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Clinical Trial
. 2025 Apr 1;31(7):1257-1267.
doi: 10.1158/1078-0432.CCR-24-1991.

First-in-Human Phase I Study of a CD16A Bispecific Innate Cell Engager, AFM24, Targeting EGFR-Expressing Solid Tumors

Anthony El-Khoueiry  1 , Omar Saavedra  2   3 , Jacob Thomas  1 , Claire Livings  4 , Elena Garralda  2 , Gabriele Hintzen  5 , Laura Kohlhas  5 , Dessislava Vanosmael  5 , Joachim Koch  5 , Erich Rajkovic  5 , Paulien Ravenstijn  5 , Paolo Nuciforo  2 , Todd A Fehniger  6 , Mark Foster  6 , Melissa M Berrien-Elliott  6 , Susanne Wingert  5 , Sina Stäble  5 , Daniela Morales-Espinosa  5 , Delcia Rivas  7 , Michael Emig  5 , Juanita Lopez  4
Affiliations
Clinical Trial

First-in-Human Phase I Study of a CD16A Bispecific Innate Cell Engager, AFM24, Targeting EGFR-Expressing Solid Tumors

Anthony El-Khoueiry et al. Clin Cancer Res. .

Abstract

Purpose: Innate immune cell-based therapies have shown promising antitumor activity against solid and hematologic malignancies. AFM24, a bispecific innate cell engager, binds CD16A on NK cells/macrophages and EGFR on tumor cells, redirecting antitumor activity toward tumors. The safety and tolerability of AFM24 were evaluated in this phase I/IIa dose-escalation/dose-expansion study in patients with recurrent or persistent, advanced solid tumors known to express EGFR.

Patients and methods: The main objective in phase I was to determine the MTD and/or recommended phase II dose. The primary endpoint was the incidence of dose-limiting toxicities during the observation period. Secondary endpoints included the incidence of treatment-emergent adverse events and pharmacokinetics.

Results: In the dose-escalation phase, 35 patients received AFM24 weekly across seven dose cohorts (14-720 mg). One patient experienced a dose-limiting toxicity of grade 3 infusion-related reaction. Infusion-related reactions were mainly reported after the first infusion; these were manageable with premedication and a gradual increase in infusion rate. Pharmacokinetics was dose-proportional, and CD16A receptor occupancy on NK cells approached saturation between 320 and 480 mg. Paired tumor biopsies demonstrated the activation of innate and adaptive immune responses within the tumor. The best objective response was stable disease in 10/35 patients; four patients had stable disease for 4.3 to 7.1 months.

Conclusions: AFM24 was well tolerated, with 480 mg established as the recommended phase II dose. AFM24 could be a novel therapy for patients with EGFR-expressing solid tumors, with suitable tolerability and appropriate pharmacokinetic properties for further development in combination with other immuno-oncology therapeutics.

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Conflict of interest statement

A. El-Khoueiry reports grants and nonfinancial support from Affimed during the conduct of the study, as well as personal fees from Roche/Genentech, Eisai, Merck, Bristol Myers Squibb, Exelixis, Qurient, Terumo, Elevar, and Senti Biosciences; grants and personal fees from AstraZeneca; grants from Auransa, Fulgent Genetics, and Astex Pharmaceuticals; and other support from Affimed outside the submitted work. J. Thomas reports personal fees from Coherus BioSciences, Inc. and Kura Oncology, Inc. outside the submitted work. E. Garralda reports grants from Novartis, Roche, Thermo Fisher Scientific, AstraZeneca, Taiho Pharmaceutical, BeiGene, Janssen Pharmaceuticals, and ANAVEON, as well as personal fees from Roche, Ellipses Pharma, Boehringer Ingelheim, Janssen Global Services, Seattle Genetics, Skypta, SOTIO, Sanofi-Aventis, ANAVEON, AbbVie, Astex Therapeutics, Alentis Therapeutics, Marengo Therapeutics, Jiangsu Hengrui, Incyte, Medpace, Medscape, Pfizer, Amgen, Genmab, Greywolf, Gilead Sciences, Daiichi Sankyo, MSD, Roche, Novartis, Seagen, PPD, Aran, TRRF, ESMO, Fundación SEOM, CDDF, Springer Nature, Karger, Doctaforum, Tactics, AEFI, Fundación ECO, MeetingPharma, AstraZeneca, Alcura Health, Horizon CME, and ESO outside the submitted work; in addition, E. Garralda reports employment with NEXT Oncology and stock ownership in 1TRIALSP. J. Koch reports employment with Affimed at the time of the study. E. Rajkovic reports other support from Affimed during the conduct of the study as well as other support from Affimed outside the submitted work. P. Ravenstijn reports employment with Astellas Pharma Europe B.V. P. Nuciforo reports grants from Affimed during the conduct of the study as well as personal fees from Novartis, MSD Oncology, Bayer HealthCare, and Targos Molecular Pathology GmbH outside the submitted work. T.A. Fehniger reports grants and personal fees from Affimed during the conduct of the study as well as grants, personal fees, and other support from Wugen, Orca Bio, and Indapta and grants from HCW Biologics and AI Proteins outside the submitted work; in addition, T.A. Fehniger has a patent for 15/983,275 pending, a patent for 62/963,971 pending, and a patent for PCT/US2019/060005 pending. M.M. Berrien-Elliott reports personal fees from Wugen outside the submitted work. S. Wingert reports personal fees from Affimed outside the submitted work. D. Morales-Espinosa reports other support from Affimed outside the submitted work; in addition, D. Morales-Espinosa is an employee of Affimed GmbH, the sponsor of the study. M. Emig reports personal fees from Affimed GmbH during the conduct of the study as well as personal fees from Affimed GmbH outside the submitted work; in addition, M. Emig reports Affimed stock options. J. Lopez reports grants and personal fees from Roche-Genentech and Basilea Pharmaceutica, grants from MSD and Ex Pharmaceuticals, and personal fees from GSK and Servier outside the submitted work. No disclosures were reported by the other authors.

Figures

Figure 1.
Figure 1.
Phase I dose-escalation study design of the Phase I/IIa study of AFM24 in patients with EGFR-expressing solid tumors (NCT04259450). The study design included a 21-day screening period followed by a DLT observation period (cycle 1). Patients received AFM24 administered as a weekly intravenous infusion on day 1, day 8, day 15, and day 22 of a 28-day cycle using flat, fixed dosing. The starting dose of AFM24 was 14 mg, with six incrementally increasing dose levels for the dose escalation (i.e., 40, 80, 160, 320, 480, and 720 mg). Tumor assessment with CT and/or MRI took place at screening and during the last week of cycles 2, 4, 6, and 8, and every three cycles thereafter.
Figure 2.
Figure 2.
A, Tumor status and treatment duration as assessed by the investigator; (B) change in tumor diameter from baseline (N = 28). A, Tumor response assessments per RECIST v1.1 are shown, with the best objective response of SD achieved in 10 of 35 patients. Four patients had SD assessed at least twice, with the duration of SD ranging from 4.3 to 7.1 months. B, Two patients with SD exhibited tumor regression at the best percentage change in sum of the longest diameter from baseline. *, The patient died, but their death date is unknown. PD, progressive disease; SCCHN, squamous cell carcinoma of the head and neck.
Figure 3.
Figure 3.
Analysis of tissue biopsies indicates an increase in cytotoxic NK and CD8 T cells in the tumor upon AFM24 treatment. Tumor biopsies were taken at screening and C1D24 of patients treated with AFM24 at doses higher than 160 mg and further analyzed by IHC and gene expression profiling using the NanoString nCounter PanCancer Immune Profiling Panel. A, IHC staining of CD3 of tumor biopsies at screening and C1D24, n = 13. B, Representative CD3 IHC staining of a patient with NSCLC treated with 480 mg AFM24 at screening and C1D24. C, Box plot showing log2 cell type score for CD56dim NK cells, n = 10. D, Box plot showing log2 cell type score for CD8 T cells, n = 10. E, Box plot showing log2 cell type score for cytotoxic cells (as defined by the NanoString nCounter PanCancer Immune Profiling Panel), n = 10.
Figure 4.
Figure 4.
AFM24 activates NK cells in peripheral blood and indirectly triggers adaptive immunity through the activation of CD8 T cells. Immune cell populations in isolated PBMCs and relevant activation markers have been longitudinally analyzed by cytometry time-of-flight. Cell populations have been identified by Boolean gating. Box plots showing (A) the CD56dim NK-cell frequency in CD45+ cells, (B) the frequency of Ki-67+ CD56dim NK cells, (C) the geometric mean of CD16 on CD56dim NK cells, (D) the CD8 T-cell frequency in CD45+ cells, and (E) the frequency of Ki-67+ CD8 T cells.
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