Humanized Research Articles

Human antibodies neutralizing the alpha-latrotoxin of the European black widow.

Poisoning by widow-spider (genus Latrodectus) bites occurs worldwide. The illness, termed latrodectism, can cause severe and persistent pain and can lead to muscle rigidity, respiratory complications, and cardiac problems. It is a global health challenge especially in developing countries. Equine serum-derived polyclonal anti-sera are commercially available as a medication for patients with latrodectism, but the use of sera imposes potential inherent risks related to its animal origin. The treatment may cause allergic reactions in humans (serum sickness), including anaphylactic shock. Furthermore, equine-derived antivenom is observed to have batch-to-batch variability and poor specificity, as it is always an undefined mix of antibodies. Because latrodectism can be extremely painful but is rarely fatal, the use of antivenom is controversial and only a small fraction of patients is treated. In this work, recombinant human antibodies were selected against alpha-latrotoxin of the European black widow (Latrodectus tredecimguttatus) by phage display from a naïve antibody gene library. Alpha-Latrotoxin (α-LTX) binding scFv were recloned and produced as fully human IgG. A novel alamarBlue assay for venom neutralization was developed and used to select neutralizing IgGs. The human antibodies showed in vitro neutralization efficacy both as single antibodies and antibody combinations. This was also confirmed by electrophysiological measurements of neuronal activity in cell culture. The best neutralizing antibodies showed nanomolar affinities. Antibody MRU44-4-A1 showed outstanding neutralization efficacy and affinity to L. tredecimguttatus α-LTX. Interestingly, only two of the neutralizing antibodies showed cross-neutralization of the venom of the Southern black widow (Latrodectus mactans). This was unexpected, because in the current literature the alpha-latrotoxins are described as highly conserved. The here-engineered antibodies are candidates for future development as potential therapeutics and diagnostic tools, as they for the first time would provide unlimited supply of a chemically completely defined drug of constant quality and efficacy, which is also made without the use of animals.

Evaluation of PET/CT imaging with [89Zr]Zr-DFO-girentuximab: a phase 1 clinical study in Japanese patients with renal cell carcinoma (Zirdac-JP).

PET/CT imaging with Zirconium-89 labeled [89Zr]Zr-DFO-girentuximab, which targets tumor antigen CAIX, may aid in the differentiation and characterization of clear cell renal cell carcinomas (RCC) and other renal and extrarenal lesions, and has been studied in European and American cohorts. We report results from a phase I study that evaluated the safety profile, biodistribution, and dosimetry of [89Zr]Zr-DFO-girentuximab in Japanese patients with suspected RCC. Eligible adult patients received 37MBq (± 10%; 10mg mass dose) of intravenous [89Zr]Zr-DFO-girentuximab. Safety and tolerability profile was assessed based on adverse events, concomitant medications, physical examination, vital signs, hematology, serum chemistry, urinalysis, human anti-chimeric antibody measurement, and 12-lead electrocardiograms at predefined intervals. Biodistribution and normal organ and tumor dosimetry were evaluated with PET/CT images acquired at 0.5, 4, 24, 72h and Day 5±2d after administration. [89Zr]Zr-DFO-girentuximab was administered in six patients as per protocol. No treatment-emergent adverse events were reported. Dosimetry analysis showed that radioactivity was widely distributed in the body, and that the absorbed dose in healthy organs was highest in the liver (mean±standard deviation) (1.365±0.245mGy/MBq), kidney (1.126±0.190mGy/MBq), heart wall (1.096±0.232mGy/MBq), and spleen (1.072±0.466mGy/MBq). The mean effective dose, adjusted by the radioactive dose administered, was 0.470mSv/MBq. The radiation dose was highly accumulated in the targeted tumor, while any abnormal accumulation in other organs was not reported. This study demonstrates that [89Zr]Zr-DFO-girentuximab administered to Japanese patients with suspected RCC has a favorable safety profile and is well tolerated and has a similar dosimetry profile to previously studied populations.

Human milk antibodies to global pathogens reveal geographic and interindividual variations in IgA and IgG.

BACKGROUNDThe use of high-throughput technologies has enabled rapid advancement in the knowledge of host immune responses to pathogens. Our objective was to compare the repertoire, protection, and maternal factors associated with human milk antibodies to infectious pathogens in different economic and geographic locations.METHODSUsing multipathogen protein microarrays, 878 milk and 94 paired serum samples collected from 695 women in 5 high and low-to-middle income countries (Bangladesh, Finland, Peru, Pakistan, and the United States) were assessed for specific IgA and IgG antibodies to 1,607 proteins from 30 enteric, respiratory, and bloodborne pathogens.RESULTSThe antibody coverage across enteric and respiratory pathogens was highest in Bangladeshi and Pakistani cohorts and lowest in the U.S. and Finland. While some pathogens induced a dominant IgA response (Campylobacter, Klebsiella, Acinetobacter, Cryptosporidium, and pertussis), others elicited both IgA and IgG antibodies in milk and serum, possibly related to the invasiveness of the infection (Shigella, enteropathogenic E. coli "EPEC", Streptococcus pneumoniae, Staphylococcus aureus, and Group B Streptococcus). Besides the differences between economic regions and decreases in concentrations over time, human milk IgA and IgG antibody concentrations were lower in mothers with high BMI and higher parity, respectively. In Bangladeshi infants, a higher specific IgA concentration in human milk was associated with delayed time to rotavirus infection, implying protective properties of antirotavirus antibodies, whereas a higher IgA antibody concentration was associated with greater incidence of Campylobacter infection.CONCLUSIONThis comprehensive assessment of human milk antibody profiles may be used to guide the development of passive protection strategies against infant morbidity and mortality.FUNDINGBill and Melinda Gates Foundation grant OPP1172222 (to KMJ); Bill and Melinda Gates Foundation grant OPP1066764 funded the MDIG trial (to DER); University of Rochester CTSI and Environmental Health Sciences Center funded the Rochester Lifestyle study (to RJL); and R01 AI043596 funded PROVIDE (to WAP).

Functional and structural basis of human parainfluenza virus type 3 neutralization with human monoclonal antibodies.

Human parainfluenza virus type 3 (hPIV3) is a respiratory pathogen that can cause severe disease in older people and infants. Currently, vaccines against hPIV3 are in clinical trials but none have been approved yet. The haemagglutinin-neuraminidase (HN) and fusion (F) surface glycoproteins of hPIV3 are major antigenic determinants. Here we describe naturally occurring potently neutralizing human antibodies directed against both surface glycoproteins of hPIV3. We isolated seven neutralizing HN-reactive antibodies and a pre-fusion conformation F-reactive antibody from human memory B cells. One HN-binding monoclonal antibody (mAb), designated PIV3-23, exhibited functional attributes including haemagglutination and neuraminidase inhibition. We also delineated the structural basis of neutralization for two HN and one F mAbs. MAbs that neutralized hPIV3 in vitro protected against infection and disease in vivo in a cotton rat model of hPIV3 infection, suggesting correlates of protection for hPIV3 and the potential clinical utility of these mAbs.

Effectiveness and safety of secukinumab updosing in patients with moderate to severe plaque psoriasis: data from the PURE registry

Secukinumab is a fully human IgG1 antibody that selectively binds to and neutralizes the proinflammatory cytokine interleukin-17A. Secukinumab is an effective and well-tolerated treatment for plaque psoriasis. There is a limited real-word evidence for dose optimisation of secukinumab based on clinical response. PURE is a multi-national, prospective, observational study in patients with moderate to severe chronic plaque psoriasis in Canada and Latin America, assessing the real-world safety and effectiveness of secukinumab and other indicated therapies. The aim of the current snapshot analysis was to evaluate the effectiveness and safety of on-label dose and updosed secukinumab in patients with plaque psoriasis enrolled in the PURE study. At the time of analysis, 676 patients received secukinumab, of which 84.6% (n = 572) remained on the on-label dose, while 15.4% (n = 104) were updosed. With on-label secukinumab, the absolute Psoriasis Area and Severity Index (PASI) score was reduced from 13.6 at baseline to 1.2 over 36 months, with treatment persistence of 73% at 40 months. At Month 36, 73.2% of the patients receiving on-label secukinumab achieved Investigator’s Global Assessment (IGA) 0/1. With updosed secukinumab (300 mg every 2 weeks, 300 mg every 3 weeks, 450 mg every 4 weeks, or 450 mg every 3 weeks), 57.9% of the patients showed improvement in the absolute PASI score at the first visit after updosing, with treatment persistence of 50% at 12 months after updosing. At Month 15, 40% of patients receiving updosed secukinumab achieved IGA 0/1. Patients with previous biologic exposure (odds ratio [OR]: 3.25; 95% confidence interval [CI]: 2.03, 5.18, p < 0.0001) were more likely to be updosed while those with a body weight < 90 kg (OR: 0.49; 95% CI [0.31, 0.77], p = 0.0019) were less likely to be updosed. Previous biologic exposure (HR [hazard ratio]: 1.47; 95% CI [1.24, 1.75], p < 0.0001) and current biologic exposure (secukinumab vs. other indicated therapies: HR 0.57; 95% CI [0.43, 0.75], p = 0.0001) were significantly associated with time to secukinumab updosing. No new or unexpected safety signals were observed with updosed secukinumab. Secukinumab updosing was efficacious and well-tolerated in patients with psoriasis who failed to respond to the approved on-label regimen, suggesting that updosing may be a useful therapeutic option for approved dose non-responders.

Aspergillus oryzae as a host for SARS-CoV-2 RBD and NTD expression

The COVID-19 pandemic has increased demand for effective diagnostics, and extensive research has been conducted on the N-terminal domain (NTD) and the receptor-binding domain (RBD) of the SARS-CoV-2 spike glycoprotein, which are critical for viral binding. This study focuses on the expression of NTD and RBD in pyrG auxotrophic Aspergillus oryzae for the first time. Recombinant NTD and RBD were expressed as glucoamylase-fusion proteins and purified using metal affinity chromatography. Size-exclusion chromatography was used to confirm the correct folding and purity of the recombinant proteins. Employing an enzyme-linked immunosorbent assay, the binding ability of the fusion proteins to human anti-IgG antibodies in serum samples was evaluated. The results indicated a significant and concentration-dependent interaction, affirming the functionality of the NTD and RBD fusion proteins and establishing their efficacy in antigen-antibody interactions. This study not only elucidates the usage potential of the fusion proteins in immunoassays but also addresses the suitability of the A. oryzae expression system as a biotechnological platform to produce SARS-CoV-2 proteins. Furthermore, this study lays the foundation for scalable and cost-effective mass production of effective NTD and RBD proteins in A. oryzae, opening up a new era of COVID-19 research, vaccine development, and immunoassay design.

Safety and effectiveness of mogamulizumab in relapsed or refractory CC chemokine receptor 4-positive peripheral T-cell lymphoma and relapsed or refractory cutaneous T-cell lymphoma: A post-marketing surveillance in Japan.

Mogamulizumab is a humanized antibody targeting CC chemokine receptor 4 (CCR4). This post-marketing surveillance was conducted in Japan as a regulatory requirement from 2014 to 2020 to ensure the safety and effectiveness of mogamulizumab in patients with relapsed or refractory (r/r) CCR4-positive peripheral T-cell lymphoma (PTCL) or r/r cutaneous T-cell lymphoma (CTCL). Safety and effectiveness data were collected for up to 31weeks after treatment initiation. A total of 142 patients were registered; safety was evaluated in 136 patients. The median number of doses was 8.0 (range, 1-18). The main reasons for treatment termination were insufficient response (22.1%) and adverse events (13.2%). The frequency of any grade adverse drug reaction was 57.4%, including skin disorders (26.5%), infections and immune system disorders (16.2%), and infusion-related reactions (13.2%). Graft-versus-host disease, grade 2, developed in one of two patients who underwent allogeneic-hematopoietic stem cell transplantation after receiving mogamulizumab. Effectiveness was evaluated in 131 patients (103 with PTCL; 28 with CTCL). The best overall response rate was 45.8% (PTCL, 47.6%; CTCL, 39.3%). At week 31, the survival rate was 69.0% (95% confidence interval, 59.8%-76.5%) [PTCL, 64.4% (54.0%-73.0%); CTCL, 90.5% (67.0%-97.5%)]. Safety and effectiveness were comparable between patients <70 and≥70years old and between those with relapsed and refractory disease. The safety and effectiveness of mogamulizumab for PTCL and CTCL in the real world were comparable with the data reported in previous clinical trials. Clinical Trial Registration.

Affimer reagents as tool molecules to modulate platelet GPVI-ligand interactions and specifically bind GPVI dimer

AbstractGlycoprotein VI (GPVI) plays a key role in collagen-induced platelet aggregation. Affimers are engineered binding protein alternatives to antibodies. We screened and characterized GPVI-binding Affimers as novel tools to probe GPVI function. Among the positive clones, M17, D22, and D18 bound GPVI with the highest affinities (dissociation constant (KD) in the nanomolar range). These Affimers inhibited GPVI-collagen-related peptide (CRP)-XL/collagen interactions, CRP-XL/collagen-induced platelet aggregation, and D22 also inhibited in vitro thrombus formation on a collagen surface under flow. D18 bound GPVI dimer but not monomer. GPVI binding was increased for D18 but not M17/D22 upon platelet activation by CRP-XL and adenosine 5′-diphosphate. D22 but not M17/D18 displaced nanobody 2 (Nb2) binding to GPVI, indicating similar epitopes for D22 with Nb2 but not for M17/D18. Mapping of binding sites revealed that D22 binds a site that overlaps with Nb2 on the D1 domain, whereas M17 targets a site on the D2 domain, overlapping in part with the glenzocimab binding site, a humanized GPVI antibody fragment antigen-binding fragment. D18 targets a new region on the D2 domain. We found that D18 is a stable noncovalent dimer and forms a stable complex with dimeric GPVI with 1:1 stoichiometry. Taken together, our data demonstrate that Affimers modulate GPVI-ligand interactions and bind different sites on GPVI D1/D2 domains. D18 is dimer-specific and could be used as a tool to detect GPVI dimerization or clustering in platelets. A dimeric epitope regulating ligand binding was identified on the GPVI D2 domain, which could be used for the development of novel bivalent antithrombotic agents selectively targeting GPVI dimer on platelets.

Blocking Oncostatin M receptor abrogates STAT3 mediated integrin signaling and overcomes chemoresistance in ovarian cancer

Chemotherapy such as cisplatin is widely used to treat ovarian cancer either before or after surgical debulking. However, cancer relapse due to chemotherapy resistance is a major challenge in the treatment of ovarian cancer. The underlying mechanisms related to chemotherapy resistance remain largely unclear. Therefore, identification of effective therapeutic strategies is urgently needed to overcome therapy resistance. Transcriptome-based analysis, in vitro studies and functional assays identified that cisplatin-resistant ovarian cancer cells express high levels of OSMR compared to cisplatin sensitive cells. Furthermore, OSMR expression associated with a module of integrin family genes and predominantly linked with integrin αV (ITGAV) and integrin β3 (ITGB3) for cisplatin resistance. Using ectopic expression and knockdown approaches, we proved that OSMR directly regulates ITGAV and ITGB3 gene expression through STAT3 activation. Notably, targeting OSMR using anti-OSMR human antibody inhibited the growth and metastasis of ovarian cancer cells and sensitized cisplatin treatment. Taken together, our results underscore the pivotal role of OSMR as a requirement for cisplatin resistance in ovarian cancer. Notably, OSMR fostered the expression of a distinct set of integrin genes, which in turn resulted into a crosstalk between OSMR and integrins for signaling activation that is critical for cisplatin resistance. Therefore, targeting OSMR emerges as a promising and viable strategy to reverse cisplatin-resistance in ovarian cancer.

The effect of teprotumumab infusion on ocular alignment in patients with symptomatic thyroid eye disease

BackgroundThyroid eye disease (TED) can result in proptosis and ocular misalignment, leading to eye pain, diplopia, and vision loss. Teprotumumab, a humanized antibody against insulin-like growth factor 1 receptor, was approved in 2020 for the treatment of TED. The purpose of this study was to describe the effect of a full course of teprotumumab on ocular misalignment. MethodsThe medical records of patients who underwent treatment with teprotumumab for active moderate-to-severe TED at a single institution from April 2020 to September 2023 were reviewed retroactively. Sensorimotor examination was performed at each visit using simultaneous prism-cover testing. Demographic information and previous history of radioactive iodine, steroids, strabismus surgery, and smoking were extracted from the record for analysis. ResultsA total of 19 patients were treated during the study period, of whom 11 had strabismus and diplopia. The initial absolute horizontal misalignment in these 11 was 6.0Δ ± 1.5Δ, vertical misalignment was 7.7Δ ± 2.4Δ, and total misalignment was 11.5Δ ± 2.0Δ. On completion of treatment, these measurements decreased by 2.0Δ ± 1.5Δ, 2.2Δ ± 1.0Δ, and 3.2Δ ± 1.6Δ, respectively (P = 0.10, 0.02, and 0.04, resp.). Eight patients (73%) had a decrease in their strabismus, and 5 (46%) reported complete resolution of their diplopia at the final visit. No factors were predictive of which patients would have resolution of their misalignment. Of the remaining 3 patients who had no improvement in ocular alignment, 2 (66%) underwent strabismus surgery. Of the 8 patients with improvement of strabismus, only a single patient (13%) underwent strabismus surgery for persistent diplopia. ConclusionsIn our study cohort, a full course of teprotumumab coincided with complete resolution of diplopia in 46% of patients and a decrease in strabismus in 73% of patients.

Combining CD40 agonist mitazalimab with mFOLFIRINOX in previously untreated metastatic pancreatic ductal adenocarcinoma (OPTIMIZE-1): a single-arm, multicentre phase 1b/2 study

Current systemic therapies for metastatic pancreatic ductal adenocarcinoma are associated with poor outcomes with a 5-year overall survival rate under 5%. We aimed to assess the safety and antitumour activity of mitazalimab, a human CD40 agonistic IgG1 antibody, with modified FOLFIRINOX (mFOLFIRINOX; fluorouracil, leucovorin, oxaliplatin, and irinotecan), in chemotherapy-naive patients with metastatic pancreatic ductal adenocarcinoma. OPTIMIZE-1 was a single-arm, multicentre, phase 1b/2 study which enrolled adults with histologically-confirmed metastatic pancreatic ductal adenocarcinoma and European Cooperative Oncology Group performance status 0 or 1 in 14 university hospitals in Belgium, France, and Spain. The primary endpoint of phase 1b was to determine the recommended phase 2 dose of intravenous mitazalimab (450 μg/kg or 900 μg/kg) when combined with intravenous mFOLFIRINOX (oxaliplatin 85 mg/m2, leucovorin 400 mg/m2, irinotecan 150 mg/m2, fluorouracil 2400 mg/m2). In the first 21-day treatment cycle, mitazalimab was administered on days 1 and 10, and mFOLFIRINOX on day 8. In subsequent 14-day cycles mitazalimab was administered 2 days after mFOLFIRINOX. The phase 2 primary endpoint was objective response rate. Activity and safety analyses were conducted on the full analysis set (all patients who received the combination of mitazalimab at the recommended phase 2 dose and mFOLFIRINOX for at least two treatment cycles) and safety set (all patients who received any study treatment), respectively. Enrolment is complete, and data represents a primary analysis of the ongoing trial. The trial is registered at Clinicaltrials.gov (NCT04888312). Between Sept 29, 2021, and March 28, 2023, 88 patients were screened and 70 patients were enrolled (40 [57%] were female and 30 [43%] were male). In phase 1b, 900 μg/kg mitazalimab was determined as the recommended phase 2 dose. Overall, five patients received 450 μg/kg mitazalimab; 65 received 900 μg/kg mitazalimab. No dose-limiting toxicities were observed at 450 μg/kg, and one dose-limiting toxicity was observed at 900 μg/kg. 57 patients were evaluated for activity, and all 70 patients were included in the safety set. At data cutoff on Nov 14, 2023, median follow-up was 12·7 months (95% CI 11·1-15·7). Of the 57 patients, 29 (51%) remained on study and 18 (32%) remained on treatment. The primary endpoint (objective response rate >30%) was met (objective response rates in 23 [40%]; one-sided 90% CI ≥32 of 57 patients). The most common grade 3 or worse adverse events were neutropenia (18 [26%] of 70 patients), hypokalaemia (11 patients [16%]), and anaemia and thrombocytopenia (eight patients [11%]). Serious adverse events were reported in 29 (41%) of 70 patients, the most common being vomiting (five [7%] of 70 patients), decreased appetite (four [6%]), and diarrhoea and cholangitis (three [4%] of 70 patients for each), none considered related to mitazalimab. No treatment-related deaths were reported. Mitazalimab with mFOLFIRINOX demonstrated manageable safety and encouraging activity, warranting continued development in a phase 3, randomised, controlled trial. The results from OPTIMIZE-1 pave the way for further exploration and confirmation of a novel immunotherapy treatment regimen for metastatic pancreatic ductal adenocarcinoma, which is a complex and aggressive cancer with very low survival rates and restricted treatment options. Alligator Bioscience.

Evaluation of cytokine release syndrome (CRS) in patients with relapsed or refractory multiple myeloma (RRMM) receiving step-up priming doses and longer dosing intervals of elranatamab: MagnetisMM-9.

7522 Background: Elranatamab (ELRA) is a humanized BCMA-CD3 bispecific antibody. In the phase 2 registrational MagnetisMM-3 (MM-3) trial, SC ELRA was given as 2 step-up priming doses (12 mg on C1D1 and 32 mg on C1D4) followed by 76 mg QW in patients (pts) with RRMM. Overall, 56.3% of pts had CRS (grade 2, 14.3%; no grade ≥3). Most events occurred after doses 1 (44.5%), 2 (20.2%), and 3 (5.9%); 0.8% (1 pt) had CRS with doses 4+. Recurrent CRS (&gt;1 event) occurred in 15.1% of pts (Lesokhin Nat Med 2023). Methods: MagnetisMM-9 (MM-9; NCT05014412) is a phase 1/2, open-label, nonrandomized study of ELRA examining an alternative 2-dose step-up priming regimen (4 and 20 mg on C1D1 and C1D4, respectively). Eligible pts had RRMM and were refractory to ≥1 IMiD, ≥1 PI, and ≥1 anti-CD38 antibody. After the priming doses, ELRA 76 mg was given QW for 6 cycles (Part 1) or for 1 cycle followed by 116 or 152 mg Q2W for 5 cycles (Part 2A). The RP2D from Part 2A (152 mg) was evaluated in Part 2B (dose expansion). The rate of grade ≥2 CRS per ASTCT criteria during C1 is the primary endpoint for both parts. Secondary endpoints include evaluation of AEs and PK. Here, we report the overall safety and CRS profile associated with the 4/20 mg priming regimen. Results: For 85 treated pts, median age was 64.0 y; 49.4% were male; 23.5% had EMD; 31.8% had high-risk cytogenetics. Pts had a median of 5.0 (range, 1-12) prior LOTs; 85.9% had triple-class refractory disease. After a median follow-up of 7.4 mo, the most common (&gt;50%) AEs were CRS (63.5%; grade ≥2, 15.3%) and neutropenia (54.1%; all grade ≥2). ICANS occurred in 4.7% of pts (all grade ≤2). The grade ≥2 CRS rate in C1 was 14.1% (90% CI, 8.4-21.9). CRS rates after the first 3 doses are in the the table. For doses 4+, any grade (grade ≥2) CRS was observed in 10.6% (3.5%) of pts overall, 12.1% (3.0%) of pts continuing to receive 76 mg (n=33), 25.0% (0%) of pts receiving 116 mg (n=12), and 5.0% (5.0%) of pts receiving 152 mg (RP2D; n=40). Overall, recurrent CRS was observed in 20.0% of pts. The geometric means (CV%) of free ELRA concentrations 24 h (Cmax-24h) after step-up doses 1 and 2 were 85.64 (48%) and 242.8 (55%). Conclusions: The 4/20 mg step-up priming regimen and alternative dosing schedules resulted in similar safety and incidence of overall and grade ≥2 CRS events vs the regimen used in MM-3 (12/32 mg), with no new safety signals identified. However, the CRS profile in this study differed, with more CRS after doses 2, 3, and 4+ and a higher prevalence of recurrent CRS. The Cmax-24h of free ELRA (CV%) after the priming doses were lower than those in MM-3 (107.4 [47%] and 405.1 [72%], respectively). Thus, the priming regimen used in MM-3 remains the optimal regimen for mitigating CRS. Future analyses of ongoing studies will be used to confirm these results. Clinical trial information: NCT05014412 . [Table: see text]

Phase I/II trial of LAVA-1207, a novel bispecific gamma-delta T-cell engager alone, or with low dose IL-2 or pembrolizumab, in metastatic castration resistant prostate cancer (mCRPC).

TPS2672 Background: LAVA-1207 is a humanized bispecific antibody that binds with high affinity to the Vδ2 chain of Vγ9Vδ2-T cells and to prostate-specific membrane antigen (PSMA). It comprises a heterodimer of two fusion proteins, each consisting of a VHH linked to a human IgG1 Fc domain. Preclinical evidence demonstrates that, upon binding both targets, LAVA-1207 leads to potent Vγ9Vδ2-T cell degranulation and cytolytic activity against PSMA-expressing prostate cancer cells. IL-2 is an immune modulator which has been shown to support expansion of activated Vγ9Vδ2-T cells. PD-1 is an inhibitory immune checkpoint receptor that can dampen (Vγ9Vδ2-) T cell reactivity, suggesting that pembrolizumab could potentiate the effect of LAVA-1207. Methods: This trial is a phase 1/2a open label study with a 3+3 design in patients with refractory mCRPC to assess the safety of LAVA-1207 alone or with low dose IL-2 or with pembrolizumab, and to determine the recommended Phase 2a dose (RP2D). Secondary objectives include evaluation of pharmacokinetics, pharmacodynamics, immunogenicity, and preliminary antitumor activity. Exploratory endpoints include evaluation of the effect of study treatment on circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA). LAVA-1207 is administered IV every two weeks. Two parallel cohorts assessing LAVA-1207 with low dose subcutaneous IL-2 have been implemented: (1) single IL-2 administration and (2) three IL-2 administrations on consecutive days per cycle for up to four cycles. An additional dose escalation arm evaluates LAVA-1207 in combination with pembrolizumab, 400mg Q6W, IV. Patients with mCRPC that have failed at least one prior AR therapy and taxane-based chemotherapy (unless deemed medically unsuitable to receive a taxane) will be enrolled on the study. Patients should have progressive disease either by PSA or by RECIST 1.1 or appearance of 2 or more bone metastases. Patients must have ECOG performance status of 0-1. PSMA-PET is performed at baseline. Paired biopsies are requested to further assess LAVA-1207 activity. Dose escalation is ongoing. Expansion arm(s) will be included based on available data from part 1 of the study and may include one or more of LAVA-1207, LAVA-1207 with low dose IL-2, or LAVA-1207 in combination with pembrolizumab. Clinical trial information: NCT05369000 .

A phase II study of cadonilimab plus mFOLFIRINOX as induction therapy for locally advanced pancreatic adenocarcinoma (LAPC).

TPS4213 Background: Locally advanced pancreatic adenocarcinoma (LAPC) constitutes a significant proportion of pancreatic cancer, which ranks among the most lethal malignancies globally. Treatment options specifically tailored for LAPC patients (pts) are scarce, and chemotherapy alone yields limited efficacy. Various studies have provided supportive evidence for the synergistic effects of combining immunotherapy with chemotherapy in the context of pancreatic cancer. Cadonilimab, a novel recombinant humanized bispecific antibody, holds the capability to concurrently inhibit PD-1 and CTLA-4 pathways, thereby restoring T-cell immune response to the tumor. This study aims to assess the efficacy and safety of combining cadonilimab with modified FOLFIRINOX for the treatment of LAPC. Methods: This ongoing phase II trial is enrolling pts with histologically or cytologically confirmed unresectable LAPC who have an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0-1 and have not previously received systemic anti-tumor therapy. Eligible pts will be administered cadonilimab (6mg/kg, intravenous drip, Day 1, every 2 weeks) plus mFOLFIRINOX (oxaliplatin 85mg/m2, Day 2 + leucovorin 400mg/ m2, Day 2 + irinotecan 150mg/ m2, Day 2 + 5-fluorouracil 2,400mg/ m2, continuous infusion for 46 hours) for a total of 4 cycles (8 weeks). After the completion of every 4 treatment cycles, pts will undergo imaging examinations of tumor lesions. Pts will receive treatment continuously until surgical resection, disease progression, intolerable toxic reactions, initiation of new anticancer drug treatments, withdrawal from the study, death, or loss of follow-up. Following the 12th cycle of treatment, maintenance treatment will consist of capecitabine or S-1 in combination with cadonilimab. The primary endpoint of this study was the R0/R1 resection rate. The main secondary endpoints include the objective response rate (ORR) per RECIST 1.1, progression-free survival (PFS), overall survival (OS), and safety assessments. Additionally, pts will undergo peripheral blood next-generation sequencing (NGS) panel analysis before and after treatment to investigate the correlation between circulating tumor DNA (ctDNA) changes, surgical decisions, and prognosis. Enrollment is ongoing. Clinical trial information: NCT06153368 .

Preliminary results from a multi-center phase Ib/II study of RC48-ADC combined with tislelizumab as neoadjuvant treatment in patients with HER2 positive locally advanced muscle-invasive urothelial bladder cancer (Hope-03).

e16595 Background: To evaluate the safety and efficacy of RC48-ADC, a humanized anti-HER2 antibody conjugated with monomethyl auristatin E, and tislelizumab, a PD-1 antibody, as a novel neoadjuvant treatment combination in patients with HER2 positive locally advanced muscle-invasive bladder cancer (MIBC). The study design has been presented at 2022 ESMO Asia meeting. The preliminary results would be reported this time. Methods: This is a Ib/II, multi-center, open-label, single-arm study (ChiECRCT20210564). 51 patients with pathological and imaging diagnosed cT2-4bN0-3M0-1a HER2 positive MIBC will be included. RC48-ADC is given every 2 weeks with a maximum dose of 120mg intravenously, and tislelizumab is given every three weeks at the dose of 200mg intravenously. Treatment efficacy will be performed by imaging and transurethral resection of tumors after the neoadjuvant treatment. Patients without disease progression will receive radical cystectomy or bladder-sparing therapies based on individual risk profiles and preferences. The primary endpoints are clinical complete remission rate (cCR, T0/Ta/Tis), pathological complete remission rate (pCR) and safety. The secondary endpoints are disease control rate (DCR), overall survival (OS), local recurrence free survival (LRFS), distant metastasis free survival (DMFS) and quality of life. Results: Until now, 18 patients were included successfully, with 3 female patients and 15 male patients. And the median age was 64.47 years old. Of them, 7 patients were HER2(2+), and 11 patients were HER2(3+). The clinical stages were T2-4aN0-3M1a. Sixteen patients had the primary efficacy evaluation by now. After the neoadjuvant treatment, 7 patients were T0, 4 patients Tis, 2 patients partial response (PR), 2 patients stable disease (SD) and 1 patient suffered from progress of local disease. Hence the cCR rate was 68.75%, and the DCR was 90.91%. Fourteen patients chose radiotherapy as bladder-sparing therapy and no evidence of tumor in 6 patients who received treatment efficacy after radiotherapy. Two patients received radical cystectomy and pT3N0M0 was achieved for both. No patient died so far. For safety analysis, 4 patients suffered from immune-related adverse event, namely, grade 2 myositis, grade 1 elevated transaminase and grade 1 hyperthyroidism which led to treatment interruption of tislelizumab. And 10 patients experienced RC48-ADC related toxicities, including grade 1 elevated transaminase, grade 1 erythra and grade 1 paresthesia. No treatment related dose reduction happened. Conclusions: The novel neoadjuvant combination of RC48-ADC and tislelizumab showed promising down stage efficacy in patients with HER2 positive locally advanced MIBC and the toxicities were manageable, which would be verified by the final analysis. Clinical trial information: ChiECRCT20210564.

Expression of Concern: Human Anti-CXCR4 Antibodies Undergo VH Replacement, Exhibit Functional V-Region Sulfation, and Define CXCR4 Antigenic Heterogeneity.

Expression of Concern: Human Anti-CXCR4 Antibodies Undergo VH Replacement, Exhibit Functional V-Region Sulfation, and Define CXCR4 Antigenic Heterogeneity.

First-in-human study of ZGGS15, a dual specific antibody targeting LAG-3 and TIGIT, as monotherapy in patients with advanced solid tumors.

e14678 Background: ZGGS15 is a recombinant humanized bispecific antibody composed of a monoclonal antibody against LAG-3 and TIGIT. It can specifically bind LAG-3 and TIGIT. It reverses LAG-3 and TIGIT immune suppression to T and NK cells, relieves suppression of Treg to T and NK cells, promotes the activation and proliferation of T and NK cells, and cytokines release. ZGGS15 restores T and NK cell functions to kill tumor cells. In non-clinical studies, we found that ZGGS15 had significant anti-tumor effects and synergistic anti-tumor effects with Anti-PD-1 antibody. Therefore, we conducted a Phase 1 clinical study to assess the tolerability, safety, and preliminary efficacy of this drug as monotherapy in patients with advanced solid tumors. Methods: During the dose escalation stage, an accelerated titration design (ATD) in the first dose (1 subject if ≤Grade 2 treatment-related adverse event occurred) and the standard "3+3" design in the rest doses were used. Subjects were patients with advanced solid tumors who failed to the available standard treatments. The dose groups were set from 0.3 to 30 (0.3, 1, 3, 10, 20, 30) mg/kg, intravenous infusion, once every 3 weeks. The first 21-day period was defined as the dose-limiting toxicity (DLT) observation period. Subjects could continue to receive ZGGS15 until treatment discontinuation criteria were met. Tumor response was assessed by RECIST1.1 and iRECIST. Pharmacokinetics (PK) and receptor occupancy (RO) profiles were also assessed in this study. Results: A total of 12 patients (4 males and 8 females) completed the DLT observation in the first four dose groups (0.3 to 10 mg), with a median age of 57 years. Eight (66.7%) of them received at least 3 lines of antineoplastic therapies, and five (41.7%) have been exposed to PD-1 or PD-L1 inhibitors. There was no DLT event observed. Thirty-eight treatment-related adverse events (TRAEs) occurred. Up to now, TRAEs were all grade 1 ~ 2. The most frequent TRAEs were proteinuria (33.3%, 4/12), hypokalemia (25%, 3/12), hypoalbuminemia (25%, 3/12), and hypertriglyceridemia (25%, 3/12). The Cmax and AUC increased from 0.3-1 mg/kg approximately in dose proportion. Nearly complete and sustained RO of T and NK cells in PBMCs was observed at 1 mg/kg dose of ZGGS15 for at least 3 weeks. Conclusions: The first four dose levels of ZGGS15 were very well tolerated. A good PK profile, and a long-lasting RO were observed in this escalation study. It is anticipated that this product could provide an additional benefit only when use in combination with an anti-PD-1 antibody. Clinical trial information: NCT05864573 .

Updated safety and antitumor activity of BB-1701 from study 101 in the multiple dose level cohort of patients with locally advanced/metastatic HER2-low expressing breast cancer.

1110 Background: BB-1701 is an antibody-drug conjugate (ADC) consisting of a humanized anti-HER2 antibody and eribulin. After BB-1701 is internalized in HER2 expressing cancer cells, free eribulin is cleaved from the ADC by cathepsin b and causes cytotoxicity to cancer cells. The neighboring cells are affected with bystander effects, like cytotoxicity on tumor cells and non-cytotoxic effects on microenvironment by free eribulin. Here, we report updated results from the ongoing cohort expansion of the first-in-human phase I study (NCT 04257110). Methods: Patients enrolled were ≥18 years of age; had confirmed locally advanced/metastatic HER2 low-expressing (IHC 2+ and FISH negative, or IHC 1+; tested before enrollment) breast cancer; disease progression after ≥2 lines of prior standard therapies; an ECOG PS &lt;2; and measurable lesion(s) (per RECIST v1.1). Four dose levels of BB-1701 (1.0, 1.2, 1.4 and 1.6 mg/kg) were administered during the cohort expansion. Results: As of 31 January 2024, 40 pts with HER2 low-expressing breast cancer were enrolled, 5 at 1.0 mg/kg, 20 at 1.2 mg/kg, 5 at 1.4 mg/kg and 10 at 1.6 mg/kg. Median age was 55 years, 97.5% ps were female, and 30.0%/70.0% pts had ECOG PS 0/1. The median number of prior lines of systemic therapy was 3. The most common (≥20%) all grade treatment-related adverse events (TRAEs) were peripheral neuropathy, AST increased, ALT increased, anemia, WBC decreased and hypertriglyceridemia. The most common (≥ 5%) grade 3 TRAEs were peripheral neuropathy and peripheral sensory neuropathy. There were no grade 4 or grade 5 events. Four treatment related serious adverse events were peripheral sensory neuropathy, anemia, spinal compression fracture and infusion related reaction. One patient discontinued BB-1701 treatment due to peripheral neuropathy. Of the 40 pts, 38 were evaluable for efficacy. At 1.0 mg/kg dose level, there were 2 partial response (PR), 2 stable disease (SD), with disease control rate (DCR) of 80.0% and 6-month PFS rate of 20%. At 1.2 mg/kg dose level, there were 5 PR, 11 SD with DCR of 88.9% and 6-month PFS rate of 50%. At 1.4 mg/kg dose level, there were 2 PR, 2 SD with DCR of 80.0% and 6-month PFS rate of 40%. At 1.6 mg/kg dose level, there were 1 complete response (CR), 2 PR with objective response rate of 30.0%, DCR of 60.0% and 6-month PFS rate of 50%. Among the 10 pts at 1.6 mg/kg dose level, 1 pt who had previously been treated with disitamab vedotin maintain CR and has been treated by BB-1701 for 9 months, and 1 pt who had previously been treated with trastuzumab deruxtecan maintain PR and has been treated by BB-1701 for 12 months. Conclusions: BB-1701 shows promising antitumor activity and a manageable safety profile in HER2 low-expressing breast cancer, including patients who received prior anti-HER2 ADCs. Clinical trial information: NCT04257110 .

ADU-1604, a novel CTLA-4 blocking antibody, to modulate pharmacodynamic markers in patients with PD1 relapse/refractory melanoma.

9552 Background: Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is a negative regulator of T-cell responses, also known as an immune checkpoint. The clinical relevance of CTLA-4 blockade was demonstrated by the approval of ipilimumab for the treatment of melanoma, both in the adjuvant as well as metastatic settings. ADU-1604 is a humanized hIgG1 CTLA-4 antagonist antibody. ADU-1604 binds a unique epitope on CTLA-4 demonstrating, in contrast to ipilimumab full blockade of both CD80 and CD86 interactions. In vitro and in vivo ADU-1604 demonstrates at least as potent efficacy as compared to ipilimumab, was well tolerated in non-human primates and demonstrated enhanced immunogenicity against hepatitis B vaccine in non-human primates. Methods: This is a phase 1, first-in-human (FIH), two-part, open-label clinical trial of intravenous (IV) administration of ADU-1604 given as monotherapy in subjects with advanced-stage, relapsed/refractory melanoma who relapsed or were refractory to a prior anti-PD-1/PD-L1 therapy. Main endpoints are safety of ADU-1604 monotherapy, pharmacokinetics, pharmacodynamics (upregulation of ICOS and Ki-67 on circulation CD4+ T cells and ALC, CD4+ and CD8+ T cells) as well as preliminary clinical efficacy. 20 subjects received escalating doses of ADU-1604 IV (25, 75, 225, 450 mg flat dose) Q3W. In the dose expansion part up to 20 additional patients will be treated with 225 mg dose to confirm recommended Phase 2 dose (RP2D). Safety and preliminary efficacy of ADU-1604 monotherapy in PD1 relapsed/refractory melanoma patients will be evaluated. The study was initiated in June 2022. Results: ADU-1604 was demonstrated to have a typical pharmacokinetic behavior for a human IgG1 antibody and similar exposure was observed as described for ipilimumab. Administration of ADU-1604 in cycle 1 and 2 showed a dose-dependent modulation of ICOS and Ki-67 on circulating CD4+ T cells. Similarly, in cycles 3 and 4 a dose-dependent increase of ALC and CD4+ and CD8+ T cells was detected. Notably, no DLTs across the 25, 75, 225 and 450 mg dose level have occurred. Of the patients treated at 225 and 450 mg dose levels (N=6 at 225 mg and N=6 at 450 mg), two Grade 2 severe adverse events (both immune-related enterocolitis) and two Grade 3 AESIs (ALT elevation and immune-related gastritis) suggesting that ADU-1604 has a relatively mild safety profile. Two patients at 225 mg and one patient at 450 mg demonstrated clinical efficacy. Conclusions: ADU-1604 Phase 1 dose-escalation data indicates clinical activity in line with what has been observed with other CTLA-4 blocking antibodies. Importantly, no DLTs and very limited safety signals were reported during the study. Dose expansion at 225 mg dose is ongoing in subjects with advanced-stage, relapsed/refractory melanoma who relapsed or were refractory to a prior anti-PD-1/PD-L1 therapy. Clinical trial information: 2021-002623-38 .

Thioredoxin-related transmembrane protein 1 negatively regulates coagulation and phosphatidylserine exposure

BackgroundFive secreted platelet protein disulfide isomerases (PDIs) and 1 transmembrane PDI regulate platelet function and thrombosis. Thioredoxin-related transmembrane protein 1 (TMX1) was the first member of the PDI family found to negatively regulate platelet aggregation and platelet accumulation in vivo. The effect of TMX1 on coagulation is unknown. ObjectivesTo determine the effect of TMX1 on coagulation. MethodsTMX1-/- mice were used to study platelet accumulation and fibrin deposition in vivo in the laser-induced thrombosis injury model. Annexin V deposition at the site of vascular injury was studied using conditional TMX1 knockout mice. Annexin V binding to platelets was studied using human platelets, anti-TMX1 antibodies, and TMX1-deficient platelets. ResultsTMX1-/- mice had increased fibrin deposition that was reversed with infusion of recombinant TMX1. Infusion of recombinant TMX1 inhibited platelet accumulation and fibrin deposition in wild-type mice and inhibited fibrin deposition in β3-null mice. Platelet accumulation is absent in β3-null mice, suggesting that TMX1 inhibits coagulation independently of platelets. Annexin V binding was increased in activated human platelets incubated with an anti-TMX1 antibody and mouse platelets lacking TMX1. Addition of recombinant TMX1 decreased annexin V binding to platelets. Annexin V binding was increased at the site of vascular injury in Tie2-Cre/TMX1fl/fl mice deficient in endothelial cell TMX1. ConclusionTMX1 decreases coagulation at the site of vascular injury and negatively regulates phosphatidylserine exposure on endothelial cells and platelets.