Real-world data on T-DM1 efficacy - results of a single-center retrospective study of HER2-positive breast cancer patients

Assessing the Clinical Efficacy of Therapeutic Drug Monitoring for Risperidone and Paliperidone in Patients with Schizophrenia: Insights from a Clinical Data Warehouse

This study investigated the usage patterns and impact of therapeutic drug monitoring (TDM) for risperidone and paliperidone in patients diagnosed with schizophrenia, utilizing retrospective real-world data sourced from a single center's Clinical Data Warehouse. Our study cohort comprised patients diagnosed with schizophrenia undergoing treatment with either risperidone or paliperidone. Data on demographic characteristics, comorbidities, medication utilization, and clinical outcomes were collected. Patients were categorized into two groups: those undergoing TDM and those not undergoing TDM. Additionally, within the TDM group, patients were further stratified based on their risperidone and paliperidone concentrations relative to the reference range. The findings revealed that patients in the TDM group received higher risperidone and paliperidone doses (320 mg/day and 252 mg/day, p = 0.0045) compared to their non-TDM counterparts. Nevertheless, no significant disparities were observed in hospitalization rates, duration of hospital stays, or compliance between the two groups (p = 0.9082, 0.5861, 0.7516, respectively). Subgroup analysis within the TDM cohort exhibited no notable distinctions in clinical outcomes between patients with concentrations within or surpassing the reference range. Despite the possibility of a selection bias in assigning patients to the groups, this study provides a comprehensive analysis of TDM utilization and its ramifications on schizophrenia treatment outcomes.

Influence of tumor microenvironment on the different breast cancer subtypes and applied therapies

Despite the significant improvements made in breast cancer therapy during the last decades, this disease still has increasing incidence and mortality rates. Different targets involved in general processes, like cell proliferation and survival, have become alternative therapeutic options for this disease, with some of them already used in clinic, like the CDK4/6 inhibitors for luminal A tumors treatment. Nevertheless, there is a demand for novel therapeutic strategies focused not only on tumor cells, but also on their microenvironment. Tumor microenvironment (TME) is a very complex and dynamic system that, more than surrounding and supporting tumor cells, actively participates in tumor development and progression. During the last decades, it has become clear that the cellular and acellular components of TME differ between the various breast cancer subtypes and shape the differences regarding their severity and prognosis. The pivotal role of the TME in controlling tumor growth and influencing responses to therapy represents a potential source for novel targets and therapeutic strategies. In this review, we present a description of the multiple therapeutic options used for different breast cancer subtypes, as well as the influence that the TME may exert on the development of the disease and on the response to the distinct therapies, which in some cases may explain their failure by the occurrence of relapses and resistance. Furthermore, the ongoing studies focused on the use of TME components for developing potential cancer treatments are described.

Real-world treatment patterns and outcomes of pyrotinib-based therapy in patients with HER2-positive advanced breast cancer (PRETTY): A nationwide, prospective, observational study

Pyrotinib, an irreversible pan-ErbB inhibitor, has been approved for treating HER2-positive advanced breast cancer in China. We conducted a nationwide, prospective observational study to examine the real-world data of pyrotinib-based therapy in this population. Patients from 61 sites across China were included. Pyrotinib-based regimens were prescribed at local physician's discretion. Demographics, treatment patterns, prognosis and safety were evaluated. The primary outcome was real-world progression-free survival (rwPFS). Of 1129 patients, pyrotinib-based therapy was prescribed as first-, second- and third- or later-line treatment in 437 (38.7%), 476 (42.2%) and 216 (19.1%) patients, respectively. Median rwPFS (mrwPFS) was 14.3 (95% CI, 13.3-15.2) months in the total population, with the longest mrwPFS of 17.8 (95% CI, 15.2-24.9) months in the first-line setting, followed by 14.4 (95% CI, 12.9-15.3) months in the second-line setting. Patients with third- or later-line treatment also achieved a mrwPFS of 9.3 (95% CI, 8.4-11.8) months. Patients with trastuzumab- or trastuzumab-pertuzumab-treated disease achieved a mrwPFS of 14.3 and 13.6 months, respectively. Dual HER2 blockade with pyrotinib plus trastuzumab showed a mrwPFS of 16.2 months in the total population, with data not mature in the first-line setting. For patients with baseline brain metastases, the mrwPFS was 11.7 months. The most common adverse event was diarrhea (any grade, 73.5%; grade ≥ 3, 15.3%). In real world, pyrotinib-based therapy shows promising effectiveness in the first-, as well as second- and later-line treatment, with acceptable tolerability. Further investigations regarding front-line use or novel combinations of pyrotinib might facilitate to maximize its anti-tumor potential.

Development, efficacy and side effects of antibody‑drug conjugates for cancer therapy (Review)

Antibody-drug conjugates (ADCs) are anticancer drugs that combine cytotoxic small-molecule drugs (payloads) with monoclonal antibodies through a chemical linker and that transfer toxic payloads to tumor cells expressing target antigens. All ADCs are based on human IgG. In 2009, the Food and Drug Administration (FDA) approved gemtuzumab ozogamicin as the initial first-generation ADC. Since then, at least 100 ADC-related projects have been initiated, and 14 ADCs are currently being tested in clinical trials. The limited success of gemtuzumab ozogamicin has led to the development of optimization strategies for the next generation of drugs. Subsequently, experts have improved the first-generation ADCs and have developed second-generation ADCs such as ado-trastuzumab emtansine. Second-generation ADCs have higher specific antigen levels, more stable linkers and longer half-lives and show great potential to transform cancer treatment models. Since the first two generations of ADCs have served as a good foundation, the development of ADCs is accelerating, and third-generation ADCs, represented by trastuzumab deruxtecan, are ready for wide application. Third-generation ADCs are characterized by strong pharmacokinetics and high pharmaceutical activity, and their drug-to-antibody ratio mainly ranges from 2 to 4. In the past decade, the research prospects of ADCs have broadened, and an increasing number of specific antigen targets and mechanisms of cytotoxic drug release have been discovered and studied. To date, seven ADCs have been approved by the FDA for lymphoma, and three have been approved to treat breast cancer. The present review explores the function and development of ADCs and their clinical use in cancer treatment.

Primary results of ELAINA: a randomized, multicenter, open-label, phase III study of the efficacy and safety of trastuzumab emtansine vs. lapatinib plus capecitabine in Chinese patients with HER2-positive locally advanced or metastatic breast cancer who have received prior trastuzumab-based therapy

Background

The antibody-drug conjugate (ADCs) trastuzumab emtansine (T-DM1) is approved for human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (mBC) previously treated with trastuzumab and a taxane. The phase III ELAINA trial aimed to determine the clinical utility of T-DM1 in Chinese patients.

Methods

ELAINA was a randomized, multicenter, open-label bridging study of Chinese patients with HER2-positive locally advanced breast cancer (LABC) or mBC previously treated with trastuzumab and a taxane. Using an interactive voice/internet response system, patients were randomized 3:1 to receive T-DM1 or lapatinib plus capecitabine. Patents were stratified by number of prior therapies in this disease setting and by presence of visceral disease using a permuted block randomization scheme. Patients received treatment until disease progression, unmanageable toxicity, or study termination. After that, data on survival and subsequent cancer therapies were collected at approximately 3-month intervals. The primary endpoint was investigator-assessed progression-free survival (PFS). Secondary endpoints were overall response rate, duration of response, overall survival (OS), safety, patient-reported quality of life, and pharmacokinetics (PKs).

Results

ELAINA was fully enrolled with 200 patients randomized to T-DM1 (n=151) or lapatinib plus capecitabine (n=49). Median treatment duration was approximately 6 months in each study arm. Median follow-up time was approximately 9 months for all analyses except for OS. T-DM1 was associated with a 15% reduction in risk of disease progression or death compared with lapatinib plus capecitabine [stratified hazard ratio (HR) =0.85; 95% confidence interval (CI): 0.56-1.29] in the intent-to-treat (ITT) population. The objective response rate (ORR) was similar with T-DM1 (50.4%) and lapatinib plus capecitabine (55.8%); median duration of response was 8.4 months for both treatments. At a median follow-up time of approximately 30 months, OS was similar in each treatment arm. Incidence of grade ≥3 adverse events (AEs) was similar with T-DM1 (54.3%) and lapatinib plus capecitabine (57.1%). Grade ≥3 thrombocytopenia was greater with T-DM1 (40.4%) than with lapatinib plus capecitabine (4.1%); there was no grade ≥3 hemorrhage with either treatment.

Conclusions

T-DM1 demonstrated an acceptable benefit-risk profile in Chinese patients with HER2-positive LABC/mBC previously treated with trastuzumab and a taxane. T-DM1 therefore provides a chemotherapy-free option in this setting.

Trial Registration

ClinicalTrials.gov identifier: NCT03084939.

Trastuzumab emtansine vs lapatinib and capecitabine in HER2-positive metastatic breast cancer brain metastases: A real-world study

BACKGROUND

Trastuzumab emtansine (T-DM1) has demonstrated improvements in survival and neurological symptoms in patients with breast cancer with brain metastases (BCBM). This real-world study investigated the effectiveness of T-DM1 versus lapatinib plus capecitabine (LC) in patients with BCBM.

METHODS

This retrospective, observational study evaluated patients with HER2-positive BCBM using a real-world database. Eligible patients had initiated T-DM1 or LC with a prior diagnosis of brain metastasis and ≥1 prior metastatic breast cancer treatment. The primary endpoint was overall survival (OS); secondary endpoints were time to next relevant treatment or death (TTNT) and real-world progression-free survival (rwPFS). An inverse probability of treatment weighting (IPTW) approach was used to account for differences in potential baseline characteristics between treatment groups. Outcomes were described using the Kaplan-Meier method, and the average treatment effect of initiating T-DM1 versus LC was estimated using weighted Cox proportional hazard models and hazard ratio (HR).

RESULTS

A total of 214 patients were available for analysis (T-DM1, n = 161; LC, n = 53). Demographics and baseline characteristics were generally well-balanced between treatment groups after weighting. After weighting, median OS was 17.7 (T-DM1) versus 9.6 (LC) months (HR, 0.55 [95% CI, 0.34-0.89]; P=0.013). Median TTNT was 9.0 (T-DM1) versus 6.0 (LC) months (HR, 0.55 [95% CI, 0.36-0.85]; P = 0.005). After weighting, median rwPFS was 6.0 (T-DM1) versus 4.0 (LC) months (HR, 0.50 [95% CI, 0.36-0.69]; P < 0.001).

CONCLUSIONS

These results support the superior effectiveness and clinical relevance of T-DM1 versus LC in patients with HER2-positive BCBM in the real world.

Real-World Study: A Powerful Tool for Malignant Tumor Research in General Surgery

Real-world study (RWS) is a method to draw conclusions by collecting and analyzing real-world data under a real clinical background. Compared with traditional randomized controlled trials (RCTs), RWSs are favored by clinicians because of their low cost and good extrapolation. In recent years, RWS has made remarkable achievements in the field of general surgery, especially in the drug treatment of advanced malignant tumors. Therefore, to further understand the main contents of the existing RWS and the application prospect of RWS in the future, this paper systematically reviews the clinical application of RWS in malignant tumors in general surgery in the past three years.

Final results of the global and Asia cohorts of KAMILLA, a phase IIIB safety trial of trastuzumab emtansine in patients with HER2-positive advanced breast cancer

Background

KAMILLA is a single-arm safety study of trastuzumab emtansine (T-DM1) in patients with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer (BC; NCT01702571). We report the final analysis of cohort 2 (Asia) within the context of published cohort 1 (Global) findings.

Methods

Patients had HER2-positive, locally advanced, or metastatic BC progressing after chemotherapy and anti-HER2 therapy or ≤6 months after adjuvant therapy. The primary objective was to further evaluate T-DM1 (3.6 mg/kg, administered intravenously every 3 weeks) safety/tolerability, including the following adverse events of primary interest (AEPIs): grade ≥3 AEPIs (hepatic events, allergic reactions, thrombocytopenia, hemorrhage events), all grade ≥3 treatment-related AEs, and all-grade pneumonitis.

Results

KAMILLA enrolled 2185 patients (cohort 1, n = 2003; cohort 2, n = 182) as of 31 July 2019. Of these, 2002 and 181 per cohort were treated and included in the safety population. Approximately 70% of patients had two or more previous treatment lines in the metastatic setting. Median T-DM1 exposure was 5.6 and 5.0 months per cohort; median follow-up was 20.6 and 15.1 months. The overall AEPI rate was higher in cohort 2 (93/181; 51.4%) versus cohort 1 (462/2002; 23.1%), mostly driven by a higher grade ≥3 thrombocytopenia rate in cohort 2. In cohort 2, grade ≥3 thrombocytopenia was not associated with grade ≥3 hemorrhagic events and most (128/138) fully resolved. Grade ≥3 treatment-related AEPI rates were 18.4% (cohort 1) and 48.6% (cohort 2), the latter mainly due to thrombocytopenia. Any-grade pneumonitis rates were 1.0% and 2.2%. No new safety signals were identified. Median (95% confidence interval) progression-free survival was 6.8 months (5.8-7.6 months) and 5.7 months (5.5-7.0 months) in cohorts 1 and 2, respectively; median overall survival was 27.2 months (25.5-28.7 months) and 29.5 months (21.1 months to non-estimable). In both cohorts, median progression-free survival and overall survival decreased with increasing prior therapy lines.

Conclusions

Cohort 2 results aligned with previous findings in Asian patients, supporting the manageable safety profile and use of T-DM1 in advanced BC.

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KAMILLA safety results for cohorts 1 (global; n = 2002) and 2 (Asia; n = 181) aligned with results from prior T-DM1 mBC trials.

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The overall rate of adverse events of primary interest (AEPIs) was higher in cohort 2 (51.4%) versus cohort 1 (23.1%).

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The higher AEPI rate was mostly due to a higher grade ≥3 thrombocytopenia event rate in cohort 2, most of which resolved.

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Median PFS and OS were similar for both cohorts, and decreased with increasing prior therapy lines.

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The manageable safety profile and efficacy of T-DM1 further support its favorable benefit/risk balance.

Current and future landscape of targeted therapy in HER2-positive advanced breast cancer: redrawing the lines

BACKGROUND

Evidence to date supports continued human epidermal growth factor receptor 2 (HER2) suppression beyond progression on HER2-directed therapy for advanced HER2-positive breast cancer. Data from several phase II and III trials evaluating HER2-directed therapy following second-line T-DM1 have recently become available.

METHODS

We performed a systematic search of the published and presented literature to identify phase II and phase III trials assessing novel HER2-targeted agents as third-line therapy or beyond for HER2-positive advanced breast cancer using search terms 'breast cancer' AND 'HER2' AND 'advanced' AND ('phase II' OR 'phase III').

RESULTS

Eight clinical trials reporting efficacy outcomes on third-line or greater HER2-directed therapy for HER2-positive advanced breast cancer were identified. In phase III trials, margetuximab and neratinib combinations demonstrated significant 1.3-month (hazard ratio, HR = 0.71, p < 0.001) and 0.1-month (HR = 0.76, p = 0.006) net improvements in median progression-free survival (PFS), respectively, with no significant improvements in overall survival (OS). Tucatinib added to trastuzumab and capecitabine demonstrated a significant 2.7-month improvement in median PFS (HR = 0.57, p < 0.00001) and a 5.5-month improvement in median OS (HR = 0.73, p = 0.004) in a randomized phase II trial, including significant clinical benefit for patients with brain metastases. Finally, trastuzumab-deruxtecan, zenocutuzumab, and poziotinib demonstrated benefit in phase II trials with the most robust overall response rate (62.0%) and median duration of response (18.2 months) observed for trastuzumab-deruxtecan among heavily pretreated patients.

CONCLUSION

Tucatinib plus trastuzumab and capecitabine significantly prolongs OS, and promising preliminary response outcomes for trastuzumab-deruxtecan suggest that sequencing of these regimens following second-line therapy is reasonable.

RAB5A expression is a predictive biomarker for trastuzumab emtansine in breast cancer

HER2 is a predictive biomarker for HER2-targeted therapeutics. For antibody-drug conjugates (ADCs; e.g., trastuzumab emtansine (T-DM1)), HER2 is utilized as a transport gate for cytotoxic agents into the cell. ADC biomarkers may therefore be more complex, also reflecting the intracellular drug transport. Here we report on a positive correlation between the early endosome marker RAB5A and T-DM1 sensitivity in five HER2-positive cell lines. Correlation between RAB5A expression and T-DM1 sensitivity is confirmed in breast cancer patients treated with trastuzumab emtansine/pertuzumab in the I-SPY2 trial (NCT01042379), but not in the trastuzumab/paclitaxel control arm. The clinical correlation is further verified in patients from the KAMILLA trial (NCT01702571). In conclusion, our results suggest RAB5A as a predictive biomarker for T-DM1 response and outline proteins involved in endocytic trafficking as predictive biomarkers for ADCs.

Assessment of racial differences in the incidence of thrombocytopenia induced by trastuzumab emtansine: a systematic review and meta-analysis

Background

Trastuzumab emtansine (T-DM1) has been proved to have value and efficacy in the treatment of advanced metastatic cancer, including in the adjuvant setting. However, there is increasing concern about T-DM1-induced thrombocytopenia (TCP), which shows racial differences in incidence. This meta-analysis aimed to evaluate differences in the incidence of T-DM1-related TCP between Asian and non-Asian patients by combining accessible information from all single-agent T-DM1 clinical trials published to date.

Methods

We conducted systematic searches of the PubMed, Embase, and the Cochrane Library databases to identify relevant clinical studies of T-DM1 that reported on safety, including the incidence of TCP, which were published between January 1980 and March 2020. Two reviewers were responsible for the screening and extraction of data. The pooled-effect estimate calculated with a fixed-effects or random-effects model was represented as incidence with 95% confidence intervals (CIs).

Results

A total of 29 studies involving 6,188 patients were included. The incidence of all-grade TCP in Asian patients and non-Asian patients was 0.39 (95% CI: 0.11–0.67) and 0.29 (95% CI: 0.23–0.35), respectively. The incidence of TCP of grade 3 or higher in Asians was 0.20 (95% CI: 0.10–0.29), compared with 0.02 (95% CI: 0.01–0.03) in non-Asians. Gastrointestinal cancer type and a T-DM1 treatment dose of 2.4 mg/kg Q3W were related to grade 3 or higher TCP events.

Discussion

Asian patients have a higher risk of developing TCP after receiving T-DM1 than non-Asian patients. Clinicians should be aware of the importance of careful observation of platelet count in patients receiving T-DM1 therapy.

Efficacy and safety of trastuzumab emtansine in older patients with HER2-positive advanced breast cancer: a real-world study

INTRODUCTION

Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate and its survival advantage has been shown in advanced human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, clinical trials underrepresent patients ⩾65 years of age, leading to a lack of information in this population. We analyzed the real-world outcomes of older women who were treated with T-DM1 therapy.

METHODS

We performed a multicenter, observational, retrospective analysis of patients aged ⩾65 years treated with T-DM1. A total of 93 patients from 10 cancer centers were involved in the study. Our goal was to determine the survival, response rates, and toxicity profile in T-DM1-treated patients, as well as the factors that influence survival.

RESULTS

Median follow-up was 12.2 months. Objective response rate was 29%. Median progression-free survival (PFS) and overall survival (OS) were 8.47 and 15.0 months, respectively. In multivariate analysis, Eastern Cooperative Oncology Group Performance Score 2 was found to be an independent prognostic factor for worse PFS (hazard ratio [HR] 1.81, p = 0.032) and OS (HR 2.33, p = 0.006). Any adverse event (AE) was seen in 92.5% of patients; grade 3 or 4 AEs were seen in 30.1%. Dose reduction or treatment discontinuation rates were 11.8% and 6.5%, respectively.

CONCLUSION

The efficacy of T-DM1 was acceptable and it was generally well-tolerated among older patients with advanced HER2-positive breast cancer.

Pyrotinib in the Treatment of Women With HER2-Positive Advanced Breast Cancer: A Multicenter, Prospective, Real-World Study

Background

HER2-positive breast cancer was aggressive, resulting in a poorer prognosis. This multicenter study analyzed the real-world data of women treated with pyrotinib-based therapy, aiming to describe their characteristics, treatment regimens, and to investigate the clinical outcomes.

Methods

A total of 141 patients with HER2-positive breast cancer were enrolled from February 2019 to April 2020. Last follow-up time was February 2021. All patients were treated with pyrotinib-based therapy in 21-day cycles. The primary endpoint was progression-free survival (PFS).

Results

The median PFS (mPFS) for pyrotinib-based therapy was 12.0 months (95%CI 8.1-17.8) in all patients. Among the patients with liver metastases, mPFS was 8.7 months (95%CI, 6.3-15.4) compared to 12.3 months (95%CI, 8.8-23.3) for patients without liver metastases (P=0.172). In addition, patients receiving pyrotinib-based therapy as their >2 lines treatment had a numerically lower mPFS than those receiving pyrotinib-based therapy as their ≤2 lines treatment [8.4 (95%CI, 5.9-15.4) vs. 15.1 (95%CI, 9.3-22.9) months, P=0.107]. The mPFS was 12.2 months (95%CI, 7.9-18.8) in patients with previous exposure to trastuzumab and 11.8 months (95%CI, 6.8-22.9) in patients without previous exposure to trastuzumab (P=0.732). Moreover, mPFS in patients receiving regimens with and without capecitabine were 15.1 months (95%CI, 10.0-18.8) and 8.4 months (95%CI, 6.7-22.9), respectively (P=0.070). Furthermore, in patients with brain metastases, estimated 6-month PFS rate was 70.0%, and rate at 12 months was 60.0%. Seventy patients with measurable lesions were evaluable for response. The objective response rate was 38.6% and disease control rate was 85.7%. The most common adverse event was diarrhea (85.0%).

Conclusion

Pyrotinib-based therapy showed promising efficacy in patients with HER2-positive breast cancer and was well tolerated, especially in patients treated with pyrotinib as ≤2 lines treatment and receiving regimens with capecitabine. The results of this real-world study further confirmed the intriguing efficacy of pyrotinib.

The Cellular Prion Protein: A Promising Therapeutic Target for Cancer

Studies on the cellular prion protein (PrP^C) have been actively conducted because misfolded PrP^C is known to cause transmissible spongiform encephalopathies or prion disease. PrP^C is a glycophosphatidylinositol-anchored cell surface glycoprotein that has been reported to affect several cellular functions such as stress protection, cellular differentiation, mitochondrial homeostasis, circadian rhythm, myelin homeostasis, and immune modulation. Recently, it has also been reported that PrP^C mediates tumor progression by enhancing the proliferation, metastasis, and drug resistance of cancer cells. In addition, PrP^C regulates cancer stem cell properties by interacting with cancer stem cell marker proteins. In this review, we summarize how PrP^C promotes tumor progression in terms of proliferation, metastasis, drug resistance, and cancer stem cell properties. In addition, we discuss strategies to treat tumors by modulating the function and expression of PrP^C via the regulation of HSPA1L/HIF-1α expression and using an anti-prion antibody.

Safety and efficacy of T-DM1 in patients with advanced HER2-positive breast cancer The Royal Marsden experience

BACKGROUND

Ado-trastuzumab emtansine (T-DM1) is standard of care for patients with advanced HER2+ breast cancer who relapse within 6 months of adjuvant trastuzumab or progress on first-line anti-HER2 therapy. We evaluated its safety and efficacy in our real-world population.

METHODS

We identified patients on T-DM1 from 01/01/2014 to 12/03/2018 from our electronic records. Patients', tumour characteristics, safety and efficacy outcomes were recorded. Chi-squared/Fishers exact test and Kaplan-Meier methods were utilised.

RESULTS

128 patients receiving T-DM1 were included in the analysis with a median age of 55 years (26-85). 89.8% of patients had ECOG PS 0-1 and 21.1% had presented with de novo metastatic disease. 57.8% had ER-positive disease and 38.3% central nervous system involvement. 88.3% of patients had received trastuzumab for advanced disease (with pertuzumab in 28.9%) and 11.7% had only received trastuzumab in the adjuvant setting. Grade ≥3 adverse events occurred in 35.9% of patients. These were liver toxicity (19.5%), anaemia (6.2%) and thrombocytopenia (4.7%). Peripheral neuropathy of any grade was reported in 21.9% of cases, bleeding in 9.4% and ejection fraction decline in 5 patients. Median progression-free survival was 8.7 months and overall survival 20.4 months. Prior pertuzumab did not influence survival outcomes.

CONCLUSIONS

The safety of T-DM1 in our population is similar to available literature, although we observed higher rates of peripheral neuropathy and deranged liver function. These findings are relevant for the potential role of TDM-1 in the curative setting.

HER2-targeted therapy prolongs survival in patients with HER2-positive breast cancer and intracranial metastatic disease: a systematic review and meta-analysis

BACKGROUND

Intracranial metastatic disease (IMD) is a serious and known complication of human epidermal growth factor receptor 2 (HER2)-positive breast cancer. The role of targeted therapy for patients with HER2-positive breast cancer and IMD remains unclear. In this study, we sought to evaluate the effect of HER2-targeted therapy on IMD from HER2-positive breast cancer.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, and gray literature sources for interventional and observational studies reporting survival, response, and safety outcomes for patients with IMD receiving HER2-targeted therapy. We pooled outcomes through meta-analysis and examined confounder effects through forest plot stratification and meta-regression. Evidence quality was evaluated using GRADE (PROSPERO CRD42020161209).

RESULTS

A total of 97 studies (37 interventional and 60 observational) were included. HER2-targeted therapy was associated with prolonged overall survival (hazard ratio [HR] 0.47; 95% confidence interval [CI], 0.39-0.56) without significantly prolonged progression-free survival (HR 0.52; 95% CI, 0.27-1.02) versus non-targeted therapy; the intracranial objective response rate was 19% (95% CI, 12-27%), intracranial disease control rate 62% (95% CI, 55-69%), intracranial complete response rate 0% (95% CI, 0-0.01%), and grade 3+ adverse event rate 26% (95% CI, 11-45%). Risk of bias was high in 40% (39/97) of studies.

CONCLUSION

These findings support a potential role for systemic HER2-targeted therapy in the treatment of patients with IMD from HER2-positive metastatic breast cancer.