Pemetrexed in patients with thymic malignancies previously treated with chemotherapy

Thymic epithelial tumor medical treatment: A narrative review

Thymic epithelial tumors, a malignancy originating in the thymus, are the commonest primary neoplasm of the anterior mediastinum; however, among thoracic tumors, they have a relatively low incidence rare. Thymic epithelial tumors can be broadly classified into thymic carcinoma and thymoma. As the cornerstone of thymic tumor treatment, surgery is the preferred treatment for early-stage patients, whereas, for advanced unresectable thymic tumors, the treatment is chemoradiotherapy. Targeted therapy is less effective for thymic tumors. Moreover, the use of immune checkpoint inhibitors as another effective treatment option for advanced unresectable thymic tumors, particularly thymomas, is limited owing to immune-related adverse effects. Here, we have summarized all pertinent information regarding chemotherapy, especially preoperative neoadjuvant chemotherapy, and chemotherapy in combination with other treatments, and reviewed the effectiveness of these procedures and recent advances in targeted therapy. In addition, we analyzed the efficacy and safety of immune checkpoint inhibitors in thymic epithelial tumors, to provide a holistic treatment view.

A late relapse thymoma and pure red cell aplasia case with an over 5 years of clinical response under everolimus

Although several agents showed some clinical activity in patients with recurrent thymoma, there is no standard treatment option. Here, we report a late relapse thymoma and pure red cell aplasia case, responsive to everolimus with over 5 years of clinical benefit following multiple lines of treatment. Everolimus controlled the rapidly progressive disease in our patient without significant toxicity.

Salvage Chemotherapy in Patients with Previously Treated Thymic Carcinoma

Thymic carcinoma is a rare neoplasm, and it is difficult to achieve complete remission with systemic chemotherapy. In advanced or recurrent thymic carcinoma, platinum-based chemotherapy is chosen as the first-line setting; however, it remains unclear which regimen is better to improve its outcome. It remains unknown whether salvage chemotherapy should be administered to patients with platinum-based chemotherapy-refractory thymic carcinoma. Currently, several clinical studies have investigated the efficacy of second-line settings for advanced thymic carcinoma. As cytotoxic agents, S-1, amrubicin, pemetrexed, docetaxel, paclitaxel, and gemcitabine have been reported as prospective phase II studies or retrospective studies. The overall response rates (ORRs) of S-1, amrubicin, and pemetrexed were 25-50%, 11-44.4%, and 9-10%, respectively. Molecular targeting drugs, such as sunitinib, everolimus, and lenvatinib, also provide clinical effectiveness with tolerability after the failure of platinum-based regimens. Based on the results of the prospective phase II study, the ORR, median progression-free survival, and median overall survival were 16.6% and 5.6 months, respectively, in everolimus, 26% and 7.2 months, respectively, in sunitinib, and 38% and 9.3 months, respectively, in lenvatinib. Although it is difficult to compare each study, lenvatinib appears to be better in increasing efficacy as a second-line setting. However, each study had a small sample size, which may have biased the results of their studies. Further investigation is warranted to elucidate the therapeutic significance of salvage chemotherapy in advanced thymic carcinoma in a large-scale study.

Phase II trial of S-1 treatment as palliative-intent chemotherapy for previously treated advanced thymic carcinoma

Thymic carcinoma (TC) is a rare cancer with minimal evidence of survival following palliative-intent chemotherapy. Sunitinib, everolimus, and pembrolizumab have been proposed as active agents based on previous phase II trials. In this phase II study, TC patients previously treated with platinum-based chemotherapy were enrolled. The patients received S-1 orally twice daily at a dose of 40-60 mg/m² for 4 weeks, followed by 2 weeks off until the progression of the disease or the presence of unacceptable toxicities. The primary endpoint was the objective response rate (ORR), and secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety. The sample size of 26 patients was planned to reject the ORR of 10% under the expectation of 30% with a power of 0.80 and a type I error of 0.05 (one-sided). Twenty-six patients were recruited between 2013 and 2016; 23 patients had squamous cell carcinoma and 10 had an ECOG performance status of 0. One patient showed complete response and seven patients showed partial responses, resulting in a 30.8% response rate (90% confidence interval [CI], 18.3-46.9) and an 80.8% disease control rate (90% CI, 65.4-90.3). The median PFS was 4.3 months (95% CI, 2.3-10.3 months) and median OS was 27.4 months (95% CI, 16.6-34.3). Adverse events of grade ≥ 3 included neutropenia (12%), skin rash (8%), elevated alanine aminotransferase, and fatigue (4%). No treatment-related death was observed. S-1 confirmed clinical activity with tolerability in patients with previously treated TC. (UMIN000010736).

Clinical Outcomes of Second-Line Chemotherapy in Patients with Previously Treated Advanced Thymic Carcinoma: A Retrospective Analysis of 191 Patients from the NEJ023 Study

BACKGROUND

Owing to the rarity of this tumor, there is limited information about second-line chemotherapy for patients with previously treated advanced thymic carcinoma.

MATERIAL AND METHODS

We performed a multi-institutional, retrospective study named NEJ023 for patients with advanced thymic carcinoma. Patients without indications for curative treatment were treated with chemotherapy from 1995 to 2014 at 40 institutions in the North East Japan Study Group. Demographic and clinicopathologic characteristics, data on treatment methods, and outcomes of second-line chemotherapy were obtained from medical records.

RESULTS

In total, 191 patients were enrolled in this study. Second-line chemotherapy included platinum-based doublets in 57.6% of patients, other multidrug chemotherapy (e.g., cisplatin, doxorubicin, vincristine, and cyclophosphamide) in 13.6%, and monotherapy in 28.8%. The median follow-up time was 50.5 months, and the median overall survival (OS) from the start of second-line chemotherapy was 22.4 (95% confidence interval, 17.5-26.7) months. The average response rate (RR) was 20.0% overall; it was 21.6% for patients treated with platinum-based doublet chemotherapy, 13.6% for those treated with other multidrug chemotherapy, and 19.6% for those treated with single agent chemotherapy. There was no significant difference in OS between platinum-based doublet chemotherapy, other multidrug chemotherapy, and monotherapy (the median OS was 22.4, 25.7, and 21.4 months, respectively).

CONCLUSION

The median OS was 22.4 months in patients with advanced thymic carcinoma treated with second-line chemotherapy. There were no significant differences in RR and OS between monotherapy and multidrug chemotherapy in this study.

IMPLICATIONS FOR PRACTICE

Owing to the rarity of this tumor, there is limited information about second-line chemotherapy for patients with previously treated advanced thymic carcinoma. This is the largest data for those patients treated with second-line chemotherapy. This study suggests there is no significant difference in efficacy between monotherapy and multidrug chemotherapy for previously treated advanced thymic carcinoma. This result can support the adequacy to select monotherapy as treatment of those patients.

S-1 salvage chemotherapy for stage IV thymic carcinoma: a study of 44 cases

Background

Thymic carcinoma (TC) is a rare mediastinal tumor, and patients with stage IV TC have a poor prognosis. No optimal chemotherapeutic regimen has yet been established. In this study, we evaluated the efficacy and safety of S-1 as a salvage mono-therapy in stage IV TC.

Methods

Patients with histologically confirmed stage IV TC were enrolled in this study when front-lined chemotherapy failed. S-1 capsules were orally taken twice a day. The daily dose was prescribed in three levels (80, 100, 120 mg) based on body surface area (BSA). One cycle of treatment consists of 4 weeks of drug use and 2 weeks of rest. The cycle was repeated until tumor progressed or intolerable toxicity occurred. The response rate, progression-free survival (PFS), overall survival (OS), and toxicity were evaluated.

Results

Forty-four patients with stage IV TC were included between January 2013 and July 2017. Squamous cell carcinoma accounted for 84% of cases (37/44). There were 22 males and 22 females with a median age of 57 years (27-78 years). S-1 was prescribed at a dose of 80 mg for 18 (41%) patients, 100 mg for 17 patients (38%), and 120 mg for 9 patients (21%). The median number of cycles of administrated per patient was 3 [1-32]. Among 44 patients, 13 (30%) achieved a partial response, 22 (50%) remained stable disease, and 9 (20%) showed a rapid progression. With a median follow-up time of 14 months, the median PFS and OS of the whole group were 6 (95% CI, 7.0-13.9) months and 15 (95% CI, 13.2-21.6) months, respectively. For the 13 patients who showed response to S-1, the median PFS was 22 (95% CI, 15.5-30) months. Anorexia was the most common side effect, but all cases were mild. Other toxicities of grade ≥3 were bone marrow suppression (n=6) and rash (n=1). No drug-related deaths occurred.

Conclusions

S-1 is a safe and effective treatment for stage IV TC as a salvage monotherapy. It is especially effective in disease control when the tumor shows response to S-1.

Optimal management of thymic malignancies: current perspectives

Thymic epithelial tumors (TETs) belong to orphan oncology. The incidence of TETs is about 1.3–3.2 cases per million worldwide. Following pathology, evolution and prognosis are variable. The World Health Organization classification distinguishes thymomas and thymic carcinomas. TETs are composed of thymic epithelial tumoral cells and normal lymphocytes. The mean age at diagnosis is 50–60 years-old. There are no identified risk factors. TETs are frequently associated with paraneoplastic syndromes as myasthenia gravis. The complete R₀ surgical resection is the most significant prognosis factor on survival. In 2010, the French National Institute of Cancer labeled the RYTHMIC network as a specific tumor board including thoracic surgeons, oncologist, and radiation therapist to define standard of care for the management of TETs. The aim of the review was to update knowledge to optimize the standard of care.

Systemic treatments for thymoma and thymic carcinoma: A systematic review

Thymic tumours are rare diseases that for most of the cases are cured with surgery and eventually adjuvant radiotherapy. However, about 30% of patients present with advanced stage or relapsing tumours, which require administration of chemotherapy. While cisplatin-adriamycin-cyclophosphamide combination is regularly prescribed, other drugs have been assessed in the literature. Our aim is to evaluate the effectiveness (response rate) of systemic treatments, whatever the therapeutic line, including chemotherapy, targeted therapies and immunotherapies, in thymoma and thymic carcinoma, using the principles of evidence-based medicine. A systematic review was designed using the PICO system, by an experienced librarian and clinicians' experts in thoracic oncology, through the Ovid Medline system. Only phase II-IV trials and retrospective studies including at least 14 patients treated with the same regimen were considered. Articles were independently selected by at least two investigators. Fifty-five eligible articles were retrieved. Sixty% were dealing with platinum-based regimens, mainly cisplatin, and showed overall similar activity (mostly response rate above 50%) independently of the line of treatment or histological type (thymoma versus thymic carcinoma). Non-platinum based regimens included octreotide-prednisone and capecitabine-gemcitabine. Promising data of immunotherapy with antiPDL1 antibody (pembrolizumab) requires confirmation. Based on available data, the most popular and active regimens are cisplatin-anthracycline (CAP or ADOC) or cisplatin-etoposide combinations that should be recommended when considering first-line chemotherapy in thymoma or thymic carcinoma.

A Phase II Study of Pemetrexed in Patients with Recurrent Thymoma and Thymic Carcinoma

INTRODUCTION

Thymoma and thymic carcinoma (TC) are neoplastic diseases with reported chemosensitivity to a broad range of agents. However, because of the rarity of these diseases, few prospective trials have been conducted in patients with advanced thymic malignancies. We conducted a prospective phase II trial to evaluate the clinical activity of pemetrexed, a multitargeted antifolate agent, in previously treated patients with thymoma and TC.

METHODS

A total of 27 previously treated patients (16 with thymoma and 11 with TC) with advanced, unresectable disease were treated with pemetrexed, 500 mg/m², intravenously every 3 weeks for a maximum of six cycles or until undue toxicity or progressive disease. All patients received folic acid, vitamin B₁₂, and steroid prophylaxis.

RESULTS

The median number of cycles administered was 6 (range 1-6). Nine patients with a total of 14 events had grade 3 toxicities; no grade 4 toxicities were noted. In 26 fully evaluable patients, two complete and three partial responses (according to the Response Evaluation Criteria in Solid Tumors) were documented (all in patients with stage IVA thymoma, except for one partial response with stage IVA TC). A total of 14 patients completed the full six cycles of treatment, 7 patients progressed while undergoing therapy, 5 patients discontinued therapy because of intolerance, and 1 patient discontinued therapy because of progressive Morvan syndrome. The median progression-free survival time for all patients was 10.6 months (12.1 months for those with thymoma versus 2.9 months for those with TC). With 23 deaths at data cutoff, the median overall survival time was 28.7 months (46.4 months for those with thymoma versus 9.8 months for those with TC).

CONCLUSIONS

Pemetrexed is an active agent in this heavily pretreated population of patients with recurrent thymic malignancies, especially thymoma.

Pembrolizumab for Patients With Refractory or Relapsed Thymic Epithelial Tumor: An Open-Label Phase II Trial

PURPOSE

Limited treatment options exist for patients with thymic epithelial tumor (TET) whose disease progresses after platinum-based chemotherapy. We conducted a phase II study of pembrolizumab in patients with TET to evaluate its efficacy and safety.

METHODS

Patients with histologically confirmed TET whose disease progressed after at least one line of platinum-based chemotherapy were eligible for the study. Patients were excluded if they had an active autoimmune disease requiring systemic treatment within the past year or documented history of clinically severe autoimmune disease. Patients received 200 mg of pembrolizumab intravenously every 3 weeks until tumor progression or unacceptable toxicity. The primary objective of response rate was assessed every 9 weeks by investigators.

RESULTS

Of 33 patients enrolled, 26 had thymic carcinoma and seven had thymoma. Of seven thymoma, two (28.6%; 95% CI, 8.2% to 64.1%) had partial response, and five (71.6%) had stable disease. Of 26 thymic carcinoma, five (19.2%; 95% CI, 8.5% to 37.9%) had partial response and 14 (53.8%) had stable disease. The median progression-free survival was 6.1 months for both groups. The most common adverse events of any grade included dyspnea (11; 33.3%), chest wall pain (10; 30.3%), anorexia (seven; 21.2%), and fatigue (seven; 21.2%). Five (71.4%) of seven patients with thymoma and four (15.4%) of 26 patients with thymic carcinoma reported grade ≥ 3 immune-related adverse events, including hepatitis (four; 12.1%), myocarditis (three; 9.1%), myasthenia gravis (two; 6.1%), thyroiditis (one; 3.0%), antineutrophil cytoplasmic antibody-associated rapidly progressive glomerulonephritis (one; 3.0%), colitis (one; 3.0%), and subacute myoclonus (one; 3.0%).

CONCLUSIONS

Pembrolizumab showed encouraging antitumor activity in patients with advanced TET. Given the high incidence of autoimmunity, additional studies are needed to identify those who can benefit from pembrolizumab without immune-related adverse events.

EGFR exon 20 insertion mutation in advanced thymic squamous cell carcinoma: Response to apatinib and clinical outcomes

Thymic carcinoma (TC) is a rare malignant tumor of the mediastinum with occult onset, rapid development, and poor prognosis. Surgery is the main treatment for early TC, but the majority of patients are diagnosed at Masaoka‐Koga stage III or IV with local invasion or distant metastasis. Platinum and anthracyclines are currently considered key components of first‐line chemotherapy for advanced TC; however, there are no standard treatment plans for patients who are refractory to first‐line and further chemotherapy. The clinical effect is also unsatisfactory. Apatinib has been successfully applied as third‐line treatment for advanced gastric cancer and has shown high efficacy in the treatment of various cancers, such as lung, liver, and colorectal cancers. Herein we report a case of advanced thymic squamous cell carcinoma harboring EGFR exon 20 insertion in which apatinib was administered after multi‐line chemotherapy and radiotherapy and a partial response was achieved after five months of treatment. To date, a five month overall response and 10 months of progression‐free survival have been achieved. Adverse reactions can be controlled and the patient's quality of life has improved. Apatinib provides a new option for clinicians to treat patients with advanced TC.

Expression of excision repair cross-complementation group 1 and class III β-tubulin in thymic carcinoma

Thymic carcinoma is a rare mediastinum malignant tumor derived from thymic epithelial cells. With the exception of complete resection, an effective therapy has not been established to date for advanced or relapsed thymic carcinoma. The present study examined the protein expression of excision repair cross-complementation group 1 (ERCC1) and class III β-tubulin (TUBB3), which are consider to be indicators of the anticancer activity of platinum-based and taxane-based chemotherapy, respectively. The expression of ERCC1 and TUBB3 proteins was examined in 40 thymic carcinoma patients who underwent either surgical resection or core-needle biopsy. The present study investigated whether the expression of ERCC1 and TUBB3 proteins was associated with the overall survival and clinicopathological factors of thymic carcinoma patients. The expression of ERCC1 and TUBB3 proteins was also evaluated in 50 patients who underwent curative resection for non-small cell lung cancer (NSCLC). The expression of ERCC1 and TUBB3 proteins was positive in 8 cases (20%) among the thymic carcinoma patients. ERCC1 was expressed in 21 cases (42%), while TUBB3 was expressed in 27 cases (54%), among the 50 NSCLC patients evaluated in the present study. Only complete resection was observed to be associated with a better prognosis than incomplete resection (P=0.0341). Other clinicopathological factors, including expression of ERCC1 and TUBB3 proteins, exhibited no effect on overall survival. The expression of ERCC1 and TUBB3 proteins in the thymic carcinoma cases was lower than that in the NSCLC cases. The present results suggest a possibility for better antitumor effects of platinum-based and taxane-based chemotherapy on thymic carcinoma patients.

Efficacy of pemetrexed-based regimen in relapsed advanced thymic epithelial tumors and its association with thymidylate synthetase level

Purpose

Due to the rarity of thymic epithelial tumors (TET), no standard chemotherapy regimen has been identified in the relapsed setting. The aim of this study was to investigate the activity of a pemetrexed-based regimen in advanced TET as palliative treatment after failure of previous chemotherapy, and to detect its association with thymidylate synthetase (TS) level.

Methods

Patients with pathologically confirmed TET and treated with pemetrexed-based regimen were evaluated from 2006 to 2014 in Zhejiang Cancer Hospital. TS mRNA level was detected by real-time polymerase chain reaction. The Kaplan–Meier method was used for survival analysis.

Results

A total of 22 TET patients were identified, of whom eight had thymoma and 14 had thymic carcinoma. In total, the objective response rate and disease control rate of the 22 patients were 22.7% and 68.2%, respectively. Median progression-free survival and overall survival were 4.5 months and 34.9 months, respectively. A trend of lower TS mRNA levels existed in patients with disease control compared to those with progressive disease (268.0±160.5×10⁻⁴ vs 567.0±445.0×10⁻⁴, P=0.065).

Conclusion

Patients with advanced TET may benefit from pemetrexed-based regimen therapy. TS mRNA level is valuable for predicting the efficacy of pemetrexed in TET.

Correlation between S-1 treatment outcome and expression of biomarkers for refractory thymic carcinoma

BACKGROUND

Thymic carcinoma is a rare cancer with minimal evidence of a survival benefit following chemotherapy. An oral fluoropyrimidine of S-1, however, is the recommended active cytotoxic chemotherapy agent for refractory thymic carcinoma based on a case series, whereas sunitinib or everolimus are recommended as molecular-targeted agents based on Phase II trials. We retrospectively investigated the efficacy of S-1 for refractory thymic carcinoma and performed a biomarker analysis.

METHODS

We assessed the clinicopathological variables of 14 consecutive patients who underwent S-1 for refractory thymic carcinoma and correlated the clinical outcomes with potential biomarkers using paraffin-embedded cancer tissues of eight patients in the cohort.

RESULTS

A total of 178 thymic malignancies were identified, of whom 14 patients included 12 cases of squamous cell carcinoma, one lymphoepithelioma-like carcinoma, and one undifferentiated carcinoma. Six patients exhibited a partial response (42.9 %: 95 % confidence interval [CI], 21.4-67.4) and the disease control rate was 85.7 % (60.0-96.0 %). After a median follow-up of 24.2 months, the median progression-free survival was 8.1 months (range, 2.6-12.2 months), and median overall survival was 30.0 months (range, 6.2-41.9 months). No significant correlation between biomarker expression and response was noted. However, thymidine synthase (TS)/dihydropyrimidine dehydrogenase and TS/orotate phosphoribosyltransferase were observed.

CONCLUSIONS

S-1 for refractory thymic carcinoma offered clinical activity and achieved an 85 % disease control rate. Although the biomarkers did not correlate with clinical outcome, the study results showed efficacy of S-1 as a cytotoxic chemotherapy for refractory thymic carcinoma, which warrants future investigation.

Gemcitabine in patients previously treated with platinum-containing chemotherapy for refractory thymic carcinoma: radiographic assessment using the RECIST criteria and the ITMIG recommendations

BACKGROUND

The key drugs for chemotherapy of thymic carcinoma are gradually being revealed in phase II and conventional retrospective studies. Gemcitabine is regarded as one of these key drugs according to the findings of clinical trials in which it was combined with capecitabine. However, the activity of single-agent gemcitabine concerning refractory thymic carcinoma remains unclear.

PATIENTS AND METHODS

We conducted a retrospective review of the medical records of refractory thymic carcinoma patients previously treated with platinum-containing chemotherapy between 1980 and 2014.

RESULTS

Of all 11 patients in this study, the objective response rate regarding gemcitabine was 36.4 % [95 % confidence interval (CI) 15.2-64.6] using the RECIST criteria and the response criteria proposed by the ITMIG. The median progression-free survival time was 4.3 months (95 % CI 0.7-11.0). The survival time from the start of gemcitabine treatment was 28.5 months (95 % CI 5.5-47.8), and from the start of first-line chemotherapy was 46.5 months (95 % CI 7.3-47.8).

CONCLUSIONS

Gemcitabine achieved a moderate response and has the potential to be used as a key drug for thymic carcinoma. Some patients treated with gemcitabine demonstrated prolonged cancer control even in later lines of chemotherapy.

Docetaxel for platinum-refractory advanced thymic carcinoma

OBJECTIVE

Thymic carcinoma is a rare mediastinal neoplasm. While platinum-based chemotherapy has been reported to be effective for advanced thymic carcinoma in a first-line setting, little information is available regarding the benefits of salvage chemotherapy for platinum-refractory thymic carcinoma. This study assessed the efficacy and safety profiles of docetaxel monotherapy for platinum-refractory thymic carcinoma.

METHODS

A total of 13 thymic carcinoma patients treated with docetaxel monotherapy in a second- or later-line setting between January 2003 and April 2014 were retrospectively reviewed. The median age was 61 years (range, 41-75 years).

RESULTS

The overall response rate and disease control rate were 31% [95% confidence interval (CI), 6-56%] and 77% (95% CI, 54-100%), respectively. The median progression-free survival and overall survival after docetaxel monotherapy were 5.5 months (95% CI, 2.3-6.5 months) and 24.0 months (95% CI, 9.4-31.2 months), respectively. The most common Grade ≥3 toxicity was neutropenia (62%). No incidents of febrile neutropenia and no treatment-related deaths were recorded.

CONCLUSIONS

This retrospective analysis demonstrated that docetaxel was active against platinum-refractory thymic carcinoma with acceptable toxicities. Docetaxel monotherapy might be a promising therapeutic option for patients with platinum-refractory thymic carcinoma.