Comparing cytotoxic backbones for first-line trastuzumab-containing regimens in human epidermal growth factor receptor 2-positive advanced oesophagogastric cancer: A meta-analysis

Is there a preferred platinum and fluoropyrimidine regimen for advanced HER2-negative esophagogastric adenocarcinoma? Insights from 1293 patients in AGAMENON-SEOM registry

BACKGROUND

The optimal chemotherapy backbone for HER2-negative advanced esophagogastric cancer, either in combination with targeted therapies or as a comparator in clinical trials, is uncertain. The subtle yet crucial differences in platinum-based regimens' safety and synergy with combination treatments need consideration.

METHODS

We analyzed cases from the AGAMENON-SEOM Spanish registry of HER2-negative advanced esophagogastric adenocarcinoma treated with platinum and fluoropyrimidine from 2008 to 2021. This study focused exclusively on patients receiving one of the four regimens: FOLFOX (5-FU and oxaliplatin), CAPOX (capecitabine and oxaliplatin), CP (capecitabine and cisplatin) and FP (5-FU and cisplatin). The aim was to determine the most effective and tolerable platinum and fluoropyrimidine-based chemotherapy regimen and to identify any prognostic factors.

RESULTS

Among 1293 patients, 36% received either FOLFOX (n = 468) or CAPOX (n = 466), 20% CP (n = 252), and 8% FP (n = 107). FOLFOX significantly increased PFS (progression free survival) compared to CP, with a hazard ratio of 0.73 (95% CI 0.58-0.92, p = 0.009). The duration of treatment was similar across all groups. Survival outcomes among regimens were similar, but analysis revealed worse ECOG-PS (Eastern Cooperative Oncology Group-Performance Status), > 2 metastatic sites, bone metastases, hypoalbuminemia, higher NLR (neutrophil-to-lymphocyte ratio), and CP regimen as predictors of poor PFS. Fatigue was common in all treatments, with the highest incidence in FOLFOX (77%), followed by FP (72%), CAPOX (68%), and CP (60%). Other notable toxicities included neuropathy (FOLFOX 69%, CAPOX 62%), neutropenia (FOLFOX 52%, FP 55%), hand-foot syndrome in CP (46%), and thromboembolic events (FP 12%, CP 11%).

CONCLUSIONS

FOLFOX shown better PFS than CP. Adverse effects varied: neuropathy was more common with oxaliplatin, while thromboembolism was more frequent with cisplatin.

HER2-Positive Gastric Cancer and Antibody Treatment: State of the Art and Future Developments

Despite a decreasing incidence in Western countries, gastric cancer is among the most common cancer subtypes globally and is associated with one of the highest tumor-related mortality rates. Biomarkers play an increasing role in the treatment against gastric cancer. HER2 was one of the first biomarkers that found its way into clinical practice. Since the ToGA trial, trastuzumab has been part of first-line palliative chemotherapy in metastatic or unresectable gastric cancer. HER2-targeting agents, such as the tyrosine kinase inhibitor lapatinib, the antibody drug conjugate (ADC) trastuzumab-emtansine or dual HER2 inhibition (pertuzumab and trastuzumab), have been investigated in the second-line setting but led to negative study results. More recently, the ADC trastuzumab-deruxtecan was authorized after the failure of trastuzumab-based treatment. However, further improvements in HER2-directed therapy are required as resistance mechanisms and HER2 heterogeneity limit the existing treatment options. This review aims to give an overview of the current standard-of-care HER2-directed therapy in gastric cancer, as well as its challenges and future developments.

The AGAMENON-SEOM model for prediction of survival in patients with advanced HER2-positive oesophagogastric adenocarcinoma receiving first-line trastuzumab-based therapy

Background

Trastuzumab and chemotherapy is the standard first-line treatment in human epidermal growth factor receptor 2 (HER2)-positive advanced gastro-oesophageal cancer. The objective was to develop a predictive model for overall survival (OS) and progression-free survival (PFS) in patients treated with trastuzumab.

Methods

Patients with HER2-positive advanced gastro-oesophageal adenocarcinoma (AGA) from the Spanish Society of Medical Oncology (SEOM)-AGAMENON registry and treated first line with trastuzumab and chemotherapy between 2008 and 2021 were included. The model was externally validated in an independent series (The Christie NHS Foundation Trust, Manchester, UK).

Results

In all, 737 patients were recruited (AGAMENON-SEOM, n = 654; Manchester, n = 83). Median PFS and OS in the training cohort were 7.76 [95% confidence interval (CI), 7.13-8.25] and 14.0 months (95% CI, 13.0-14.9), respectively. Six covariates were significantly associated with OS: neutrophil-to-lymphocyte ratio, Eastern Cooperative Oncology Group performance status, Lauren subtype, HER2 expression, histological grade and tumour burden. The AGAMENON-HER2 model demonstrated adequate calibration and fair discriminatory ability with a c-index for corrected PFS/OS of 0.606 (95% CI, 0.578-0.636) and 0.623 (95% CI, 0.594-0.655), respectively. In the validation cohort, the model is well calibrated, with a c-index of 0.650 and 0.683 for PFS and OS, respectively.

Conclusion

The AGAMENON-HER2 prognostic tool stratifies HER2-positive AGA patients receiving trastuzumab and chemotherapy according to their estimated survival endpoints.

Breakthroughs in the Systemic Treatment of HER2-Positive Advanced/Metastatic Gastric Cancer: From Singlet Chemotherapy to Triple Combination

Gastric cancer is heterogeneous in morphology, biology, genomics, and treatment response. Alterations in human epidermal growth factor receptor 2 (HER2) overexpression, microsatellite instability (MSI) status, programmed death-ligand 1 (PD-L1) levels, and fibroblast growth factor receptor 2 (FGFR2) can be used as biomarkers. Since the combination of fluoropyrimidine/platinum plus trastuzumab that was investigated in the ToGA trial was approved as a standard of care in HER2-positive patients in 2010, no other agents showed efficacy in the first- (HELOISE, LOGiC, JACOB trials) and second- (TyTAN, GATSBY, T-ACT trials) line treatments. Despite the success in treating breast cancer, various anti-HER2 agents, including a monoclonal antibody (pertuzumab), an antibody-drug conjugate (ADC; trastuzumab emtansine [T-DM1]), and a small molecule (lapatinib) failed to translate into clinical benefits until the KEYNOTE-811 (first-line) and DESTINY-Gastri01 (≥second-line) trials were conducted. The incorporation of HER2-directed treatment with immune checkpoint inhibitors in the form of a monoclonal antibody or ADC is now approved as a standard treatment. Despite the promising results of new agents (engineered monoclonal antibodies, bi-specific antibodies, fusion proteins, and small molecules) in the early phase of development, the management of HER2-positive gastric cancer requires further optimization to achieve precision medicine with a chemotherapeutic backbone. Treatment resistance is a complex process that can be overcome using a combination of chemotherapy, targeted agents, and immune checkpoint inhibitors, including novel agents. HER2 status must be reassessed in patients undergoing anti-HER2 treatment with disease progression after the first-line treatment. As a general guideline, patients who need systemic treatment should receive chemotherapy plus targeted agents, anti-angiogenic agents, immune checkpoint inhibitors, or their combinations.

Targeting HER2 in metastatic gastroesophageal adenocarcinomas: What is new?

Gastric and esophageal adenocarcinomas represent a biologically heterogeneous disease. The identification, in early eighties, of human epidermal growth factor receptor 2 (HER2) overexpression, being present in 12 to 20% of the cases, marked a major milestone in the efforts of unraveling the molecular complexity of this disease. This led to the development of anti-HER2-therapies, trastuzumab being the first to demonstrate, in combination with cisplatin and 5FU/capecitabine chemotherapy, an improvement in response rate and survival in the first-line setting of patients with metastatic, HER2-positive gastroesophageal adenocarcinomas. Afterwards, during a decade, several studies have tried new strategies either to block HER2 pathway differently or to combine different anti-HER2, without efficacy. Everything changed with studies demonstrating additive effect between anti-HER2 and immune checkpoint inhibitors and leading to phase III clinical trials combining anti-HER2 and anti-PD-L1/PD1 therapies. Pembrolizumab, a PD-1 inhibitor, was recently granted by FDA an accelerated approval, in patients with HER2-positive gastro-oesophageal adenocarcinomas, in combination with trastuzumab and platinum-based chemotherapy following meaningful improvement in overall response rate over standard treatment. Progression-free and overall-survival results are still awaited to change our first-line standard treatment. Furthermore, new HER2 inhibitors have been developed, blocking HER2-mediated pathway signaling via different mechanisms from pan-HER inhibition to anti-HER2 antibody drug conjugates with promising results in pretreated patients. Trastuzumab-deruxtecan has in particular showed interesting results in pretreated patients. We present here a review of the recent data and perspectives in HER2-positive metastatic gastroesophageal adenocarcinomas.

Triplet Chemotherapy with Cisplatin versus Oxaliplatin in the CRITICS Trial: Treatment Compliance, Toxicity, Outcomes and Quality of Life in Patients with Resectable Gastric Cancer

(1) Background: Perioperative chemotherapy is the current standard treatment for patients with resectable gastric cancer. Based on studies in patients with metastatic gastric cancer, oxaliplatin has replaced cisplatin in the curative setting as well. However, evidence to prefer oxaliplatin over cisplatin in the curative setting is limited. (2) Methods: We compared patient-related and tumor-related outcomes for cisplatin versus oxaliplatin in patients with resectable gastric cancer treated with perioperative chemotherapy in the CRITICS trial. (3) Results: Preoperatively, 632 patients received cisplatin and 149 patients received oxaliplatin. Preoperative severe toxicity was encountered in 422 (67%) patients who received cisplatin versus 89 (60%) patients who received oxaliplatin (p = 0.105). Severe neuropathy was observed in 5 (1%) versus 6 (4%; p = 0.009) patients, respectively. Postoperative severe toxicity occurred in 109 (60%) versus 26 (51%) (p = 0.266) patients; severe neuropathy in 2 (1%) versus 2 (4%; p = 0.209) for patients who received cisplatin or oxaliplatin, respectively. Diarrhea impacted the quality of life more frequently in patients who received oxaliplatin compared to cisplatin. Complete or near-complete pathological response was achieved in 94 (21%) versus 16 (15%; p = 0.126) patients who received cisplatin or oxaliplatin, respectively. Overall survival was not significantly different in both groups (p = 0.300). (4) Conclusions: Both cisplatin and oxaliplatin are legitimate options as part of systemic treatment in patients with resectable gastric cancer.

Changing Landscape of Systemic Therapy in Biliary Tract Cancer

Biliary tract cancers (BTC) are often diagnosed at advanced stages and have a grave outcome due to limited systemic options. Gemcitabine and cisplatin combination (GC) has been the first-line standard for more than a decade. Second-line chemotherapy (CT) options are limited. Targeted therapy or TT (fibroblast growth factor 2 inhibitors or FGFR2, isocitrate dehydrogenase 1 or IDH-1, and neurotrophic tyrosine receptor kinase or NTRK gene fusions inhibitors) have had reasonable success, but <5% of total BTC patients are eligible for them. The use of immune checkpoint inhibitors (ICI) such as pembrolizumab is restricted to microsatellite instability high (MSI-H) patients in the first line. The success of the TOPAZ-1 trial (GC plus durvalumab) is promising, with numerous trials underway that might soon bring targeted therapy (pemigatinib and infrigatinib) and ICI combinations (with CT or TT in microsatellite stable cancers) in the first line. Newer targets and newer agents for established targets are being investigated, and this may change the BTC management landscape in the coming years from traditional CT to individualized therapy (TT) or ICI-centered combinations. The latter group may occupy major space in BTC management due to the paucity of targetable mutations and a greater toxicity profile.

Current status and future perspectives in HER2 positive advanced gastric cancer

Gastric cancer is one of the most common malignancy worldwide with a prognosis less than 1 year in unresectable or metastatic disease. HER2 expression is the main biomarker to lead the addition of trastuzumab to first line systemic chemotherapy improving the overall survival in advanced HER2-positivegastric adenocarcinoma. The inevitable development of resistance to trastuzumab remains a great problem inasmuch several treatment strategies that have proven effective in breast cancer failed to show clinical benefit in advanced gastric cancer. In this review, we summarize the available data on the mechanisms underlying primary and secondary resistance toHER2-targeted therapy and current challenges in the treatment of HER2-positive advanced gastric cancer refractory to trastuzumab. Further, we describe the prognostic value of new non-invasive screening techniques, the current development of novel agents such us HER2 antibody-drug conjugates and bispecific antibodies, and the strategies with antitumor activity on going.

HER2-Directed Therapy in Advanced Gastric and Gastroesophageal Adenocarcinoma: Triumphs and Troubles

OPINION STATEMENT

Gastric and gastroesophageal junction (GEJ) cancers represent the third leading cause of malignancy-associated death worldwide. Approximately 15-20% of these adenocarcinomas overexpress the human epidermal growth factor receptor 2 (HER2), a pro-proliferative receptor tyrosine kinase that has been therapeutically exploited in other disease contexts. The landmark ToGA trial demonstrated that trastuzumab, an anti-HER2 antibody, could improve overall survival for patients with HER2 overexpressing advanced gastric and GEJ adenocarcinomas. In the ensuing decade, great effort has been made to refine and expand this therapeutic strategy through a variety of avenues including optimization of chemotherapy backbones, identifying potential synergy with immune checkpoint inhibition, deployment of alternative HER2-targeted antibodies, use of small molecule inhibitors, and development of HER2-directed antibody drug conjugates. While the results of these efforts have had variable success, they have led to a greater understanding of the mechanisms of both primary and acquired resistance to HER2-directed therapies, laying the groundwork for future investigations. Recently, KEYNOTE-811 and DESTINY-Gastric01 have led to the FDA approvals of pembrolizumab in combination with trastuzumab and chemotherapy in the 1st-line advanced setting and trastuzumab deruxtecan (fam-trastuzumab deruxtecan-nxki) in the 2nd-line setting, respectively. Herein, we review these significant works as well as discuss the ongoing investigations they have inspired, which aim to find and utilize additional means for targeting HER2 in gastric and GEJ cancers.

Hopes and failures in front-line advanced HER2-positive gastric cancer therapy

Human epidermal growth-factor receptor 2 (HER2) was an important therapeutic target in gastric cancer. Through the last decade, strategy with trastuzumab-based chemotherapy remains the first-line standard of treatment in advanced HER2-positive gastric cancer. Based on the Trastuzumab for Gastric Cancer trial, trastuzumab plus systemic chemotherapy of cisplatin and fluoropyrimidine as the backbone was established as the first-line therapy in advanced HER2-positive gastric cancer. Since then, studies have explored the optimization of the front-line strategy, including the dose of trastuzumab, chemotherapy regimen and maintenance therapy. A large number of clinical trials were conducted to explore the optimal front-line therapy regimens, such as lapatinib and pertuzumab. Safe and effective first-line regimens are still lacking. Recently, two phase II studies of combining immune checkpoint inhibitor in first-line treatment of advanced HER2-positive gastric cancer showed promising results. The progress of immunotherapy has gradually promoted the development of front-line treatment of advanced HER2-positive gastric cancer to potential chemotherapy-free strategies. Therefore, this article reviewed these significant clinical trials and focus on the front-line treatment strategies for HER2-positive gastric cancer.

Human epidermal growth factor receptor 2 (HER2) in advanced gastric cancer: where do we stand?

Gastric cancer is one of the most common malignancy worldwide. In unresectable or metastatic disease, the prognosis is poor and in generally less than a year. HER2 expression remains an important biomarker to lead the addition of trastuzumab to first-line systemic chemotherapy in unresectable or metastatic gastroesophageal adenocarcinoma. To date, a major issue is represented by resistance to trastuzumab developed during treatment, considering the not improved outcomes in this molecular subtype of gastroesophageal adenocarcinoma to other HER2 target strategies. In this review, we summarize the available data on the mechanisms underlying primary and secondary resistance to HER2-targeted therapy and current challenges in the treatment of HER2-positive advanced gastric cancer refractory to trastuzumab. Furthermore, we describe the prognostic value of new non-invasive screening methods, under development novel agents (e.g., HER2 antibody-drug conjugates and bispecific antibodies) and strategies with antitumor activity in early studies.

External validity of clinical trials with diverse trastuzumab-based chemotherapy regimens in advanced gastroesophageal adenocarcinoma: data from the AGAMENON-SEOM registry

BACKGROUND

Trastuzumab combined with cisplatin and fluoropyrimidines, either capecitabine or 5-fluorouracile (XP/FP), is the standard first-line treatment for advanced, HER2-positive, gastric cancer patients based on the ToGA trial. Despite the lack of phase III trials, many clinicians administer trastuzumab with alternative regimens. One meta-analysis suggests that substituting cisplatin for oxaliplatin might lead to greater efficacy and less toxicity.

METHODS

594 patients with HER2-positive gastroesophageal adenocarcinoma were recruited from the AGAMENON-SEOM registry. The objective was to evaluate the external validity of clinical trials with chemotherapy and trastuzumab.

RESULTS

The regimens used in at least 5% of the patients were XP (27%), oxaliplatin and capecitabine (CAPOX) (26%), oxaliplatin and 5-fluorouracil (FOLFOX) (14%), FP (14%), triplet with anthracycline/docetaxel (7%), and carboplatin-FU (5%). Median exposure to trastuzumab was longer with FOLFOX (11.4 months, 95% CI, 9.1-21.0) versus ToGA regimens (7.5, 6.4-8.5), p < 0.001. Patients with HER2-IHC 3+ cancers had higher response rates than those with IHC 2+/FISH+, odds-ratio 1.97 (95% CI, 1.25-3.09). The results achieved with CAPOX-trastuzumab were comparable to those attained with ToGA regimens. FOLFOX-trastuzumab was superior to ToGA schemes in terms of overall survival (OS), with a greater magnitude of effect in IHC 2+/FISH+ tumors (HR 0.47, 0.24-0.92) compared with IHC 3+ (HR 0.69, 0.49-0.96), and in diffuse (HR 0.37, 0.20-0.69) versus intestinal-type tumors (HR 0.76, 0.54-1.06).

CONCLUSION

We have updated the external validity of clinical trials with trastuzumab in first-line treatment of gastric cancer. Our data confirm the comparable outcomes of ToGA regimens and CAPOX-trastuzumab in clinical practice and point toward a possible benefit of FOLFOX-trastuzumab, contingent on the subtypes typically less sensitive to trastuzumab, to be confirmed in clinical trials.

Trastuzumab ± Capecitabine Maintenance After the First-Line Treatment of HER2-Positive Advanced Gastric Cancer: Retrospective Observational Real-Life Data of Turkish Oncology Group

PURPOSE

In the ToGA trial for HER2-positive advanced gastric cancer, cisplatin plus fluoropyrimidine was given for 6 cycles; trastuzumab was given until disease progression. However, there is a lack of real-life data about trastuzumab maintenance after 6 cycle chemotherapy. This study aims to present real-life data of trastuzumab ± capecitabine maintenance after 6 cycles of platinum, fluoropyrimidine, and trastuzumab in non-progressive patients.

METHODS

This is a retrospective multicenter study of the Turkish Oncology Group. A total of 35 HER2-positive, inoperable locally advanced, recurrent, or metastatic gastric adenocarcinoma patients being non-progressive at the end of 6 cycle chemotherapy and being given trastuzumab ± capecitabine as maintenance treatment were included from sixteen oncology centers. Baseline characteristics, objective tumor responses, progression free and overall survival data, and toxicities were determined.

RESULTS

About 68% of the patients were given CF, and 32% were given FOLFOX with trastuzumab as the first-line treatment. The best response in 6 cycle chemotherapy was complete 8 (22%), partial 24 (68%), and stable disease 3 (8%). All patients had trastuzumab maintenance (median cycle 13; range 7-51), and 49% of the patients had capecitabine with trastuzumab (median capecitabine cycle 6; range 2-30). The median PFS of the patients was 12.0 months (95% CI 10.3-13.7), and median OS was 17.4 months (95% CI 15.2-19.5). There were 2 patients with grade 1 cardiotoxicity.

CONCLUSION

Trastuzumab maintenance ± capecitabine after 6 cycles of trastuzumab plus combined chemotherapy treatment revealed efficacy and safety in non-progressive HER2-positive advanced gastric cancer.

Combination of trastuzumab and taxane-containing intensified chemotherapy in first-line treatment of HER2-positive advanced gastric cancer

PURPOSE

Taxane-containing combinations are recommended for the first-line therapy of advanced gastric cancer. It is not known which chemotherapy regimen is the best with trastuzumab for HER2-positive patients. The aim of this study was to compare taxane-containing intensified chemotherapy versus standard chemotherapy in combination with trastuzumab in the first-line treatment of HER2-positive advanced gastric adenocarcinoma.

METHODS

This study is a retrospective multicenter study of the Turkish Oncology Group. A total of 130 HER2-positive patients with inoperable locally advanced, recurrent, or metastatic gastric adenocarcinoma being given chemotherapy plus trastuzumab as the first-line treatment were included from 16 different oncology centers. Trastuzumab combination with intensified chemotherapy including taxane or standard chemotherapy was compared in terms of progression-free survival (PFS), overall survival (OS), and toxicity.

RESULTS

There were 108 patients in the standard and 22 patients in the intensified chemotherapy group. PFS of the standard and intensified group were 5.6 months (95% confidence interval [CI] 4.8-6.4) and 5.3 months (95% CI 2.6-8), respectively (p = 0.70). OS of the standard and intensified group were 11.1 months (95% CI 8.3-13.9) and 15.2 months (95% CI 12.7-17.7), respectively (p = 0.03). Repeated analysis excluding patients given any previous therapy revealed similar results. The intensified group had more fever and febrile neutropenia.

CONCLUSION

Trastuzumab combination with intensified chemotherapy provides better OS in first-line treatment of HER2-positive advanced gastric cancer. Further large-scale studies should be performed in HER2-positive patients.

Local and Central Evaluation of HER2 Positivity and Clinical Outcome in Advanced Gastric and Gastroesophageal Cancer-Results from the AGMT GASTRIC-5 Registry

Trastuzumab in combination with a platinum and fluorouracil is the treatment of choice for patients with advanced human epidermal growth factor receptor 2 (HER2) positive gastric cancer and gastroesophageal junction (GEJ) cancer. Pathological assessment of the HER2 status in gastric/GEJ cancer, however, still remains difficult. However, it is a crucial prerequisite for optimal treatment. The GASTRIC-5 registry was designed as an observational, multi-center research initiative comparing local and central HER2 testing. HER2 status was assessed by immunohistochemistry (IHC) and in equivocal cases (IHC score 2+) by additional in-situ hybridization. Between May 2011 and August 2018, tumor samples of 183 patients were tested in local and central pathology laboratories, respectively. Central testing revealed HER2 positivity in 38 samples (21%). Discordant HER2 results were found in 12% (22 out of 183) with locally HER2 positive/centrally HER2 negative results (9%, 17 out of 183), exceeding locally HER2 negative/centrally HER2 positive results (3%, 5 out of 183). Centrally confirmed HER2 positive patients receiving trastuzumab-based palliative first-line therapy showed a longer median overall survival compared to centrally HER2 positive patients not receiving trastuzumab (17.7 months (95% CI: 10,870–24,530) vs. 6.9 months (95% CI: 3.980–9.820), p = 0.016). The findings of the GASTRIC-5 registry corroborate the challenge of HER2 testing in gastric/GEJ cancer and highlight the necessity for central quality control to optimize individual treatment options. Centrally HER2 positive patients not receiving trastuzumab had the worst outcome in a Western real-world gastric/GEJ cancer cohort.

Emerging Targeted Therapies for HER2 Positive Gastric Cancer That Can Overcome Trastuzumab Resistance

Trastuzumab, a monoclonal antibody to human epidermal growth factor receptor 2 (HER2), has improved survival in patients with HER2-positive advanced gastric or gastroesophageal junction cancer (AGC). The inevitable development of resistance to trastuzumab remains a problem, however, with several treatment strategies that have proven effective in breast cancer having failed to show clinical benefit in AGC. In this review, we summarize the mechanisms underlying resistance to HER2-targeted therapy and outline past and current challenges in the treatment of HER2-positive AGC refractory to trastuzumab. We further describe novel agents such as HER2 antibody-drug conjugates that are under development and have shown promising antitumor activity in early studies.

Heterogeneity of first-line palliative systemic treatment in synchronous metastatic esophagogastric cancer patients: A real-world evidence study

The optimal first-line palliative systemic treatment strategy for metastatic esophagogastric cancer is not well defined. The aim of our study was to explore real-world use of first-line systemic treatment in esophagogastric cancer and assess the effect of treatment strategy on overall survival (OS), time to failure (TTF) of first-line treatment and toxicity. We selected synchronous metastatic esophagogastric cancer patients treated with systemic therapy (2010-2016) from the nationwide Netherlands Cancer Registry (n = 2,204). Systemic treatment strategies were divided into monotherapy, doublet and triplet chemotherapy, and trastuzumab-containing regimens. Data on OS were available for all patients, on TTF for patients diagnosed from 2010 to 2015 (n = 1,700), and on toxicity for patients diagnosed from 2010 to 2014 (n = 1,221). OS and TTF were analyzed using multivariable Cox regression, with adjustment for relevant tumor and patient characteristics. Up to 45 different systemic treatment regimens were found to be administered, with a median TTF of 4.6 and OS of 7.5 months. Most patients (45%) were treated with doublet chemotherapy; 34% received triplets, 10% monotherapy and 10% a trastuzumab-containing regimen. The highest median OS was found in patients receiving a trastuzumab-containing regimen (11.9 months). Triplet chemotherapy showed equal survival rates compared to doublets (OS: HR 0.92, 95%CI 0.83-1.02; TTF: HR 0.92, 95%CI 0.82-1.04) but significantly more grade 3-5 toxicity than doublets (33% vs. 21%, respectively). In conclusion, heterogeneity of first-line palliative systemic treatment in metastatic esophagogastric cancer patients is striking. Based on our data, doublet chemotherapy is the preferred treatment strategy because of similar survival and less toxicity compared to triplets.

Continuation of trastuzumab beyond progression in HER2-positive advanced esophagogastric cancer: a meta-analysis

INTRODUCTION

After progression on first-line trastuzumab-based therapy, no HER2-targeted agent is available for patients with HER2-positive esophagogastric cancer. However, continuation of trastuzumab after progression is an established strategy in HER2-positive breast cancer. We conducted a meta-analysis to investigate whether continuation of trastuzumab beyond first-line therapy in combination with chemotherapy is more effective compared to chemotherapy-alone.

METHODS

PubMed, EMBASE, CENTRAL and meeting abstracts from ASCO and ESMO were searched up to June 2018 for studies (any design) investigating second-line trastuzumab plus chemotherapy compared to chemotherapy-alone for patients with HER2-positive esophagogastric cancer that progressed on first-line trastuzumab-based therapy. Meta-analysis was performed on the primary outcome, overall survival (OS), and on secondary outcomes progression-free survival (PFS), objective-response rate (ORR), and adverse events.

RESULTS

Four cohort studies and one randomized controlled trial (RCT) were included with n = 200 patients who received second-line trastuzumab plus chemotherapy and n = 183 who received chemotherapy-alone. Meta-analysis showed that trastuzumab plus chemotherapy did not prolonged OS [HR = 0.72, 95% confidence interval (95% CI) = 0.47-1.08, p=.11). PFS was longer with trastzumab plus chemotherapy compared to chemotherapy-alone (HR = 0.64, 95% CI = 0.45-0.91, p<.05). There was no significant difference in ORR between the trastuzumab plus chemotherapy-group and the chemotherapy-alone group (ORR = 19.1% versus ORR = 13.4%, p=.13) and no significant differences in grade 3/4 and grade 1/2 adverse events.

CONCLUSIONS

This meta-analysis showed that patients who progressed on first-line trastuzumab-based therapy but of whom trastuzumab was continued in second-line and added to chemotherapy did not show longer OS or a higher ORR compared to patients receiving second-line chemotherapy-alone. However, PFS was prolonged and trastuzumab was not associated with additional safety concerns. In absence of available second-line HER2-targeted agents, a large prospective RCT should investigate if continuation of trastuzumab might be an attractive strategy, as this meta-analysis was mostly based on non-randomized studies and a RCT with a small sample size.

Pertuzumab plus trastuzumab and chemotherapy for HER2-positive metastatic gastric or gastro-oesophageal junction cancer (JACOB): final analysis of a double-blind, randomised, placebo-controlled phase 3 study

BACKGROUND

Adding pertuzumab to trastuzumab and chemotherapy improves survival in HER2-positive early breast cancer and metastatic breast cancer. We assessed the efficacy and safety of pertuzumab versus placebo in combination with trastuzumab and chemotherapy in first-line HER2-positive metastatic gastric or gastro-oesophageal junction cancer.

METHODS

JACOB was a double-blind, placebo-controlled, randomised, multicentre, phase 3 trial in patients aged 18 years or older with HER2-positive metastatic gastric or gastro-oesophageal junction cancer. Eligible patients had measurable or evaluable non-measurable disease at baseline, Eastern Cooperative Oncology Group performance status of 0 or 1, and baseline left ventricular ejection fraction of 55% or more. Patients at 197 oncology clinics (in 30 countries) were randomly assigned (1:1) to receive either pertuzumab (840 mg intravenously) or placebo every 3 weeks, with trastuzumab (8 mg/kg loading dose, then 6 mg/kg every 3 weeks intravenously), plus chemotherapy (cisplatin 80 mg/m² every 3 weeks intravenously, oral capecitabine 1000 mg/m² twice a day [2000 mg/m² every 24 h] for 28 doses every 3 weeks, or 5-fluorouracil 800 mg/m² every 24 h intravenously [120 h continuous infusion] every 3 weeks). Randomisation was by a central permuted block randomisation scheme (block size of 4) with an interactive voice or web response system, stratified by geographical region, previous gastrectomy, and HER2 positivity. The primary endpoint was overall survival in the intention-to-treat population. This trial is registered with Clinicaltrials.gov, number NCT01774786 (ongoing, but closed to enrolment).

FINDINGS

Between June 10, 2013, and Jan 12, 2016, of 3287 patients assessed, 780 eligible patients were randomly assigned to receive either pertuzumab plus trastuzumab and chemotherapy (pertuzumab group, n=388) or placebo plus trastuzumab and chemotherapy (control group, n=392). Median duration of follow-up was 24·4 months (95% CI 22·3-26·1) in the pertuzumab group and 25·0 months (22·3-28·9) in the control group. After 242 deaths in the pertuzumab group and 262 deaths in the control group (the study was not stopped at this point), overall survival was not significantly different between treatment groups (median overall survival 17·5 months [95% CI 16·2-19·3] in the pertuzumab group and 14·2 months [12·9-15·5] in the control group; hazard ratio 0·84 [95% CI 0·71-1·00]; p=0·057). Serious adverse events occurred in 175 (45%) of 385 patients in the pertuzumab group and 152 (39%) of 388 patients in the control group. Diarrhoea was the most common serious adverse event in both groups (17 [4%] patients in the pertuzumab group vs 20 [5%] patients in the control group). The most common grade 3-5 adverse events were neutropenia (116 [30%] patients in the pertuzumab group vs 108 [28%] patients in the control group), anaemia (56 [15%] vs 65 [17%]), and diarrhoea (51 [13%] vs 25 [6%]). Treatment-related deaths occurred in seven (2%) patients in the control group; no treatment-related deaths occurred in the pertuzumab group.

INTERPRETATION

Adding pertuzumab to trastuzumab and chemotherapy did not significantly improve overall survival in patients with HER2-positive metastatic gastric or gastro-oesophageal junction cancer compared with placebo. Further studies are needed to identify improved first-line treatment options in these types of cancer and to identify patients with HER2-driven tumours who might benefit from dual HER2-targeted therapy.

FUNDING

F. Hoffmann-La Roche Ltd.

The dynamics of HER2 status in esophageal adenocarcinoma

Trastuzumab, a monoclonal antibody against HER2, has become standard of care for metastatic HER2-overexpressing esophagogastric adenocarcinoma and is currently investigated as (neo)adjuvant treatment option in HER2-positive esophagogastric adenocarcinoma. The HER2 status is commonly determined on archived material of the primary tumor. However, this status may change over the course of treatment or disease progression. The aim of this study was to assess the dynamics of HER2 status in esophageal adenocarcinoma (EAC) in patients with resectable and recurrent disease, and to determine the associations of these changes with clinical outcome. Discordance, defined as any change in HER2 status between matched biopsy and post-neoadjuvant chemoradiation therapy resection specimen (N = 170), or between matched resection specimen and recurrence of patients not eligible for curative treatment (N = 61), was determined using the standardized HER2 status scoring system. Clinically relevant positive discordance was defined as a change to HER2 positive status, as this would imply eligibility for HER2-targeted therapy. A difference in HER2 status between biopsy and resection specimen and resection specimen and metachronous recurrence was observed in 2.1% (n = 3) and 3.3% (n = 2) of the paired cases, respectively. Clinically relevant discordance was detected in 1.4% (n = 2) of the resectable patients and 1.6% (n = 1) of the patients with recurrent disease. Patients with HER2-positive status tumors before start of neoadjuvant treatment showed better overall survival, but not statistically significant. No association between HER2 status discordance and survival was found. Clinically relevant HER2 status discordance was observed and in order to prevent under-treatment of patients, the assessment of HER2 status in the metastatic setting should preferably be performed on the most recently developed lesions if the previous HER2 assessment on archival material of the primary tumor was negative.