Can white blood cell levels predict response to ipilimumab in metastatic melanoma?

This study investigated whether the neutrophil count (NC; a type of white blood cell) and neutrophil-to-lymphocyte (another type of white blood cell) ratio (NLR) can predict prognosis in metastatic (spread to other parts of the body) melanoma patients treated with ipilimumab (Yervoy).

Researchers suggested that the NC and NLR are important prognostic factors to better identify patients who will benefit most from treatment.

Ipilimumab is an important treatment option for melanoma patients. This treatment stimulates the immune system to fight melanoma cells the way it would a virus or bacteria. However, some patients do not benefit as much from treatment with this drug. Some blood factors were associated with survival of patients treated with ipilimumab, including the NC and NLR. The NC and NLR could be an efficient way to evaluate prognosis and identify who would benefit most from this treatment.  

The objective of this study was to evaluate the association between NC, NLR and melanoma outcome.

This study reviewed the records of 720 patients treated with ipilimumab. Patients received 3mg/kg of the drug every 3 weeks and blood cells were analyzed before and after treatment. Tumor response was checked at the beginning of the treatment, at week 12 and every 12 weeks thereafter. The average follow-up period was 16.5 months.

Overall survival (OS; time from treatment to death from any cause) and progression-free survival (PFS; time from treatment to disease progression) were evaluated.

For patients with a normal NC the OS was 8.7 months and PFS was 4 months. In patients with an increased NC, OS was 2.3 months and PFS was 1.7 months. An increased NC was associated with 3.38 times the mortality risk and 2.52 times the risk of disease progression.   

For patients with a normal NLR, the OS was 9.2 months and PFS was 4.3 months, compared with an OS of 2.7 months and a PFS of 2.4 months for patients with an increased NLR. An increased NLR was associated with 2.29 times the mortality risk and 2.03 times the risk of disease progression.

The two increased factors combined were also associated with worse disease progression and survival. And an increase in NC, NLR and LDH (lactate dehydrogenase, an enzyme that indicates cell damage in the body) was associated with a 13-fold increase in risk of death when compared with patients with normal levels. 

This study suggested that NC and NRL are good factors to determine the prognosis of patients treated with ipilimumab.