Ruxolitinib Enables Safe Rechallenge of BRAF/MEK Inhibitors in HLH-Like Syndrome

Overview

This case study reports the first instance of hemophagocytic lymphohistiocytosis (HLH)-like hyperinflammatory syndrome induced by dabrafenib and trametinib in a patient with BRAF V600E-mutated lung adenocarcinoma. The patient’s HLH-like symptoms were refractory to corticosteroids but successfully managed with ruxolitinib, allowing continued targeted cancer therapy and sustained disease control.

Background

BRAF V600E mutations drive a subset of lung adenocarcinomas and are effectively targeted by combined BRAF and MEK inhibitors such as dabrafenib and trametinib. Although generally well tolerated, these agents can rarely trigger immune-mediated toxicities including HLH, a severe hyperinflammatory syndrome characterized by excessive cytokine release and multiorgan dysfunction. HLH is more commonly associated with hematologic malignancies, infections, or immune checkpoint inhibitors, but emerging reports implicate targeted therapies as potential triggers. Prompt recognition and management of HLH-like syndromes are critical to prevent life-threatening complications.

Data Highlights

Key Findings

• Dabrafenib and trametinib induced an HLH-like hyperinflammatory syndrome shortly after initiation in a patient with metastatic BRAF V600E-mutated lung adenocarcinoma.
• The patient exhibited markedly elevated ferritin and inflammatory markers with clinical deterioration but did not fulfill full HLH-2004 diagnostic criteria.
• Corticosteroids initially improved symptoms and ferritin levels, but HLH-like features recurred upon rechallenge with BRAF/MEK inhibitors.
• Introduction of ruxolitinib, a JAK1/2 inhibitor, alongside low-dose corticosteroids allowed continued BRAF/MEK inhibitor therapy with improved inflammatory markers and symptom control.
• Adjustments in ruxolitinib dosing and BRAF/MEK inhibitor frequency facilitated steroid discontinuation and sustained disease control of both HLH-like syndrome and lung adenocarcinoma.

Clinical Implications

Clinicians should be aware of HLH-like hyperinflammatory syndrome as a rare but serious immune-mediated toxicity of BRAF/MEK inhibitors in lung adenocarcinoma patients. Early recognition and intervention with corticosteroids are essential, but steroid-sparing agents such as ruxolitinib may be necessary to manage refractory cases. Co-administration of ruxolitinib can enable safe rechallenge with targeted therapies, maintaining oncologic control while mitigating hyperinflammation.

Conclusion

This case highlights HLH-like hyperinflammatory syndrome as an uncommon toxicity of BRAF/MEK inhibitors and demonstrates that ruxolitinib is a promising adjunctive therapy to safely continue targeted treatment in affected patients. Further studies are warranted to establish standardized management protocols.

References

1. HLH-2004 Guidelines -- Diagnostic Criteria for Hemophagocytic Lymphohistiocytosis