Stability assessment of antibody-drug conjugate Trastuzumab emtansine in comparison to parent monoclonal antibody using orthogonal testing protocol.

Antibody-drug conjugates (ADC) represent an emerging, novel class of biopharmaceuticals. The heterogeneity originating from the sophisticated structure requires orthogonal analytical techniques for quality and stability assessment of ADC to ensure safety and efficacy. In this study, the stability of Trastuzumab (recombinant humanized IgG1 mAb, targeting HER2 receptor) and its ADC with DM1 (anti-tubulin anticancer drug), Trastuzumab emtansine (T-DM1) were studied. SE-HPLC was used to monitor formation of aggregates and/or fragments of the monoclonal antibodies (mAb). Correlation with the results of reducing and non-reducing sodium dodecyl sulphate - polyacrylamide gel electrophoresis (SDS-PAGE) and dynamic light scattering (DLS) were performed to interpret the obtained results. RP-HPLC was used for assessment of the stability of DM1 in ADC while spectrophotometry was employed to determine drug antibody ratio (DAR) . The studied drugs were subjected to several stress conditions including pH, temperature, mechanical agitation and repeated freeze and thaw to generate possible degradation products and ensure suitability of the assay protocol. The degradation pattern and extent were demonstrated under the indicated stress conditions. The correlation between the results of SE-HPLC and those of SDS-PAGE and DLS ensured the validity of the orthogonal assay protocol and indicated aggregates that were not detected using SE-HPLC. Results showed clearly that T-DM1 is relatively less stable than its parent mAb. This was attributed to the presence of the drug-linker part that is attached to the mAb. RP-HPLC showed that the cytotoxic drug moiety is liable for degradation under the studied conditions resulting in alteration of DAR as well as formation of degradation products. This confirmed the need for more robust coupling chemistries for production of safe and effective ADC and highlighted the importance of orthogonal testing protocols for quality assessment. The assay protocol should be applicable for quality and stability assessment of various ADC.

Economic evaluation of sequencing strategies in HER2-positive metastatic breast cancer in Mexico: a contrast between public and private payer perspectives.

PURPOSE: Breast cancer is the most common malignancy among women in Mexico. A large proportion of Mexican patients present with advanced disease, and 25% have HER2-positive tumors. We performed a cost-effectiveness analysis of different sequencing strategies of HER2-targeted agents in Mexico according to various payer perspectives. METHODS: A Markov model was constructed to evaluate the cost-effectiveness of four different HER2-targeted treatment sequences among patients with HER2-positive metastatic breast cancer treated in Mexico according to three public and one private payer perspectives. Patients were followed weekly over their remaining life expectancies within the model. Health states considered were progression-free survival (PFS) 1st-3rd lines, and death. Transition probabilities between states were based on published trials. Cost data were obtained from official publications from Mexican healthcare institutions. The evaluated outcomes were PFS, OS, costs, QALYs, and incremental cost effectiveness ratio (ICER). RESULTS: In the public payer perspective, sequences containing pertuzumab or T-DM1 were not cost-effective when compared with a sequence including the combination of trastuzumab/docetaxel as first line without subsequent T-DM1 or pertuzumab, even when utilizing alternate definitions for willingness to pay thresholds. In the private payer perspective, a sequence containing T-DM1 but not pertuzumab proved cost-effective at a lower clinical effectiveness. CONCLUSIONS: In Mexico, the use of at least three lines of trastuzumab in combination with other therapies, but not with pertuzumab or TDM-1, represents the most cost-effective option for patients covered by the public healthcare system, and this sequence should be made available for all patients.

De-Escalation Strategies in Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Early Breast Cancer (BC): Final Analysis of the West German Study Group Adjuvant Dynamic Marker-Adjusted Personalized Therapy Trial Optimizing Risk Assessment and Therapy Response Prediction in Early BC HER2- and Hormone Receptor-Positive Phase II Randomized Trial-Efficacy, Safety, and Predictive Markers for 12 Weeks of Neoadjuvant Trastuzumab Emtansine With or Without Endocrine Therapy (ET) Versus Trastuzumab Plus ET.

Purpose Human epidermal growth factor receptor 2 (HER2)-positive/hormone receptor (HR)-positive breast cancer is a distinct subgroup associated with lower chemotherapy sensitivity and slightly better outcome than HER2-positive/HR-negative disease. Little is known about the efficacy of the combination of endocrine therapy (ET) with trastuzumab or with the potent antibody-cytotoxic, anti-HER2 compound trastuzumab emtansine (T-DM1) with or without ET for this subgroup. The West German Study Group trial, ADAPT (Adjuvant Dynamic Marker-Adjusted Personalized Therapy Trial Optimizing Risk Assessment and Therapy Response Prediction in Early Breast Cancer) compares pathologic complete response (pCR) rates of T-DM1 versus trastuzumab with ET in early HER2-positive/HR-positive breast cancer. Patients and Methods In this prospective, neoadjuvant, phase II trial, 375 patients with early breast cancer with HER2-positive and HR-positive status (n = 463 screened) were randomly assigned to 12 weeks of T-DM1 with or without ET or to trastuzumab with ET. The primary end point was pCR (ypT0/is/ypN0). Early response was assessed in 3-week post-therapeutic core biopsies (proliferation decrease ≥ 30% Ki-67 or cellularity response). Secondary end points included safety and predictive impact of early response on pCR. Adjuvant therapy followed national standards. Results Baseline characteristics were well balanced among the arms. More than 90% of patients completed the therapy per protocol. pCR was observed in 41.0% of patients treated with T-DM1, 41.5% of patients treated with T-DM1 and ET, and 15.1% with trastuzumab and ET ( P < .001). Early responders (67% of patients with assessable response) achieved pCR in 35.7% compared with 19.8% in nonresponders (odds ratio, 2.2; 95% CI, 1.24 to 4.19). T-DM1 was associated with a significantly higher prevalence of grade 1 to 2 toxicities, especially thrombocytopenia, nausea, and elevation of liver enzymes. Overall toxicity was low; seventeen therapy-related severe adverse events (T-DM1 arms v trastuzumab plus ET; 5.3% v 3.1%, respectively) were reported. Conclusion The ADAPT HER2-positive/HR-positive trial demonstrates that neoadjuvant T-DM1 (with or without ET) given for only 12 weeks results in a clinically meaningful pCR rate. Thus, a substantial number of patients are spared the adverse effects of systemic chemotherapy.

Cost-effectiveness analysis of trastuzumab emtansine (T-DM1) in human epidermal growth factor receptor 2 (HER2): positive advanced breast cancer.

PURPOSE: The EMILIA trial demonstrated that trastuzumab emtansine (T-DM1) significantly increased the median profession-free and overall survival relative to combination therapy with lapatinib plus capecitabine (LC) in patients with HER2-positive advanced breast cancer (ABC) previously treated with trastuzumab and a taxane. We performed an economic analysis of T-DM1 as a second-line therapy compared to LC and monotherapy with capecitabine (C) from both perspectives of the US payer and society. METHODS: We developed four possible Markov models for ABC to compare the projected life-time costs and outcomes of T-DM1, LC, and C. Model transition probabilities were estimated from the EMILIA and EGF100151 clinical trials. Direct costs of the therapies, major adverse events, laboratory tests, and disease progression, indirect costs (productivity losses due to morbidity and mortality), and health utilities were obtained from published sources. The models used 3 % discount rate and reported in 2015 US dollars. Probabilistic sensitivity analysis and model averaging were used to account for model parametric and structural uncertainty. RESULTS: When incorporating both model parametric and structural uncertainty, the resulting incremental cost-effectiveness ratios (ICER) comparing T-DM1 to LC and T-DM1 to C were $183,828 per quality-adjusted life year (QALY) and $126,001/QALY from the societal perspective, respectively. From the payer's perspective, the ICERs were $220,385/QALY (T-DM1 vs. LC) and $168,355/QALY (T-DM1 vs. C). CONCLUSIONS: From both perspectives of the US payer and society, T-DM1 is not cost-effective when comparing to the LC combination therapy at a willingness-to-pay threshold of $150,000/QALY. T-DM1 might have a better chance to be cost-effective compared to capecitabine monotherapy from the US societal perspective.

Ethnic sensitivity assessment of the antibody-drug conjugate trastuzumab emtansine (T-DM1) in patients with HER2-positive locally advanced or metastatic breast cancer.

PURPOSE: Trastuzumab emtansine (T-DM1) is indicated for previously treated HER2-positive metastatic breast cancer. Ethnic sensitivity assessment of T-DM1 was conducted using data from eight clinical studies to ensure that the clinically recommended dose is appropriate across ethnicities. METHODS: Four approaches were used: (1) non-compartmental analysis (NCA) comparing pharmacokinetic parameters of T-DM1 and relevant analytes across ethnic groups, (2) population pharmacokinetic (popPK) analysis assessing the impact of ethnicity on pharmacokinetics, (3) comparison of T-DM1 pharmacokinetics in Japanese patients versus the global population, and (4) exposure-response analyses assessing the impact of ethnicity on safety and efficacy. RESULTS: NCA pharmacokinetic parameters (T-DM1, total trastuzumab, DM1) were comparable across ethnic groups; mean cycle 1 T-DM1 AUCinf was 475, 442, and 518 day µg/mL for white (n = 461), Asian (n = 68), and others (n = 57), respectively. PopPK analysis showed that ethnicity (white, Asian, and others) was not a significant covariate for T-DM1 pharmacokinetics (n = 671). Additionally, visual predictive check plots indicated that observed pharmacokinetic profiles in Japanese patients (n = 42) were within the prediction interval generated from the final PopPK model. Exposure-response analyses showed that ethnicity was not a significant covariate impacting efficacy or hepatotoxicity risk, but there was a trend of greater thrombocytopenia risk among Asians versus non-Asians, which could not be explained by similar exposure between the ethnic groups. Most Asians with thrombocytopenia were able to continue T-DM1 using dose-adjustment rules recommended for the global population. CONCLUSIONS: These results suggest that T-DM1 pharmacokinetics are comparable across ethnic groups and that use of the current dosing regimen is appropriate across ethnicities.

Trastuzumab Emtansine for Treating HER2-Positive, Unresectable, Locally Advanced or Metastatic Breast Cancer After Treatment with Trastuzumab and a Taxane: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

The National Institute for Health and Care Excellence (NICE) invited the manufacturer of trastuzumab emtansine (T-DM1) (Kadcyla(®); Roche) to submit evidence of its clinical and cost-effectiveness for treating human epidermal growth factor receptor 2 (HER2)-positive, unresectable, locally advanced or metastatic breast cancer after treatment with trastuzumab and a taxane. The School of Health and Related Research Technology Appraisal Group (ScHARR-TAG) at the University of Sheffield were the independent Evidence Review Group (ERG) who produced a critical review of the company's submission to NICE. The ERG also independently searched for relevant evidence and modified the submitted decision analytic model to produce a revised estimate of cost-effectiveness and examine the impact of altering some of the key assumptions. The clinical effectiveness data were taken from two randomised controlled trials that reported a significant advantage in progression-free survival (PFS) for T-DM1 over lapatinib in combination with capecitabine (EMILIA trial), and over the treatment of physician's choice (TH3RESA trial). A network meta-analysis suggested T-DM1 was the best treatment in terms of both overall survival and PFS compared with lapatinib in combination with capecitabine; trastuzumab in combination with capecitabine; and capecitabine monotherapy. Adverse event (AE) data were taken from a pooled analysis of additional trials of T-DM1 as a single agent. The most common grade 3 or greater AEs for T-DM1 were thrombocytopenia and hepatotoxicity. Following the clarification process, the manufacturer reported a deterministic incremental cost-effectiveness ratio (ICER) for T-DM1 compared with lapatinib in combination with capecitabine of £167,236, the latter of which was estimated to have an ICER of £49,798 compared with capecitabine monotherapy. The ERG produced similar values of £166,429 and £50,620 respectively. All other comparators were dominated. During the appraisal, the manufacturer offered an analysis of a patient access scheme (PAS), which suggested that T-DM1 had a 0 % probability of being cost-effective at an ICER of £30,000 per QALY gained. The NICE Appraisal Committee concluded that while the clinical effectiveness of T-DM1 had been proven, it was not likely to represent a cost-effective use of National Health Service resources and therefore its use could not be recommended.

Safety Profile and Costs of Related Adverse Events of Trastuzumab Emtansine for the Treatment of HER2-Positive Locally Advanced or Metastatic Breast Cancer Compared to Capecitabine Plus Lapatinib from the Perspective of the Canadian Health-Care System.

BACKGROUND AND OBJECTIVES: Trastuzumab emtansine (T-DM1, KADCYLA(®)) is an antibody-drug conjugate comprised of the cytotoxic agent DM1 and trastuzumab (HERCEPTIN(®)). The safety profile of T-DM1 in human epidermal growth factor receptor 2 (HER2)-positive locally advanced or metastatic breast cancer previously treated with trastuzumab and a taxane was investigated in the phase III EMILIA trial. The trial demonstrated clinically and statistically meaningful differences in the safety profile between T-DM1 and capecitabine plus lapatinib (CAP + LAP). The objective of this study was to estimate the costs of managing treatment-related grade ≥ 3 adverse events (AEs) that occurred in ≥ 2% of patients and grade 2 AEs that occurred in ≥ 5% of patients taking T-DM1 compared with patients taking CAP + LAP based on the EMILIA trial, from the perspective of Canadian public payers. METHODS: An Excel-based model was utilized to estimate the relevant costs. Clinical data were obtained from the EMILIA trial. Cost information was obtained from the literature, clinical experts, and standard cost sources. The analysis was conducted from the Canadian public-payer perspective and reported in 2014 Canadian dollars (CAD). RESULTS: The management of included treatment-related AEs resulted in higher estimated per-patient costs of CAD6901 for CAP + LAP versus CAD3380 for T-DM1, resulting in savings of CAD3521. CONCLUSIONS: From a Canadian perspective, this analysis demonstrated that utilizing T-DM1 for the management of HER2-positive metastatic breast cancer results in substantial savings to the public health-care system when considering the costs of treatment-related AEs, due to fewer amount of toxicities compared with CAP + LAP. Results of various sensitivity analyses investigating changes in number and costs of AEs confirmed the findings; however, the magnitude of cost savings varied. Further analyses are necessary to determine whether these cost savings would occur in other countries and health-care systems.

Trastuzumab emtansine in locally advanced or metastatic HER2 positive breast cancer; GENESIS-SEFH drug evaluation report.

Trastuzumab emtansina (T-DM1) is an antibody-drug conjugate directed against the HER2 for the treatment of HER2+ mestastatic breast cancer (MBC), who has previously received trastuzumab plus a taxane. According to the results of the EMILIA trial versus lapatinib plus capecitabine T-DM1 shows an improvement in progression-free survival (PFS) and the overall survival (OS). It has a favorable profile reducing the incidence of grade 3-4 adverse reactions such as hand-foot syndrome and diarrhea. On the contrary increases significantly severe thrombocytopenia; bleeding risk and liver function should also be monitored. With the current import price T-DM1 has a cost per QALY of over 120,000 €. The price of the drug for the Spanish NHS has not yet been established. Drug cost would be the key factor in the sensitivity analysis and a 50% reduction in the price of the drug would place it close to the threshold of cost-effectiveness usually considered in our midst. According to the budget impact model used, a maximum of 1,218 patients / year and the budgetary impact throughout the Spanish state would be at € 70,490,850. In the initial analysis no advantage was found for T-DM1 in those patients without visceral involvement. Although a subsequent re-analysis of the results of PFS in which the definition of visceral involvement was specified a significant benefit was shown in this subgroup. We believe that this approach introduces a high degree of uncertainty, which does not guarantee the benefit achieved for this subgroup of patients.

T-DM1 es un conjugado anticuerpo-farmaco dirigido contra el HER2 para el tratamiento del cancer de mama metastasico (CMM) HER2 +, que ha recibido previamente trastuzumab mas un taxano. De acuerdo con los resultados del ensayo EMILIA frente a lapatinib mas capecitabina T-DM1 muestra una mejora en la supervivencia libre de progresion (SLP) y la supervivencia global (SG). Tiene un perfil favorable reducir la incidencia de reacciones adversas grado 3-4 tales como el sindrome mano- pie y la diarrea. Sin embargo, aumenta significativamente el riesgo de trombocitopenia grave y debe monitorizarse el riesgo de hemorragia y la funcion hepatica. Con el precio de importacion actual T-DM1 tiene un coste por AVAC de mas de 120.000 €. El precio del farmaco para el Sistema Nacional de Salud en Espana aun no ha sido establecido. El precio del farmaco seria el factor clave en el analisis de sensibilidad y una reduccion del 50% en el precio lo situaria cerca del umbral de coste-efectividad generalmente considerada en nuestro medio como aceptable. De acuerdo con el modelo de impacto presupuestario utilizado, se trataria un maximo de 1.218 pacientes / ano y el impacto presupuestario de todo el estado espanol estaria entorno a 70.490.850 € para este volumen de pacientes. En el analisis inicial no se encontro ninguna ventaja para T-DM1 en aquellos pacientes sin afectacion visceral. Aunque un re-analisis posterior de los resultados de SLP en el que se especifica la definicion de la afectacion visceral se muestra un beneficio significativo en este subgrupo. Creemos que este enfoque presenta un alto grado de incertidumbre, y no garantiza el beneficio logrado para este subgrupo de pacientes.

Systemic therapy for patients with advanced human epidermal growth factor receptor 2-positive breast cancer: American Society of Clinical Oncology clinical practice guideline.

PURPOSE: To provide evidence-based recommendations to practicing oncologists and others on systemic therapy for patients with human epidermal growth factor receptor 2 (HER2) -positive advanced breast cancer. METHODS: The American Society of Clinical Oncology convened a panel of medical oncology, radiation oncology, guideline implementation, and advocacy experts and conducted a systematic literature review from January 2009 to October 2012. Outcomes of interest included overall survival, progression-free survival (PFS), and adverse events. RESULTS: A total of 16 trials met the systematic review criteria. The CLEOPATRA trial found survival and PFS benefits for docetaxel, trastuzumab, and pertuzumab in first-line treatment, and the EMILIA trial found survival and PFS benefits for trastuzumab emtansine (T-DM1) in second-line treatment. T-DM1 also showed a third-line PFS benefit. One trial reported on duration of HER2-targeted therapy, and three others reported on endocrine therapy for patients with HER-positive advanced breast cancer. RECOMMENDATIONS: HER2-targeted therapy is recommended for patients with HER2-positive advanced breast cancer, except for those with clinical congestive heart failure or significantly compromised left ventricular ejection fraction, who should be evaluated on a case-by-case basis. Trastuzumab, pertuzumab, and taxane for first-line treatment and T-DM1 for second-line treatment are recommended. In the third-line setting, clinicians should offer other HER2-targeted therapy combinations or T-DM1 (if not previously administered) and may offer pertuzumab, if the patient has not previously received it. Optimal duration of chemotherapy is at least 4 to 6 months or until maximum response, depending on toxicity and in the absence of progression. HER2-targeted therapy can continue until time of progression or unacceptable toxicities. For patients with HER2-positive and estrogen receptor-positive/progesterone receptor-positive breast cancer, clinicians may recommend either standard first-line therapy or, for selected patients, endocrine therapy plus HER2-targeted therapy or endocrine therapy alone.

Ado-trastuzumab emtansine for the treatment of human epidermal growth factor receptor 2-positive metastatic breast cancer.

PURPOSE: An update on completed and ongoing clinical trials of ado-trastuzumab emtansine for the treatment of metastatic breast cancer (MBC) is presented. SUMMARY: Ado-trastuzumab emtansine (Kadcyla, Genentech), the first U.S.-approved antibody-drug conjugate for MBC, is indicated for use as a single-agent therapy in patients with human epidermal growth factor receptor 2 (HER2)-positive MBC who have received prior treatment with unconjugated trastuzumab and a taxane-based regimen. The standard dosage of ado-trastuzumab is 3.6 mg/kg i.v. every three weeks. In completed Phase II or III clinical trials, ado-trastuzumab was found to confer significant survival and quality-of-life benefits. The largest of those trials (the EMILIA study, n = 991) showed that ado-trastuzumab was superior to a regimen of lapatinib plus capecitabine in terms of progression-free survival (9.6 months versus 6.4 months, p < 0.001) and overall survival (30.9 months versus 25.1 months, p < 0.001); it also had a more favorable tolerability profile, with lower rates of treatment-limiting adverse effects. The most common adverse effects of ado-trastuzumab are thrombocytopenia (reported in about 12% of clinical trial participants overall) and increased transaminase levels. Two ongoing Phase III trials-the TH3RESA study (slated for completion in June 2015) and the MARIANNE study (estimated completion in 2016)-may help determine the optimal role of ado-trastuzumab relative to other HER2-targeted agents and its potential use as a front-line therapy for both heavily pretreated and treatment-naive patients with MBC. CONCLUSION: With a novel targeted mechanism of action, ado-trastuzumab is an effective treatment option for HER2-positive MBC in previously treated patient populations.

Induction of apoptosis in hormone refractory breast cancer: horizontal modulation is superior to vertical.

Women with estrogen receptor positive (ER+) breast cancer receive treatment with tamoxifen or aromatase inhibitors as adjuvant hormone therapy, but their tumors frequently exhibit de novo or acquired resistance. Current strategies being developed to overcome resistance involve a combination of growth factor pathway inhibitors in addition to hormone therapy. Unfortunately, prolongation of responses with these new approaches is measured only in months. We reasoned that a pro-apoptotic strategy would be preferable since cell death would abrogate the process of adaptive reprogramming and eliminate the resistant cells rather than inhibiting their growth. Our hypothesis was that combinations of pro-apoptotic agents could be designed that would act synergistically as opposed to a merely additively. We examined two model strategies to determine which would result in the greatest synergy: a vertical approach that involved the targeting of two or more steps in a single pathway and a horizontal one, targeting steps in more than one parallel pathway. We found that combinations involving horizontal activation resulted in greater synergy than vertical. Combination index and isobologram analyses revealed that the horizontal combination of the small molecule 4-(4-chloro-2-methylphenoxy)-N-hydroxybutanamide (CMH) along with T-DM1 displayed the strongest synergy for inducing apoptosis in hormone refractory breast cancer cells. Both the reprogrammed, hormone resistant cells and the wild type responded to certain combinations with synergistic enhancement of apoptosis. These data suggest that combinations using T-DM1 are promising for further in vivo studies both in xenografts and in patients.