived from current knowledge are provided. Prospective studies to inform management are required.

Engineering tetravalent IgGs with enhanced agglutination potencies for trapping vigorously motile sperm in mucin matrix.

Multivalent antibodies such as sIgA can crosslink motile entities such as sperm and bacteria, creating agglomerates that are too large to permeate the dense mucin matrix in mucus, a process commonly referred to as immune exclusion. Unfortunately, sIgA remains challenging to produce in large quantities, and easily aggregates, which prevented their use in clinical applications. To develop sIgA-like tetravalent antibodies that are stable and can be easily produced in large quantities, we designed two IgGs possessing 4 identical Fab domains, with the Fabs arranged either in serial or in the diametrically opposite orientation. As a proof-of-concept, we engineered these tetravalent IgG constructs to bind a ubiquitous sperm antigen using a Fab previously isolated from an immune infertile woman. Both constructs possess at least 4-fold greater agglutination potency and induced much more rapid sperm agglutination than the parent IgG, while exhibiting comparable production yields and identical thermostability as the parent IgG. These tetravalent IgGs offer promise for non-hormonal contraception and underscores the multimerization of IgG as a promising strategy to enhance antibody effector functions based on immune exclusion.

Impact of high tumor mutational burden in solid tumors and challenges for biomarker application.

Accurate identification of patients with solid tumors likely to respond to immunotherapy is crucial. Tumor mutational burden (TMB) measures the number of somatic mutations in a tumor and is an emerging prognostic and predictive biomarker for anti-programmed cell death (PD) 1/anti-PD-ligand 1 therapy and other immunotherapeutic agents. Tumor mutational burden is assessed optimally by whole exome sequencing, but next generation sequencing provides TMB estimates in a more timely and cost-effective manner. Blood-based measurement of TMB in plasma offers an alternative to the need for adequate tumor tissue for molecular testing, and has demonstrated the ability to identify patients who derive benefit from immunotherapy. Tumor mutational burden has diverse prognostic impact in different solid tumor types and also has a demonstrated role in predicting improved survival in patients receiving immunotherapy. There are challenges to TMB adoption into standard clinical practice, including variations in its definition, with the mutational number defining TMB-high appearing to vary across cancer types. The magnitude of TMB also varies across different tumor types, with the highest levels reported in melanoma and other skin cancers (where ultraviolet light is the dominant mutational process), followed by non-small cell lung cancer and other squamous carcinomas. Concerns regarding inter-laboratory and inter-platform variations in analysis methods have been raised, highlighting the need for standardization. Integration of other genomic or pathological biomarkers with TMB may increase its prognostic and predictive capabilities and validation of individual or combination models in prospective trials is warranted.

Second-line treatment in patients with advanced extra-pulmonary poorly differentiated neuroendocrine carcinoma: a systematic review and meta-analysis.

BACKGROUND: There is no standard second-line treatment for patients with advanced extra-pulmonary poorly differentiated neuroendocrine carcinoma (EP-PD-NEC). This study explored data evaluating second-line treatment in these patients. METHODS: A search of MEDLINE and EMBASE identified studies reporting survival and/or response data for patients with EP-PD-NEC receiving second-line therapy. Association between various factors (age, gender, ECOG performance status, primary tumour location, morphology, Ki-67, treatment and grade 3/4 haematological toxicity) and response rate (RR), progression-free (PFS) and overall survival (OS) were assessed with a mixed effects meta-regression weighted by individual study sample size. Due to a small sample size, associations were reported quantitatively, based on magnitude of beta coefficient rather than statistical significance. RESULTS: Of 83 identified studies, 19 were eligible, including 4 prospective and 15 retrospective studies. Analysis comprised 582 patients, with a median number of 19 patients in each study (range 5-100). Median age was 59 years (range 53-66). Median RR was 18% (range 0-50; 0% for single-agent everolimus, temozolomide, topotecan; 50% with amrubicin), median PFS was 2.5 months (range 1.15-6.0) and median OS was 7.64 months (range 3.2-22.0). Studies with a higher proportion of patients with a Ki-67>55% had lower RR (ß = -0.73) and shorter OS (ß = -0.82). CONCLUSION: Second-line therapy for patients with advanced EP-PD-NEC has limited efficacy and the variety of regimens used is diverse. Ki-67>55% is associated with worse outcomes. Prospective randomised studies are warranted to enable exploration of new treatment strategies.

Efficient and Highly Specific Gene Transfer Using Mutated Lentiviral Vectors Redirected with Bispecific Antibodies.

Despite their exceptional potencies, the broad tropism of most commonly used lentivirus (LV) vectors limits their use for targeted gene delivery in vivo We hypothesized that we could improve the specificity of LV targeting by coupling (i) reduction of their binding to off-target cells with (ii) redirection of the vectors with a bispecific antibody (bsAb) that binds both LV and receptors on target cells. As a proof of concept, we pseudotyped nonreplicating LV using a mutated Sindbis envelope (mSindbis) with ablated binding to native receptors, while retaining the capacity to facilitate efficient fusion and endosomal escape. We then evaluated the transduction potencies of the mSindbis LV for HER2-positive (HER2+) (SKBR3) breast and HER2-negative (HER2-) (A2780) cells when redirected with different bsAbs. mSindbis LV alone failed to induce appreciable green fluorescent protein (GFP) expression in either cell. When mixed with HER2-targeting bsAb, mSindbis LV was exceptionally potent, transducing 12% to 16% of the SKBR3 cells at a multiplicity of infection (MOI [ratio of viral genome copies to target cells]) of 3. Transduction was highly specific, resulting in ∼50-fold-greater selectivity toward SKBR3 cells versus A2780 cells. Redirecting mSindbis LV led to a 10-fold improvement in cell-specific targeting compared to redirecting wild-type Sindbis LV with the same bsAb, underscoring the importance of ablating native virus tropism in order to maximize targeting specificity. The redirection of mutated LV using bsAb represents a potent and highly versatile platform for targeted gene therapy.IMPORTANCE The goal of gene therapy is specific delivery and expression of therapeutic genes to target cells and tissues. Common lentivirus (LV) vectors are efficient gene delivery vehicles but offer little specificity. Here, we report an effective and versatile strategy to redirect LV to target cells using bispecific antibodies (bsAbs) that bind both cell receptors and LV envelope domains. Importantly, we ablated the native receptor binding of LV to minimize off-target transduction. Coupling bsAb specificity and ablated native LV tropism synergistically enhanced the selectivity of our targeted gene delivery system. The modular nature of our bsAb-based redirection enables facile targeting of the same LV to diverse tissues/cells. By abrogating the native broad tropism of LV, our bsAb-LV redirection strategy may enable lentivirus-based gene delivery in vivo, expanding the current use of LV beyond ex vivo applications.

Pretargeted delivery of PEG-coated drug carriers to breast tumors using multivalent, bispecific antibody against polyethylene glycol and HER2.

Pretargeting is an increasingly explored strategy to improve nanoparticle targeting, in which pretargeting molecules that bind both selected epitopes on target cells and nanocarriers are first administered, followed by the drug-loaded nanocarriers. Bispecific antibodies (bsAb) represent a promising class of pretargeting molecules, but how different bsAb formats may impact the efficiency of pretargeting remains poorly understood, in particular Fab valency and Fc receptor (FcR)-binding of bsAb. We found the tetravalent bsAb markedly enhanced PEGylated nanoparticle binding to target HER2+ cells relative to the bivalent bsAb in vitro. Pretargeting with tetravalent bsAb with abrogated FcR binding increased tumor accumulation of PEGylated liposomal doxorubicin (PLD) 3-fold compared to passively targeted PLD alone, and 5-fold vs pretargeting with tetravalent bsAb with normal FcR binding in vivo. Our work demonstrates that multivalency and elimination of FcRn recycling are both important features of pretargeting molecules, and further supports pretargeting as a promising nanoparticle delivery strategy.

Analysis of Pre-existing IgG and IgM Antibodies against Polyethylene Glycol (PEG) in the General Population.

Circulating antibodies (Ab) that specifically bind polyethylene glycol (PEG), a biocompatible polymer routinely used in protein and nanoparticle therapeutics, have been associated with reduced efficacy of and/or adverse reactions to therapeutics modified with or containing PEG. Unlike most antidrug antibodies that are induced following initial drug dosing, anti-PEG Ab can be found in treatment-naïve individuals (i.e., individuals who have never undergone treatment with PEGylated drugs but most likely have been exposed to PEG through other means). Unfortunately, the true prevalence, quantitative levels, and Ab isotype of pre-existing anti-PEG Ab remain poorly understood. Here, using rigorously validated competitive ELISAs with engineered chimeric anti-PEG monoclonal Ab standards, we quantified the levels of anti-PEG IgM and different subclasses of anti-PEG IgG (IgG1-4) in both contemporary and historical human samples. We unexpectedly found, with 90% confidence, detectable levels of anti-PEG Ab in ∼72% of the contemporary specimens (18% IgG, 25% IgM, 30% both IgG and IgM). The vast majority of these samples contained low levels of anti-PEG Ab, with only ∼7% and ∼1% of all specimens possessing anti-PEG IgG and IgM in excess of 500 ng/mL, respectively. IgG2 was the predominant anti-PEG IgG subclass. Anti-PEG Ab's were also observed in ∼56% of serum samples collected during 1970-1999 (20% IgG, 19% IgM, and 16% both IgG and IgM), suggesting that the presence of PEG-specific antibodies may be a longstanding phenomenon. Anti-PEG IgG levels demonstrated correlation with patient age, but not with gender or race. The widespread prevalence of pre-existing anti-PEG Ab, coupled with high Ab levels in a subset of the population, underscores the potential importance of screening patients for anti-PEG Ab levels prior to administration of therapeutics containing PEG.