A phase 2 study of TMX-101, intravesical imiquimod, for the treatment of carcinoma in situ bladder cancer.

PURPOSE: Imiquimod is a toll-like receptor agonist with proven antitumor activity as a topical treatment for skin cancer. TMX-101 (Vesimune) is a novel liquid formulation of imiquimod optimized for intravesical delivery. The agent demonstrated safety as an intravesical treatment for non-muscle-invasive bladder cancer in a phase 1 clinical trial. We report the results of a phase 2 prospective multicenter clinical trial assessing the safety and activity of TMX-101. MATERIALS AND METHODS: Patients with non-muscle-invasive bladder cancer containing carcinoma in situ were eligible for inclusion. Enrolled patients received 6 weekly intravesical administrations of 200mg/50ml TMX-101 0.4%. End points included rate of adverse events, changes in urinary cytokine levels following treatment, and clinical response at 6 weeks following final instillation, defined as negative posttreatment bladder biopsy and urine cytology results. RESULTS: A total of 12 patients were enrolled, with 10 available for efficacy analysis. Half of the patients (6/12) had received≥2 prior induction courses of bacillus Calmette-Guerin. All patients received all 6 doses of TMX-101 per protocol. Overall, 75% of patients experienced treatment-related adverse events, only 1 of which was>grade 2 (urinary tract infection). Furthermore, 2 patients demonstrated a negative cytology and biopsy result at 6 weeks following treatment. Significant increases in urinary cytokines, including IL-6 and IL-18, were seen following treatment. CONCLUSION: In this phase 2 pilot study in patients with carcinoma in situ bladder cancer, intravesical TMX-101 was safe and well tolerated with common, mild genitourinary adverse effects. Clinical activity was suggested by the increase in posttreatment urinary cytokines. Complete responders were seen. Further investigation of the agent is warranted.

Toll-like receptors as therapeutic targets for cancer.

Stimulation of Toll-like receptors (TLRs) to activate the innate immune system has been a legitimate therapeutic strategy for some years. TLRs 3, 4, 7, 8 and 9 are all validated targets for cancer and a number of companies are developing agonists and vaccine adjuvants. TLR7 in particular has established proof-of-concept as a target in the topical treatment of bladder and skin cancers. However, the development of systemic treatments targeting TLR7 for most other cancers has proved difficult owing to cardiotoxicity or myelosuppression. Tantalisingly, recent animal data have demonstrated that a new class of modified TLR7 agonists can be administered systemically with a good toxicology profile, opening up this target in therapeutic interventions for systemic cancers.

Inhibition of keratinocyte proliferation by phospholipid-conjugates of a TLR7 ligand in a Myc-induced hyperplastic actinic keratosis model in the absence of systemic side effects.

BACKGROUND: The Toll-like receptor 7 (TLR7) activator imiquimod (IMQ) is safe and effective in treating actinic keratosis; however, an intermittent treatment regimen is necessary because of excessive local reactions. OBJECTIVES: To evaluate in vitro potency, pharmacodynamics/pharmacokinetics, toxicity and efficacy in vivo of the newly developed TLR7 ligand-phospholipid conjugate, TMX-202, in a gel formulation. MATERIAL AND METHODS: The effects of TMX-202 were assessed both in vitro on a murine macrophage cell line and in primary bone marrow-derived dendritic cells and in vivo on mice (C57BL/6-wild type, Myd88(-/-) and Tlr7(-/-)). RESULTS: TMX-202 was more potent than IMQ in vitro using murine and human cells. In contrast, in vivo it showed less systemic pro-inflammatory activity and better safety than IMQ. Moreover, the TMX-202 gel formulation exhibited at least comparable efficacy to Aldara in a mouse model for skin proliferative diseases. CONCLUSION: TMX-202 is safe and efficacious without causing excessive adverse effects, suggesting that it may be an alternative to Aldara for the treatment of proliferative skin conditions.