Ocular toxicity of investigational anti-cancer drugs in early phase clinical trials

Ocular toxicities arising from anti-cancer drugs occur sporadically and are sometimes underestimated because they are not life-threatening. Reports focusing on ocular toxicities from cancer therapy are limited. We investigated the detailed progress of ocular toxicities of anti-cancer drugs including first-in-class ones. A retrospective review of medical records was conducted for patients who were involved in early phase clinical trials with scheduled ophthalmologic examinations according to their protocols between January 2014 and August 2021. Patients with ocular toxicity suspected to be related to the investigational drugs in the ophthalmic examination were investigated in detail. In total, 37 ocular toxicities related to investigational drugs occurred in 7.6% of patients (33/434). The median age of the 33 patients was 61 years (range, 33–76 years), and 20 were male. Causal drugs with a high incidence of ocular toxicities were HSP90 inhibitors and FGFR inhibitors. Retinopathy was most frequent, while conjunctivitis, dry eye, keratitis, keratopathy, and uveitis were also observed. Dim vision as a subjective finding was a unique adverse event. Most patients developed ocular toxicities even though their dose was below the drug’s maximum tolerated dose. Except for one case, all ocular toxicities occurred bilaterally. About 60% (22/37) of ocular toxicity cases needed a temporary hold of the drug. All except for three cases fully recovered. This study reported the risks and timing of the onset of a variety of ocular toxicities of anti-cancer drugs, which were fundamentally controllable. (Trial registration number. Retrospectively registered)