Redmond, Washington, August 5, 2026
SystImmune, Inc., a clinical-stage biotechnology company and subsidiary of Biokin, has announced that the first patient has been dosed in the BrenDeLL-Lung01 global Phase 3 registrational clinical trial evaluating its investigational DLL3-targeted antibody-drug conjugate (ADC) BL-M14D1 in combination with atezolizumab for the treatment of previously untreated extensive-stage small cell lung cancer (ES-SCLC). The milestone represents a significant advancement for SystImmune’s oncology pipeline and marks the transition of BL-M14D1 into late-stage global clinical development. Built on the company’s proprietary brengitecan ADC platform, BL-M14D1 is designed to selectively target DLL3-positive tumor cells, delivering a potent topoisomerase I inhibitor payload while minimizing exposure to healthy tissues. The initiation of the pivotal Phase 3 study underscores SystImmune’s commitment to developing innovative therapies for patients with aggressive neuroendocrine malignancies who continue to face limited treatment options despite recent advances in cancer care.
Global Phase 3 Trial Targets First-Line Small Cell Lung Cancer
The BrenDeLL-Lung01 (NCT07625644) study is a global, multicenter, randomized Phase 3 registrational trial evaluating BL-M14D1 plus atezolizumab against the current standard-of-care regimen, consisting of platinum-based chemotherapy and etoposide induction followed by atezolizumab maintenance, with or without lurbinectedin. The study plans to enroll approximately 580 patients diagnosed with previously untreated extensive-stage small cell lung cancer, one of the most aggressive forms of lung cancer characterized by rapid progression and poor long-term survival. The trial’s primary endpoint is progression-free survival as assessed through blinded independent central review (BICR). By initiating this pivotal global study, SystImmune aims to determine whether the addition of its novel DLL3-targeted ADC can improve clinical outcomes beyond the current treatment standard while providing physicians with a more targeted therapeutic option for first-line disease management.
BL-M14D1 Demonstrates Promise Through Proprietary ADC Platform
BL-M14D1 is one of several next-generation antibody-drug conjugates being developed using SystImmune’s proprietary brengitecan platform, which combines targeted antibody technology with a potent topoisomerase I inhibitor payload engineered to selectively destroy cancer cells expressing DLL3, a protein highly expressed in small cell lung cancer and several neuroendocrine tumors. Advancement into Phase 3 follows encouraging clinical findings from the ongoing Phase 1 BL-M14D1-101 trial, recently presented at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting. The early-stage study demonstrated promising anti-tumor activity together with a manageable safety profile in heavily pretreated patients with small cell lung cancer and other neuroendocrine carcinomas. These positive clinical results provided the scientific rationale for advancing BL-M14D1 into late-stage registrational development while further validating the therapeutic potential of the brengitecan ADC platform across multiple solid tumor indications.
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SystImmune Expands Leadership in Precision Oncology Innovation
The initiation of the global Phase 3 BrenDeLL-Lung01 trial reinforces SystImmune’s growing position as an innovator in precision oncology and antibody-drug conjugate development. The company continues to build a diversified pipeline focused on bispecific antibodies, multispecific antibodies, and ADC therapies targeting both solid tumors and hematologic malignancies. Supported by a robust discovery and preclinical research portfolio, SystImmune is leveraging its proprietary technology platforms to develop highly targeted cancer therapies designed to improve efficacy while reducing systemic toxicity. With BL-M14D1 now advancing into registrational development, the company moves closer to potentially delivering a new first-line treatment option for patients with extensive-stage small cell lung cancer, an area where significant unmet medical need remains. The successful initiation of the global Phase 3 study highlights the continued momentum of SystImmune’s oncology pipeline and its long-term commitment to advancing innovative biologics for patients worldwide.
Source: SystImmune press release
