Arfolitixorin, a proprietary drug candidate being developed by clinical stage biotech company Isofol Medical to increase the efficacy of standard of care chemotherapy for advanced colorectal cancer, has received a clinical patent in the United States.

The drug candidate is currently being studied in a global Phase III clinical trial (NCT03750786) [1]

This trial is a multicenter, randomized, parallel-group, Phase III study in at least 440 patients with advanced colorectal cancer to compare the efficacy of treatment with arfolitixorin versus leucovorin (folinic acid) in combination with 5-fluorouracil (Adrucil?; Teva Generics), oxaliplatin (Eloxatin?; Sanofi Genzyme), and bevacizumab (Avastin?; Genentech/Roche) according to modified FOLFOX-6* until Progressive Disease (PD) according to the Response Evaluation Criteria in Solid Tumors (RECIST 1.1 criteria).

Folate-based drugs

Today, more than 500,000 patients in the United States, Japan and Europe, are treated with folate-based therapies annually.

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While beneficial, current folate-based therapies are prodrugs that need multiple activation steps into an active metabolite to exert their actions.

In contrast, as the key active metabolite of the widely used folate-based drugs, arfolitixorin can potentially benefit patients with advanced colorectal cancer, as it does not require complicated metabolic activation to become effective.

“This patent, which has been applied for world-wide, is considered of high importance for Isofol.” noted Anders Rabbe, Chief Executive Officer of Isofol Medical.


The patent, which expires in 2038 and is the first in a series of clinical patent applications to be granted to the company, is for a method of increasing blood concentration of deoxyuridine, a blood biomarker for inhibition of tumor growth in human cancer treatment.

The granted patent, US 10,292,984, is directed towards a dose regime for the combination of arfolitixorin and 5-fluorouracil injections to cancer patients and its superior effectiveness of reducing tumor growth compared to leucovorin and 5-fluorouracil. This better effect is due to a stronger inhibition of Thymidylate Synthase (TS), a vital enzyme for the DNA synthesis and tumor growth, which can be simply measured as the increased level of the biomarker deoxyuridine in blood samples from patients.[2]

?This patent, which has been applied for world-wide, is considered of high importance for Isofol.” noted Anders Rabbe, Chief Executive Officer of Isofol Medical.

“It is a clinical patent based on data derived from clinical studies with arfolitixorin demonstrating potential superior activity for arfolitixorin and 5-fluorouracil treatment compared to today?s standard of care therapy with leucovorin and 5-fluorouracil,? he added.

Isofol Medical holds a worldwide exclusive license agreement with Merck KGaA, Darmstadt, Germany to develop and commercialize arfolitixorin for oncology indications.


[1] A Study to Compare the Efficacy of Arfolitixorin Versus Leucovorin in Combination With 5 Fluorouracil, Oxaliplatin, and Bevacizumab in Patients With Advanced Colorectal Cancer (AGENT) – NCT03750786.

[2] US Patent: Methods for increasing blood plasma 2′-deoxyuridine (dUrd) and thymidylate synthase inhibition [Online]

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