ALK-R3HDM1 and EML4-ALK fusion as a mechanism of acquired resistance to gefitinib: A case report and literature review

Case report: Durable response of ensartinib targeting EML4-ALK fusion in osimertinib-resistant non-small cell lung cancer

Background

Despite significant benefits from targeted therapy in patients with driver mutations, inevitable drug resistance usually occurred in non-small cell lung cancer, highlighting the necessity for sequential treatments to prolong overall survival. Unfortunately, durable drug response has not been reported in posterior-line therapy of cases with acquired EML4-ALK fusion after resistance to osimertinib, urging the need of referable decision-making in clinical management.

Case presentation

We present a case of a 71-year-old Chinese female, never smoker, diagnosed with invasive adenocarcinoma in the left inferior lobe of her lung, with metastases in regional lymph nodes. She received erlotinib treatment after the detection of coexistent EGFR L858R/G719S and BRAF V600E via next-generation sequencing of resected tumor tissue. Routine imaging revealed disease progression approximately 14 months after starting erlotinib treatment, followed by the detection of EGFR L858R through non-invasive liquid biopsy. Subsequently, osimertinib was administered, showing clinical activities for nearly 19 months until the emergence of an EML4-ALK fusion. Given the EML4-ALK fusion, a relatively rare resistance mechanism to osimertinib, she received third-line ensartinib treatment. One month later, alleviated tumor lesions plus normal serum marker levels demonstrated the effectiveness of ensartinib in overcoming resistance to osimertinib. Of note, the clinical response to ensartinib persisted for more than 14 months, superior to the previously reported efficacy of aletinib and crizotinib in osimertinib-failure cases. As of the last follow-up in July 2022, the patient showed no signs of recurrence and maintained a good life quality.

Conclusion

We reported a third-line ensartinib therapy in a patient with lung adenocarcinoma who developed an acquired EML4-ALK fusion after sequential treatment with erlotinib and osimertinib. Given the rarity of the EML4-ALK fusion as a resistance mechanism to osimertinib, ensartinib emerges as a promising treatment option for this specific clinical challenge, offering superior efficacy and good safety.

An advanced NSCLC patient with ALK-RNF144A and HIP1-ALK fusions treated with ALK-TKI combination therapy: a case report

Background

Anaplastic lymphoma kinase (ALK) rearrangement is one of the most important drivers in non-small cell lung cancer (NSCLC). Despite the effectiveness to canonical 3'-ALK fusions, the clinical efficacy of ALK inhibitors in patients with complex ALK fusions, such as nonreciprocal/reciprocal translocation remains uncertain. Exploring the optimal therapeutic regimens for this subset of patients is of crucial clinical significance.

Case Description

We reported a female patient diagnosed with stage IVB lung adenocarcinoma (LUAD) harboring a novel ALK-RNF144A fusion, concurrent with a Huntingtin-interacting protein 1 (HIP1)-ALK fusion and a RB1 loss-of-function variant. The patient sequentially received multiple lines of treatment with ALK-tyrosine kinase inhibitor (TKI), chemotherapy, radiotherapy and ALK-TKI combined with anti-angiogenesis. Disease progression accompanied by a squamous cell carcinoma transformation was indicated after ALK-TKI combined with anti-angiogenesis and both ALK-RNF144A and HIP1-ALK fusions were retained in the tumor. The patient was subsequently treated with a third generation ALK-TKI, lorlatinib, in combination with albumin-bound paclitaxel and anlotinib, and then achieved stable disease. The patient remained on the treatment as of the last follow-up resulting in an overall survival (OS) of more than 18 months.

Conclusions

We have reported an advanced NSCLC patient with a complex nonreciprocal/reciprocal ALK translocation containing a novel ALK-RNF144A fusion, concurrent with a RB1 loss-of-function mutation, who subsequently experienced pathological squamous cell carcinoma transformation. The combined treatment with ALK-TKI, chemotherapy, and anti-angiogenesis demonstrates clinical efficacy and may provide optional therapeutic strategies for this phenotype.