Efficacy and Safety of Add-on Topical Timolol in the Management of Epidermal Growth Factor and Anaplastic Lymphoma Kinase Receptor Tyrosine Kinase Inhibitor-induced Paronychia: a Prospective Randomized Open-labelled Trial

Lung cancer is the second leading cause of cancer and the leading cause of cancer-related death in Hong Kong. Non-small cell lung cancer (NSCLC) accounts for 85% of lung cancer patients. Adenocarcinoma and squamous cell carcinoma accounts for 40% and 25-30% of NSCLC patients, respectively. More than 75% of patients are diagnosed with stage III and IV lung cancer. The age-standardized one-year overall survival rate of stage III and IV NSCLC are 35-46% and 15.9-15.6%, respectively. Therefore, the management of locally advanced and metastatic lung cancer is important to improve the overall survival of NSCLC patients.

The management of locally advanced and metastatic NSCLC is actionable driver mutation dependent. Patients are recommended to have tissue biopsy to detect the actionable driver mutation. Epidermal growth factor receptor (EGFR) mutation accounts for 55.4% of actionable driver mutation in Hong Kong. Patients with EGFR mutation positive are recommended to receive EGFR tyrosine kinase inhibitor (EGFR-TKI) by the European Society of Medical Oncology and the National Comprehensive Cancer Network. Anaplastic lymphoma kinase (ALK) is another common is actionable driver mutation with tyrosine kinase inhibitor (TKI) including crizotinib, ceritinib, alectinib, brigatinib and lorlatinib.

Paronychia is one of the common adverse events in patients who receive EGFR-TKI(s) and other TKI. 17.6-57% of patients experienced paronychia in randomized controlled trials. There were 0.6-11% of patients who experienced grade 3 paronychia according to the Common Terminology Criteria for Adverse Events version 5.0 (CTCAEv5.0) in randomized controlled trials.

Timolol and betaxolol are beta-blockers, which are hypothesized to be effective in managing paronychia. Beta-blockers were effective in hemangiomas and has been the first line treatment for severe infantile hemangiomas. Previous case reports and case series suggested the potential use of topical beta-blocker. However, the evidence of topical beta-blocker treatment was limited by small sample size and low level of evidence. Therefore, this study aims to compare the safety and efficacy of topical timolol with routine clinical care with paronychia (fingernails, toenails, or both) as an adverse effect of EGFR-TKI and ALK-TKI.

This study would assess the clinical efficacy of add-on topical timolol 0.5% eye drops to betamethasone valerate 0.1% for the treatment of EGFR-TKI and ALK-TKI induced paronychia. Eligible patients, who develop paronychia (affecting fingernails, toenails or both), will be included in this study. They will be randomized in 1:1 ratio using computer-generated randomization list to receive either combination of topical timolol 0.5% eye drops and betamethasone valerate 0.1% lotion application twice daily or betamethasone valerate 0.1% lotion application twice daily. Patients in timolol combination treatment group will receive topical timolol 0.5% eye drops twice daily with occlusion (i.e. covered with adhesive badge) and betamethasone valerate 0.1% lotion twice daily with occlusion for 1 month. Patients in routine arm would receive the management according to routine clinical practice, including prescription of betamethasone valerate 0.1% lotion twice daily for 1 month with occlusion. For patients who do not have paronychia completely resolved after 4 weeks, the treatment assigned will be continued for another 4 to 8 weeks , up to 12 weeks to see the effect.