Novartis Acquires Mariana Oncology, Republicans Back Trial Diversity

Novartis announced its intent to acquire Mariana Oncology for $1 billion upfront, with an additional $750 million in potential milestone payments. This move significantly expands Novartis's radioligand therapy (RLT) pipeline, a class of cancer treatments that delivers targeted radiation directly to tumor cells. The company already markets Pluvicto (lutetium Lu 177 vipivotide tetraxetan) for metastatic castration-resistant prostate cancer (mCRPC), a therapy that has demonstrated a median overall survival benefit of 4 months (HR 0.62; 95% CI, 0.52-0.74; P<.001) in the VISION trial.¹

Mariana Oncology, a private biotechnology company, specializes in developing RLTs for solid tumors. Its lead program is a novel Lu-177-based RLT targeting GPC3 (glypican-3), a protein overexpressed in various solid tumors, including hepatocellular carcinoma (HCC). This acquisition positions Novartis to explore RLT applications beyond prostate cancer, potentially addressing other difficult-to-treat malignancies where targeted radiation could offer a therapeutic advantage. The preclinical data supporting Mariana's GPC3-targeting RLT showed selective tumor uptake and dose-dependent anti-tumor activity in xenograft models, indicating a favorable therapeutic index.²

Expanding the Radioligand Frontier

The rationale behind this acquisition is clear: Novartis aims to leverage Mariana's expertise in peptide discovery and radiochemistry to accelerate the development of next-generation RLTs. Mariana's platform focuses on optimizing peptide linkers and chelators to improve tumor specificity and reduce off-target toxicity, crucial factors for expanding the utility of RLTs. The current RLT landscape is largely dominated by prostate cancer indications, but the potential for these therapies in other solid tumors, particularly those with high unmet needs like HCC, remains substantial. The GPC3 target, for instance, is expressed in up to 80% of HCC cases, making it an attractive candidate for targeted therapies.³

Novartis's existing RLT manufacturing infrastructure, bolstered by its acquisition of Advanced Accelerator Applications (AAA) in 2017, provides a significant advantage in scaling up production for Mariana's pipeline. RLTs require specialized manufacturing and logistics due to their short half-lives and radioactive nature, presenting a considerable barrier to entry for smaller companies. Integrating Mariana's discovery capabilities with Novartis's established manufacturing and clinical development expertise could expedite the translation of promising preclinical candidates into clinical trials. This vertical integration is a strategic move to maintain a competitive edge in a rapidly evolving therapeutic area.

But the RLT field is not without its challenges. The complex logistics of handling radioactive materials, the need for specialized imaging to confirm target expression, and the potential for dose-limiting toxicities, particularly myelosuppression, require careful patient selection and monitoring. While Pluvicto has shown a manageable safety profile, expanding RLTs to new tumor types may reveal different toxicity profiles depending on target expression in healthy tissues. The GPC3 target, while highly expressed in HCC, also has some expression in normal kidney and lung tissue, which will necessitate careful evaluation of safety margins in human trials.⁴

In parallel, Republican lawmakers are advocating for increased diversity in clinical trials, a critical issue that impacts the generalizability of trial results and exacerbates health disparities. Representative Anna Eshoo (D-CA) and Senator Michael Bennet (D-CO) have previously championed legislation aimed at improving trial diversity, but this new bipartisan support from Republicans, including Senator Bill Cassidy (R-LA), signals a broader consensus. The push for diversity stems from the recognition that many clinical trials fail to adequately represent the demographic diversity of the patient populations affected by the diseases being studied. This lack of representation can lead to treatments that are less effective or have different safety profiles in underrepresented groups.⁵

The specific legislative proposals from Republicans focus on enhancing recruitment strategies, providing incentives for diverse participation, and improving data collection on race, ethnicity, and other demographic factors. These efforts aim to address systemic barriers that prevent diverse populations from participating in trials, such as lack of access to trial sites, financial burdens, and historical mistrust in the medical system. For instance, a 2020 FDA analysis revealed that while Black individuals constitute 13% of the US population, they made up only 5% of participants in trials for new drugs approved that year. This disparity is even more pronounced for certain conditions.⁶

Still, implementing effective diversity initiatives requires more than just legislative mandates. It demands a fundamental shift in how trials are designed, funded, and executed. This includes engaging with community leaders, decentralizing trial sites, and providing culturally competent care. The financial implications for sponsors could be substantial, as diverse recruitment often requires additional resources for outreach, transportation, and patient support. The trial was not powered to detect differences in efficacy or safety across all racial and ethnic subgroups, and that gap matters for real-world applicability.