Apatinib in patients with recurrent or metastatic adenoid cystic carcinoma of the head and neck: a single-arm, phase II prospective study

Current diagnosis and treatment of salivary gland-type tumors of the lung

Salivary gland-type tumors of the lung are thought to originate from the submucosal exocrine glands of the large airways. Due to their rare occurrence, reports of their study are limited to small-scale or case reports. Therefore, daily clinical practices often require a search for previous reports. In the last 20 years, several genetic rearrangements have been identified, such as MYB::NF1B rearrangements in adenoid cystic carcinoma, CRTC1::MAML2 rearrangements in mucoepidermoid carcinoma, EWSR1::ATF1 rearrangements in hyalinizing clear cell carcinoma and rearrangements of the EWSR1 locus or FUS (TLS) locus in myoepithelioma and myoepithelial carcinoma. These molecular alterations have been useful in diagnosing these tumors, although they have not yet been linked to molecularly targeted therapies. The morphologic, immunophenotypic, and molecular characteristics of these tumors are similar to those of their counterparts of extrapulmonary origin, so clinical and radiologic differential diagnosis is required to distinguish between primary and metastatic disease of other primary sites. However, these molecular alterations can be useful in differentiating them from other primary lung cancer histologic types. The management of these tumors requires broad knowledge of the latest diagnostics, surgery, radiotherapy, bronchoscopic interventions, chemotherapy, immunotherapy as well as therapeutic agents in development, including molecularly targeted agents. This review provides a comprehensive overview of the current diagnosis and treatment of pulmonary salivary gland tumors, with a focus on adenoid cystic carcinoma and mucoepidermoid carcinoma, which are the two most common subtypes.

Translational Insights in the Landscape of Salivary Gland Cancers: Ready for a New Era?

Salivary gland carcinomas (SGCs) are rare neoplasms, representing less than 10% of all head and neck tumors, but they are extremely heterogeneous from the histological point of view, their clinical behavior, and their genetics. The guidelines regarding their treatment include surgery in most cases, which can also play an important role in oligometastatic disease. Where surgery cannot be used, systemic therapy comes into play. Systemic therapy for many years has been represented by polychemotherapy, but recently, with the affirmation of translational research, it can also count on targeted therapy, at least in some subtypes of SGCs. Interestingly, in some SGC histotypes, predominant mutations have been identified, which in some cases behave as "driver mutations", namely mutations capable of governing the carcinogenesis process. Targeting these driver mutations may be an effective therapeutic strategy. Nonetheless, it is not always possible to have drugs suitable for targeting driver mutations-and targeting driver mutations is not always accompanied by a clinical benefit. In this review, we will analyze the main mutations predominant in the various histotypes of SGCs.

Analysis of B7-H4 Expression Across Salivary Gland Carcinomas Reveals Adenoid Cystic Carcinoma-Specific Prognostic Relevance

B7-H4 (VTCN1), a member of the B7 family, is overexpressed in several types of cancer. Here we investigated the pattern of expression of B7-H4 in salivary gland carcinomas (SGC) and assessed its potential as a prognostic marker and therapeutic target. Immunohistochemistry (IHC) analyses were performed in a cohort of 340 patient tumors, composed of 124 adenoid cystic carcinomas (ACC), 107 salivary duct carcinomas (SDC), 64 acinic cell carcinomas, 36 mucoepidermoid carcinomas (MEC), 9 secretory carcinomas (SC), as well as 20 normal salivary glands (controls). B7-H4 expression was scored and categorized into negative (<5% expression of any intensity), low (5%-70% expression of any intensity or >70% with weak intensity), or high (>70% moderate or strong diffuse intensity). The associations between B7-H4 expression and clinicopathologic characteristics, as well as overall survival, were assessed. Among all tumors, B7-H4 expression was more prevalent in ACC (94%) compared with those of SC (67%), MEC (44%), SDC (32%), and acinic cell carcinomas (0%). Normal salivary gland tissue did not express B7-H4. High expression of B7-H4 was found exclusively in ACC (27%), SDC (11%), and MEC (8%). In SDC, B7-H4 expression was associated with female gender (P = .002) and lack of androgen receptor expression (P = .012). In ACC, B7-H4 expression was significantly associated with solid histology (P < .0001) and minor salivary gland primary (P = .02). High B7-H4 expression was associated with a poorer prognosis in ACC, regardless of clinical stage and histologic subtype. B7-H4 expression was not prognostic in the non-ACC SGC evaluated. Our comparative study revealed distinct patterns of B7-H4 expression according to SGC histology, which has potential therapeutic implications. B7-H4 expression was particularly high in solid ACC and was an independent prognostic marker in this disease but not in the other SGC assessed.

A Phase II Trial of Rivoceranib, an Oral Vascular Endothelial Growth Factor Receptor 2 Inhibitor, for Recurrent or Metastatic Adenoid Cystic Carcinoma

PURPOSE

This open-label, single-arm, phase II study evaluated the vascular endothelial growth factor receptor 2 (VEGFR2) tyrosine kinase inhibitor (TKI) rivoceranib in patients with recurrent or metastatic (R/M) adenoid cystic carcinoma (ACC).

PATIENTS AND METHODS

Eligible patients had confirmed disease progression per Response Evaluation Criteria in Solid Tumors (RECIST) with ≥20% increase in radiologically or clinically measurable lesions or appearance of new lesions within the preceding 6 months. Patients received oral rivoceranib 700 mg once daily. Primary outcomes were objective response rate (ORR) by investigator review and by blinded independent review committee (BIRC).

RESULTS

Eighty patients were enrolled and 72 were efficacy evaluable. Seventy-four patients had distant metastases and 49 received prior systemic treatment (14 received VEGFR TKIs). Per investigator and BIRC, respectively, ORR was 15.3% [95% confidence interval (95% CI), 7.9-25.7] and 9.7% (95% CI, 4.0-19.0); median duration of response was 14.9 months (95% CI, 4.9-17.3) and 7.2 months (95% CI, 3.5-8.4); and median progression-free survival was 9.0 months (95% CI, 7.3-11.5) and 9.0 months (95% CI, 7.7-11.5). Grade ≥3 treatment-related adverse events occurred in 56 patients (70.0%); the most common were hypertension (34, 42.5%) and stomatitis (6, 7.5%). Four grade 5 events occurred with one attributed to rivoceranib (epistaxis). Sixty-eight patients (85.0%) had ≥1 dose modifications and 16 patients (20.0%) discontinued rivoceranib for toxicity.

CONCLUSIONS

In patients with progressing R/M ACC, rivoceranib demonstrated antitumor activity and a manageable safety profile consistent with other VEGFR TKIs.

Salivary glands adenoid cystic carcinoma: a molecular profile update and potential implications

Adenoid cystic carcinoma (ACC) is an aggressive tumor with a high propensity for distant metastasis and perineural invasion. This tumor is more commonly found in regions of the head and neck, mainly the salivary glands. In general, the primary treatment modality for ACC is surgical resection and, in some cases, postoperative radiotherapy. However, no effective systemic treatment is available for patients with advanced disease. Furthermore, this tumor type is characterized by recurrent molecular alterations, especially rearrangements involving the MYB, MYBL1, and NFIB genes. In addition, they also reported copy number alterations (CNAs) that impact genes. One of them is C-KIT, mutations that affect signaling pathways such as NOTCH, PI3KCA, and PTEN, as well as alterations in chromatin remodeling genes. The identification of new molecular targets enables the development of specific therapies. Despite ongoing investigations into immunotherapy, tyrosine kinase inhibitors, and anti-angiogenics, no systemic therapy is approved by the FDA for ACC. In this review, we report the genetic and cytogenetic findings on head and neck ACC, highlighting possible targets for therapeutic interventions.

A molecular guide to systemic therapy in salivary gland carcinoma

Salivary gland carcinomas (SGC) are a rare and variable group of head and neck cancers with historically poor response to cytotoxic chemotherapy and immunotherapy in the recurrent, advanced, and metastatic settings. In the last decade, a number of targetable molecular alterations have been identified in SGCs including HER2 upregulation, androgen receptor overexpression, Notch receptor activation, NTRK gene fusions, and RET alterations which have dramatically improved treatment outcomes in this disease. Here, we review the landscape of precision therapy in SGC including current options for systemic management, ongoing clinical trials, and promising future directions.

Combined all-trans retinoic acid with low-dose apatinib in treatment of recurrent/metastatic head and neck adenoid cystic carcinoma: A single-center, secondary analysis of a phase II study

BACKGROUND

Treatment options are limited for recurrent/metastatic adenoid cystic carcinoma of the head and neck (R/M ACCHN). We aimed to evaluate the preliminary results of the efficacy and safety of all-trans retinoic acid (ATRA) combined with low-dose apatinib in patients with R/M ACCHN according to a secondary analysis of a phase II study.

METHODS

Patients from a phase II study (NCT02775370) who orally administered 500 milligram (mg) apatinib daily until treatment-related adverse events (AEs) intolerance or progression occurred were eligible for inclusion. Patients were further treated with combination therapy of ATRA (25 mg/m² /day) and apatinib (250 mg/day) between March 2019 and October 2021 until progression of disease (PD).

RESULTS

A total of 16 patients were included with nine (56.3%) males and aged 35-69 years old. All recruited patients previously received anti-angiogenic therapy then withdrew due to toxicities or progression occurred. The objective response rate (ORR) and disease control rate (DCR) were 18.8% and 100%, respectively. During a median follow-up of 23.9 months (range:17.8-31.7 months), 11 (68.8%) patients developed PD and one of them died in 20.9 months. The median of progression-free survival (PFS) was 16.3 months (95% CI: 7.2-25.4 months), and the 6-month, 12-month, and 24-month PFS rates were 100%, 81.3%, and 33.3%, respectively. The grade 3 adverse events were albuminuria (n = 2, 12.5%) and hand-foot syndrome (n = 1, 6.25%).

CONCLUSION

All-trans retinoic acid combined with low-dose apatinib might be a potential efficacy therapeutic option for patients with R/M ACCHN. This finding will be further confirmed by our registered ongoing trial, the APLUS study (NCT04433169).

Systemic and Targeted Therapies in Adenoid Cystic Carcinoma

OPINION STATEMENT

Adenoid cystic carcinoma (ACC) is an often-indolent type of salivary gland cancer (SGC). A subset of patients develops progression or aggressive disease warranting systemic therapy in the recurrent/metastatic (R/M) setting. We recommend genomic testing for all patients with R/M disease to aid with prognostication and eligibility for potential experimental therapies. Here, we review the currently available treatment options (cytotoxic chemotherapies and vascular endothelial growth factor receptor (VEGFR)-targeting tyrosine kinase inhibitors (TKIs)). Based on limited data, we nominate regimens which may have more favorable efficacy profiles. Among the cytotoxic chemotherapies, several regimens are acceptable when incorporating a platinum agent. Among the VEGFR-targeting TKIs, lenvatinib and axitinib are the preferred options. Larger, randomized studies prioritizing combinations with mechanistic synergism are needed. Predictive biomarkers are critical, as there is currently little evidence to guide sequencing of available options for individual patients. Immunotherapy is an available option, but has been associated with only modest benefit in ACC. We go on to review other therapies that have been studied and nominate those with promise based on early clinical data.

Drug-based therapy for advanced adenoid cystic carcinoma: Current landscape and challenges based on an overview of registered clinical trials

Adenoid cystic carcinoma (ACC) has a significant patient-population in need of effective systemic therapy, as no drug is currently approved by the FDA for its management. We critically reviewed ACC-clinical trials (CT) registered on the ClinicalTrials.gov website using "ACC" under condition or disease. Trials specifically designed to test a drug-based therapy for ACC (n = 33) were analyzed with most being one-arm phase II trials enrolling advanced, recurrent/metastatic, incurable ACC cases. Site restriction, maximum ECOG status, and period of disease progression varied as inclusion criteria. Small-molecule inhibitors were those most commonly investigated with Apatinib, Axitinib and Lenvatinib showing the best results in association with rigid enrollment criteria. The overall median time to progression remains modest and more efforts are urgently needed in this field. CTs designed to test drugs that act on key pathways associated with ACC aggressiveness are being conducted and represent a promising pathway if efficacy is proved.

The Therapeutic Landscape of Salivary Gland Malignancies-Where Are We Now?

Salivary gland malignancies (SGMs) account for less than 5% of new diagnoses in head and neck tumors. If feasible, surgery is the preferred treatment modality. Nevertheless, some malignancies have a tendency of recurrence, with possible distant metastasis. Alternative treatment strategies, such as primary radiation or chemotherapeutics, often present low response rates. As a result, there is an unmet need for novel therapeutic approaches. Nowadays, target-based therapies (e.g., small inhibitors and immunotherapy) are used by the medical oncologist for possible treatment of advanced SGMs. Based on recent published trials, some novel treatments may provide additional disease control for some patients. However, sample sizes are small, the general findings are unsatisfactory, and a lot of uncertainties remain to be elucidated. Nevertheless, research shows that patients do not benefit from blind administration of systemic treatments and therefore a more personalized approach is highly needed. The aim of this review paper is to summarize the most recent advances in the biological understanding and molecular pathways of salivary gland cancers, the association of these pathways with the current treatments used and their implications for more personalized targeted-based therapies.

Approaches to the Management of Metastatic Adenoid Cystic Carcinoma

High rates of recurrence and distant metastasis are a foremost challenge in the management of adenoid cystic carcinoma (ACC), occurring in approximately 40% of all ACC patients. Despite the morbidity and mortality resulting from recurrent/metastatic (R/M) disease, there are no FDA-approved systemic agents for these patients. In this review, we summarize pertinent ACC pathophysiology and its implications for different systemic treatment regimens in R/M ACC. We review the evidence for the most widely used systemic agents - cytotoxic chemotherapy and tyrosine kinase inhibitors (TKIs) targeting VEGFR - in addition to immune checkpoint inhibitors and non-TKI biologic agents. Exciting emerging targets for R/M ACC, including inhibitors of Notch signaling, stemness, PRMT5, and Axl, are also discussed. Lastly, we review local therapies for small-volume lung disease in patients with oligometastatic ACC, specifically pulmonary metastasectomy and stereotactic body radiation therapy (SBRT). Future development of targeted molecular agents which exploit the underlying biology of this disease may yield novel therapeutic options to improve clinical outcomes in patients with R/M ACC.

Metastatic Adenoid Cystic Carcinoma: Genomic Landscape and Emerging Treatments

OPINION STATEMENT

Adenoid cystic carcinoma (ACC) is a heterogeneous cancer that commonly develops in the salivary glands. Approximately 40 to 50% of patients with ACC develop recurrence and/or metastasis. Although most patients with ACC have slow-growing disease, a subset experiences aggressive disease with early visceral and/or bone metastasis. Thus far, there is no consensus on the best time to start palliative treatment in patients with indolent disease. The only systemic therapies available for recurrent or metastatic ACC are cytotoxic agents and multikinase inhibitors targeting vascular endothelial growth factor receptor, and both types of therapy have modest activity. Studies integrating proteomics, genomics, and clinical data have revealed distinct molecular ACC subtypes, ACC-I and ACC-II, with ACC-I generally associated with more aggressive disease biology. ACC-I tumors were enriched for NOTCH1-activating mutation and upregulation of MYC and MYC targets, while ACC-II tumors exhibited upregulation of TP63 and receptor tyrosine kinases. These findings highlight the importance of patient selection for surveillance and targeted therapy development in ACC. In recent clinical trials of targeted therapy in ACC, patients are being selected according to tumor molecular profile (e.g., presence of NOTCH-activating mutations), which represents a major advance in the field. Ongoing collaborative research focusing on the development of novel therapeutic strategies for ACC patients based on disease biology will increase the drug armamentarium and improve survival outcomes for these patients in dire need.

Treatment of Recurrent or Metastatic Adenoid Cystic Carcinoma

PURPOSE OF REVIEW

Adenoid cystic carcinoma (ACC) is a rare and heterogeneous malignancy of secretory glands. Recurrence after curative-intent treatment is common, and approximately 40% of patients develop metastatic disease, for which consensus is lacking regarding therapeutic approaches. Here, we review the available therapies for recurrent/metastatic (R/M) ACC and offer our perspectives on future treatment options.

RECENT FINDINGS

Proteogenomic studies of ACC revealed two molecular subtypes with therapeutic implications: ACC-I (37% of cases) and ACC-II (63%); each has distinct disease biology and prognosis. Molecular drivers, such as NOTCH1, have emerged as potential therapeutic targets for ACC-I and are being explored in clinical trials. Despite its biological heterogeneity, treatment for R/M ACC is not personalized and limited to cytotoxic agents and VEGFR inhibitors, which produce modest responses and significant toxicity. The increasing understanding of ACC's molecular biology might guide the development of biomarkers for patient selection and new therapies development.

Centralised RECIST Assessment and Clinical Outcomes with Lenvatinib Monotherapy in Recurrent and Metastatic Adenoid Cystic Carcinoma

Simple Summary

Adenoid cystic carcinoma (ACC) is a rare cancer of the head and neck. Initial treatment may involve surgery and/or radiotherapy with the aim of removing the cancer and preventing spread to other parts of the body. In patients in whom ACC has recurred or spread, systemic therapies such as chemotherapy or immunotherapy have been shown to have minimal benefit and there are currently no recommended standard systemic treatment options. More recently, the targeted therapy lenvatinib has shown promising results in treating ACC patients. We aimed to summarise the real-world experience of lenvatinib use in ACC patients in the UK and found that although some patients obtained clinical benefit, there were no significant responses on radiological imaging by centralized assessment.

Abstract

Adenoid cystic carcinoma (ACC) is a rare cancer of secretory glands. Recurrent or metastatic (R/M) ACC is generally considered resistant to cytotoxic chemotherapy. Recent phase II studies have reported improved objective response rates (ORR) with the use of the multi-kinase inhibitor lenvatinib. We sought to evaluate real-world experience of R/M ACC patients treated with lenvatinib monotherapy within the UK National Health Service (NHS) to determine the response rates by Response Evaluation Criteria of Solid Tumour (RECIST) and clinical outcomes. Twenty-three R/M ACC patients from eleven cancer centres were included. All treatment assessments for clinical decision making related to drug therapy were undertaken at the local oncology centre. Central radiology review was performed by an independent clinical trial radiologist and blinded to the clinical decision making. In contrast to previously reported ORR of 12–15%, complete or partial response was not observed in any patients. Eleven patients (52.4%) had stable disease and 5 patients (23.8%) had progression of disease as the best overall response. The median time on treatment was 4 months and the median survival from discontinuation was 1 month. The median PFS and OS from treatment initiation were 4.5 months and 12 months respectively. Multicentre collaborative studies such as this are required to evaluate rare cancers with no recommended standard of care therapy and variable disease courses.