Research on arfolitixorin consolidated into a solid evidence platform

The drug candidate arfolitixorin is the first and only direct-acting form of folate that requires no conversion in the body. Preclinical studies have demonstrated that arfolitixorin can achieve higher concentrations in tumor tissue than existing folate-based drugs, and accumulated clinical data suggest that arfolitixorin has potential as a future cancer treatment with good efficacy and safety profiles.

In recent years, Isofol has conducted several early phase clinical studies to investigate the efficacy and safety profile of arfolitixorin. The results indicate that the drug is safe, well tolerated and effective.

Shown promising efficacy in phase III

Arfolitixorin has shown promising efficacy and safety results in previous studies, including the global phase III AGENT study. The study compared the effectiveness and safety of arfolitixorin with the current folate therapy, leucovorin. The results showed that arfolitixorin provided numerically comparable efficacy to leucovorin but did not demonstrate superior results. Subsequent analyses concluded that the study’s dosing regimen was suboptimal, which likely explains why no efficacy difference was observed. Recent preclinical research demonstrates that optimized dosing, involving higher doses administered in a modified sequence, has the potential to provide better treatment results.

Preclinical studies show an enhanced effect with higher dose

Other analyses conducted during 2024–2025, using different approaches and methodologies, have in various ways demonstrated that the dosing and administration regimen used in the AGENT study was suboptimal, and that an alternative dosing strategy is expected to result in a higher efficacy. Two preclinical studies have demonstrated a clear dose-response relationship for arfolitixorin – meaning efficacy increases with dose – unique to arfolitixorin and is not observed with leucovorin, the current standard of care. Therefore, higher doses are being used in the ongoing study with arfolitixorin. The preclinical studies have also made comparisons of arfolitixorin and leucovorin and found that arfolitixorin demonstrates better efficacy. This appears to hold across multiple drug combinations.

Timing of administration is key

In addition to this, analyses have demonstrated the importance of administering arfolitixorin and other folates at the optimal time to ensure concentrations of the active substance is at it’s highest when needed. It is pharmacologically essential that the concentration of the active substance is high in the tumor tissue before the biochemical reaction with 5-FU begins. Therefore, in the revised dosing regimen, arfolitixorin is administered before 5-FU rather than after. This ensures that the concentration is high from the start. As clinical studies have shown that arfolitixorin levels remain elevated in tumor cells for a prolonged period, this likely allows arfolitixorin to interact with both the initial bolus dose of 5-FU and the second, infused dose. This maximizes the potential for achieving a good therapeutic effect.

Significant commercial potential

Arfolitixorin has significant potential to contribute with something unique: a product that, once approved for marketing, can be integrated into globally established treatment regimens for some of the world’s most common forms of cancer. With patent protection until the 2040s and blockbuster potential exceeding SEK 10 billion, the foundation is in place for both scientific and commercial success.

The evidence platform in short

Unlike other early-stage clinical development programs, arfolitixorin is supported by an extensive data package based on preclinical and clinical studies conducted. The key findings from these studies are as follows:

• Dose-response relationships demonstrated in previous preclinical studies indicate that higher doses may yield improved efficacy. Furthermore, optimizing the timing of administration should further enhance efficacy due to synergistic effects between arfolitixorin and 5-FU.
• Higher doses may potentially be administered without compromising the safety profile, as indicated by PK simulations and safety data from prior studies.
• In a comprehensive global phase III study, arfolitixorin demonstrated efficacy comparable to that of the control group.

Based on these studies and analyses, a new study program is now being implemented to evaluate new dose regimens with ensured protocol compliance. The design of the new program is based on the large data package generated so far, which constitutes a strong evidence platform that strengthens Isofol’s confidence in being able to show positive results.