Changes in Blood Count as Possible Prognostic Markers of Response to Panitumumab in Patients with mCRC

At the European Society for Medical Oncology (ESMO) congress in Barcelona in the fall of 2019, data from the VALENTINO study with the administration of panitumumab in maintenance therapy in patients with metastatic colorectal cancer (mCRC) without RAS mutation were presented.

Study Methodology

The authors focused on the connection between laboratory parameters (blood count as a reflection of the inflammatory response), clinicopathological parameters, and clinical outcomes in patients randomized to administration of panitumumab with induction FOLFOX4, followed by maintenance therapy with panitumumab along with 5-fluorouracil and leucovorin or without them.

Blood count parameters were determined in patients before the start of the treatment. The authors evaluated the neutrophil-to-lymphocyte ratio (NLR), absolute monocyte count (AMC), and platelet count (PC). The definition of the inflammatory response was as follows: NLR ≥ 4, AMC ≥ 900/μl, and PC higher than the median platelet count in the study population.

Results

Overall, data from 215 patients were evaluated. NLR and AMC were significantly associated with the performance status according to the ECOG scale (ECOG PS). AMC and PC were associated with the presence of synchronous metastases and primary tumor resection.

At a median follow-up of 26.7 months, it was observed that high NLR was associated with poorer progression-free survival (PFS) with a hazard ratio (HR) of 1.51 (p = 0.015) and overall survival (OS) with a HR of 2.18 (p < 0.001). The same was true for AMC (HR for PFS 1.85; p = 0.003 and HR for OS 2.49; p < 0.001) and high PC (HR for PFS 1.65; p = 0.001 and HR for OS 1.85; p = 0.003).

In a multivariate model, it was confirmed that only PC was independently associated with PFS and OS, while AMC was independently associated only with PFS. No significance was shown for NLR.

The benefit of adding 5-fluorouracil and leucovorin to panitumumab in maintenance therapy on PFS was independent of NLR and AMC, but was significantly maintained only in the group with low PC.

Conclusion

In patients with metastatic colorectal cancer without RAS mutation, the VALENTINO study found that baseline platelet count was independently associated with OS and PFS, baseline AMC was independently associated with PFS. Patients with high platelet count did not benefit from the addition of 5-fluorouracil and leucovorin to panitumumab in maintenance therapy.

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Source: Fuca G., Guarini V., Corallo S. et al. Prognostic role of blood cell count-based immunoinflammatory parameters in the Valentino trial. Ann Oncol 2019; 30 (Suppl. 5): V228; doi: 10.1093/annonc/mdz246.082.