There is considerable interest in the pharmaceutical industry toward development of antibody-based biotherapeutics because they can selectively bind diverse receptors and often possess desirable pharmacology. Here, we studied product characteristics of 89 marketed antibody-based biotherapeutics that were approved from 1986 to mid-2020 by gathering publicly available information. Our analyses revealed major trends in their emergence as the best-selling class of pharmaceuticals. Early on, most therapeutic monoclonal antibodies were developed to treat cancer, with CD20 being the most common target. Thanks to industrialization of antibody manufacturing technologies, their use has now blossomed to include 15 different therapeutic areas and nearly 60 targets, and the field is still growing! Drug manufacturers are solidifying their choices regarding types of antibodies and their molecular formats. IgG1 kappa continues to be the most common molecular format among marketed antibody-based biotherapeutics. Most antibody-based biotherapeutics approved since 2015 are either humanized or fully human, but the data we collected do not show a direct correlation between humanness and reported incidence of anti-drug antibodies. Furthermore, there have also been improvements in terms of drug product stability and high concentration liquid formulations suitable for subcutaneous route of administration, which are being approved more often in recent years. These improvements, however, have not been uniformly adopted across all therapeutic areas, suggesting that multiple options for drug product development are being used to serve diverse therapeutic purposes. Insights gained from this analysis may help us devise better end-to-end antibody-based biotherapeutic drug discovery and development strategies.

Purpose Although lymphocyte activation gene-3 (LAG-3) directed therapies demonstrate promising clinical anti-cancer activity, only a subset of patients seems to benefit and predictive biomarkers are lacking. Here, we explored the potential use of the anti-LAG-3 antibody tracer [89Zr]Zr-BI 754111 as a predictive imaging biomarker and investigated its target specific uptake as well as the correlation of its tumor uptake and the tumor immune infiltration. Methods Patients with head and neck (N = 2) or lung cancer (N = 4) were included in an imaging substudy of a phase 1 trial with BI 754091 (anti-PD-1) and BI 754111 (anti-LAG-3). After baseline tumor biopsy and [18F]FDG-PET, patients were given 240 mg of BI 754091, followed 8 days later by administration of [89Zr]Zr-BI 754111 (37 MBq, 4 mg). PET scans were performed 2 h, 96 h, and 144 h post-injection. To investigate target specificity, a second tracer administration was given two weeks later, this time with pre-administration of 40 (N = 3) or 600 mg (N = 3) unlabeled BI 754111, followed by PET scans at 96 h and 144 h post-injection. Tumor immune cell infiltration was assessed by immunohistochemistry and RNA sequencing. Results Tracer uptake in tumors was clearly visible at the 4-mg mass dose (tumor-to-plasma ratio 1.63 [IQR 0.37-2.89]) and could be saturated by increasing mass doses (44 mg: 0.67 [IQR 0.50–0.85]; 604 mg: 0.56 [IQR 0.42–0.75]), demonstrating target specificity. Tumor uptake correlated to immune cell-derived RNA signatures. Conclusions [89Zr]Zr-BI-754111 PET imaging shows favorable technical and biological characteristics for developing a potential predictive imaging biomarker for LAG-3-directed therapies. Trial registration ClinicalTrials.gov, NCT03780725. Registered 19 December 2018

3004 Background: The highly potent MDM2–p53 antagonist BI 907828 showed antitumor efficacy in vivo, particularly in TP53 wild-type, MDM2-amplified de-differentiated LPS (DDLPS) patient-derived xenografts and syngeneic models. This phase I study (NCT03449381) is assessing BI 907828 monotherapy in patients with advanced solid tumors, including LPS. In Part A (dose escalation), patients received one of two BI 907828 dosing schedules: Arm A, day 1 of 21-day cycles (q3w); Arm B, days 1 and 8 of 28-day cycles. Based on previously reported results from Part A (LoRusso ASCO 2021), the MTD was 60 mg q3w and the recommended dose for expansion (RDE) was selected as 45 mg q3w. Methods: In Part B (dose expansion), patients received BI 907828 45 mg q3w. The primary endpoint was PFS. Secondary endpoints/objectives included objective response rate, overall survival, the number of patients with grade ≥3 treatment-related AEs, and PK parameters. Here, we report overall safety data and efficacy data in the subgroup of patients with advanced LPS. Results: As of January 10, 2022, 90 patients had been enrolled; 49 (54.4%) were male, 55 (61.1%)/34 (37.8%) were ECOG PS 0/1, the median number of prior systemic therapies was 2 (range, 0–11), 44 had advanced LPS (28 DDLPS, 16 well-differentiated LPS [WDLPS]). At data cut-off, 31/90 patients (34.4%) had received treatment for ≥6 months. In the 41 evaluable patients with advanced LPS, best response of PR or SD was observed in 24/27 patients with DDLPS (88.9%) and 13/14 patients with WDLPS (92.9%). Two DDLPS and 4 WDLPS patients achieved a PR; all had MDM2-amplified disease. In Part A, 5/11 DDLPS patients and 4/8 WDLPS patients have achieved PFS ≥10.5 months. In the 42 patients who received the RDE of 45 mg q3w, 18 patients (42.9%) had grade ≥3 AEs; the most common grade ≥3 AEs were neutropenia (23.8%), thrombocytopenia (21.4%), and anemia (11.9%). Seven patients (16.7%) had SAEs; the most common were thrombocytopenia (4.8%) and pyrexia (4.8%). PK analysis showed that mean plasma exposures (Cmax and AUC0-inf) increased with dose and showed no significant deviation from linearity in the dose range 10–60 mg. A correlation was observed between exposure and GDF-15 levels in plasma, as a target engagement marker. Conclusions: BI 907828 showed a manageable safety profile, high plasma exposure, target engagement and encouraging signs of antitumor activity in patients with advanced DDLPS and WDLPS. The Part B dose expansion is ongoing. Clinical trial information: NCT03449381.

The E3 ligase MDM2 controls the tumor suppressor function of p53, which is encoded by the TP53gene. Compounds designed to bind to MDM2 preventing its interaction with p53 restore the ability of p53 to combat the pathogenic processes that underly cancer development. It has become clear from early clinical experience that thrombocytopenia represents an on-target, dose-limiting toxicity that may restrict the therapeutic utility of first-generation MDM2 inhibitors. Dosing less frequently, while maintaining efficacious exposure levels, has been proposed as an approach to mitigate side effects and improve the therapeutic window. In this -Late Breaking- session we present the discovery and preclinical evaluation of BI 907828, a highly potent, orally bioavailable and selective molecule binding to MDM2 and preventing its interaction with p53. The compound was designed to have a long half-life to enable intermittent dosing schedules in the clinic where it showed a manageable safety profile in a Phase Ia/Ib, dose-escalation/expansion study and encouraging signs of antitumor activity in patients with advanced DDLPS and WDLPS. BI 907828 is actively investigated in several clinical trials including the Phase II/III Brightline-1 study that aims to evaluate whether it is superior to doxorubicin in the first-line treatment of advanced/metastatic DDLPS. BI 907828 belongs to the class of spiro-oxindole MDM2-p53 antagonists and was discovered starting from an optimized core structure with improved chemical stability. Structure-based medicinal chemistry optimization including rigidification of the scaffold were key to accomplish the desired profile which was tested preclinically in several in vivo MDM2-amplified xenograft models where treatment with BI 907828 showed efficient tumor growth inhibition and regression. Citation Format: Andreas Gollner, Patrizia Sini, Dorothea Rudolph, Harald Weinstabl, Juergen Ramharter, Ulrike Weyer-Czernilofsky, Bojana Golubovic, Rolf Grempler, Alejandro Pérez Pitarch, Reinhard Sailer, Darryl B. McConnell, Norbert Kraut. BI 907828: A highly potent MDM2-p53 antagonist suitable for intermittent dose schedules [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB003.