San Francisco, CA – October 13, 2023 – BioNTech SE, a pioneer in mRNA technology, is navigating a critical juncture in its quest to develop a groundbreaking cancer vaccine. The company’s investigational mRNA cancer immunotherapy, BNT113, combined with MSD’s Keytruda (pembrolizumab), has failed to meet its primary endpoint of statistically significant improvement in progression-free survival (PFS) in a Phase II/III AHEAD-MERIT study (NCT04534205) for patients with head and neck squamous cell carcinoma (HNSCC). This outcome, while a disappointment, does not spell the end for the trial, as the Independent Data Monitoring Committee (IDMC) has recommended its continuation to assess the crucial endpoint of overall survival (OS).
The AHEAD-MERIT Study: A Dual-Endpoint Approach
The AHEAD-MERIT study was designed to evaluate the efficacy of BioNTech’s BNT113, an off-the-shelf mRNA cancer vaccine targeting the human papillomavirus type 16 (HPV16) oncoprotein, in combination with the immune checkpoint inhibitor Keytruda. The trial specifically enrolled patients with unresectable, recurrent, or metastatic HPV16-positive HNSCC who also expressed PD-L1. The study’s dual primary endpoints were progression-free survival (PFS) and overall survival (OS).
The failure to demonstrate a statistically significant improvement in PFS in the combination arm compared to Keytruda alone means the trial has missed one of its pre-specified primary objectives. PFS is a critical measure in cancer trials, indicating the length of time patients live without their cancer worsening. However, the trial’s design allows for a positive outcome if the second primary endpoint, OS, demonstrates a statistically significant benefit. OS, which measures the total length of time patients live from the start of the study until death, is often considered the most definitive measure of a treatment’s efficacy.
A Glimmer of Hope: The Significance of Overall Survival
Despite the initial setback with PFS, the IDMC’s recommendation to continue the trial underscores the continued potential of BNT113. The rationale behind this decision likely stems from the understanding that mRNA cancer immunotherapies can elicit immune responses that take time to mature and translate into significant clinical benefits. Professor Özlem Türeci, co-founder and Chief Medical Officer at BioNTech, elaborated on this point, stating, "The potential of mRNA cancer immunotherapies in combination regimens lies in their ability to induce immune responses that may translate into durable clinical benefit and, ultimately, prolonged survival of patients."
She further explained, "While the PFS result was not statistically significant at this first analysis, the data support continued evaluation of BNT113 plus pembrolizumab in this trial and show that it is engaging its intended therapeutic mechanism. As immune-mediated anti-tumour effects build and deepen over time, the analysis of the second dual primary endpoint, overall survival, will be critical to fully assess the potential of this approach to deliver durable benefit for patients with HPV-driven head and neck cancer."
This sentiment highlights the complex nature of cancer immunotherapy trials. The immune system’s response to novel therapies can be dynamic, with delayed but sustained anti-tumor effects potentially leading to long-term survival benefits that might not be immediately apparent in PFS data. Therefore, the upcoming analysis of OS will be pivotal in determining the true impact of BNT113 in this patient population.
The Landscape of HPV-Driven Head and Neck Cancer
Head and neck squamous cell carcinoma (HNSCC) is a significant global health challenge. A notable subset of these cancers, approximately one-third, are linked to persistent infections with the human papillomavirus (HPV), with HPV type 16 (HPV16) being the most prevalent. These HPV-driven tumors exhibit distinct molecular characteristics compared to their HPV-negative counterparts, often being more responsive to immunotherapy.
Despite the growing understanding of HPV’s role in HNSCC and the promise of immunotherapeutic approaches, there remains a significant unmet need for effective HPV-targeted treatments. Currently, no specific therapies directly target HPV-driven cancers. This underscores the importance of BioNTech’s efforts with BNT113, which is specifically designed to target the oncoproteins expressed by HPV16-infected cells. The US Food and Drug Administration (FDA) has recognized the potential of BNT113 by granting it Fast Track designation for HPV16+ HNSCC, a designation that aims to expedite the development and review of drugs that treat serious conditions and fill an unmet medical need.
Market Reaction and BioNTech’s Broader Portfolio
The news of the missed PFS endpoint has not gone unnoticed by investors. BioNTech’s stock experienced a decline of 3.63% at market open on October 13th, closing at $92.36 compared to $95.84 on October 12th. This market reaction reflects the inherent volatility and high expectations surrounding clinical trial results, particularly for innovative therapies like mRNA cancer vaccines.
It is important to contextualize this development within BioNTech’s broader pipeline. The company is actively pursuing multiple avenues in cancer vaccine development. Beyond BNT113, BioNTech is also collaborating with Genentech on autogene cevumeran, a personalized mRNA cancer vaccine currently in mid-stage trials. The company has also experienced setbacks with other cancer vaccine candidates; one study in bowel cancer was terminated due to a low likelihood of demonstrating benefit, while another in pancreatic cancer remains ongoing. This highlights the challenging and often iterative nature of drug development, where success in one area does not guarantee success in others.
A Contrasting Success: MSD and Moderna’s Breakthrough
In contrast to BioNTech’s recent challenges, the partnership between MSD (Merck & Co. in the US and Canada) and Moderna has achieved a landmark success in the mRNA cancer immunotherapy space. Their flagship candidate, intisomer autogene (also known as mRNA-4157/V940), has achieved the first-ever successful Phase III trial readout for an individualized mRNA cancer therapy.
The INTerpath-001 trial investigated intisomer autogene in combination with MSD’s Keytruda versus Keytruda alone in over 1,100 patients with high-risk (Stage IIB-IV) resected melanoma. The results demonstrated a statistically significant and clinically meaningful improvement in both recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) for the combination therapy. This breakthrough has propelled intisomer autogene towards potential blockbuster status, with GlobalData forecasting sales to surpass $1 billion by 2031.
This success has been hailed by key opinion leaders as a significant turning point for individualized mRNA cancer therapies. The detailed data from this pivotal study are highly anticipated and are expected to be presented at the upcoming European Society of Clinical Oncology (ESMO) meeting in Madrid, Spain, from October 23rd to 27th. The achievements of MSD and Moderna provide a powerful validation of the potential of mRNA technology in cancer treatment and set a high bar for other companies in the field.
Looking Ahead: The Path Forward for BioNTech
While the AHEAD-MERIT study has encountered a hurdle, the focus now shifts to the overall survival data. The continued investigation of BNT113 in combination with Keytruda offers BioNTech a critical opportunity to demonstrate its therapeutic value. The company’s commitment to pursuing this second primary endpoint, coupled with the ongoing research into personalized cancer vaccines, underscores its dedication to advancing cancer care through innovative mRNA technologies.
The journey of cancer drug development is rarely linear. Setbacks are common, but they also provide invaluable learning opportunities. BioNTech’s experience in the AHEAD-MERIT study, while disappointing on one front, highlights the complexities of immune-mediated therapies and the importance of robust, long-term data collection. The scientific community will be closely watching the OS results of the AHEAD-MERIT trial, as they hold the key to understanding the full potential of BNT113 and its contribution to the evolving landscape of cancer immunotherapy. The ongoing advancements by competitors like MSD and Moderna serve as a powerful reminder of the transformative impact that mRNA technology can have, motivating BioNTech to persevere in its pursuit of effective cancer treatments.
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