8-K: Theriva's VCN-01 Boosts Pancreatic Cancer Survival

Theriva Biologics announced positive Phase 2b VIRAGE trial results for VCN-01 in metastatic pancreatic cancer, showing significant improvements in overall survival and progression-free survival.

Summary

• The VIRAGE Phase 2b trial evaluated VCN-01 (zabilugene almadenorepvec) combined with gemcitabine/nab-paclitaxel (SoC) versus SoC alone in patients with newly-diagnosed metastatic pancreatic ductal adenocarcinoma (mPDAC).
• The primary endpoint of Overall Survival (OS) was met, with VCN-01+SoC achieving a median OS of 10.8 months (95% CI: 7.4-15.8) compared to 8.6 months (95% CI: 6.9-11.6) for SoC alone (HR=0.57, p=0.034).
• Progression-Free Survival (PFS) was significantly improved, with VCN-01+SoC showing a median PFS of 7.0 months (95% CI: 4.8-11.2) versus 4.6 months (95% CI: 3.5-6.5) for SoC alone (HR=0.55, p=0.012).
• The Duration of Response (DoR) for VCN-01+SoC was 11.2 months (95% CI: 7.4-NE), more than double the 5.4 months (95% CI: 2.0-6.8) for SoC alone (HR=0.22, p=0.0035).
• Objective Response Rate (ORR) was numerically higher in the VCN-01+SoC arm at 39.6% (19/48) compared to 31.3% (15/48) for SoC.
• Disease Control Rate (DCR) was 77.1% (37/48) for VCN-01+SoC versus 70.8% (34/48) for SoC.
• A preplanned subgroup analysis of patients who received two VCN-01 doses and started the 4th cycle of SoC showed even greater benefits, with median OS of 14.8 months and median PFS of 11.2 months.
• VCN-01 combined with SoC was safe and well tolerated; VCN-01-related serious adverse events were transient and resolved, primarily flu-like symptoms, transaminase increase, and drug-induced liver injury.
• Biologic data indicated sustained VCN-01 genome levels, confirming persistent replication and bioactivity of the second dose despite the presence of neutralizing antibodies.

Sentiment

Score: 9

Explanation: The filing reports statistically significant positive results for the primary and key secondary endpoints of a Phase 2b clinical trial in a high-unmet-need cancer, indicating strong potential for the drug candidate.

Positives

• VCN-01 significantly improved Overall Survival (OS), the primary endpoint, by 2.2 months (10.8 months vs. 8.6 months) with a Hazard Ratio of 0.57 (p=0.034).
• Progression-Free Survival (PFS) was significantly extended by 2.4 months (7.0 months vs. 4.6 months) with a Hazard Ratio of 0.55 (p=0.012).
• Duration of Response (DoR) more than doubled to 11.2 months for VCN-01+SoC compared to 5.4 months for SoC alone (p=0.0035).
• Objective Response Rate (ORR) was numerically higher at 39.6% for the VCN-01 combination arm.
• The combination therapy demonstrated an acceptable safety profile and was well tolerated, with VCN-01-related adverse events being transient and resolving.
• Greater survival benefit was observed in patients who received two VCN-01 doses and had longer follow-up, suggesting a dose-dependent or cumulative effect.

Negatives

• The VCN-01+SoC arm showed a higher incidence of certain treatment-emergent adverse events (TEAEs) compared to SoC alone, including anaemia (52.8% vs 47.9%), neutropenia (50.9% vs 37.5%), thrombocytopenia (43.4% vs 35.4%), abdominal pain (49.1% vs 27.1%), nausea (60.4% vs 27.1%), vomiting (43.4% vs 20.9%), asthenia/fatigue (90.6% vs 75.0%), pyrexia (77.4% vs 25.0%), and transaminases increased (50.9% vs 20.8%).
• Two TEAEs led to death (one in each arm), though none were related to VCN-01 or SoC.

Risks

• The trial was open-label, which could introduce bias, and further evaluation in a larger, blinded clinical trial is needed.
• Adverse events, though generally manageable, were more frequent in the VCN-01 combination arm, requiring careful monitoring.
• The presence of neutralizing antibodies (NAbs) against VCN-01 was observed, although sustained VCN-01 genome levels indicated persistent replication despite NAbs.

Future Outlook

The encouraging data from the VIRAGE Phase 2b trial support further evaluation of the VCN-01 combination in a larger, blinded clinical trial with additional VCN-01 doses.

Industry Context

Metastatic pancreatic ductal adenocarcinoma (mPDAC) remains one of the most challenging cancers to treat, with a high unmet medical need and poor prognosis. The development of novel therapies like oncolytic adenoviruses, designed to selectively replicate in cancer cells, degrade tumor stroma, and enhance immune response, represents a significant advancement in oncology. VCN-01's mechanism of action, which includes expressing hyaluronidase (PH20) to improve chemotherapy penetrance, addresses key challenges in treating solid tumors like pancreatic cancer, where dense stroma often limits drug delivery and immune cell infiltration. Positive results in this difficult indication could position VCN-01 as a valuable addition to the therapeutic landscape.

Comparison to Industry Standards

• The standard of care (SoC) for mPDAC, gemcitabine/nab-paclitaxel, typically yields median overall survival rates in the range of 8-11 months in first-line settings. The 8.6 months median OS for the SoC arm in this trial is consistent with historical data.
• The VCN-01 combination's median OS of 10.8 months and median PFS of 7.0 months represent a clinically meaningful improvement over SoC alone, particularly given the aggressive nature of mPDAC.
• While direct comparisons to other investigational agents in mPDAC are not provided in the filing, the magnitude of improvement in OS and PFS, along with the doubling of DoR, suggests VCN-01 could be competitive with or superior to other emerging therapies in this space, which often struggle to demonstrate significant survival advantages.

Stakeholder Impact

• Shareholders are likely to experience a positive impact due to the significant and statistically meaningful clinical trial results, which de-risk the VCN-01 program and enhance the company's valuation.
• Patients with metastatic pancreatic ductal adenocarcinoma could benefit from a new, more effective treatment option, potentially extending their lives and improving disease control.
• The medical community gains valuable data supporting the efficacy and safety of an oncolytic adenovirus in a challenging cancer, potentially influencing future treatment guidelines and research directions.

Next Steps

• Conduct a larger, blinded clinical trial to further evaluate the VCN-01 combination, potentially incorporating additional VCN-01 doses.

Key Dates

Recommendation

The VIRAGE Phase 2b trial demonstrated statistically significant improvements in overall survival (primary endpoint), progression-free survival, and duration of response for VCN-01 combined with standard of care in metastatic pancreatic cancer. This positive clinical data for a difficult-to-treat cancer with high unmet medical need suggests strong potential for the drug and future value creation, warranting a strong buy recommendation. The meeting of the primary endpoint and the magnitude of benefit in this aggressive disease are highly encouraging.

Keywords

Theriva Biologics, VCN-01, pancreatic cancer, mPDAC, VIRAGE trial, oncolytic virus, Phase 2b, oncology, clinical trial, ESMO, zabilugene almadenorepvec, overall survival, progression-free survival