Monoclonal Antibody-drug Conjugates Research Articles

Inotuzumab Ozogamicin: First Pediatric Approval.

Inotuzumab ozogamicin (BESPONSA™) is a CD22-targeted monoclonal antibody drug conjugate (ADC) developed by Pfizer for the treatment of CD22-postive B-cell precursor acute lymphoblastic leukaemia (ALL). Inotuzumab ozogamicin comprises a humanized IgG4 anti-CD22 monoclonal antibody covalently linked to the potent DNA-binding cytotoxic agent N-acetyl-gamma-calicheamicin dimethylhydrazide (CalichDMH) via a linker. Inotuzumab ozogamicin binds to CD22-expressing tumour cells, facilitating the delivery of conjugated CalichDMH, which after intracellular activation induces double strand DNA breaks, ultimately leading to cell cycle arrest and apoptotic cell death. Inotuzumab ozogamicin is approved in the USA, Europe and several countries worldwide for the treatment of relapsed or refractory CD22-positive B-cell precursor ALL in adults. On 6 March 2024, inotuzumab ozogamicin received its first pediatric approval in the USA for this indication in patients aged ≥1 years. Inotuzumab ozogamicin has since been approved in Japan in March 2024 for the same indication in pediatric patients. This article summarizes the milestones in the development of inotuzumab ozogamicin leading to this first approval for the treatment of relapsed or refractory CD22-positive B-cell precursor ALL in pediatric patients.

Longitudinal efficacy and safety modeling and simulation framework to aid dose selection of belantamab mafodotin for patients with multiple myeloma.

Belantamab mafodotin, a monomethyl auristatin F (MMAF)-containing monoclonal antibody-drug conjugate (ADC), demonstrated deep and durable responses in the DRiving Excellence in Approaches to Multiple Myeloma (DREAMM)-1 and pivotal DREAMM-2 studies in patients with relapsed/refractory multiple myeloma. As with other MMAF-containing ADCs, ocular adverse events were observed. To predict the effects of belantamab mafodotin dosing regimens and dose-modification strategies on efficacy and ocular safety end points, DREAMM-1 and DREAMM-2 data across a range of doses were used to develop an integrated simulation framework incorporating two separate longitudinal models and the published population pharmacokinetic model. A concentration-driven tumor growth inhibition model described the time course of serum M-protein concentration, a measure of treatment response, whereas a discrete time Markov model described the time course of ocular events graded with the GSK Keratopathy and Visual Acuity scale. Significant covariates included baseline β2 -microglobulin on growth rate, baseline M-protein on kill rate, extramedullary disease on the effect compartment rate constant, and baseline soluble B cell maturation antigen on maximal effect. Efficacy and safety end points were simulated for various doses with dosing intervals of 1, 3, 6, and 9 weeks and various event-driven dose-modification strategies. Simulations predicted that lower doses and longer dosing intervals were associated with lower probability and lower overall time with Grade 3+ and Grade 2+ ocular events compared with the reference regimen (2.5 mg/kg every 3 weeks), with a less-than-proportional reduction in efficacy. The predicted improved benefit-risk profiles of certain dosing schedules and dose modifications from this integrated framework has informed trial designs for belantamab mafodotin, supporting dose-optimization strategies.

Business Risk Mitigation in the Development Process of New Monoclonal Antibody Drug Conjugates for Cancer Treatment.

Recent developments aim to extend the cytotoxic effect and therapeutic window of mAbs by constructing antibody-drug conjugates (ADCs), in which the targeting moiety is the mAb that is linked to a highly toxic drug. According to a report from mid of last year, the global ADCs market accounted for USD 1387 million in 2016 and was worth USD 7.82 billion in 2022. It is estimated to increase in value to USD 13.15 billion by 2030. One of the critical points is the linkage of any substituent to the functional group of the mAb. Increasing the efficacy against cancer cells' highly cytotoxic molecules (warheads) are connected biologically. The connections are completed by different types of linkers, or there are efforts to add biopolymer-based nanoparticles, including chemotherapeutic agents. Recently, a combination of ADC technology and nanomedicine opened a new pathway. To fulfill the scientific knowledge for this complex development, our aim is to write an overview article that provides a basic introduction to ADC which describes the current and future opportunities in therapeutic areas and markets. Through this approach, we show which development directions are relevant both in terms of therapeutic area and market potential. Opportunities to reduce business risks are presented as new development principles.

Preclinical and early clinical data of ZN-1041 in combination with trastuzumab deruxtecan to treat breast cancer with or without CNS metastases.

1041 Background: While treatment options for advanced HER2+ breast cancer have improved, HER2+ breast cancer brain metastases (BCBM) remain a clinical challenge warranting the development of additional, brain permeable HER2-targeted therapies. ZN-1041 is a brain permeable, selective HER2-targeted oral tyrosine kinase inhibitor. Preclinical studies have demonstrated efficacy and safety of ZN-1041 warranting clinical development alone and in combination with approved monoclonal antibodies or antibody drug conjugates for patients (pts) with HER2+ BCBM. Methods: Anti-tumor activity of ZN-1041 alone or in combination with trastuzumab emtansine (TDM1), trastuzumab deruxtecan (TDXd), or trastuzumab (H) plus pertuzumab (P) was evaluated in BT474 BM orthotopic xenograft models. ZN-A-1041-101-US (NCT05593094) is an on-going phase 1, multicenter, open-label study. The study comprises dose escalation of ZN-1041 monotherapy (Phase 1a) in pts with HER2+ solid tumors with or without BM, dose escalation (Phase 1b) and expansion (phase 1c) of ZN-1041 in combination with TDM1 (Arm 1), TDXd (Arm 2), or HP as maintenance therapy (Arm 3) in pts with HER2+ mBC with or without BM. The primary objectives were safety, tolerability and recommended phase 2 dose. The secondary objective includes pharmacokinetics (PK) and preliminary efficacy per RECIST 1.1. Results: Preclinically, ZN-1041 alone or combined with TDM1, TDXd or HP demonstrated significant improvement in intracranial tumor growth inhibition compared to TDM1, TDXd, or HP alone. As of data cutoff, Phase 1a (n = 7 pts) and Arm 2 of Phase 1b (n = 3 pts) were completed. Among 10 pts enrolled, 8 pts had received prior HER2 TKI. In Phase 1a, ZN-1041 was well tolerated with no dose-limiting toxicities (DLTs) or drug discontinuation due to toxicity up to a dose of 800 mg BID. Adverse reactions were mainly grade 1. The most common treatment related adverse reactions (TRAEs≥15%) were grade 1 nausea (43%) and vomiting (29%), with no ≥ grade 2 diarrhea reported. PK exposure was increased with dose escalation. In Phase 1a, one pt with mBC (without BM) achieved a confirmed partial response (PR) at 400 mg BID dose for > 15 months; one with gastric cancer achieved stable disease at the first dose level of 50mg BID for nearly 1 year. In Phase 1b, pts who had previously progressed on TDXd and/or TKI were enrolled and received ZN-1041 at a dose of 800 mg BID in combination with TDXd. Combination therapy was well tolerated with no DLTs reported. One pt with BCBM who was previously on tucatinib and TDXd had a confirmed PR. Conclusions: Safety and tolerability was observed for ZN-1041 with maximum tolerated dose 800 mg BID as monotherapy and combined with TDXd in pts with advanced HER2+ malignancies. Encouraging efficacy was observed in treatment-refractory settings. Additional safety and efficacy data of ZN-1041 in combination with TDM1, TDXd or HP are warranted. Clinical trial information: NCT05593094 .

Development of Centrifugal Partition Chromatography for the Purification of Antibody-Drug Conjugates.

Monoclonal antibody-drug conjugates (ADCs) are an expanding therapeutic class of biomolecules for which relatively few analytical and preparative separation options exist. Purification of ADCs with a specific drug antibody ratio is even more challenging. We report the first application of countercurrent separation (CCS) to this problem. An ADC mimic was successfully chromatographed using an aqueous two-phase system (ATPS) consisting of PEG 1000/sodium citrate pH 7.5/water, 17.75/17.75/64.50 (w/w/w). Notably, different partition coefficients (K) in this ATPS for the ADC mimic (0.09 < K < 0.16) and its monoclonal antibody backbone, IgG (0.16 < K < 0.27), were observed using CCS. Differential elution behavior of such high-molecular-weight biomolecules, 146,441 vs. ∼150,000 Da, using CCS has no precedent. The results provide a proof of concept for further exploration of the application of ATPSs and CCS to the separation of ADCs.

Post-Transplantation Sinusoidal Obstruction Syndrome in Adult Patients with B Cell Acute Lymphoblastic Leukemia Treated with Pretransplantation Inotuzumab

Sinusoidal obstruction syndrome (SOS) is a potentially life-threatening complication that can be observed after allogeneic hematopoietic cell transplantation (HCT). Inotuzumab ozogamicin is an anti-CD22 monoclonal antibody-drug conjugate that has demonstrated high efficacy in relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) but is associated with an increased risk of SOS in HCT recipients. Here we aimed to examine the incidence and outcomes of SOS in 47 adult patients with R/R ALL who received inotuzumab therapy and subsequently underwent HCT at our institution. All patients received prophylactic therapy with ursodiol, and continuous low-dose heparin also was administered to patients receiving myeloablative conditioning (MAC). SOS occurred in 12 patients (26%) post-HCT, at a median onset of 11 days (range, 3 to 41 days). SOS was graded as very severe in 50% (n=6), severe in 25% (n=3), and mild in 25% (n=3). All patients diagnosed with SOS received treatment with defibrotide for a median of 21 days (range, 3 to 34 days), with resolution of SOS occurring in 8 patients (67%). Mortality from SOS was 33% (n=4) and occurred at a median of 10 days from diagnosis (range, 3 to 31 days) in patients graded as very severe (n=3) or severe (n=1). There were no significant differences between patients who developed SOS and those who did not develop SOS in the median time from the last dose of inotuzumab to transplantation (46 days versus 53 days; P = .37), use of an MAC regimen (42% versus 49%; P=.75), number of lines of therapy prior to inotuzumab (P=.79), median number of administered cycles of inotuzumab (2 versus 2; P=.14), or receipt of inotuzumab as the last therapy prior to HCT (67% versus 66%; P=1.0). Sirolimus-based graft-versus-host disease (GVHD) prophylaxis was used more frequently in the SOS group (75% versus 29%; P < .01), but there was no between-group difference in the peak sirolimus level (P=.81) or the median time to peak sirolimus level (7 days versus 3.5 days; P=.39). In univariable analysis, only the use of sirolimus-based GVHD prophylaxis was significantly associated with an increased risk of SOS (hazard ratio [HR], 7.50; 95% confidence interval [CI], 1.7 to 33.6; P < .01). In the SOS group, the 100-day mortality rate was 33% (n=4), and median overall survival (OS) post-HCT was 4.3 months (range, 0.2 to 57.2 months). In the group without SOS, the 100-day mortality rate was 14% (n=5) and the median OS post-HCT was 10.7 months (range, .52 to 39.6 months). In this study cohort, SOS was prevalent in HCT recipients who had been treated with inotuzumab prior to transplantation, and sirolimus-based GVHD prophylaxis was a risk factor for SOS in inotuzumab recipients.

Therapeutic effect of a MUC1-specific monoclonal antibody-drug conjugates against pancreatic cancer model

BackgroundPancreatic cancer is one of the most aggressive malignancies without effective targeted therapies. MUC1 has emerged as a potential common target for cancer therapy because it is overexpressed in a variety of different cancers including the majority of pancreatic cancer. However, there are still no approved monoclonal antibody drugs targeting MUC1 have been reported. Recently, we generated a humanized MUC1 antibody (HzMUC1) specific to the interaction region between MUC1-N and MUC1-C. In this study, we generated the antibody drug conjugate (ADC) by conjugating HzMUC1 with monomethyl auristatin (MMAE), and examined the efficacy of HzMUC1-MMAE against the MUC1-positive pancreatic cancer in vitro and in vivo.MethodsWestern blot and immunoprecipitation were used to detect MUC1 in pancreatic cancer cells. MUC1 localization in pancreatic cancer cells was determined by confocal microscopy. HzMUC1 was conjugated with the monomethyl auristatin (MMAE), generating the HzMUC1-MMAE ADC. Colony formation assay and flow cytometry were used to assess the effects of the HzMUC1-MMAE cell viability, cell cycle progression and apoptosis. Capan-2 and CFPAC-1 xenograft model were used to test the efficacy of HzMUC1-MMAE against pancreatic cancer.ResultsHzMUC1 antibody binds to MUC1 on the cell surface of pancreatic cancer cells. HzMUC1-MMAE significantly inhibited cell growth by inducing G2/M cell cycle arrest and apoptosis in pancreatic cancer cells. Importantly, HzMUC1-MMAE significantly reduced the growth of pancreatic xenograft tumors by inhibiting cell proliferation and enhancing cell death.ConclusionOur results indicate that HzMUC1-ADC is a promising novel targeted therapy for pancreatic cancer. HzMUC1-ADC should also be an effective drug for the treatment of different MUC1-positive cancers.

Brentuximab in Children, Adolescent and Young Adults with Relapsed/Refractory Anaplastic Large Cell Lymphoma

Background: Anaplastic Large Cell Lymphoma (ALCL) is an aggressive malignancy characterized by strong expression of CD30. Multi-agent chemotherapy cures 65-90% of newly diagnosed patients, the rate of relapse approaching 30%. Targeted agents eventually followed by allogeneic stem cell transplantation (SCT) may represent a valuable salvage therapy in patients with relapsed/refractory ALCL. Brentuximab vedotin is a CD30-directed monoclonal antibody-drug conjugate (ADC) that comprises a monoclonal human/murine antibody linked to the microtubule-disrupting agent monomethyl auristatin E (MMAE) via a protease-cleavable linker. Design and methods: We retrospectively analyzed monocentric data of 20 patients with ALCL treated with Brentuximab from 2.10.2014 to 22.05.2022. Treatment was characterized by the intravenous infusion of 1.8 mg/kg Brentuximab in monotherapy or as part of a polychemotherapy regimen, in children with either relapsed disease or not fully responding to first-line treatment. More in detail, chemotherapy regimens administered in combination with the immunotherapy were: bendamustine, AM and BM blocks (ALCL99 Trial), or AA, BB and CC blocks (LNH97 Trial). Objective response rate (ORR) was assessed through computed tomography (CT)/FDG-PET scans. Results: Eight patients received Brentuximab for incomplete response to first-line treatment (2 of them had haemophagocytic lymphohistiocytosis at diagnosis, and underwent genetic testing that revealed the heterozygous variant c.1336C>T (p.Arg446Trp) in IKBKB gene and the hemizygous variant c.622T>C (p.Ala91Val) in IL2RG gene, respectively). In these patients, Brentuximab was mostly used in combination with the ALCL99 regimen. Three of these 8 patients experienced a subsequent relapse and were re-exposed to the drug after disease recurrence. Fifteen patients received Brentuximab at relapse. Median time between diagnosis and relapse was 10.3 months (range 3.4-34 months). The median number of Brentuximab infusions was 7 (range 2-25). The combination of Brentuximab 1.8 mg/kg/dose on Day 1 and Bendamustine 120 mg/m2/dose on Day 2 and 3, was the principal reinduction regimen in the relapsed cohort, having been infused in 9 patients with a median of 4 cycles (range 2 to 5). This drug combination was very well tolerated and showed a 100% complete response (CR) assessed by CT and FDG-PET scans, allowing to perform allogeneic SCT in all of them. Allogeneic SCT was performed in 15 patients (one of them was the child with haemophagocytic lymphohistiocytosis at diagnosis given Brentuximab during the first-line treatment because of incomplete response), while the remaining child, who had relapsed 34 months after the diagnosis, was treated with Brentuximab monotherapy and remains in CR. Nine patients received HLA-haploidentical SCT, while the remaining 6 were transplanted using either a matched sibling donor (3 patient) or an unrelated volunteer (3 patients) respectively. Sixteen out of the 20 patients (80%) are alive and disease free with a median follow-up of 28.6 months (range 3-78.7). Three patients died due to transplant related causes and 1 patient due to disease progression. Conclusions: Despite the limitations of a limited number of patients analyzed and the retrospective nature of the study, our data suggest that Brentuximab administered either in monotherapy or in combination with chemotherapy is a valuable salvage option and may represent a suitable bridge to allogeneic SCT.

Sinusoidal Obstruction Syndrome in Adult Patients with B-Cell Acute Lymphoblastic Leukemia Treated with Inotuzumab Prior to Hematopoietic Stem Cell Transplantation

BACKGROUND: Sinusoidal obstruction syndrome (SOS), also known as veno-occlusive disease, is a potentially life-threatening toxicity observed post allo-HCT, with the reported incidence estimated to be 10-15% and mortality as high as 80% based on the severity (Coppell et al. BBMT 2010). Current management of SOS focusses on minimizing transplant- and patient-related factors. Inotuzumab ozogamicin (InO) is a humanized monoclonal antibody-drug conjugate targeting the CD22 antigen and has proven to be more efficacious than conventional chemotherapy in relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) in the INO-VATE ALL phase 3 trial. However, liver-adverse events were more frequently encountered in the InO group with SOS occurring in 22.8% (n=18) of patients who proceeded to allo-HCT (Kantarjian et al. NEJM 2016). Given the effectiveness of InO as salvage therapy pre-HCT, we aimed to investigate incidence and outcomes of SOS in adult patients with R/R ALL that received InO and proceeded to consolidation with HCT. METHODS: We retrospectively studied adult patients (pts) with R/R B-ALL that received InO as salvage therapy and underwent consolidation with allo-HCT at City of Hope from 2014 to 2022. Graft source was peripheral blood for all patients. All pts. received prophylactic therapy with ursodiol and heparin was added to pts receiving myeloablative conditioning. Diagnosis and severity grading for SOS was in accordance with the revised EBMT criteria (Mohty et al. Bone Marrow Transplantation 2016). All pts. with SOS were treated with defibrotide. Fischer's exact test was used to complete the case-control analysis of patients with SOS vs. those without, and univariable analysis was completed using Cox regression. RESULTS: We identified 47 patients in our study, with 12 pts (25.5%) developing SOS post-HCT. Median time to diagnosis of SOS was 11 days (range: 3-41) and grade was very severe in 50% (n=6), severe in 25% (n=3), and mild in 25% (n=3). All pts. received treatment with defibrotide for median 20.5 days (range: 3-34), with resolution of SOS in 66.7% (n=8) of patients. Mortality from SOS was 33.3% (n=4) within a median of 10 days from diagnosis (range: 3-31), with pts. being graded as very severe (n=3, 75%) or severe (n=1, 25%). The group of pts with SOS compared to those without SOS did not have any significant difference in median duration between last dose of InO and HCT (46 vs. 53 days, P=0.37), myeloablative conditioning regimen (42% vs. 49%, P=0.75), TBI-based preparative regimen (50% vs. 57%, P=0.74), or disease status at transplant >CR1 (83% vs. 68%, P=0.83). There was no significant difference between the groups in lines of therapy prior to InO (P=0.79). Both groups received median 2 cycles of InO (P=0.14) and received InO as last therapy prior to HCT in 67% of patients with SOS and 66% in those patients without SOS (P=1.0). Sirolimus-based GVHD prophylaxis was more common in the SOS group (75% vs. 29%, P<0.01), but there was no difference in peak sirolimus level (P=0.81) or median time to peak sirolimus level (7 vs. 3.5 days, P=0.39) between the two subgroups. On univariable analysis, the use of sirolimus as GVHD prophylaxis was the only variable significant for SOS development, HR=7.50 [95% CI:1.7-33.6, P<0.01]. In the SOS group, the 100-day mortality rate was 33.3% (n=4) with median overall survival (OS) post-SOS of 4.3 months (range: 0.2 - 57.2). In the group without SOS, the 100-day mortality rate was 14.2% (n=5) and median OS post-HCT was 10.7 months (range: 0.52 - 39.6). CONCLUSION: To our knowledge, this is the largest single-center retrospective analysis of R/R ALL patients that received InO as salvage therapy pre-HCT. The incidence of SOS was high, and prompt initiation of defibrotide demonstrated efficacy in treating SOS. Despite the effectiveness of Ino as salvage therapy, the risk of SOS can potentially be mitigated by minimizing risk factors, especially the use of sirolimus-based GVHD prophylaxis. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Abstract 332: Development of a novel therapeutic CLDN18.2 monoclonal antibody and antibody drug conjugate for the treatment of CLDN18.2 positive cancers

Abstract Background: Claudin 18 is a member of the claudin family of tight junction tetraspan cell surface proteins. The 18.2 isoform of claudin 18 (CLDN18.2) is expressed in healthy gastric mucosa cells and largely absent from other normal adult cell types. In contrast to the low expression in healthy tissues, CLDN18.2 is highly overexpressed in many cancer types including gastric and pancreatic malignancies at high frequencies (50-80%). The high tumor-normal expression differential of CLDN18.2 make it an attractive target for both therapeutic monoclonal antibodies (mAbs) and antibody drug conjugate (ADCs). Here, we describe the preclinical development of a novel therapeutic CLDN18.2 mAb and ADC. Materials and Methods: CLDN18.2 specific mAbs were generated through a multiplexed immunization strategy by which mice were immunized with either peptides spanning loop 2 of the CLDN18.2 extracellular domain or mouse NIH3T3 cells overexpressing the full length CLDN18.2 protein. Antibody clones were screened by flow cytometry for selective binding to cell surface CLDN18.2. A CLDN18.2-directed ADC was generated from the fully humanized clinical candidate CLDN18.2 mAb by MMAE conjugation with a cleavable linker. CLDN18.2 positivity in cell line (CDX) and patient derived xenograft (PDX) models was determined by IHC assay. Results: Selective binding of the CLDN18.2-mAb to CLDN18.2, without cross reactivity to the more widely expressed CLDN18.1 isoform, was confirmed in human cancer cell lines and cells engineered to overexpress each isoform. The CLDN18.2-mAb demonstrated strong induction of both antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cell-mediated phagocytosis (ADCP) in in vitro assays; suggesting that Fc effector function is a key component of the mechanism of action of the mAb. Treatment of CLDN18.2 positive gastric and pancreatic CDXs with CLDN18.2-mAb monotherapy induced significant inhibition of tumor growth in CD-1 nude mice. Binding of CLDN18.2-mAb or CLDN18.2-ADC to the cell surface CLDN18.2 induced internalization of the protein-antibody complex. Complete regression of CDX tumors was observed in response to treatment with the CLDN18.2-ADC in three separate CLDN18.2 positive models (two pancreas, one gastric). Moreover, complete loss of xenograft tumor burden was also observed in 4/5 CLDN18.2 positive pancreas PDX models. No impact on xenograft tumor growth as observed in response to treatment with either the CLDN18.2-mAb or CLDN18.2-ADC in CLDN18.2 negative CDX/PDX models. Discussion: These data support the clinical development of this CLDN18.2-mAb and CLDN18.2-ADC for the treatment of CLDN18.2 positive cancers. Each of these molecules will begin phase 1 clinical testing in early 2022. Citation Format: Neil A. O'brien, Martina S. McDermott, Jun Zhang, Ke Wei Gong, Ming Lu, Benjamin G. Hoffstrom, Dylan Conklin, Tong Luo, Kevin Chau, Min Liang, Timothy R. Donahue, John A. Glaspy, Leonard Presta, Dennis J. Slamon. Development of a novel therapeutic CLDN18.2 monoclonal antibody and antibody drug conjugate for the treatment of CLDN18.2 positive cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 332.

Enfortumab vedotin-ejfv for the treatment of advanced urothelial carcinoma

ABSTRACT Introduction Metastatic urothelial carcinoma is an aggressive malignancy with a poor prognosis. Research in recent years has led to the approval of new treatments that offer improved survival for patients. Enfortumab vedotin-ejfv is a first-in-class monoclonal antibody drug conjugate that binds Nectin-4, a protein expressed on bladder cancer cells, and delivers the tubulin toxin, monomethyl auristatin E, into the cell causing cell death. Enfortumab vedotin-ejfv has changed the standard of care treatment in urothelial carcinoma with a high response and disease-control rate, acceptable toxicity profile and improved overall survival for patients who previously had limited options after failure of chemotherapy and/or immunotherapy. Areas covered We review the pharmacology, clinical efficacy, safety, and tolerability of enfortumab vedotin. Expert opinion Enfortumab vedotin-ejfv has shown promising efficacy and safety in pretreated patients with advanced urothelial carcinoma. It is currently being evaluated in clinical trials in earlier lines of treatment and in combination therapy.

The efficacy of lapatinib in patients with metastatic HER2 positive breast cancer who received prior therapy with monoclonal antibodies and antibody-drug conjugate: a single institutional experience

The choice of the anti-HER2 agent depends on country-specific availability, the specific, previously administered anti-HER2 therapy and the relapse-free interval, although there is not much published data on the use of lapatinib after progression on pertuzumab and/or T-DM1. The aim of this research is to determine efficacy of lapatinib in this setting. This research included 111 patients with metastatic HER2 positive breast cancer who received lapatinib with capecitabine at The Oncology Institute of Vojvodina. Lapatinib was given to 83 patients after trastuzumab without prior exposure to pertuzumab or T-DM1 while 28 patients received lapatinib after prior exposure to trastuzumab, pertuzumab and/or T-DM1. In order to determine efficacy of lapatinib in both groups, we measured progression free survival (PFS) and overall survival (OS), as well as by subsets: hormonal status (ER-positive and/or PR-positive tumours versus ER-negative and PR-negative tumours), the number of positive axillary lymph nodes (four or more positive axillary lymph nodes versus less than four positive axillary lymph nodes), marker of proliferation (Ki-67 ≥ 30 versus Ki-67 < 30), disease free interval (metastatic recurrence ≤ 1 year after initial diagnosis versus metastatic recurrence > 1 year after initial diagnosis or de novo metastatic disease. Median PFS was 5.6 months (95% CI 4.6–6.6) in the group of patients who received lapatinib after prior exposure to trastuzumab, pertuzumab and/or T-DM 1 and 7.4 months (95% CI 6.1–10.2) in the group of patients who received lapatinib after trastuzumab (HR, 0.79; 95% CI 0.61–0.98; P = 0.09). The patients with negative prognostic factors such as hormone receptor negativity, more than four positive axillary lymph nodes, marker of proliferation Ki 67 ≥ 30 and metastatic recurrence ≤ 1 year after initial diagnosis, had a similar PFS, regardless of receiving lapatinib after prior exposure to trastuzumab, pertuzumab and/or T-DM1 or without prior exposure. Median OS was 10.1 months (95% CI 8.6-NR) in the group that received lapatinib after exposure to trastuzumab, pertuzumab and/or T-DM1 and 16.3 months (95% CI 14.4–20.2) in the group of patients who received lapatinib after trastuzumab (HR, 0.76; 95% CI, 0.59–0.94; P = 0.04). Patients with negative prognostic factors such as hormone receptor negativity, more than four positive axillary lymph nodes and marker of proliferation Ki 67 ≥ 30, had no distinctly worse OS, regardless of receiving lapatinib after prior exposure to trastuzumab, pertuzumab and/or T-DM1 or without prior exposure. Lapatinib with capecitabine is an effective therapeutic option, especially in patients with negative prognostic factors, who have received prior chemotherapy, trastuzumab, pertuzumab, T-DM1 and remains an acceptable option for HER2 positive metastatic breast cancer until the novel drugs are approved in developing countries.

A Novel Antibody Drug Conjugate (ADC) Targeting Cell Surface Heat Shock Protein 70 (csHSP70) Is Active Against Pre-Clinical Models of Peripheral T-Cell Lymphoma (PTCL)

A Novel Antibody Drug Conjugate (ADC) Targeting Cell Surface Heat Shock Protein 70 (csHSP70) Is Active Against Pre-Clinical Models of Peripheral T-Cell Lymphoma (PTCL)

Anti-CD47 Monoclonal Antibody-Drug Conjugate: A Targeted Therapy to Treat Triple-Negative Breast Cancers.

Triple-negative breast cancers (TNBCs) are frequently recurrent due to the development of drug resistance post chemotherapy. Both the existing literature and our study found that surface receptor CD47 (cluster of differentiation 47) was upregulated in chemotherapy-treated TNBC cells. The goal of this study was to develop a monoclonal antibody (mAb)-based targeting strategy to treat TNBC after standard treatment. Specifically, a new mAb that targets the extracellular domain of receptor CD47 was developed using hybridoma technology and produced in fed-batch culture. Flow cytometry, confocal microscopy, and in vivo imaging system (IVIS) showed that the anti-CD47 mAb effectively targeted human and mouse TNBC cells and xenograft models with high specificity. The antibody–drug conjugate (ADC) carrying mertansine was constructed and demonstrated higher potency with reduced IC50 in TNBC cells than did the free drug and significantly inhibited tumor growth post gemcitabine treatment in MDA-MB-231 xenograft NSG model. Finally, whole blood analysis indicated that the anti-CD47 mAb had no general immune toxicity, flow cytometry analysis of lymph nodes revealed an increase of CD69+ NK, CD11c+ DC, and CD4+ T cells, and IHC staining showed tumoral infiltration of macrophage in the 4T1 xenograft BALB/cJ model. This study demonstrated that targeting CD47 with ADC has great potential to treat TNBCs as a targeted therapy.

Advances in Immunotherapy for Diffuse Large B Cell Lymphoma.

Diffuse large B cell lymphoma (DLBCL) is a heterogeneous disease that is normally treated with combination chemotherapy combined with the anti-CD20 monoclonal antibody rituximab. Although about two-thirds of patients are cured with initial chemo-immunotherapy, a sizable minority of patients will have relapsed or refractory (r/r) DLBCL. Standard therapy for r/r DLBCL is salvage chemotherapy followed by autologous stem cell transplantation (ASCT); however, a minority of patients have long-term remission with this approach. In recent years, there has been a proliferation of immunotherapies for the treatment of DLBCL that have expanded our treatment options for these patients, providing the opportunity for durable remissions that were not previously possible. In this review, we discuss these novel immunotherapies, including monoclonal antibodies, antibody-drug conjugates, bispecific antibodies and chimeric antigen receptor (CAR) T cells. The plethora of novel agents leaves patients with more therapeutic options, but leaves the practitioner faced with challenging decisions regarding the timing and indications for use of these immunotherapies. Although studies are ongoing, no agents have been verified as alternatives to standard salvage therapy followed by ASCT at first relapse. The opportunity for durable response and broad age range eligibility makes a strong case for CAR T cells to be used as third-line therapy. The remainder of the agents discussed can be useful in specific clinical scenarios including in patients who are not candidates for ASCT or CAR T cells, as bridging therapy to CAR T cells, or in the r/r setting after CAR T cell therapy failure.

Evaluation of ROR1 Targeted Antibody Drug Conjugates in Acute and Chronic Lymphocytic Leukemia and Mantle Cell Lymphoma

Introduction: Receptor tyrosine kinase like orphan receptor 1 (ROR1) is a developmentally restricted receptor tyrosine kinase that is expressed on the surface of multiple hematological and solid malignancies but not on normal adult tissues. Recently, there has been an increased interest in ROR1 as a potential therapeutic target in multiple ROR1 positive leukemia and lymphomas. In this study, we present novel anti-ROR1 monoclonal antibody drug conjugates (ADCs) based on chimeric rabbit/human mAb “XBR1-402” or its humanized version “huXBR1-402”, that show both in vitro and in vivo efficacy at eliminating ROR1 positive chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), and pre B cell acute lymphocytic leukemia (pre B cell ALL) leukemic cells.Methods: From our studies, we saw no difference in activity between XBR1-402-PNU and huXBR1-402-PNU. XBR1-402-PNU was used for our studies in pre B cell ALL and huXBR1-402-PNU was used for our studies in MCL and CLL. For ALL in vitro experiments, we monitored cytotoxicity in Kasumi2 and 697 cell lines. For MCL in vitro experiments we monitored cytotoxicity in Jeko and Mino cell lines. For CLL in vitro experiments, we monitored cytotoxicity in primary CLL samples. For ALL in vivo experiments we monitored overall survival in a murine disseminated 697 model. For CLL in vivo experiments we monitored ROR1+ leukemic cell depletion in human ROR1 transgenic mice engrafted with human ROR1+TCL1 leukemia.Results: We observed a decrease in viability for all XBR1-402-PNU and huXBR1-402-PNU treated ROR1 positive leukemic cell lines and primary cells in vitro . In the in vitro model of pre B cell ALL we observed a significant decrease in viability of the ROR1 positive pre B cell ALL cell lines 697 and Kasumi-2 when treated with XBR1-402-PNU(EC50 = 77 and 1 ng/mL, respectively) when compared to treatment with the isotype-matched control ADC Trastuzumab-PNU (Tras-PNU) (EC50 = 2987 and 5330 ng/mL, respectively). In the in vitro model of MCL, we observed a decrease in viability for huXBR1-402-PNU treated ROR1 positive Jeko and Mino cell lines but not ROR1 negative Mec-1 and Jurkat cell lines when compared to the unconjugated huXBR1-402 antibody or the control Tras-PNU. Additionally, we tested primary CLL samples confirmed to be positive for ROR1 and found a significant decrease in viability over 96 hours when treated with the antibody-drug-conjugate huXBR1-402 (78.6 + 6.1%)as compared to the unconjugated antibody (100% + 2.4; p=0.022, N=7) and the control Tras-PNU (87.4% +/- 6.1; p=0.038). We have also detected promising in vivo activity with XBR1-402-PNU and huXBR1-402-PNU in ALL and CLL models, respectively. In vivo studies on a murine disseminated 697 ALL model showed that treatment with XBR1-402-PNU increased overall survival when compared to treatment with Tras-PNU control (Median survival of 32 and 23 days after implantation respectively, p=0.021, n=6). In addition, in preliminarily experiments, we have tested depletion of human ROR1+ leukemic cells and normal B cells in vivo using human ROR1 transgenic mice engrafted with human ROR+TCL1 leukemia and observed a preferential depletion of ROR1+TCL1 leukemic cells upon treatment with huXBR1-402-PNU compared to control Tras-PNU.Conclusion: Our results suggest that anti-ROR1 ADC huXBR1-402-PNU is an effective and promising targeted cytotoxic therapy for ROR1 positive leukemic cells of CLL, MCL, and pre B ALL and warrants further evaluation for clinical consideration in patients with ROR1 positive leukemia and lymphomas. Current long-term studies are ongoing to evaluate the in vivo cytotoxic effects of huXBR1-402-PNU on total tumor burden, disease progression, and overall survival.(EH is supported by Graduate Pelotonia Fellowship) DisclosuresWaldmeier:NBE-Therapeutics Ltd: Employment. Beerli:NBE-Therapeutics Ltd: Employment. Grawunder:NBE-Therapeutics Ltd: Employment. Byrd:The Ohio State University: Patents & Royalties: OSU-2S; Genentech: Research Funding; Pharmacyclics: Research Funding; Acerta Pharma: Research Funding; Janssen: Research Funding.

Belantamab Mafodotin for the Treatment of Multiple Myeloma: An Overview of the Clinical Efficacy and Safety.

Despite the introduction of immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs), and, more recently, monoclonal antibodies (mAbs), in the chemotherapy regimens for newly diagnosed (NDMM) and relapsed/refractory MM (RRMM), the occurrence of drug resistance remains a challenge in MM patients. This is mainly in the advanced stage of the disease when treatments are limited, and the prognosis is abysmal. Nevertheless, novel molecules and therapeutic approaches are rapidly moving through the several phases of drug development and could address the need for new treatment options. The recent innovative B-cell maturation antigen (BCMA) targeted immunotherapies, such as belantamab mafodotin, the first-in-class monoclonal antibody-drug conjugate (ADC), induce an effective and durable response in triple-class refractory disease and to be approved in MM. In contrast with the other BCMA-targeted therapies as CAR T cells with a complex manufacturing process, and bispecific antibodies, both requiring inpatient hospitalization to monitor the occurrence of severe adverse events, belantamab mafodotin is an “off-the-shelf” drug that can be administered in an outpatient setting. Many belantamab mafodotin-based combinations are under evaluation in Phase I, II, and III clinical trials either late or in early RRMM patients. Ocular toxicity represents a peculiar side effect of belantamab mafodotin. This toxicity is generally manageable with adequate dose reductions or delays since most patients who developed keratopathy recovered on treatment and discontinued ADC are rare. Here, we described the most recent clinical data of belantamab mafodotin and discussed the possible leading role of this intriguing agent in the near future of MM treatment.

Monoclonal Antibodies and Antibody Drug Conjugates in Multiple Myeloma.

Simple SummaryMonoclonal antibodies represent a major therapeutic progress in multiple myeloma during the last decade. The use of antibodies as well as antibody drug conjugates has changed the treatment landscape rapidly. The intent of this paper is to summarize the current major results of monoclonal antibody treatments in multiple myeloma.Multiple myeloma is the second most common hematologic malignancy. Current treatment strategies are mainly based on immunomodulatory drugs, proteasome inhibitors or combination of both. Novel agents added to these backbone treatments represent a promising strategy in treatment of newly diagnosed as well as relapsed and refractory multiple myeloma patients. In this respect, the incorporation of monoclonal antibodies into standard-of-care regimens markedly improved prognosis of myeloma patients during the last years. More specifically, monoclonal anti-CD38 antibodies, daratumumab and isatuximab, have been implemented into treatment strategies from first-line treatment to refractory disease. In addition, the monoclonal anti-SLAM-F7 antibody elotuzumab in combination with immunomodulatory drugs has improved the clinical outcomes of patients with relapsed/refractory disease. Belantamab mafodotin is the first approved antibody drug conjugate directed against B cell maturation antigen and is currently used as a monotherapy for patients with advanced disease. This review focuses on clinical efficacy and safety of monoclonal antibodies as well as antibody drug conjugates in multiple myeloma.

Elution Profiles of Antibody-Drug Conjugates in Preparative Chromatography

Monoclonal antibody drug conjugate (ADCs) have received much attention as pharmaceutical agents for treating serious diseases such as cancer. However, it is difficult to separate them on the basis of the drug to antibody ratio, DAR. Hydrophobic chromatography (HIC) is commonly used for the analysis of the drug to antibody ratio, DAR. The retention of ADCs on HIC can be controlled by the hydrophobic nature of ADCs, depending on the mobile phase conditions. They are sometimes performed at the restricted conditions where the solubility is too low. Ion exchange chromatography (IEC) using electrostatic interaction is an orthogonal method to HIC. IEC is widely used because of its higher capacity than HIC. We investigated the retention behavior of the protein conjugated with surrogate drugs on IEC. The surrogate drugs employed are 7-diethylamino-3-(4’-maleimidylhenyl) 4-methylcoumarin (CPM), N-(1-pyrenyl) maleimide (NPM). Bovine serum albumin (BSA) was used as a model protein. The molar ratio (CPM and NPM to protein) was set to 3. The maleimide group of CPM and NPM reacts with the thiol group of the proteins. On the linear gradient elution experiments, the elution salt concentrations of the conjugated and non-conjugated proteins were measured to obtain chromatographic parameter of the number of binding sites, B.

Polatuzumab Vedotin-Based Salvage Chemotherapy in the Third-Line or Above Treatment for Diffuse Large B-Cell Lymphoma

Introduction Diffuse large B-cell lymphoma (DLBCL) is the most common B-cell malignancy worldwide. A sizable fraction of these patients ended up succumbing to this fatal disease, so the standard of care after the second-line chemotherapy and/or autologous stem cell transplants (ASCT) remains to be improved. Polatuzumab vedotin-piiq (PoV), an anti-CD79b antibody-drug conjugate, gained accelerated approval by the U.S. Food and Drug Administration in June, 2019. The phase II randomized controlled study (GO29365) showed PoV in combination with bendamustine and rituximab (BR) conferred an additional 22% complete response rate for relapsed/refractory DLBCL, compared with BR alone (40% vs. 18%) . Interestingly, how PoV fares when combined with other salvage therapy remains as an open question. Method DLBCL patients who developed progressive diseases after at least 2 prior lines of therapy including R-CHOP and not previously treated with BR were enrolled into this study between Nov. 2018 and Apr. 2020 at the National Taiwan University Hospital. PoV was given at 1.8 mg/kg in combination with salvage chemotherapies based on clinicians' choices. The compassionate use of PoV was approved by the ethics committee, and clinical data were retrospectively analyzed. Results Thirty-two patients were enrolled in this study. According to the Hans' criteria of immunohistochemical subtypes, 13 patients were germinal center B cell-like (GCB), 17 were non-GCB, and 2 patients were unclassifiable. The median age was 62.5 years (range 20-82). At diagnosis, 26 (81%) patients had stage III or IV diseases, 22 (68.8%) had extranodal involvement, and 24 (75%) had the IPI scores equaled to 3 or higher. The median of failed prior lines of treatment was 4 (range 2-11), including 7 (21.9%) relapsing from ASCT and 16 (50%) were of primary refractory disease. Regarding combination therapies, 20 (62.5%) received BR, 5 (15.6%) had rituximab, 5 (15.6%) had rituximab/carmustine-containing regimens, and rituximab/gemcitabine-based ones were given to 4 (12.5%) patients. The median of cycles of PoV was 4 (range 1-7). Notably, the combinatory use of PoV and salvage chemotherapy helped transition 5 patients to ASCT and 4 to allogeneic SCT. The median overall survival (OS) was 8.9 months (95% confidence interval 6.2-not estimable) with the median follow-up of 11.4 months (range 0.3-20.7). The overall response rate (ORR) was 45.2%, including 29.1% complete response (CR) and 16.1% partial response (PR). The patients achieving CR or PR after PoV had better overall survival (OS) than those who did not (median OS: not reached (NR) vs. 5.6 months, p=0.0001, Figure A). The ORR for patients failing prior 2, 3, 4, and ≥5 lines of treatment were 50% (3/6), 40% (2/5), 50% (4/8), and 42% (5/12), respectively. The patients failing prior 4 lines of treatment had better OS than those with failed prior 5 or more lines (NR vs. 6.47 months). Non-GCB patients had better ORR (69.2% vs. 30.8%) and OS (NR vs. 6.23 months) than GCB ones did. Intriguingly, the patients received SCT had better OS compared with the others (NR vs. 6.23 months, p=0.011, Figure B). As for grade 3 &amp; 4 hematological adverse effects, 16 (50%) patients developed anemia, 20 (62.5%) had thrombocytopenia, and 18 (56.3%) were neutropenic. Grade 5 toxicities included pneumonia (2 patients, 6.3%), fungemia (1, 3.1%), intracranial hemorrhage (1, 3.1%), and other infections (2, 6.3%). Conclusion As the third-line or above treatment for DLBCL in this study, the efficacy and safety associated with PoV-based therapies not only were encouraging but also helped bridge to transplants. The application of this monoclonal antibody-drug conjugate in future clinical trials for DLBCL is expected. Figure Disclosures Tsai: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Chugai: Honoraria; Harvester: Honoraria; Janssen: Honoraria; Kirin: Honoraria; Takeda: Honoraria; BMS: Honoraria; Astellas: Honoraria; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. Ko:Roche: Honoraria. Cheng:Roche: Honoraria. Huang:MundiPharma: Honoraria; Chugai: Honoraria; Roche: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Janssen: Honoraria; Takeda: Honoraria; Bristol Meyer &amp; Squibb: Honoraria.