Tenofovir Exalidex (TXL™)

Tenofovir exalidex (TXL) is a highly potent prodrug of the antiviral tenofovir. Tenofovir is the active component of both Vemlidy® (tenofovir alafenamide) and Viread® (tenofovir disoproxil fumarate). TXL’s novel liver-targeting prodrug structure results in decreased systemic circulating levels of tenofovir, thereby reducing the potential for off-target effects, including renal and bone side effects. ContraVir has completed a Phase 2 trial of TXL, in which HBV-infected subjects were administered doses up to 100 mg for 28 days. The oral dosage formulation is now being optimized to further enhance drug delivery to the liver. To date, TXL has achieved clinical proof of concept for antiviral activity and displayed an excellent safety, tolerability, and pharmacokinetic profile. Based on the agent’s best-in-class potential, ContraVir believes TXL can become the cornerstone of a curative combination therapy for hepatitis B, as HBV DNA levels were significantly reduced in clinical trials.

Healthy Liver
Liver with Cirrhosis

Potential Advantages of TXL

Potent Antiviral Activity at Lower Doses
  • 50 mg/day TXL comparable to Viread® 300 mg/day
Favorable Pharmacokinetics Compared to Viread®
  • Profile consistent with target organ specificity (liver) resulting in fewer “off-target” effects
  • Significantly lower levels of systemically circulating tenofovir in blood
Safety Profile
  • Well-tolerated up to 100 mg daily, with no safety signal
  • No dose adjustments for patients with severe renal impairment
  • Potential for decreased bone and kidney toxicity
Strong Candidate to be Partner of Choice
  • Expected to be stand-alone product and backbone to functional cure based on strong safety and efficacy profile
  • Potential to be economically more attractive for potential partners as a Phase 3-ready asset
  • May not be required to be taken with food
  • Potential to offer “best-in-class” target organ specificity (liver)