Platinum-resistant ovarian cancer presents a critical unmet need in oncology, characterized by rapid disease progression following platinum-based chemotherapy—a cornerstone of ovarian cancer treatment. As tumor cells adopt mechanisms to evade immune clearance, including the upregulation of “don’t eat me” signals like CD47, therapeutic options become severely limited. This biological insight underpins the strategic rationale behind therapeutics like SL-172154, which simultaneously blocks CD47 to promote phagocytosis of tumor cells by macrophages, while activating CD40 to enhance antigen presentation and stimulate T-cell responses. By harnessing the dual actions of this bispecific protein, scientists hope to turn the tide against cancers that have developed sophisticated immune evasion strategies.

The trial setup involved combining SL-172154 with two established agents: mirvetuximab soravtansine (MIRV), an antibody-drug conjugate targeting folate receptor alpha frequently overexpressed on ovarian cancer cells, and pegylated liposomal doxorubicin (PLD), a chemotherapeutic with a favorable toxicity profile used in recurrent disease. This pairing aims to leverage SL-172154’s immune-modulating properties alongside the direct cytotoxic effects of these drugs, hopeful that such integration will foster heightened tumor cell phagocytosis and invigorate adaptive immune responses. The design reflects a nuanced approach to counter the complex, immunosuppressive tumor microenvironment emblematic of PROC.

The clinical trial results reported in the British Journal of Cancer reveal encouraging signals about the safety profile and preliminary efficacy of these combinations. Patients treated with SL-172154 in conjunction with either MIRV or PLD experienced manageable adverse effects, demonstrating acceptable tolerability for this novel regimen. Importantly, biomarker analyses indicated increased macrophage infiltration and evidence of enhanced antigen presentation, corroborating the hypothesized mechanistic actions of SL-172154. Such immune activation could signify a pivotal breakthrough in the immunotherapeutic landscape for this particularly recalcitrant subtype of ovarian cancer.

Beyond safety and mechanistic validation, the trial unveiled preliminary signs of clinical benefit, with several participants exhibiting disease stabilization or modest tumor shrinkage—uncommon in the context of platinum resistance. Though early-stage, such findings ignite cautious optimism that engaging innate and adaptive immunity together might overcome therapeutic resistance and extend patient survival in a condition notoriously marked by poor outcomes. This trial thus sets the stage for larger, more definitive studies, opening avenues for future exploration into combination immunotherapy regimens.

At a molecular level, the dual targeting strategy of SL-172154 exemplifies a sophisticated approach designed to circumvent tumor immune escape. CD47, often termed a “don’t eat me” signal, allows cancer cells to evade phagocytosis by binding to signal regulatory protein alpha (SIRPα) on macrophages. By blocking CD47, SL-172154 disarms this defense, enabling macrophages to engulf and eliminate malignant cells. Concurrently, CD40 activation on dendritic cells and macrophages promotes maturation and enhanced antigen presentation to cytotoxic T lymphocytes, inspiring a robust adaptive immune response. This synergy is pivotal in transforming the tumor microenvironment from immunosuppressive to immunostimulatory.

The choice to test SL-172154 in combination with mirvetuximab soravtansine is particularly strategic. MIRV specifically targets folate receptor alpha—a distinct molecular signature of many ovarian cancers—delivering potent cytotoxic payloads directly to tumor cells. This selective attack may induce immunogenic cell death, releasing tumor antigens that are then more effectively presented to T cells via CD40 activation, facilitating a dialog between innate and adaptive immunity. Such rational combinations exemplify precision immuno-oncology, where molecular targeting and immune modulation converge.

Additionally, the combination with pegylated liposomal doxorubicin leverages the chemotherapeutic’s ability to induce tumor cell stress and death while limiting toxic side effects, maintaining patients’ quality of life during treatment. Its integration with SL-172154 aims to prime the immune system through immunogenic cell death pathways while fostering macrophage-mediated clearance via CD47 blockade. This multifaceted attack highlights the sophisticated interplay being harnessed to circumvent tumor resilience and improve patient outcomes.

An intriguing facet emerging from this research is the potential for SL-172154 to act as a backbone immunomodulatory agent, capable of augmenting the efficacy of diverse anti-cancer therapies beyond ovarian cancer. By recalibrating the immune tumor microenvironment and enhancing antigen-specific T cell responses, SL-172154 introduces a versatile tool against malignancies characterized by immune evasion and chemotherapy resistance. Its bispecific design represents a new paradigm in immunotherapy, breaking traditional mono-target approaches and engendering synergistic immunologic effects.

Despite the promising results, challenges remain before SL-172154 can be integrated into routine clinical practice. Larger randomized trials are necessary to confirm efficacy signals, refine dosing, and delineate patient populations most likely to benefit. Mechanisms of resistance to CD47/CD40 targeting, downstream immune regulation, and long-term effects require further elucidation. Nonetheless, the current findings lay a robust foundation for subsequent investigation and underscore the critical importance of innovative immunotherapeutic strategies in transforming the treatment landscape for PROC.

Parallel to clinical development, translational studies probing the molecular and cellular underpinnings of responses to SL-172154 are underway. These investigations aim to identify predictive biomarkers of response and resistance, map immune cell dynamics, and characterize alterations in the tumor microenvironment induced by therapy. Such insights will inform biomarker-driven patient selection and rational combination regimens, fostering a precision medicine framework tailored to overcome the heterogeneity and complexity of ovarian cancer.

Moreover, the trial underscores the value of exploiting immune checkpoints beyond the canonical PD-1/PD-L1 axis. Targeting CD47 and harnessing CD40 agonism carve alternative routes to immune reactivation, expanding the armamentarium of immunotherapeutic approaches. This diversification is crucial to outpace adaptive tumor escape mechanisms and achieve durable, meaningful clinical responses in cancers traditionally refractory to immunotherapy.

The implications of this study reverberate beyond ovarian cancer, illuminating pathways applicable to other solid tumors where CD47 overexpression and immune suppression hinder therapeutic success. The dual mechanism of SL-172154 offers a blueprint for designing next-generation bispecific fusion proteins capable of orchestrating multifaceted immune responses tailored to distinct tumor ecosystems. As immuno-oncology advances, such biologics embody the cutting edge of therapeutic innovation.

In conclusion, the Phase Ib trial of SL-172154 combined with mirvetuximab or pegylated liposomal doxorubicin marks a significant milestone in the quest to conquer platinum-resistant ovarian cancer. By unleashing macrophage-mediated phagocytosis and invigorating T cell immunity through a bispecific approach, this novel agent heralds a new frontier in immunotherapy. While challenges remain, the promise of durable clinical benefit fuels hope for patients facing a daunting diagnosis. This innovative strategy underscores the transformative potential of harnessing innate and adaptive immunity synergistically—a beacon lighting the way toward improved survival and quality of life in ovarian cancer.

As the oncology community eagerly anticipates expanded trials and real-world applications, the fusion of molecular insight and immunologic engineering embodied by SL-172154 exemplifies the future of cancer therapy. The pursuit of comprehensive immune engagement heralds an era where therapeutic resistance might be overcome through tailored, dynamic interventions. Beyond scientific advancement, this progress resonates profoundly with patients and families, embodying hope and renewed prospects in the battle against ovarian cancer’s most intractable forms.

Subject of Research: Novel immunotherapeutic strategies targeting CD47 and CD40 pathways in platinum-resistant ovarian cancer.

Article Title: Phase Ib trial of SL-172154, a bispecific CD47 inhibitor and CD40 agonist Fc-fusion protein, in combination with mirvetuximab soravtansine or pegylated liposomal doxorubicin in patients with platinum-resistant ovarian cancer.

Article References:
Drew, Y., Gilbert, L., Martinez Bueno, A. et al. Phase Ib trial of SL-172154, a bispecific CD47 inhibitor and CD40 agonist Fc-fusion protein, in combination with mirvetuximab soravtansine or pegylated liposomal doxorubicin in patients with platinum-resistant ovarian cancer. Br J Cancer (2026). https://doi.org/10.1038/s41416-026-03430-0

Image Credits: AI Generated

DOI: 08 April 2026

Cancer cells, including those in glioblastomas, have evolved sophisticated mechanisms to escape immune surveillance. Central to these defenses are what scientists term “don’t eat me” signals—molecular cues expressed on tumor cells that inhibit the engulfing and destruction capabilities of immune cells called macrophages. Macrophages are innate immune effectors known for their role as first responders; they patrol tissues to identify and phagocytose pathogens and abnormal cells. Under typical conditions, these cells also support adaptive immunity by processing tumor-derived antigens and presenting them to T cells, effectively educating these cytotoxic lymphocytes to recognize and eradicate malignant cells.

One well-characterized “don’t eat me” signal is the protein CD47, commonly upregulated in various cancers. CD47 interacts with the macrophage receptor SIRPα, delivering a powerful inhibitory signal preventing phagocytosis. This protective mechanism is essential for healthy cells to avoid unwarranted removal by the immune system, but cancer cells exploit this pathway to cloak themselves against immune attack. Although interventions targeting the CD47-SIRPα axis have shown promise in hematologic malignancies, their effectiveness in solid tumors such as GBM remains limited, underscoring the necessity for alternative or complementary strategies.

Intriguingly, the MD Anderson team has identified another critical immune checkpoint molecule, CD24, which operates similarly by functioning as a “don’t eat me” signal and is abundantly expressed on glioblastoma cells. CD24 interacts with the immune receptor Siglec-10 on macrophages, further impeding their capacity to engulf tumor cells. The redundancy of these immune evasion pathways suggests that targeting CD47 alone may be insufficient to unlock the full potential of the innate immune response against GBM. This discovery prompted an investigation into the combined blockade of both CD47 and CD24 to synergize and amplify immune-mediated tumor clearance.

The experimental approach implemented dual inhibition of these two signaling pathways alongside standard immunotherapeutic agents in preclinical glioblastoma models. Results demonstrated a significantly enhanced anti-tumor effect compared to monotherapies targeting either CD47 or CD24 alone. Macrophages, liberated from the inhibitory constraints imposed by both signals, exhibited substantially increased phagocytic activity, leading to elevated tumor cell clearance. Subsequently, this heightened activity facilitated the presentation of tumor antigens to T cells, catalyzing a robust adaptive immune response capable of eradicating malignancy more effectively.

This novel combination strategy addresses a fundamental issue in GBM treatment: the immune system’s failure to recognize and mount an effective assault on glioblastoma cells. By simultaneously disabling two independent “don’t eat me” signals, the immune system’s front-line defenders—macrophages—not only clear cancer cells more efficiently but also stimulate downstream T cell responses critical for sustained tumor suppression. This dual blockade approach effectively removes the “invisibility cloak” that tumor cells employ, thereby unmasking the cancer to the immune system.

Dr. Wen Jiang, associate professor of Radiation Oncology at MD Anderson, emphasizes the concept of this “one-two punch,” wherein blocking both CD47 and CD24 unleashes a synergistic immune activation far greater than targeting a single pathway. She refers to it as dismantling the tumor’s stealth tactics, reinvigorating immune surveillance by empowering macrophages to act decisively. This layered defense dismantling holds promise not only for GBM but potentially for other solid tumors with similar immune evasion mechanisms.

Further insights from Dr. Betty Kim, professor of Neurosurgery and an integral member of the James P. Allison Institute™, underscore the adaptability and complexity of cancer. Tumors employ multiple, often overlapping, strategies to thwart immune destruction, necessitating multi-targeted approaches to overcome their resilience. She stresses that the redundancy of immune evasion pathways in glioblastoma challenges single-agent immunotherapies, underscoring why combined blockade may initiate a more potent, sustained antitumor immune response.

While these findings herald an exciting therapeutic avenue, translation into clinical application requires additional research. Several CD47 antagonists are currently in clinical trials for various cancers, illustrating a wave of momentum in this field. However, therapeutic agents targeting CD24 remain in nascent stages of development. The path forward includes refining these therapies, evaluating their safety and efficacy in combination, and identifying patient populations poised to benefit most from this immunomodulatory strategy.

The implications of this study extend beyond glioblastoma, shedding light on innate immune-driven therapies leveraging macrophages’ critical role within the tumor microenvironment. It marks a paradigm shift, emphasizing that successful immunotherapy may demand not only activation of T cells but also strategic modulation of macrophages and other innate immune components. This comprehensive immune engagement addresses tumor heterogeneity and evasion multiple axes, potentially overcoming resistance mechanisms that have hampered immunotherapy in tough-to-treat cancers.

Supported by prominent institutions such as the National Institutes of Health, the American Cancer Society, and the Cancer Prevention and Research Institute of Texas, this research represents a collaborative effort aimed at redefining cancer immunotherapy frameworks. By dissecting the molecular interplay governing tumor immunity and resistance, the investigators have taken a decisive step toward novel therapeutic strategies that harness the full armamentarium of the immune system.

As the oncology community eagerly anticipates the development of effective CD24 inhibitors, the current work invigorates hope for patients afflicted with glioblastoma—disease for which therapeutic options and survival rates remain dishearteningly limited. Targeting the sophisticated immune evasion employed by GBM with these dual blockade strategies may unlock previously inaccessible avenues for durable tumor control and improved patient outcomes.

Ultimately, this research exemplifies the quintessential intersection of fundamental immunology and translational medicine, crafting innovative interventions from detailed mechanistic insights. While much work remains, the concept of simultaneously “unmasking” cancer cells by disabling multiple “don’t eat me” signals may well define the next frontier in immunotherapy for glioblastoma and beyond, reinvigorating the fight against this devastating disease.

Subject of Research: Immune evasion mechanisms in glioblastoma and enhancement of immunotherapy through dual blockade of CD47 and CD24 “don’t eat me” signals.

Article Title: Dual Blockade of CD47 and CD24 Reinvigorates Macrophage-Mediated Immunity to Enhance Immunotherapy in Glioblastoma Models.

News Publication Date: March 11, 2026.

Web References:

• MD Anderson Cancer Center: https://www.mdanderson.org/
• Immunotherapy Overview: https://www.mdanderson.org/treatment-options/immunotherapy.html
• Glioblastoma Information: https://www.mdanderson.org/cancer-types/glioblastoma.html
• Published Study in Nature Communications: https://www.nature.com/articles/s41467-026-70221-9

References: Wen Jiang, M.D., Ph.D., Betty Kim, M.D., Ph.D., et al. “Dual blockade of CD47 and CD24 enhances macrophage-mediated phagocytosis and immunotherapy response in glioblastoma,” Nature Communications, 2026.

Keywords: Glioblastoma, Immunotherapy, Macrophages, Phagocytosis, CD47, CD24, Immune evasion, Tumor microenvironment, Cancer immunotherapy, Solid tumors, Antigen presentation, Innate immunity.