Combined BRAF G469A mutation and echinoderm microtubule associated protein like-4-anaplastic lymphoma kinase rearrangement with resistance: A case report and review of literature

Abstract

BACKGROUND

Through deeper understanding of targetable driver mutations in non-small-cell lung cancer (NSCLC) over the past years, some patients with driver mutations have benefited from the targeted molecular therapies. Although the anaplastic lymphoma kinase and BRAF mutations are not frequent subtypes in NSCLC, the availability of several targeted-drugs has been confirmed through a series of clinical trials. But little is clear about the proper strategy in rare BRAF G469A mutation, not to mention co-exhibition of anaplastic lymphoma kinase and BRAF G469A mutations, which is extremely rare in NSCLC.

CASE SUMMARY

We present a patient to stage IVA lung adenocarcinoma with coexisting echinoderm microtubule associated protein like-4 rearrangement and BRAF G469A mutation. She received several targeted drugs with unintended resistance and suffered from unbearable adverse events.

CONCLUSION

Due to the rarity of co-mutations, the case not only enriches the limited literature on NSCLC harbouring BRAF G469A and echinoderm microtubule associated protein like-4 mutations, but also suggests the efficacy and safety of specific multiple-drug therapy in such patients.

Key Words: Non-small-cell lung cancer; Driver mutation; Rearrangement; Resistance; Case report

Core Tip: We present a non-small-cell lung cancer patient with rarely co-occurring echinoderm microtubule associated protein like-4 rearrangement and BRAF G469A mutation. The patient suffered from anaplastic lymphoma kinase tyrosine kinase inhibitors resistance and adverse events. It’s a question whether the process of reducing dosage of alectinib was easier to cause resistance. Although we were unable to assess the correlation between BRAF G469A mutation and anaplastic lymphoma kinase tyrosine kinase inhibitors resistance, the safety and efficacy of combination therapy to multiple driver oncogenes are important in clinic.

INTRODUCTION

Non-small-cell lung cancer (NSCLC) as the major histology of lung cancer traditionally leads serious prognosis and cancer death, due to late diagnosis at an advanced stage and absence of effective systemic treatments[1]. With deeper cognition about molecular mechanisms, NSCLC was closely related to specific genetic mutations resulting into target medical therapy. Undoubtedly, the mutation of the epidermal growth factor receptor as the most common oncogenic driver approximately appears in 50% of Asian patients with NSCLC[2]. In addition, the rearrangement of anaplastic lymphoma kinase (ALK) is detectable in 2%-7% of NSCLC patients, who may get clinical benefit from ALK tyrosine kinase inhibitors (ALK-TKIs)[3]. Among other types of unusual mutations, BRAF harbor a mutation in 1%-4% of all NSCLC, particularly in adenocarcinomas[4]. The rearrangement of ALK is frequently found in non-smokers of NSLCL, while BRAF mutation is associated with new or past smoking[5]. Unfortunately, the published literature on co-occurring BRAF mutation and ALK rearrangement leading to target drug adjustment in NSCLC is limited. Here, we presented a patient of NSCLC with co-mutations of ALK and BRAF genes displayed target drug resistance and adverse events of combination therapy.

CASE PRESENTATION

Chief complaints

A 62-year-old female patient without smoking history visited our hospital with cough, chest pain and dyspnea for 1 week. Adenocarcinoma was confirmed by pathological examinations of exfoliated cells in pleural effusion via closing thoracic drainage. In addition, positron emission tomography-computed tomography revealed multiple bilateral pulmonary foci, especially in the upper lobe of the right lung paralleling the hilar lymph metastasis.

History of present illness

A 62-year-old female patient without smoking history visited our hospital with cough, chest pain and dyspnea for 1 week.

History of past illness

She had no past disease.

Personal and family history

There is none family history.

Physical examination

The next-generation sequencing (NGS) assay was performed on RNA isolated from the liquid biopsy, displaying ALK rearrangement harboring type of echinoderm microtubule associated protein like-4 (EML4-ALK) (MAF = 6.72%) and missense mutation of TP53 on p.P152L site (MAF = 2.25%). In order to identify the immunotherapeutic response in clinic, immunohistochemistry was used to analyze programmed cell death protein ligand 1 (PD-L1) expression and found non-stained PD-L1 with 0% in tumor proportion score and combined positive score (Figure 1). The data suggested that she limited beneficial to programmed death 1 blockade immunotherapy.

Figure 1 Pathological examination and immunostaining of programmed cell death protein ligand 1. A: Programmed cell death protein ligand 1 in tumor proportion score; B: Programmed cell death protein ligand 1 in combined positive score; C: Positive control; D: Negative control.

Laboratory examinations

To accurately and timely evaluate the efficacy of treatment, multicriteria monitors on sensitive biomarkers of NSCLC as carbohydrate antigen 125 and carcinoembryonic antigen in blood per month were used, which was shown in Table 1.

Table 1 Characteristics of blood in clinic.

	Nov 2020	Dec 2020	Jan 2021	Feb 2021	Mar 2021	Apr 2021	May 2021	Jun 2021	Jul 2021	Aug 2021	Sep 2021	Oct 2021	Nov 2021	Dec 2021	Jan 2022	Feb 2022	Mar 2022	Apr 2022
WBC (109/L)	6.7	7.3	4.4	3.7	6.8	7.2	6.1	5.8	5.3	5.4	6.4	8.2	9	19.2	4.7	5.9	4.1	3
Hb (g/L)	138	127	120	115	117	115	108	112	117	106	98	113	95	102	89	95	97	87
Plt (109/L)	253	267	223	213	242	223	267	252	265	252	301	296	432	392	423	456	349	297
ALT (IU/L)	30.4	54.3	103.8	25.3	35.2	19.6	26.1	19.7	21.4	27.9	14.3	15.1	13.1	16.6	187.9	12.1	19.8	17.1
AST (IU/L)	33.2	43.2	61.9	57.8	27.3	32.9	28.2	33.3	32.9	41.1	23.7	23.2	18.9	20.3	153.7	25.2	25.7	24.5
CEA (U/mL)	58.8	16.4	3.7	4.6	5.2	4.2	3.8	1	2.1	1.5	1.7	1.4	65.8	3.1	3.3	2	7.2	3.95
CA125 (ng/mL)	9.3	3.5	4.2	15.6	6.9	7.2	5.4	5.1	9.6	23.9	46.6	35	495.5	104.6	35.1	14.7	1.6	2.74

WBC: White blood cell; Hb: Hemoglobin; Plt: Platelet; ALT: Alanine transaminase; AST: Aspartate transaminase; CEA: Carcinoembryonic antigen; CA125: Carbohydrate antigen 125.

Imaging examinations

Chest computed tomography for the lung lesion absorption was routinely investigated per 3 months (Figure 2).

Figure 2  Computed tomography scans of the patient.

FINAL DIAGNOSIS

The clinical stage of NSCLC was IVA (cT2N1M1a).

TREATMENT

Afterward, she received alectinib 600 mg twice daily as the first-line therapy with the progression-free survival (PFS) of 3 months. To accurately and timely evaluate the efficacy of treatment, multicriteria monitors on sensitive biomarkers of NSCLC as carbohydrate antigen 125 and carcinoembryonic antigen in blood per month were used, which was shown in Table 1. Chest computed tomography for the lung lesion absorption was routinely investigated per 3 months (Figure 2). Although alectinib was confirmed to be more useful anti-ALK therapeutic agent, its adverse events also deserved more attention[6]. Routine blood examination, liver and function were monitored every month. For 88 days after alectinib administration, the patient was admitted to hospital again for unbearable vomiting, excessive fatigue and muscle soreness. We checked and found the significant dysfunction of liver, as unintended high levels of alanine transaminase and aspartate transaminase in Table 1. The adverse events of alectinib were never released by routine drugs for protecting the liver. Then, we had to adjust the dosage to alectinib at 450 mg twice a day a tentative reduction. For more than 7 months in a continuous stable with treatment, she was admitted to hospital for increased right pleural effusion. Malignant pleural effusion (MPE) by cytological examination proved an aggravation of the condition, alectinib resistance and tumor recurrence. To optimize the effective anti-cancer strategy, NGS was reperformed and revealed EML4-ALK rearrangement (MAF = 10.13%), missense mutation of TP53 on p.R273H site (MAF = 5.66%) and BRAF G496A (MAF = 6.24%). Because of unable access lorlatinib and trametinib at that time, the treatment strategy by consideration of multidisciplinary team discussion was shifted to the combination therapy of alectinib 600 mg twice daily and dabrafenib 150 mg every 12 hours. For nearly 3 months remissive state of illness, she suffered from dysfunction of the liver and rapidly growing of MPE. Dates were shown in Table 1 and Figure 2.

OUTCOME AND FOLLOW-UP

After rigorous contemplation and following the desires of patient, the combination treatment consisted ceritinib (750 mg once daily), anlotinib (12 mg once daily) and chemotherapy with pemetrexed and carboplatin. After 2 courses of treatment, clinical symptoms relieved and MPE tended to be stable.

DISCUSSION

With the increasing availability of targeted anti-cancer medications in recent years, certain individuals with NSCLC who possess certain mutations may benefit in terms of prognosis and clinical aspects. Once inevitable drug-resistant has evolved, there’s little therapy alternatives. As far as we are aware, no reports exist of co-occurring EML4-ALK rearrangement and BRAF G469A mutation in NSCLC. There is currently minimal expertise selecting medications for these people. Here, we describe a unique case of adenocarcinoma patient with a multi-gene mutation and a complex medication regimen that is generating side effects.

When adenocarcinoma histology was seen in younger non-smokers, ALK rearrangement as diamond mutation was commonly observed. Since EML4-ALK fusion in NSCLC was widely accepted[7], several clinical trials confirmed the increased PFS and overall survival in NSCLC patients with ALK-TKI treatment[8-10]. Crizotinib, the first-generation ALK-TKI, was allowed to treat NSCLC with ALK rearrangement and significantly increased 8-11 months PFS compared with chemotherapy[10,11]. On the other side, the clinical progression and brain metastasis in NSCLC patients with ALK-positive especially were developed during the first year of crizotinib use[12]. The reasons were blamed on resistance to crizotinib and low concentration of drug in the central nervous system[6]. Adverse events of crizotinib as visual impairment, diarrhea, nausea, and liver dysfunction were not obviously neglectable. Subsequently, alectinib as the second-generation ALK inhibitor showed high objective responses with median PFS of 8.9 months in crizotinib-resistant ALK-positive NSCLC patients, even who have distant metastases including central nervous system metastases[13-15]. In 2018, national comprehensive cancer network guidelines recommend alectinib as the first line treatment option[16]. In our report, alectinib was firstly used at recommended dosage to adenocarcinoma with ALK rearrangement. Although the incidence of adverse events in alectinib is less than those in crizotinib, complications of vision, gastrointestinal tract, blood system, headache, skin toxicities, pulmonary disorders and others were certain facts[17]. The female in our case occurred vomiting, excessive fatigue and muscle soreness caused by alectinib-induced abnormal liver-function. The sides were released when the dose of drug was reduced. Unfortunately, alectinib resistance and MPE progression come unexpectedly. It’s a question whether the process of reducing dosage of alectinib was easier to cause resistance. But we have to accept the condition. In addition, other second generation of ALK-TKIs as ceritinib, brigatinib and ensartinib with greater potency acceptable safety were already proved to inhibit ALK mutations after crizotinib resistance[18,19]. Given the drug access and patient’s economy, we chose ceritinib to combine with other drugs as the alternative once alectinib turned out to be useless. Moreover, the ALK in lung cancer trial of brigatinib-2 study revealed that lorlatinib could be recommended as a chosen option for progressive stage in ALK-positive NSCLC patients with first ALK inhibitor therapy[20]. The next-generation ALK inhibitor TPX-0131 was confirmed to have potencies against resistant mutations, especially the G1202R solvent front mutation and compound mutations[21]. However, it needs to integrate more data for considering the safety and side effects of these ALK-TKIs.

As a rare mutation, BRAF-positive NSCLC patients tend to be smokers and adenocarcinoma[22]. One known risk factor for lung cancer is smoking. It is true that the mortality rate from lung cancer can be lowered by quitting smoking. Certain compounds have been proposed as mutagens when inhaled. It has been established that smoking causes gene mutations, which make treatment more complex and the prognosis poorer[5,22]. The most type of BRAF mutations is V600E, while G469A accounts for nearly 23%[23]. From investigation in 2001 NSCLC cases, Kinno et al[24] confirmed the low frequency of BRAF mutation in an Asian cohort. In the previous study, the combination between dabrafenib and vemurafenib contributed an improved objective response rate of 33%-42% to BRAF V600E mutant metastatic NSCLC[25]. Notwithstanding the benefit to target therapy is attractive, the valuable information is limited for BRAF-mutated NSCLC on non-V600E, especially G469A. Although Negrao et al[26] revealed the meaningful sensitivity of human lung cancer cells with BRAF G469 mutant to trametinib plus or minus dabrafenib, the United States Food and Drug Administration approved dabrafenib plus trametinib for BRAF V600E mutant NSCLC, but not for patients with BRAF G469A mutation[27]. An in vitro study also suggested that trametinib or erlotinib significantly suppressed the growth of lung tumoroid line with BRAF G469A mutation[28]. Based on the preclinical results, some scholars considered the possibility of similar effects with trametinib alone to BRAF G469A mutation NSCLC. However, it’s not enough and needs more data to support. There’s a case report of a patient with NSCLC and the BRAF G469R mutation who showed a dramatic response to sorafenib[29]. Unfortunately, sorafenib has not been allowed to treat NSCLC by now. In our case, the second NGS confirmed the co-occurring ALK-EML4 and BRAF G469 mutations. Considering the positive effects of alectinib at 600 mg twice daily and adverse events of combination therapy, we commanded alectinib plus dabrafenib as the first choice in this case. The clinical value of anti-tumor progress was appeared for a while. Once severe adverse events and advanced MPE popped up again, we tented to use ceritinib, anlotinib and chemotherapy together under complex consideration including trametinib unobtainable. As a multi-target TKI, anlotinib mainly acts anti-tumor effects through anti-vascular endothelial growth factor, anti-VEGF biology[30,31]. And anlotinib as third-line drug was approved to treat advance NSCLC. Combination therapy significantly alleviated the progress of cancer and adverse events. The curative effects and safety need to be further investigated.

The potential impacts on target drug choice and response in co-exhibition of activating mutations should not be neglected. There may be internal roles on resistant pathways in a rare coexistence of BRAF G469A mutation and EML4-ALK rearrangement. Alrifai et al[32] reported a patient with squamous cell carcinoma harbouring both BRAF V600E mutation and an ALK rearrangement exhibited resistance to crizotinib. Another study on a patient of ALK rearranged paralleling BRAF V600E mutation lung adenocarcinoma with acquired resistance to crizotinib indicated that BRAF V600E mutation might be responsible for ALK-TKI resistance[33]. Furthermore, BRAF G469A mutation was confirmed to be an activator of resistance to osimertinib in a vitro study[34]. Although BRAF-mutant NSCLCs were reported to have a better response to immune-checkpoint inhibitors, but the specific G469A subgroup was not enrolled[35]. Due to no PD-L1 expression in our case, the immune-checkpoint inhibitors will not the better choice.

CONCLUSION

Here, we report a patient of NSCLC harboring co-occurring BRAF G469A and EML4-ALK mutations in twisting process of complicated drug therapy. Although we were unable to assess the correlation between BRAF G469A mutation and ALK-TKI resistance, the safety and efficacy of combination therapy to multiple driver oncogenes are important in clinic. Future studies are warranted to validate the mechanisms of drug resistance on patients with multiple gene co-mutation, in order to benefit from targeted treatment.