Fc Fusion Protein Research Articles

Long-term clinical outcomes of prophylaxis with an rFVIIIFc or rFIXFc in adults aged ≥50 years with hemophilia A or B

Advances in therapies for hemophilia have led to an increased life expectancy for people with hemophilia. Limited data exist on the aging population of people with hemophilia who face additional challenges of age-related comorbidities. Efmoroctocog alfa (a recombinant factor VIII Fc fusion protein [herein referred to as rFVIIIFc]) and eftrenonacog alfa (a recombinant factor IX Fc fusion protein [rFIXFc]) are extended half-life factor replacements for hemophilia A and B, respectively, with demonstrated long-term safety and efficacy. The objective of this post hoc analysis was to describe long-term outcomes in participants 50+ years of age treated with rFVIIIFc or rFIXFc in pivotal Phase 3 trials and their extension studies: A-LONG (NCT01181128; n=21) and ASPIRE (NCT01454739; n=20 [95%]); B-LONG (NCT01027364; n=26) and B-YOND (NCT01425723; n=16 [62%]). Approximately half of participants (48%) with hemophilia A and 62% of participants with hemophilia B had a comorbidity at baseline. More than half of the participants were taking 1+ concomitant medication at baseline, with arthropathy and joint pain reported as the most common indications. Prophylaxis with rFVIIIFc or rFIXFc in individuals 50+ years of age with hemophilia A or B, respectively, resulted in low annualized bleed rates and improvements in joint health. Positive impacts on health-related quality of life were observed in individuals on either rFVIIIFc or rFIXFc prophylaxis. The results for the older subgroups were consistent with the overall study populations, demonstrating that prophylaxis with rFVIIIFc or rFIXFc provides long-term clinical benefits irrespective of age and presence of target joints in patients with severe hemophilia.

Comparison of the Immunogenicity of the LZ901 Vaccine and HZ/su Vaccine in a Mouse Model.

Herpes zoster (HZ) is an infectious disease caused by the reactivation of varicella zoster virus (VZV), with 68% of cases occurring in adults over 50 years of age. HZ/su (Shingrix®) was approved by the Food and Drug Administration in 2017 for the prevention of HZ in individuals ≥ 50 years of age and showed very good protection from HZ. However, due to the use of the adjuvant AS01B, adverse reactions caused by Shingrix are a concern. Aluminum hydroxide is the most commonly used adjuvant and is widely used in a variety of vaccines. We developed a recombinant zoster vaccine (code: LZ901) consisting of a tetramer of VZV glycoprotein E (gE) and a human Fc fusion protein expressed in CHO cells, an immune complex-like molecule that can be adsorbed with an aluminum hydroxide adjuvant. We compared the immunogenicity of LZ901 with that of HZ/su in BALB/c mice. The results showed that LZ901 induced levels of gE-specific IgG antibodies comparable to those induced by HZ/su, and the results of FAMA titers further demonstrated their similar neutralizing antibody abilities. Most importantly, LZ901 induced higher levels of cell-mediated immunity (CMI) (which plays a decisive role in the efficacy of zoster vaccines) than HZ/su in BALB/c mice. The numbers of cytokine-producing T cells in LZ901-vaccinated mice were significantly greater than those in v-vaccinated mice, and the proportions of CD4+ and CD8+ T cells producing at least two types of cytokines in LZ901-vaccinated mice were significantly greater than those in HZ/su-vaccinated mice.

Combining CD38 antibody with CD47 blockade is a promising strategy for treating hematologic malignancies expressing CD38.

CD38 and CD47 are expressed in many hematologic malignancies, including multiple myeloma (MM), B-cell non-Hodgkin lymphoma (NHL), B-cell acute lymphoblastic leukemia (ALL), and B-cell chronic lymphocytic leukemia (CLL). Here, we evaluated the antitumor activities of CD38/CD47 bispecific antibodies (BsAbs). Five suitable anti-CD38 antibodies for co-targeting CD47 and CD38 BsAb were developed using a 2 + 2 "mAb-trap" platform. The activity characteristics of the CD38/CD47 BsAbs were evaluated using in vitro and in vivo systems. Using hybridoma screening technology, we obtained nine suitable anti-CD38 antibodies. All anti-CD38 antibodies bind to CD38+ tumor cells and kill tumor cells via antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). Five anti-CD38 antibodies (4A8, 12C10, 26B4, 35G5, and 65A7) were selected for designing CD38/CD47 BsAbs (IMM5605) using a "mAb-trap" platform. BsAbs had higher affinity and binding activity to the CD38 target than those to the CD47 target, decreasing the potential on-target potential and off-tumor effects. The CD38/CD47 BsAbs did not bind to RBCs and did not induce RBC agglutination; thus, BsAbs had much lower blood toxicity. The CD38/CD47 BsAbs had a greater ability to block the CD47/SIRPα signal in CD38+/CD47+ tumor cells than IMM01 (SIRPα Fc fusion protein). Through Fc domain engineering, CD38/CD47 BsAbs were shown to kill tumors more effectively by inducing ADCC and ADCP. IMM5605-26B4 had the strongest inhibitory effect on cellular CD38 enzymatic activity. IMM5605-12C10 had the strongest ability to directly induce the apoptosis of tumor cells. The anti-CD38 antibody 26B4 combined with the SIRPα-Fc fusion proteins showed strong antitumor effects, which were better than any of the mono-therapeutic agents used alone in the NCI-H929 cell xenograft model. The CD38/CD47 BsAbs exhibited strong antitumor effects; specifically, IMM5605-12C10 efficiently eradicated all established tumors in all mice. A panel of BsAbs targeting CD38 and CD47 developed based on the "mAb-tarp" platform showed potent tumor-killing ability in vitro and in vivo. As BsAbs had lower affinity for binding to CD47, higher affinity for binding to CD38, no affinity for binding to RBCs, and did not induce RBC agglutination, we concluded that CD38/CD47 BsAbs are safe and have a satisfactory tolerability profile.

IL-15/IL-15Rα-Fc-Fusion Protein XmAb24306 Potentiates Activity of CD3 Bispecific Antibodies through Enhancing T-Cell Expansion.

An insufficient quantity of functional T cells is a likely factor limiting the clinical activity of T-cell bispecific antibodies, especially in solid tumor indications. We hypothesized that XmAb24306 (efbalropendekin alfa), a lymphoproliferative interleukin (IL)-15/IL-15 receptor α (IL-15Rα) Fc-fusion protein, may potentiate the activity of T-cell dependent (TDB) antibodies. The activation of human peripheral T cells by cevostamab, an anti-FcRH5/CD3 TDB, or anti-HER2/CD3 TDB resulted in the upregulation of the IL-2/15Rβ (CD122) receptor subunit in nearly all CD8+ and majority of CD4+ T cells, suggesting that TDB treatment may sensitize T cells to IL-15. XmAb24306 enhanced T-cell bispecific antibody-induced CD8+ and CD4+ T-cell proliferation and expansion. In vitro combination of XmAb24306 with cevostamab or anti-HER2/CD3 TDB resulted in significant enhancement of tumor cell killing, which was reversed when T-cell numbers were normalized, suggesting that T-cell expansion is the main mechanism of the observed benefit. Pretreatment of immunocompetent mice with a mouse-reactive surrogate of XmAb24306 (mIL-15-Fc) resulted in a significant increase of T cells in the blood, spleen, and tumors and converted transient anti-HER2/CD3 TDB responses to complete durable responses. In summary, our results support the hypothesis that the number of tumor-infiltrating T cells is rate limiting for the activity of solid tumor-targeting TDBs. Upregulation of CD122 by TDB treatment and the observed synergy with XmAb24306 and T-cell bispecific antibodies support clinical evaluation of this novel immunotherapy combination.

Ion Mobility-Mass Spectrometry and Collision-Induced Unfolding Rapidly Characterize the Structural Polydispersity and Stability of an Fc-Fusion Protein.

Fc-fusion proteins are an emerging class of protein therapeutics that combine the properties of biological ligands with the unique properties of the fragment crystallizable (Fc) domain of an immunoglobulin G (IgG). Due to their diverse higher-order structures (HOSs), Fc-fusion proteins remain challenging characterization targets within biopharmaceutical pipelines. While high-resolution biophysical tools are available for HOS characterization, they frequently demand extended time frames and substantial quantities of purified samples, rendering them impractical for swiftly screening candidate molecules. Herein, we describe the development of ion mobility-mass spectrometry (IM-MS) and collision-induced unfolding (CIU) workflows that aim to fill this technology gap, where we focus on probing the HOS of a model Fc-Interleukin-10 (Fc-IL-10) fusion protein engineered using flexible glycine-serine linkers. We evaluate the ability of these techniques to probe the flexibility of Fc-IL-10 in the absence of bulk solvent relative to other proteins of similar size, as well as localize structural changes of low charge state Fc-IL-10 ions to specific Fc and IL-10 unfolding events during CIU. We subsequently apply these tools to probe the local effects of glycine-serine linkers on the HOS and stability of IL-10 homodimer, which is the biologically active form of IL-10. Our data reveals that Fc-IL-10 produces significantly more structural transitions during CIU and broader IM profiles when compared to a wide range of model proteins, indicative of its exceptional structural dynamism. Furthermore, we use a combination of enzymatic approaches to annotate these intricate CIU data and localize specific transitions to the unfolding of domains within Fc-IL-10. Finally, we detect a strong positive, quadratic relationship between average linker mass and fusion protein stability, suggesting a cooperative influence between glycine-serine linkers and overall fusion protein stability. This is the first reported study on the use of IM-MS and CIU to characterize HOS of Fc-fusion proteins, illustrating the practical applicability of this approach.

The promising feeder-free allogenic NK cell therapy: Clinical outcomes of GIC-102 monotherapy (GIC-102101) and synergistic potential with GI-101 (CD80-IgG4 Fc-IL2v) in advanced solid tumors and hematologic malignancies.

e14526 Background: The allogeneic Natural Killer (NK) cell therapy derived from healthy donors may overcome the short lifespan and dysfunctional anti-tumor activity of current autologous approach. This limitation often restricts treatment efficacy and necessitating high dosages and frequent infusions. GIC-102, non-engineered / feeder-free, highly potent allogeneic NK cell derived from healthy donors, is a promising alternative. Here, we present the clinical outcomes from the Phase 1 study of GIC-102, along with nonclinical evidence demonstrating outstanding pharmacokinetics (PK) and pharmacodynamics (PD) when used in combination with a novel bi-specific Fc fusion protein, GI-101 (CD80-IgG4 Fc-IL2v/NCT04977453/KEYNOTE-B59). Methods: GIC-102101, a first-in-human study, evaluated GIC-102 monotherapy at doses of 1x109 QW and 3x109 QW in patients with advanced solid tumors or hematologic malignancies. A lympho-conditioning strategy using cyclophosphamide (300 mg/m2) and fludarabine (30 mg/m2) was implemented every two cycles before GIC-102 treatment. The study employed a conventional 3+3 dose escalation scheme. The primary endpoint was to determine the safety and tolerability of GIC-102, with tumor response assessed as secondary endpoints. Additionally, the PK/PD profile of GIC-102 in combination with GI-101 was evaluated in a mouse model. Results: As of December 31, 2023, six patients have been treated with GIC-102 monotherapy including two patients with Non-Hodgkin lymphoma (NHL), and four patients with metastatic colorectal cancer (CRC). The median number of prior treatments for patients with CRC and NHL was 4 and 6, respectively. No dose limiting toxicities (DLTs) were observed and maximum tolerated dose was not reached. Treatment-related adverse events (TRAEs) occurred in 5 patients (83%), with the majority being associated with the lympho-conditioning procedure; hyponatremia, neutropenia, lymphopenia and anemia. The best overall response was complete response (CR) in 1/6 patient (NHL) and stable disease (SD) in 4/6 patients (3 CRC, 1 NHL). Treatment for 1 CR (NHL) and 2 SD (CRC) is ongoing (for NHL, 215+ days/for CRC, 160+ days and 153+ days). The in-vivo study of GIC-102 in combination with GI-101 showed significantly enhanced anti-tumor activity and in-vivo NK cell proliferation lasting up to 4 weeks. Conclusions: The GIC-102, feeder-free allogeneic NK cell, was well tolerated without DLTs and demonstrated early promise in efficacy in patients for advanced solid tumors and hematologic malignancy. Further clinical investigation of GIC-102 in combination with GI-101, bi-specific Fc fusion protein, is currently ongoing. Clinical trial information: NCT05880043 .

A phase I clinical study to evaluate the safety, tolerability, immunogenicity, pharmacokinetics and preliminary efficacy of SCB-219M in patients with chemotherapy-induced thrombocytopenia (CIT): An interim analysis.

e15015 Background: CIT is a serious, chemotherapy-associated complication observed in a wide range of cancer patients with various types of cancer. Incidence of CIT can occur in about 15-25% of patients undergoing standard chemotherapy regiments with platinum, taxane and/or gemcitabine-based regimen. CIT can lead to chemotherapy dose delay or dose reduction, and potentially bleeding events. Currently, there is no FDA-approved therapy for CIT. SCB-219M, a thrombopoietin receptor agonist (TPO-RA) mimetic bispecific Fc-fusion protein produced from CHO cells can efficiently raise PLT count under normal and pathological conditions in laboratory animals. Methods: This is a single-arm, multi-center, open-label, dose escalation Phase Ia clinical study to evaluate the safety, tolerability, and immunogenicity, PK profile and preliminary efficacy of a single ascending dose of SCB-219M administered one day after a chemotherapy in prior CIT patients with malignant solid tumors and lymphoma. The study design of accelerated titration combined with "3 + 3" is used, and the number of subjects planned to enroll is 12 to be assigned to 4 cohorts with 2, 6, 10 and 15 mg/kg subcu administration of SCB-219M, respectively. Enrollment criteria include episode of CIT experienced (<75 × 109/L in PLT count) in prior cycle of chemotherapies and PLT count has recovered to >75 × 109/L prior to initiation of this study . The chemotherapy regimen allowed include either mono or combination chemotherapy (including targeted therapy and/or immunotherapy). The observation period of dose-limiting toxicities (DLTs) is 21 days. Chemotherapy is planned at each study site. There will be no change in the planned dose or frequency of chemotherapy in the study. Results: As of Dec 20, 2023, 9 prior CIT patients including 3 at 15 mg/kg were enrolled. SCB-219M was well tolerated. There were no SAEs or AESIs (Adverse Event of Special Interest) observed. DLT was not reached. A favorable PK profile, in particular in serum availability (AUC) and half-life (T1/2) was obtained. All 9 prior CIT patients in the study maintained PLT counts >75 x 109/L from 1-week following chemotherapies with a single dose of SCB-219M, and durable responses experienced through at least 3 weeks. Conclusions: In this interim analysis, drug safety, PK profile and durable efficacy are expected to support SCB-219M dosing interval of ≥2-weeks or a single dosing regimen within a chemotherapy cycle. Accordingly, a Phase Ib trial evaluating repeated dosing of SCB-219M is planned to initiate in 2024. Clinical trial information: NCT05426369 .

#1342 Updated results from the RUBY-3 study of povetacicept, an enhanced dual BAFF/APRIL antagonist, in autoantibody-associated glomerulonephritis

Abstract Background and Aims Inhibition of BAFF and/or APRIL has shown promise in IgA nephropathy (IgAN), systemic lupus erythematosus (SLE), lupus nephritis (LN), and primary membranous nephropathy (pMN), and has the potential to exert a disease-modifying effect. Povetacicept (ALPN-303) is an Fc fusion protein of a variant TACI domain engineered for more potent dual BAFF/APRIL inhibition than wild-type TACI or anti-BAFF or anti-APRIL antibodies. In a previous report, povetacicept 80 mg every 4 weeks was initially well tolerated and demonstrated promising, clinically meaningful reductions in urine protein to creatinine ratio (UPCR) and Gd-IgA1 in participants with IgAN (Tumlin J, et al. Poster TH-PO1125 presented at ASN 2023). Updated data are reported here. Method RUBY-3 is an open-label, multiple ascending dose, phase 1b/2a study of povetacicept 80 or 240 mg administered subcutaneously once every 4 weeks. Eligible participants are aged ≥18 years with biopsy-confirmed IgAN, LN, or pMN and on maximally tolerated ACE inhibitor/ARB therapy, with well-controlled blood pressure, and disease-specific immunosuppressive therapy where applicable. The primary objective is safety; secondary objectives include pharmacokinetics, pharmacodynamics, immunogenicity, biomarkers, and efficacy. Results As of 1 Dec 2023, 12 participants with IgAN have enrolled and received povetacicept 80 mg, with 7 (58%) having received ≥24 weeks of treatment. Povetacicept continues to be well tolerated, with the majority of treatment-emergent adverse events being of low grade. There have been no incidences of severe hypogammaglobulinemia (IgG <3 g/L) or severe infections. Povetacicept 80 mg was associated with a UPCR reduction of 52.6% at 24 weeks (n = 7). Reductions in Gd-IgA1, stable renal function, and pharmacodynamically expected decreases in immunoglobulin levels were also observed. Additional results from the 80 mg cohort with longer duration of follow-up, as well as initial results from the 240 mg dosing cohort, are planned to be presented. Conclusion Povetacicept remains well tolerated with multiple dosing and continues to demonstrate very promising activity in IgAN, strongly supporting further study in IgAN as well as other glomerulonephritis and autoantibody-associated diseases.

Development of nanoparticle vaccines utilizing designed Fc-binding homo-oligomers and RBD-Fc of SARS-CoV-2

The Fc-fused receptor binding domain (RBD-Fc) vaccine for SARS-CoV-2 has garnered significant attention for its capacity to provide effective and specific immune protection. However, its immunogenicity is limited, highlighting the need for improvement in clinical application. Nanoparticle delivery has been shown to be an effective method for enhancing antigen immunogenicity. In this study, we developed bivalent nanoparticle recombinant protein vaccines by assembling the RBD-Fc of SARS-CoV-2 and Fc-binding homo-oligomers o42.1 and i52.3 into octahedral and icosahedral nanoparticles. The formation of RBD-Fc nanoparticles was confirmed through structural characterization and cell binding experiments. Compared to RBD-Fc dimers, the nanoparticle vaccines induced more potent neutralizing antibodies (nAb) and stronger cellular immune responses. Therefore, using bivalent nanoparticle vaccines based on RBD-Fc presents a promising vaccination strategy against SARS-CoV-2 and offers a universal approach for enhancing the immunogenicity of Fc fusion protein vaccines.

A recombinant adeno-associated virus expressing secretory TGF-β type Ⅱ receptor inhibits triple-negative murine breast cancer 4T1 cell proliferation and lung metastasis in mice

To investigate the effects of an adeno-associated virus (AAV2) vector expressing secretory transforming growth factor-β (TGF-β) type Ⅱ receptor (sTβRⅡ) extracellular domain-IgG2a Fc fusion protein (sTβRⅡ-Fc) on proliferation and migration of triple-negative murine breast cancer 4T1 cells in mice. The pAAV-sTβRⅡ-Fc vector expressing sTβRⅡ-Fc fusion protein constructed by molecular cloning, the capsid protein-expressing vector pAAV2 and the helper vector were co-transfected into HEK 293T cells to prepare the recombinant AAV2-sTβRⅡ virus, which was purified by density gradient centrifugation with iodixanol. Western blotting was used to examine the effects of AAV-sTβRⅡ virus on Smad2/3 phosphorylation in 4T1 cells and on expression levels of E-cadherin, vimentin and p-Smad2/3 in 4T1 cell xenografts in mice. BALB/c mice bearing subcutaneous xenografts of luciferase-expressing 4T1 cells received intravenous injections of AAV-sTβRⅡ virus, AAV-GFP virus or PBS (n=6) through the tail vein, and the proliferation and migration of 4T1 cells were analyzed with in vivo imaging. Ki67 expression in the tumor tissues and sTβRⅡ protein expressions in mouse livers were detected with immunohistochemistry and immunofluorescence staining, and tumor metastases in the vital organs were examined with HE staining. The recombinant pAAV-sTβRⅡ-Fc vector successfully expressed sTβRⅡ in HEK 293T cells. Infection with AAV2-sTβRⅡ virus significantly reduced TGF-β1-induced Smad2/3 phosphorylation in 4T1 cells and effectively inhibited proliferation and lung metastasis of 4T1 xenografts in mice (P<0.05). In the tumor-bearing mice, intravenous injection of AAV-sTβRⅡ virus significantly increased E-cadherin expression, reduced vimentin and Ki67 protein expressions and Smad2/3 phosphorylation level in the tumor tissues (P<0.05 or 0.01), and induced liver-specific sTβRⅡ expression without causing body weight loss or heart, liver, spleen or kidney pathologies. The recombinant AVV2 vector encoding sTβRⅡ extracellular domain is capable of blocking the TGF-β signaling pathway to inhibit the proliferation and lung metastasis of 4T1 cells in mice.

Comprehensive analysis and characterization of glycan pairing in therapeutic antibodies and Fc-containing biotherapeutics: Addressing current limitations and implications for N-glycan impact

N-glycosylation of the Fc part is a (critical) quality attribute of therapeutic antibodies and Fc-containing biotherapeutics, that impacts their stability, immunogenicity, pharmacokinetics, and effector functions. Current glycosylation analysis methods focus on the absolute amounts of glycans, neglecting the apparent glycan distribution over the entirety of proteins. The combination of the two Fc N-glycans, herein referred to as glyco-pair, therefore remains unknown, which is a major drawback for N-glycan impact assessment. This study presents a comprehensive workflow for the analysis and characterization of Fc N-glycan pairing in biotherapeutics, addressing the limitations of current glycosylation analysis methods. The applicability of the method across various biotherapeutic proteins including antibodies, bispecific antibody formats, and a Fc-Fusion protein is demonstrated, and the impact of method conditions on glycan pairing analysis is highlighted. Moreover, the influence of the molecular format, Fc backbone, production process, and cell line on glycan pairing pattern was investigated. The results underscore the significance of comprehensive glycan pairing analysis to accurately assess the impact of N-glycans on important product quality attributes of therapeutic antibodies and Fc-containing biotherapeutics.

Broadly Reactive Nanobody Targeting the H3 Hemagglutinin of the Influenza A Virus.

Monoclonal antibodies and recombinant antibody fragments are a very promising therapeutic tool to combat infectious diseases. Due to their unique paratope structure, nanobodies (VHHs) hold several advantages over conventional monoclonal antibodies, especially in relation to viral infections. Influenza A viruses (IAVs) remain a major threat to public health. The hemagglutinin (HA) protein is the main protective and immunodominant antigen of IAVs. In this study, three broadly reactive nanobodies (D9.2, E12.2, and D4.2) to H3N2 influenza strains were isolated and Fc-fusion proteins (VHH-Fcs) were obtained and characterized in vitro. This modification improved the nanobodies' binding activity and allowed for their interaction with a wider range of strains. The D9.2-Fc antibody showed a 100% protection rate against mortality in vivo in a mouse lethal model. Furthermore, we demonstrated that the observed protection has to do with Fc-FcγR interactions. These results indicate that D9.2-Fc can serve as an effective antiviral agent against the H3N2 influenza infection.

Effect of 4-phenylbutyrate addition timing on titer of Fc-fusion protein in Chinese hamster ovary cell cultures

Effect of 4-phenylbutyrate addition timing on titer of Fc-fusion protein in Chinese hamster ovary cell cultures

Tumor expressed BCAM impedes anti-tumor T cell immunity and can be targeted therapeutically

Abstract The significant albeit limited clinical benefit of therapeutic targeting of checkpoint inhibitors highlights the need for immunological understanding of cancer escape from anti-tumor immunity to develop novel and better therapeutics. We surmise that many protein-protein interactions that regulate T cell immunity have yet to be identified. Using human gain-of-function genetic screens, thousands of proteins were screened for their ability to inhibit primary human T cell function. B Cell Adhesion Molecule (BCAM) was identified as a potent inhibitor of T cell proliferation and cytotoxic T cell (CTL) ability to kill human tumors in vitro. Tumor cell surface BCAM inhibited anti-tumor immunity promoted tumor growth in vivo. Blockade with decoy soluble BCAM protein fused to a either a silenced or functional Fc domain (BCAM Fc fusion protein) was able to promote T cell anti-tumor immunity and reduce tumor growth in syngeneic and humanized CDX tumor models. Moreover, tumor BCAM interaction with known ligand Laminin-a5 (LAMA5) resulted in increased production of LAMA5 that was associated with ECM modifications and potent exclusion of T cells from the tumor microenvironment (TME). BCAM Fc disruption of BCAM-LAMA5 interactions resulted in decreased LAMA5 production, increased T cell infiltration and decreased tumor growth. These data support a multi-pronged role for BCAM in anti-tumor T cell suppression and exclusion that can be targeted therapeutically.

Impact of fed-batch process intensification on the productivity and product quality of two CHO cell lines expressing unique novel molecular format proteins.

While monospecific antibodies have long been the foundational offering of protein therapeutics, recent advancements in antibody engineering have allowed for the development of far more complex antibody structures. Novel molecular format (NMF) proteins, such as bispecific antibodies (BsAbs), are structures capable of multispecific binding, allowing for expanded therapeutic functionality. As demand for NMF proteins continues to rise, biomanufacturers face the challenge of increasing bioreactor process productivity while simultaneously maintaining consistent product quality. This challenge is exacerbated when producing structurally complex proteins with asymmetric modalities, as seen in NMFs. In this study, the impact of a high inoculation density (HID) fed-batch process on the productivity and product quality attributes of two CHO cell lines expressing unique NMFs, a monospecific antibody with an Fc-fusion protein and a bispecific antibody, compared to low inoculation density (LID) platform fed-batch processes was evaluated. It was observed that an intensified platform fed-batch process increased product concentrations by 33 and 109% for the two uniquely structured complex proteins in a shorter culture duration while maintaining similar product quality attributes to traditional fed-batch processes.

Cost-Effectiveness of Recombinant FactorIX Fc Prophylaxis and Recombinant FactorIX On-Demand Treatment in Patients with HaemophiliaB Without Inhibitors.

Recombinant factor IX (rFIX) and recombinant FIX Fc fusion protein (rFIXFc) are standard half-life and extended half-life FIX replacement therapies, respectively, and represent established treatment options indicated for adults and children with haemophiliaB. These FIX replacement therapies can be administered as prophylaxis (to prevent bleeding) or 'on-demand' (to stop bleeding). This analysis aimed to estimate the cost-effectiveness of once-weekly prophylaxis with rFIXFc versus on-demand treatment with rFIX in patients with haemophiliaB without inhibitors in the Italian healthcare setting. A Markov model was developed to assess a hypothetical cohort of adolescent or adult male patients (≥ 12years) with haemophiliaB (FIX level of ≤ 2IU/dL) without inhibitors. Model inputs were derived from the pivotal phase3 clinical studies for rFIXFc and rFIX, published literature and assumptions when published data were unavailable. The model employed a lifelong time horizon with 6-monthly transitions between health states, and it estimated total costs, total quality-adjusted life years (QALYs), number of bleeds, number of surgeries and incremental cost-effectiveness ratio. rFIXFc prophylaxis was associated with lower total costs per patient (€5,308,625 versus €6,564,510) and greater total QALYs per patient (15.936 versus 11.943) compared with rFIX on-demand; rFIXFc prophylaxis was therefore the dominant treatment strategy. The model also demonstrated that rFIXFc prophylaxis was associated with fewer incremental bleeds (- 682.29) and surgeries (- 0.39) compared with rFIX on-demand. rFIXFc prophylaxis provides improved health outcomes and lower costs, and represents a cost-effective treatment option compared with rFIX on-demand for adolescent and adult male patients with haemophiliaB. This comparative assessment of cost-effectiveness should help to inform both clinicians and healthcare policy makers when making treatment decisions for patients with haemophiliaB.

Quantification of Biopharmaceutically Relevant Nonionic Surfactant Excipients Using Benchtop qNMR.

Nonionic surfactant excipients (NISEs) are commonly added to biologics formulations to mitigate the effects of stress incurred by the active biotherapeutic during manufacturing, transport, and storage. During manufacturing, NISEs are added by dilution of a stock solution directly into a protein formulation, and their accurate addition is critical in maintaining the quality and integrity of the drug product and thus ensuring patient safety. This is especially true for the common NISEs, polysorbates 20 and 80 (PS20 and PS80, respectively) and poloxamer 188 (P188). With the increasing diversity of biologic modalities within modern pharmaceutical pipelines, there is thus a critical need to develop and deploy convenient and user-accessible analytical techniques that can rapidly and reliably quantify these NISEs under biopharmaceutically relevant conditions. We thus pursued 60 MHz benchtop quantitative NMR (qNMR) as a nondestructive and user-friendly analytical technique for the quantification of PS20, PS80, and P188 under such conditions. We demonstrated the ability of benchtop qNMR (1) to quantify simulated PS20, PS80, and P188 stock solutions representative of those used during the drug substance (DS) formulation step in biomanufacturing and (2) to quantify these NISEs at and below their target concentrations (≤0.025% w/v) directly in biologics formulations containing histidine, sucrose, and one of three biotherapeutic modalities (monoclonal antibody, antibody-drug conjugate, and Fc-fusion protein). Our results demonstrate that benchtop qNMR offers a fit-for-purpose, reliable, user-friendly, and green analytical route by which NISE of interest to the biopharmaceutical industry may be readily and reliably quantified. We conclude that benchtop qNMR has the potential to be applied to other excipient formulation components in the presence of various biological modalities as well as the potential for routine integration within analytical and QC laboratories across pharmaceutical development and manufacturing sites.

Covid-19 Prevention and Treatment by Targeting Fc-fusion Proteins: An Experience to Fight Emerging Diseases.

The coronavirus disease 2019 (Covid-19) pandemic has been considered a major threat to human health. Effective therapeutic approaches are urgently required. Spike protein and the Angiotensin-converting enzyme 2 (ACE2) receptors have critical roles in SARS-CoV-2 infection. As a result, these two proteins are considered potential targets for the development of a wide variety of biotherapeutics and vaccines for controlling Covid-19. The fusion proteins have desirable medicinal properties, including high serum half-life, stability, and solubility in the body. Moreover, other Fc-fusion proteins used to treat other diseases have no known side effects. These Fc-fusion proteins are valuable biopharmaceuticals and have been proposed as therapeutic candidates for the treatment and prevention of Covid-19 owing to their potential therapeutic benefits.

Kinetic modeling of the plasma pharmacokinetic profiles of ADAMTS13 fragment and its Fc-fusion counterpart in mice.

Introduction: Fusion of the fragment crystallizable (Fc) to protein therapeutics is commonly used to extend the circulation time by enhancing neonatal Fc-receptor (FcRn)-mediated endosomal recycling and slowing renal clearance. This study applied kinetic modeling to gain insights into the cellular processing contributing to the observed pharmacokinetic (PK) differences between the novel recombinant ADAMTS13 fragment (MDTCS) and its Fc-fusion protein (MDTCS-Fc). Methods: For MDTCS and MDTCS-Fc, their plasma PK profiles were obtained at two dose levels following intravenous administration of the respective proteins to mice. The plasma PK profiles of MDTCS were fitted to a kinetic model with three unknown protein-dependent parameters representing the fraction recycled (FR) and the rate constants for endocytosis (kup, for the uptake into the endosomes) and for the transfer from the plasma to the interstitial fluid (kpi). For MDTCS-Fc, the model was modified to include an additional parameter for binding to FcRn. Parameter optimization was done using the Cluster Gauss-Newton Method (CGNM), an algorithm that identifies multiple sets of approximate solutions ("accepted" parameter sets) to nonlinear least-squares problems. Results: As expected, the kinetic modeling results yielded the FR of MDTCS-Fc to be 2.8-fold greater than that of MDTCS (0.8497 and 0.3061, respectively). In addition, MDTCS-Fc was predicted to undergo endocytosis (the uptake into the endosomes) at a slower rate than MDTCS. Sensitivity analyses identified the association rate constant (kon) between MDTCS-Fc and FcRn as a potentially important factor influencing the plasma half-life in vivo. Discussion: Our analyses suggested that Fc fusion to MDTCS leads to changes in not only the FR but also the uptake into the endosomes, impacting the systemic plasma PK profiles. These findings may be used to develop recombinant protein therapeutics with extended circulation time.

Abstract 2124: Validation of the intelligent glycotransferase-dependent conjugation (iGDC) platform: A groundbreaking approach for next-generation HER2-targeting ADC GQ1012 with enhanced druggability, potency, and safety

Abstract Background: Antibody glycan remodeling has emerged as a promising site-specific conjugation technology to develop ADCs, while most reported cases suffer from complicated CMC process and scalability challenges. We report herein an innovative, streamlined one-enzyme, one-step glycan remodeling technology, i.e. intelligent Glycotransferase-Dependent Conjugation (iGDC), that enables the site-specific conjugation of various biologic modalities including monoclonal antibody, bispecific antibody and Fc fusion proteins. Employing immobilized enzymes and a continuous-flow process, iGDC efficiently tethers payloads to the N-297 glycan site without requiring antibody engineering. In contrast to alternative conjugation techniques, iGDC offers superior versatility, product quality, process efficiency, scalability, and cost-effectiveness. Validation of the iGDC platform is exemplified by GQ1012, a HER2-targeting ADC featuring the potent Topoisomerase I inhibitor, TopoIx. Preclinical studies demonstrated GQ1012's outstanding anti-tumor efficacy in diverse in vitro and in vivo models, displaying robust synergistic effects with anti-PD-1 therapy and excellent tolerability in pre-tox studies involving monkeys with no signs of lung diseases, surpassing those of Enhertu. Results: GQ1012, developed through iGDC, utilized a highly hydrophilic, stable branch linker to conjugate TopoIx to an anti-HER2 antibody, achieving high conjugation efficiency confirmed by DAR analysis. The ADC maintained comparable antigen binding affinity and internalization compared to the parental antibody, exhibiting potent cytotoxicity against HER2-positive cancer cells. Despite glycan remodeling with iGDC leading to the removal of ADCC function, GQ1012 demonstrated no off-target cytotoxicity in HER2-negative cells and displayed a robust bystander killing ability in co-culture assays. In various in vivo models, GQ1012 demonstrated similar or superior antitumor efficacy compared to Enhertu, showcasing strong synergy with anti-PD-1 therapy. Stability studies confirmed GQ1012 maintains a highly stable linker, minimizing DAR reduction. Preliminary toxicity studies in monkeys following repeated intravenous infusions of GQ1012 showcased excellent safety and pharmacokinetics at specified doses and the potential for an extended therapeutic window compared to Enhertu. Conclusion: The validation of the iGDC platform through GQ1012 highlights its adaptability and efficiency in producing highly homogeneous next-generation ADCs without requiring antibody engineering. GQ1012 presents promising potential as a next generation HER2 ADC with an expanded therapeutic window compared to Enhertu, supported by extensive in vitro, in vivo assessments, and preliminary toxicity studies. Citation Format: Meijun Xiong, Zengyan Mu, Meiling Xu, Chong Liu, Bo Dai, Junhao Wang, Xinju Gao, Lili Shi, Paul H. Song, Gang Qin. Validation of the intelligent glycotransferase-dependent conjugation (iGDC) platform: A groundbreaking approach for next-generation HER2-targeting ADC GQ1012 with enhanced druggability, potency, and safety [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2124.