Phase II study of adjuvant chemotherapy of S-1 plus oxaliplatin for patients with stage III gastric cancer after D2 gastrectomy

PGC-1α/SNAI1 axis regulates tumor growth and metastasis by targeting miR-128b in gastric cancer

Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is a transcriptional coactivator that has been characterized as master regulators of mitochondrial biogenesis. It has been reported that aberrant regulation of PGC-1α is involved in a variety of human cancers. However, whether PGC-1α is involved in the regulation of tumor growth and metastasis in gastric cancer (GC) remains unknown. In the present study, we found that the expression of PGC-1α was upregulated in GC tissues and GC cell lines. Inhibition of PGC-1α inhibited cell viability, migration, and invasion, and promoted cell apoptosis of GC cells. Furthermore, inhibition of PGC-1α downregulated the SNAI1 expression, whereas upregulated microRNA (miR)-128b expression. The expression of SNAI1 was upregulated and the expression of miR-128b was downregulated in GC tissues. We further found that there was a positive correlation between PGC-1α and SNAI1 expression, and a negative correlation between PGC-1α and miR-128b expression or between SNAI1 and miR-128b expression in GC tissues. Moreover, PGC-1α inhibition-induced increased miR-128b expression, and PGC-1α overexpression-induced decreased miR-128b expression were both markedly suppressed by SNAI1 overexpression. In addition, SNAI1 overexpression or miR-128b inhibition partly reversed the effects of PGC-1α inhibition in GC cells. Furthermore, inhibition of PGC-1α suppressed the tumor growth in a nude mouse model, which may be related with the dysregulation of SNAI1 and miR-128b. In conclusion, these data indicate that the PGC-1α/SNAI1/miR-128b axis plays a vital role in GC via regulating cell viability, migration, invasion, and apoptosis.

Implications of clinical research on adjuvant chemotherapy for gastric cancer: Where to go next?

Postoperative adjuvant chemotherapy (ACT) confers superior gastric cancer (GC) survival in the Eastern cohort. However, is the current standard of ACT already excessive, or is it still necessary to increase its intensity for specific subgroups? Tailored ACT strategies for GC depend on gradual exploration by clinical trials in selected patients. Thus, understanding the implications of previous and current research can help us respond wisely and design effective, rational trials, save medical resources and make better decisions in clinical practice. After reviewing and analyzing studies on ACT for GC patients undergoing curative resection, we found that research strategies for conducting “addition” ACT for specific stages of the disease have achieved great progress in making ACT more tailored and personalized in consideration of pathology stages. Furthermore, trials indicate that “addition” ACT strategies for GC patient subgroups based on histological characteristics might be helpful to move toward a more specific tailored and personalized management approach. Designing ACT research focused on different node statuses should also be conducted according to the biological specificity of lymph node (LN) metastasis. Therefore, future trials designed to determine tailored treatment based on histological and biological characteristics for specific subgroups are urgently needed and conducted as the theme of the 2019 American Society of Clinical Oncology (ASCO): Caring for Every Patient, Learning from Every Patient.

An increase in the neutrophil-to-lymphocyte ratio during adjuvant chemotherapy indicates a poor prognosis in patients with stage II or III gastric cancer

Background

The neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR) are associated with poor prognoses in patients with gastric cancer; however, few studies have focused on the dynamic changes in these ratios during the treatment of patients with gastric cancer. Here, we assessed the clinical utility of changes in these ratios as prognostic indicators in patients with stage II or III gastric cancer who received adjuvant chemotherapy.

Methods

We retrospectively reviewed 100 patients who received S-1 adjuvant chemotherapy at ≥70% of the relative dose intensity, and their NLRs and PLRs were evaluated at different times: prior to gastrectomy and upon commencement and termination of adjuvant chemotherapy. To assure the clinical utility of the changes in NLR and PLR as prognostic indicators, other clinical factors were assessed as well.

Results

Disease recurred in 35 patients as follows: lymph node metastasis (17 patients, 17.0%), peritoneal metastasis (12 patients, 12.0%), and hematogenous metastasis (6 patients, 6.0%); 24 patients died. An increase in the NLR during adjuvant chemotherapy with S-1 was identified as an independent indicator associated with overall survival (hazard ratio [HR] 6.736, 95% confidence interval [CI] 2.420–18.748; P < 0.001), and relapse-free survival (HR 5.309, 95% CI 2.585–10.901; P < 0.001).

Conclusion

An increase in the NLR during S-1 adjuvant chemotherapy may be a useful prognostic indicator in patients with stage II or III gastric cancer.

Survival Outcomes of Two Phase 2 Studies of Adjuvant Chemotherapy with S-1 Plus Oxaliplatin or Capecitabine Plus Oxaliplatin for Patients with Gastric Cancer After D2 Gastrectomy

BACKGROUND

Two phase 2 trials of oxaliplatin-containing adjuvant therapy for patients with gastric cancer (GC) after D2 gastrectomy were conducted in Japan. The SOXaGC trial evaluated the tolerability and safety of adjuvant therapy with S-1 plus oxaliplatin (SOX), whereas the J-CLASSIC trial evaluated the feasibility of adjuvant therapy with capecitabine plus oxaliplatin (CAPOX). Because both were studies that did not evaluate survival results as study end points, the authors evaluated the survival outcomes for the patients in the two trials.

METHODS

All 62 and 100 patients in the full analysis set of the SOXaGC and J-CLASSIC trials, respectively, were included in the current study. Their information about survival outcome was collected. The primary end point was relapse-free survival (RFS), and the secondary end point was overall survival (OS).

RESULTS

For the pathologic stage (pStage 2) patients treated with CAPOX, the 3-year RFS rate was 87.8% and the 3-year OS rate was 92.7%. For the pStage 3 patients treated with SOX and CAPOX, the 3-year RFS rates were respectively 70.9% and 67.8% (hazard ratio [HR], 0.93; 95% confidence interval [CI], 0.50-1.72), whereas the 3-year OS rates were respectively 75.7% and 79.3% (HR, 1.10; 95% CI, 0.54-2.26). Subgroup analysis showed significant interactions between the treatment (SOX vs. CAPOX) and both sex (male vs. female; P = 0.024) and histologic type (diffuse vs. other, P = 0.069).

CONCLUSIONS

This exploratory analysis demonstrated that SOX and CAPOX are suggested to have similar efficacy for pStage 3 GC patients after D2 gastrectomy. Differences in the treatment effect according to sex and histologic type warrant further evaluation.

Comparative effectiveness of adjuvant treatments for resected gastric cancer: a network meta-analysis

BACKGROUND

Different adjuvant treatments are available for patients with gastric cancer, but conventional meta-analyses performing direct comparisons between two alternative treatments did not have enough power to compare all the adjuvant treatments. Thus, we did a network meta-analysis summarizing the direct and indirect comparisons to identify the optimum treatment.

METHODS

We systematically searched for RCTs of adjuvant treatments for gastric cancer comparing two or more of the following treatments: surgery alone, radiotherapy with fluoropyrimidine, S-1-based regimens, and XELOX. The treatments offering available indirect evidence to investigate the comparative effectiveness of adjuvant treatments mentioned above were also included. Then we performed a Bayesian network meta-analysis to summarize the direct and indirect comparisons. We estimated hazard ratios with 95% credible intervals (CrI) for OS and DFS.

RESULTS

11 eligible RCTs (5620 patients) were included in the network meta-analysis. Radiotherapy with fluorouracil (5-FU/RT), S-1-based regimens, and XELOX significantly improved OS as compared with surgery alone [(HR = 0.75 with 95% CrI: 0.63-0.89), (HR = 0.63 with 95% CrI: 0.52-0.76), and (HR = 0.66 with 95% CrI: 0.51-0.85), respectively]. No treatment was clearly superior to others; however, S-1-based regimes and XELOX showed a statistically non-significant trend to better survival as compared with 5-FU/RT.

CONCLUSIONS

S-1-based chemotherapy and XELOX are likely to be the most effective adjuvant treatments for patients with resected gastric cancer. 5-FU alone provided little survival benefits as compared with surgery alone. Further clinical trials may be required to investigate S-1-based and XELOX-based adjuvant treatment strategies.

Adjuvant chemotherapy with S-1 plus oxaliplatin improves survival of patients with gastric cancer after D2 gastrectomy: A multicenter propensity score-matched study

AIM

To investigate the safety and efficacy of S-1 plus oxaliplatin (SOX) as an adjuvant chemotherapy regimen in gastric cancer (GC) after D2 dissection.

METHODS

GC Patients who underwent D2 gastrectomy from September 2009 to December 2011 in four Chinese institutions were enrolled. Patients with stage IB-IIIC GC, who received adjuvant SOX treatment were matched by propensity scores with those who underwent surgery alone and those who conducted capecitabine plus oxaliplatin (XELOX) regimen. Disease-free survival (DFS) and overall survival (OS) were compared among the groups. In addition, adverse events in SOX patients were analyzed.

RESULTS

Of 1944 GC patients who underwent D2 dissection, 867 were included for analysis. One hundred and seventeen patients treated with SOX were matched to 234 patients who conducted surgery alone. Fifty-seven patients treated with SOX were matched to 57 patients who received XELOX. The estimated five-year DFS was 57.5% in the adjuvant SOX group which was higher than that (44.6%) in the surgery alone group (P = 0.001); and the estimated five-year OS was 68.3% which was higher than that (45.8%) of surgery alone group (P < 0.001). Survival benefit was also revealed in stage III and > 60 years old subgroups (P < 0.001 and P = 0.015, respectively). Compared with XELOX regimen, SOX showed no significant difference in DFS (P = 0.340) and OS (P = 0.361). The most common ≥ 3 grade adverse events of SOX regimen were neutropenia (22.6%), leukopenia (8.9%) and thrombocytopenia (5.6%).

CONCLUSION

Compared with surgery alone, SOX regimen significantly improves the long-term survival and has acceptable toxicity in patients with stage IB-IIIC GC after D2 dissection. It may be a novel adjuvant chemotherapy regimen in GC patients.

Preoperative globulin-to-albumin ratio predicts outcome after curative resection in patients with gastric cancer

AIM

The globulin-to-albumin ratio (GAR) is useful for prognostication of patients with various cancers. However, the significance of GAR in gastric cancer (GC) remains unclear. Our purpose was to investigate the relationship between the GAR and outcome after curative resection in GC patients.

METHODS

Three-hundred and seventy-six patients who had undergone curative resection for GC were retrospectively reviewed. Univariate and multivariate analyses using the Cox proportional hazard model were performed to detect clinical characteristics that correlated with overall survival (OS), and their cut-off values were identified using receiver operating characteristic (ROC) curve analyses. Kaplan-Meier analysis and log-rank test were used for comparison of OS and relapse-free survival (RFS).

RESULTS

Multivariate analysis using 17 clinical characteristics selected by univariate analyses revealed that GAR (>0.80/≤0.80) was significantly associated with OS (hazard ratio [HR], 2.305; 95% CI, 1.122-4.735; P = 0.023), as well as lymph node metastasis (presence/absence) (HR, 2.417; 95% CI, 1.077-5.426; P = 0.032), neutrophil-to-lymphocyte ratio (>2.7/≤2.7) (HR, 2.368; 95% CI, 1.138-4.930; P = 0.002), and serosal invasion (presence/absence) (HR, 3.443; 95% CI, 1.048-11.31; P = 0.042). Kaplan-Meier analysis and log-rank test demonstrated that the OS and RFS of patients with a high GAR (>0.80) were significantly poorer than those with low GAR (≤0.80).

CONCLUSIONS

The GAR is a useful predictor of postoperative outcome among GC patients undergoing curative resection.

The association of the lymph node ratio and serum carbohydrate antigen 19-9 with early recurrence after curative gastrectomy for gastric cancer

PURPOSE

This study investigated the predictors associated with early recurrence (i.e. within 12 months) after curative gastrectomy for gastric cancer (GC).

METHODS

We evaluated the clinicopathological factors in 429 patients who underwent curative gastrectomy for GC without preoperative chemotherapy and analyzed these factors' associations with early recurrence.

RESULTS

Of 429 patients, 57 experienced recurrences, which were associated with gender, diameter, depth of invasion, lymph node (LN) metastasis, the LN ratio (LNr; LNs with metastasis/dissected LNs), lymphatic invasion, vascular invasion, carbohydrate antigen 19-9 (CA19-9) levels, C-reactive protein levels and the neutrophil/lymphocyte ratio. Twenty-one patients (36.8%) recurred within 12 months. Early recurrence was associated with a high LNr (P = 0.0020) and high CA19-9 levels (P = 0.0415). The other factors were not significantly associated with early recurrence. The 12-month recurrence rate was 33.9% in patients with a high LNr and 1.9% in those with a low LNr and 20.3% in patients with high CA19-9 levels and 3.5% in those with low CA19-9 levels. The 12-month recurrence rate was 62.5% in patients with a high LNr and high CA19-9 levels, 18.4% in those with a high LNr or high-CA19-9 levels, and 1.4% in those with a low LNr and low CA19-9 levels.

CONCLUSION

LNr ≥ 0.15 and CA19-9 ≥ 37 U/ml were effective surrogate markers for predicting early recurrence.

Phase II study of adjuvant chemotherapy with S1 plus oxaliplatin for Chinese patients with gastric cancer

Background

S-1 plus oxaliplatin(SOX) has been demonstrated to be effective and well tolerated for patients with metastatic gastric cancer. We conducted this phase II study to evaluate the feasibility of SOX as adjuvant chemotherapy for gastric cancer after curative resection.

Methods

Adjuvant chemotherapy consisted of six to eight cycles of S-1 plus oxaliplatin. Oxaliplatin was administered intravenously at a dose of 130 mg/m² on day 1. S-1 was administered orally at a dose of 70 mg/m² daily from day 1 to 14 of a 3-week cycle. A total of 58 patients were enrolled in this study. The primary end point of the trial was the treatment completion rate for six cycles. Secondary endpoints were safety, 1-year and 3-year of disease free survival (DFS) and overall survival (OS).

Results

A total of 58 patients were enrolled and 54 patients have been analysed. The completion rate of six cycles was 72.2%. Grade 4 toxicities included neutropenia (1.9%) and thrombocytopenia (3.7%). Grade 3 toxicities included leukopenia (5.6%), neutropenia (24.1%), thrombocytopenia (13.0%), nausea (7.4%), vomiting 13.0%), and diarrhea (13.0%). There was no grade 3 or higher peripheral sensory neuropathy and treatment-related death. The median follow-up time was 42.4 months. 1-year and 3-year DFS rate were 85.2 and 75.9%, respectively.1-year and 3-year OS were 98.1 and 85.2%, respectively.

Conclusion

Adjuvant chemotherapy for GC with S-1 plus oxaliplatin is safe and feasible in Chinese patients. The optimal dose of oxaliplatin and optimal cycles of treatment still need to be further investigated.

Trial registration

clinicaltrials.gov identifier NCT01542294. Trial registration date: 03/02/2012.

Treatment using oxaliplatin and S-1 adjuvant chemotherapy for pathological stage III gastric cancer: a multicenter phase II study (TOSA trial) protocol

BACKGROUND

Recent studies demonstrated the efficacy of S-1-based adjuvant chemotherapy administered for six months after curative surgery for stage III gastric cancer; however, it is unproven whether this type of combination chemotherapy is more effective than the standard adjuvant chemotherapy of S-1 for one year.

METHODS

This multicenter phase II study evaluate the efficacy and safety of adjuvant chemotherapy using S-1 plus oxaliplatin followed by S-1 for up to one year for curatively resected stage III gastric cancer in patients aged over 20 years. Treatment initially comprises oral fluoropyrimidine S-1 (80 mg/m²) administered twice daily for the first 2 weeks of a 3-week cycle. On day 1 of a second 3-week cycle, patients will receive 100 mg/m² of intravenous oxaliplatin followed by 80 mg/m² of S-1 (maximum 8 cycles). Then, the patients will receive 80 mg/m² of S-1 daily for 4 weeks, followed by 2 weeks of no chemotherapy. This 6-week cycle will be repeated during the first year after surgery. The primary endpoint is relapse-free survival for 3 years and secondary endpoints are safety, including the incidence of adverse events, and grading of neuropathy with each treatment cycle. The planned sample size of 75 patients is appropriate for this trial. The data will be analyzed on an intention-to-treat basis, assuming a two-sided test with a 5% level of significance.

DISCUSSION

In contrast to previous trials, the current study involves administration of S-1 until one year after surgery in addition to prior S-1 plus oxaliplatin, and is the first study to evaluate the safety and efficacy of S-1 plus oxaliplatin followed by S-1 for up to one year in patients with curatively resected stage III gastric cancer.

TRIAL REGISTRATION

This trial is registered in the University Hospital Medical Information Network's Clinical Trials Registry (UMIN-CTR) registration number, R000029656  ( https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000029656 ). Registered January 24, 2017.

Venous invasion as a risk factor for recurrence after gastrectomy followed by chemotherapy for stage III gastric cancer

Background

Although adjuvant chemotherapy with S-1 after curative gastrectomy has been performed as a standard treatment for Stage II and III gastric cancer (GC) in Japan, patients with Stage III GC still have a high incidence of recurrence and a poor prognostic outcome. The aim of this study was to investigate risk factors for recurrence in patients with Stage III GC despite of curative gastrectomy followed by adjuvant chemotherapy, suggesting an indicator for more intensive management.

Methods

A total of 97 patients with pathological Stage III GC underwent adjuvant chemotherapy after curative gastrectomy between 2001 and 2014, were enrolled in this study. We retrospectively analyzed their hospital records from our hospital.

Results

The 5-year relapse-free survival (RFS) rates of patients with pStage III GC were 42.0%. Univariate and multivariate analyses for RFS revealed that venous invasion (v+) was an independent factor predicting a shorter RFS (v + vs. v-, 36.5% vs. 47.4%, P = 0.034, HR 1.82, 95% CI: 1.01–3.37). Venous invasion also predicted a shorter overall survival (OS) (v + vs. v-, 33.7% vs. 50.4%, P = 0.027). Regarding the patterns of recurrence, hematogenous recurrence was significantly occurred in patients with v + GC than those without (P = 0.022).

Conclusions

Stage III GC with venous invasion is a high-risk subgroup for hematogenous recurrence after curative surgery followed by adjuvant chemotherapy. More intensive and effective adjuvant chemo and/or molecular targeted therapy for Stage III GC patients with venous invasion should be considered to improve their outcomes.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4052-z) contains supplementary material, which is available to authorized users.

The principles of the surgical management of gastric cancer

Surgery is the only curative therapy for gastric cancer but most operable gastric cancer presents in a locally advanced stage characterized by tumor infiltration of the serosa or the presence of regional lymph node metastases. Surgery alone is no longer the standard treatment for locally advanced gastric cancer as the prognosis is markedly improved by perioperative chemotherapy. The decisive factor for optimum treatment is the multidisciplinary team specialized in gastric cancer. However, despite multimodal therapy and adequate surgery only 30% of gastric cancer patients are alive at 3 years. This article reviewed the principles of the surgical management of gastric cancer (minimally invasive or open) and how this may optimize multimodal treatment.

Phase II Trial of Adjuvant Immunotherapy with Autologous Tumor-derived Gp96 Vaccination in Patients with Gastric Cancer

Background/Aims: Autologous, tumor-derived, heat shock protein gp96 peptide complexes have antitumor potential. We conducted the first Phase II trial to evaluate the safety and efficacy of gp96 vaccination in adjuvant settings for patients with gastric cancer.

Methods: We enrolled 73 consecutive patients from October 2012 to December 2015. Thirty-eight patients received gp96 vaccination plus chemotherapy and 35 received chemotherapy alone. The primary endpoints were disease-free survival (DFS) and toxicity. The secondary endpoints were overall survival (OS) and tumor-specific immune responses.

Results: There were comparable baseline characteristics between the two groups. Tumor-specific immune responses increased significantly after gp96 vaccination. gp96 vaccination plus chemotherapy was well tolerated and there were no gp96-related serious adverse events. Patients who received gp96 vaccination had improved DFS compared with those who did not [p = 0.045; hazard ratio (HR): 0.47; 95% confidence interval (CI): 0.23-0.96]. The 2-year OS rates were 81.9% and 67.9% for the gp96 vaccination and chemotherapy alone group, respectively (p = 0.123; HR: 0.42; 95% CI: 0.15-1.24).

Conclusion: gp96 vaccination elicits tumor-specific immune responses and can be safely used in adjuvant settings combined with chemotherapy. Patients with less-aggressive diseases might benefit from gp96 therapy.

East Versus West: Differences in Surgical Management in Asia Compared with Europe and North America

In recent decades, there has been considerable worldwide progress in the treatment of gastric cancer. Gastrectomy with a modified D2 lymphadenectomy (sparing the distal pancreas and spleen) has increasingly gained acceptance as a preferable standard surgical approach among surgeons in the East and the West. Despite growing consensus significant differences still exist in surgical techniques in clinical trials and clinical practices secondary to variations in epidemiology, clinicopathologic features, and surgical outcomes among geographic regions. In addition, Western physicians tend to prefer adjuvant chemotherapy and radiotherapy after surgery instead of using S-1 chemotherapy, as is the preference in the East.

The Asian Perspective on the Surgical and Adjuvant Management of Esophagogastric Cancer

In East Asia, D2 dissection has been routine surgical procedure for curable advanced gastric cancer. More extended surgery than D2 is reserved for borderline resectable disease with extended nodal metastasis. The addition of radiation therapy to adjuvant chemotherapy failed to improve the outcome after D2 dissection. Because many patients are diagnosed in East Asia with early-stage disease, postoperative adjuvant chemotherapy is preferred, and S-1 monotherapy or capecitabine-oxaliplatin is standard care. Neoadjuvant chemotherapy may be preferred for stage III tumors; for borderline resectable tumors, preoperative chemotherapy is under study given the limitations of postoperative adjuvant chemotherapy in high-risk patients.

Timing of initiation of adjuvant chemotherapy for gastric cancer: A case-matched comparison study of laparoscopic vs. open surgery

BACKGROUND

Laparoscopic gastrectomy (LG) is reported to be associated with faster recovery than open gastrectomy (OG); however, the influence of the surgical approach on initiation timing of adjuvant chemotherapy (AC) remains unclear.

METHODS

This was a single-institutional retrospective observational study. Patients with pathological stage II/III gastric cancer undergoing LG with D2 lymphadenectomy (LG group: n = 74) were matched 1:1 with patients selected from 214 similar patients undergoing OG (OG group: n = 74), identically matching gender, age, pathological stage, and type of gastrectomy, and comparing AC initiation timing between the two groups. Factors associated with delayed initiation of AC were investigated in a multivariable analysis.

RESULTS

AC was performed in 86.5% (LG) and 83.8% (OG) of patients (p = 0.64). The median time interval before AC was significantly shorter in the LG vs. OG group (5.7 vs. 6.6 weeks, respectively, p < 0.001), and significantly more patients received AC within 6 weeks (60.8% vs. 27.0%, p < 0.001). Independent factors associated with delayed initiation of AC (>6 weeks) were: morbidity (≥grade 3a; odds ratio (OR): 16.1, 95% confidence interval (CI): 1.86-143), open surgery (OR: 5.17, 95% CI: 2.50-13.1), and postoperative weight loss ≥ 8% (OR: 2.47, 95% CI: 1.07-5.71).

CONCLUSIONS

LG may be associated with shorter intervals before AC. Postoperative morbidity should be reduced as much as possible.

Postoperative chemotherapy with S-1 plus oxaliplatin versus S-1 alone in locally advanced gastric cancer (RESCUE-GC study): a protocol for a phase III randomized controlled trial

BACKGROUND

The ACTS-GC study had shown postoperative adjuvant therapy with S-1 improved survival of patients with locally advanced gastric cancer. Addition of oxaliplatin to S-1 is considered to be acceptable as one of the treatment options for gastric cancer patients after radical gastrectomy with D2 lymph node excision.

METHODS

We have commenced a randomized phase III trial in December 2016 to evaluate S-1 plus oxaliplatin compared with S-1 alone in the adjuvant setting for locally advanced gastric cancer. A total of 564 patients will be accrued from 13 Chinese institutions in two years. The primary endpoint is 3-year relapse-free survival. The secondary endpoints are 5-year overall survival, proportion of patients who complete the postoperative chemotherapy and incidence of adverse events.

ETHIC AND DISSEMINATION

The trial has been approved by the institutional review board of each participating institution and it was activated on December, 2016. The enrollment will be finished in December, 2018. Patient's follow-up will be ended until December, 2023.

TRIAL REGISTRATION

ClinicalTrials.gov, identifier: NCT02867839. Registered on August 4, 2016.