Complete response to nivolumab monotherapy in a treatment-naive, BRAF wild-type patient with advanced mucosal melanoma and elevated lactate dehydrogenase: a case report from a phase III trial.

The anti-PD-1 agent, nivolumab, has been approved both as monotherapy and in combination with ipilimumab for the treatment of unresectable or metastatic melanoma in the USA and European Union. Here we present the case of a patient with treatment-naive, metastatic mucosal melanoma and baseline LDH approximately seven times the upper limit of normal. The patient was enrolled in a clinical trial (CheckMate 066) and achieved a partial response, followed by a durable complete response with nivolumab treatment. The patient's LDH levels were documented in each cycle and dropped markedly within 2 months, when partial response to treatment was already evident. LDH levels remained low for the rest of follow-up, consistent with the ongoing complete response to treatment. The patient experienced only mild immune-related adverse events (grade 1-2), which included vitiligo and rash. This exceptional response suggests that patients with high LDH levels at baseline should be considered for nivolumab treatment. LDH levels, however, should not serve as a predictive marker of response to nivolumab. Moreover, this case suggests the need to identify patients who will achieve the greatest benefit from nivolumab monotherapy.