Highlights of the 2017 European AIDS Clinical Society (EACS) Guidelines for the treatment of adult HIV-positive persons version 9.0

Background

The European AIDS Clinical Society (EACS) Guidelines have since 2005 provided multidisciplinary recommendations for the care of HIV‐positive persons in geographically diverse areas.

Guideline highlights

Major revisions have been made in all sections of the 2017 Guidelines: antiretroviral treatment (ART), comorbidities, coinfections and opportunistic diseases. Newly added are also a summary of the main changes made, and direct video links to the EACS online course on HIV Management. Recommendations on the clinical situations in which tenofovir alafenamide may be considered over tenofovir disoproxil fumarate are provided, and recommendations on which antiretrovirals can be used safely during pregnancy have been revised. Renal and bone toxicity and hepatitis C virus (HCV) treatment have been added as potential reasons for ART switches in fully virologically suppressed individuals, and dolutegravir/rilpivirine has been included as a treatment option. In contrast, dolutegravir monotherapy is not recommended. New recommendations on non‐alcoholic fatty liver disease, chronic lung disease, solid organ transplantation, and prescribing in elderly are included, and human papilloma virus (HPV) vaccination recommendations have been expanded. All drug–drug interaction tables have been updated and new tables are included. Treatment options for direct‐acting antivirals (DAAs) have been updated and include the latest combinations of sofosbuvir/velpatasvir/voxilaprevir and glecaprevir/pibrentasvir. Recommendations on management of DAA failure and acute HCV infection have been expanded. For treatment of tuberculosis (TB), it is underlined that intermittent treatment is contraindicated, and for resistant TB new data suggest that using a three‐drug combination may be as effective as a five‐drug regimen, and may reduce treatment duration from 18‐24 to 6‐10 months.

Conclusions

Version 9.0 of the EACS Guidelines provides a holistic approach to HIV care and is translated into the six most commonly spoken languages.

Abstract 3129: Patient-derived tumor xenografts (PDXs) recapitulate the antitumor activity of novel therapies in metastatic breast cancer (MBC) patients (pts)

PDXs are preferred laboratory models that recapitulate the biology of pts’ tumors. We aimed to assess if the antitumor activity of novel therapies in PDXs correlates with the observed activity in the corresponding MBC patient, which would support cross-analysis of drug/genotype vulnerabilities.

MBC pts eligible for clinical trials were offered a research biopsy and establishment of PDX, under an IRB-approved protocol. Biopsies were implanted in nude mice subcutaneously. Upon successful engraftment, models were expanded for drug testing, specifically with the same drug/combination given to the patient. This is a retrospective analysis of our MBC patient/PDX (Pt/PDX) co-clinical trial cohort. Pts’ outcomes were measured as: RECIST response, clinical benefit [CB: partial response (PR) or stable disease (SD) >4 months], and time to progression [TTP: time until RECIST progressive disease (PD), in months). PDX endpoints were measured as: TTP (time until 25% increase in tumor volume, in days), response (WHO criteria, at week 3), and relative area under the curve (rAUC) of treated versus vehicle. A concordant Pt/PDX response was defined as CB in pts whose paired PDX showed PR/SD, or no-CB in pts whose paired PDX showed PD. Pts outcomes and PDX endpoints were correlated using Spearman's test.

We identified 10 MBC pts (7 TNBC, 3 HR+; all biopsies from skin/subcutaneous lesions) with corresponding PDX, treated with paired therapies (7 molecularly matched): 3 lurbinectedin (BRCA1-mut), 3 olaparib (BRCA1-mut), 1 AZD5363 + fulvestrant (AKT1-mut), 1 AZD5363 + paclitaxel, 1 buparlisib, 1 eribulin. In 9/10 cases we found concordant Pt/PDX responses (6 cases with no-CB in patient/PD in PDX, 3 with CB/SD; and 1 lurbinectedin case with no-CB/PR). Two pts had biopsy for PDX implantation at progression of paired therapy and were excluded from TTP analyses. In cases with concordant Pt/PDX response, we found a significant correlation between RECIST response in pts and rAUC in PDX (ρ=0.82, p=0.03), a trend for comparable TTP in pts and TTP in PDX (ρ=0.67, p=0.10), but no correlation between RECIST response in pts and response at week 3 in PDX (ρ=0.46, p=0.30).

In this cohort of MBC pts, we found high concordance in Pt/PDX response. Our results suggest that rAUC in PDX may be the best read-out to identify relevant drug/genotype associations that can potentially be translated to patient benefit. Data will be updated with additional ongoing PDX experiments.

Citation Format: Mafalda Oliveira, Javier Pascual, Cristina Cruz, Alberto Gris, Marta Palafox, Alba Llop, Marta Castroviejo, Cristina Viaplana, Yasir H Ibrahim, Joaquin Arribas, Javier Cortés, José Baselga, Jordi Rodón, Judith Balmaña, Rodrigo Dienstmann, Cristina Saura, Violeta Serra. Patient-derived tumor xenografts (PDXs) recapitulate the antitumor activity of novel therapies in metastatic breast cancer (MBC) patients (pts) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3129. doi:10.1158/1538-7445.AM2017-3129

Abstract 2630: MEN1309, a novel antibody drug conjugate (ADC) targeting Ly75 antigen, induces complete responses in several xenografts of solid tumors

The cell surface antigen Lymphocyte antigen 75 (LY75, CD205, DEC-205) is over-expressed in several tumor histotypes. It is a type I C-type lectin receptor (CLR), normally expressed on various APC subsets, characterized by a cytoplasmic domain containing protein motifs crucial for endocytosis and internalization upon ligation. These features make the antigen ideal to be exploited as a target for a novel ADC. MEN1309 is a humanized IgG1 antibody directed against the cell surface antigen Ly75, conjugated through a cleavable linker to a potent maytansinoid microtubule disruptor, DM4. In this study, we evaluated the in vitro and in vivo (xenografts and PDX) efficacy of MEN1309 in different tumor histotypes. A PK/PD relationship was also investigated in tumor-bearing mice. IHC demonstrated high prevalence of Ly75 in human pancreatic, triple negative breast, and bladder cancers, as well as in diffuse large B-cell lymphoma. In vitro experiments showed that cytotoxic activity of MEN1309 was in nM/sub nM range against several lymphoma, pancreatic, bladder and triple-negative breast cancer (TNBC) cell lines. Moreover, MEN1309 exhibited high cell-killing ability against cells having either strong as well as low to moderate antigen expression. In vivo, MEN1309 at 2.5-5 mg/kg (schedule varying from single dose, q7dx3, or q21dx3) showed an impressive antitumor activity, resulting in complete and long lasting responses in most of the xenograft models representing lymphoma, TNBC, bladder and pancreatic cancers, expressing the antigen at high but also at low levels. No treatment related toxicity in terms of change of body weight and death events were detected. Moreover, the administration of (i) isotype control-DM4, (ii) the non-conjugate antibody IgG1 and (iii) the free toxin DM4 (at a dosage corresponding to the equimolar concentration linked at 10 mg/kg ADC) showed little to no therapeutic efficacy on tumor growth. In TNBC patient-derived xenograft (PDX) model (coming from a heavily pre-treated patient and expressing high level of the antigen Ly75), MEN1309 (5 mg/kg q21dx3) showed a complete tumor regression. Finally, in the pancreatic adenocarcinoma xenograft model HPAFII, the pharmacokinetics profile in serum of MEN1309 at 5 mg/kg was characterized and it was qualitatively correlated, using immunofluorescence, with the occurrence of phosphorylation of Serine 10 of H3 Histone in cancer cells, as a pharmacodynamic (PD) marker of DM4 activity on microtubules. Initial ADC exposure was noteworthy and was followed by a relatively fast decline. In parallel with the decay of the serum ADC concentrations there was a progressive increase in the number of positive cells showing the PD marker for mitotic arrest. Overall, our data suggest that MEN1309 is a selective and potent novel antitumoral ADC and it deserves to enter into aPhase I study for a variety of Ly75 positive tumor histotypes.

Citation Format: Mario Bigioni, Giuseppe Merlino, Cristina Bernadó Morales, Rossana Bugianesi, Attilio Crea, Rosanna Manno, Joaquin Arribas, Rachel Dusek, Nickolas Attanasio, Keith Wilson, Christian Rohlff, Monica Binaschi. MEN1309, a novel antibody drug conjugate (ADC) targeting Ly75 antigen, induces complete responses in several xenografts of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2630. doi:10.1158/1538-7445.AM2017-2630

Abstract B02: Co-clinical trial of olaparib in breast and ovarian patient-derived tumor xenografts (PDX) enables the identification of response biomarkers

Background: Women with heterozygous germline mutations in BRCA1 or BRCA2 are predisposed to developing breast or ovarian cancers, since BRCA1/2 mutation results in impaired high-fidelity DNA repair by homologous recombination (HR) and subsequently genetic instability. In non-gBRCA TNBC, HR deficiency occurs at the somatic level, by means of BRCA1 mutation, BRCA1 epigenetic loss or mutation in other HR-associated genes. PARP1/2 inhibitors (PARPi) are active anti-cancer agents in gBRCA with advanced breast or ovarian cancer. However, not all HR-deficient tumors respond to PARP blockade, and eventually all develop acquired resistance. Here, we sought to identify PARPi response biomarkers using PDX derived from both the early disease and the metastatic setting.

Methods: We developed a panel of PDX from patients harboring or not germline BRCA1/2 mutations, namely from 26 primary or advanced breast cancer and 2 high-grade serous metastatic ovarian cancer (HGSOC). The antitumor activity of the PARP1/2 inhibitor olaparib as single agent (50 mg/kg) was assessed in all models. To study the mechanisms of acquired resistance, the olaparib-sensitive PDXs were exposed to olaparib for >100 days, until individual tumors regrew. The tumor's capacity to repair DNA double strand breaks was estimated by quantification of the BRCA1 and RAD51 nuclear foci in the S/G2-phase of the cell cycle. We investigated the correlation between the tumor's BRCA1/RAD51 foci formation and sensitivity to olaparib, and also identified potential genetic modifiers of PARPi sensitivity by targeted sequencing.

Results: Seven out of 28 PDX (25%) treated with single agent olaparib exhibited tumor regression or disease stabilization. Among the non-gBRCA PDX, BRCA1 hypermethylation or PALB2 mutation were present in olaparib-sensitive PDX. No genetic reversions in BRCA1/2 mutations were identified as the mechanism of olaparib resistance in gBRCA but BRCA1 foci formation was observed in 6 out of 10 resistant models (60%). Nuclear RAD51 foci formation correlated with PARPi resistance in twenty PDX models investigated, either with primary or acquired resistance. The duration of response was similar between gBRCA and non-gBRCA PDX. Acquired-resistance mechanisms involve restoration of HR functionality.

Conclusions: Our study highlights that somatic HR-deficiency is frequent in TNBC and provides the basis of sensitivity to PARPi. In our gBRCA (n=12) and non-gBRCA (n=16) PDX, reactivation of HR functionality measured as RAD51 foci formation is a frequent event that is associated with PARPi resistance.

Citation Format: Violeta Serra, Cristina Cruz, Marta Castroviejo, Sara Gutiérrez, Alba Llop, Alejandra Bruna, Beatriz Morancho, Ginevra Caratú, Ludmila Prudkin, Ana Vivancos, Paolo Nuciforo, Mark O'Connor, Jos Jonkers, Carlos Caldas, Joaquin Arribas, José Baselga, Isabel T. Rubio, Cristina Saura, Orland Díez, Judith Balmaña, Javier Cortés. Co-clinical trial of olaparib in breast and ovarian patient-derived tumor xenografts (PDX) enables the identification of response biomarkers. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B02.

Cancer Therapeutic Resistance: Progress and Perspectives (April 7-8, 2016 - Barcelona, Spain)

At the Cancer Therapeutic Resistance: Progress and Perspectives conference, in Barcelona, Spain, April 7-8, 2016, researchers, clinicians and students gathered to discuss our current understanding of intrinsic and acquired resistance of tumors to cancer therapies and to explore how to translate strategies to predict risk or overcome resistance to the clinic. The sessions covered a wide range of topics, including cancer omics, molecular classification, clinically relevant tumor models, biomarkers and novel therapeutic targets, and personalized medicine, with talks from many international experts in the field. This report highlights the main presentations that demonstrate the progress being made in predicting and identifying drug resistance in patients with cancer, personalized approaches to direct treatment and understanding the mechanisms involved. With better models of human cancer and powerful high-throughput screening techniques, translation to the clinic leading to tangible benefits for patients is attainable.

Prospective study on cost-effectiveness of home-based motor assessment in Parkinson's disease

Introduction Treatment adjustments in Parkinson's disease (PD) are in part dependent on motor assessments. The aim of this study was to evaluate the cost-effectiveness of home-based motor monitoring plus standard in-office visits versus in-office visits alone in patients with advanced PD. Methods The procedures consisted of a prospective, one-year follow-up, randomized, case-control study. A total of 40 patients with advanced PD were randomized into two groups: 20 patients underwent home-based motor monitoring by using wireless motion sensor technology, while the other 20 patients had in-office visits. Motor and non-motor symptom severities, quality of life, neuropsychiatric symptoms, and comorbidities were assessed every four months. Direct costs were assessed using a standardized questionnaire. Cost-effectiveness was assessed using the incremental cost-effectiveness ratio (ICER). Results Both groups of PD patients were largely comparable in their clinical and demographic variables at baseline; however, there were more participants using levodopa-carbidopa intestinal gel in the home-based motor monitoring group. There was a trend for lower Unified Parkinson's Disease Rating Scale functional status (UPDRS II) scores in the patients monitored at home compared to the standard clinical follow-up ( p = 0.06). However, UPDRS parts I, III, IV and quality-adjusted life-years scores were similar between both groups. Home-based motor monitoring was cost-effective in terms of improvement of functional status, motor severity, and motor complications (UPDRS II, III; IV subscales), with an ICER/UPDRS ranging from €126.72 to €701.31, respectively. Discussion Home-based motor monitoring is a tool which collects cost-effective clinical information and helps augment health care for patients with advanced PD.

High HER2 protein levels correlate with increased survival in breast cancer patients treated with anti-HER2 therapy

INTRODUCTION

Current methods to determine HER2 (human epidermal growth factor receptor 2) status are affected by reproducibility issues and do not reliably predict benefit from anti-HER2 therapy. Quantitative measurement of HER2 may more accurately identify breast cancer (BC) patients who will respond to anti-HER2 treatments.

METHODS

Using selected reaction monitoring mass spectrometry (SRM-MS), we quantified HER2 protein levels in formalin-fixed, paraffin-embedded (FFPE) tissue samples that had been classified as HER2 0, 1+, 2+ or 3+ by immunohistochemistry (IHC). Receiver operator curve (ROC) analysis was conducted to obtain optimal HER2 protein expression thresholds predictive of HER2 status (by standard IHC or in situ hybridization [ISH]) and of survival benefit after anti-HER2 therapy.

RESULTS

Absolute HER2 amol/μg levels were significantly correlated with both HER2 IHC and amplification status by ISH (p < 0.0001). A HER2 threshold of 740 amol/μg showed an agreement rate of 94% with IHC and ISH standard HER2 testing (p < 0.0001). Discordant cases (SRM-MS-negative/ISH-positive) showed a characteristic amplification pattern known as double minutes. HER2 levels >2200 amol/μg were significantly associated with longer disease-free survival (DFS) and overall survival (OS) in an adjuvant setting and with longer OS in a metastatic setting.

CONCLUSION

Quantitative HER2 measurement by SRM-MS is superior to IHC and ISH in predicting outcome after treatment with anti-HER2 therapy.

High HER2 expression correlates with response to the combination of lapatinib and trastuzumab

PURPOSE

Expression of p95HER2 has been associated with resistance to trastuzumab-based therapy in patients with metastatic breast cancer. Conversely, high levels of HER2 have been linked with increased clinical benefit from anti-HER2 therapy. In this work, we aimed to investigate whether the levels of p95HER2 and HER2 can predict response to anti-HER2 therapy in patients with breast cancer.

EXPERIMENTAL DESIGN

We measured p95HER2 and HER2 by VeraTag and HERmark, respectively, in primary tumors of patients enrolled in the neoadjuvant phase III study NeoALTTO and correlated these variables with pathologic complete response (pCR) and progression-free survival (PFS) following lapatinib (L), trastuzumab (T), or the combination of both agents (L+T).

RESULTS

A positive correlation between p95HER2 and HER2 levels was found in the 274 cases (60%) in which quantification of both markers was possible. High levels of these markers were predictive for pCR, especially in the hormone receptor (HR)-positive subset of patients. High HER2 expression was associated with increased pCR rate upon L+T irrespective of the HR status. To examine whether the levels of either p95HER2 or HER2 could predict for PFS in patients treated with lapatinib, trastuzumab or L+T, we fit to the PFS data in Cox models containing log2(p95HER2) or log2(HER2). Both variables correlated with longer PFS.

CONCLUSIONS

Increasing HER2 protein expression correlated with increased benefit of adding lapatinib to trastuzumab. HER2 expression is a stronger predictor of pCR and PFS than p95HER2 for response to lapatinib, trastuzumab and, more significantly, L+T.

Poly (ADP-ribose) polymerase inhibition enhances trastuzumab antitumour activity in HER2 overexpressing breast cancer

AIM

Poly (ADP-ribose) polymerase (PARP) inhibitors have shown promising results in Breast Cancer (BRCA) deficient breast cancer, but not in molecularly unselected patient populations. Two lines of research in this field are needed: the identification of novel subsets of patients that could potentially benefit from PARP inhibitors and the discovery of suitable targeted therapies for combination strategies.

METHODS

We tested PARP inhibition, alone or combined with the anti-HER2 antibody trastuzumab on HER2+ breast cancer. We used two PARP inhibitors in clinical development, olaparib and rucaparib, as well as genetic downmodulation of PARP-1 for in vitro studies. DNA damage was studied by the formation of γH2AX foci and comet assay. Finally, the in vivo anti-tumour effect of olaparib and trastuzumab was examined in nude mice subcutaneously implanted with BT474 cells.

RESULTS

In a panel of four HER2 overexpressing breast cancer cell lines, both olaparib and rucaparib significantly decreased cell growth and enhanced anti-tumour effects of trastuzumab. Cells exposed to olaparib and trastuzumab had greater DNA damage than cells exposed to each agent alone. Mechanistic exploratory assays showed that trastuzumab downmodulated the homologous recombination protein proliferating cell nuclear antigen (PCNA). Combination treatment in the BT474 xenograft model resulted in enhanced growth inhibition, reduced tumour cell proliferation, and increased DNA damage and apoptosis.

CONCLUSION

Taken together, our results show that PARP inhibition has antitumour effects and increases trastuzumab activity in HER2 overexpressing breast cancer. These findings make this novel combination a promising strategy for clinical development.

Enhancing the Biological Relevance of Secretome-Based Proteomics by Linking Tumor Cell Proliferation and Protein Secretion

Secretome profiling has become a methodology of choice for the identification of tumor biomarkers. We hypothesized that due to the dynamic nature of secretomes cellular perturbations could affect their composition but also change the global amount of protein secreted per cell. We confirmed our hypothesis by measuring the levels of secreted proteins taking into account the amount of proteome produced per cell. Then, we established a correlation between cell proliferation and protein secretion that explained the observed changes in global protein secretion. Next, we implemented a normalization correcting the statistical results of secretome studies by the global protein secretion of cells into a generalized linear model (GLM). The application of the normalization to two biological perturbations on tumor cells resulted in drastic changes in the list of statistically significant proteins. Furthermore, we found that known epithelial-to-mesenchymal transition (EMT) effectors were only statistically significant when the normalization was applied. Therefore, the normalization proposed here increases the sensitivity of statistical tests by increasing the number of true-positives. From an oncology perspective, the correlation between protein secretion and cellular proliferation suggests that slow-growing tumors could have high-protein secretion rates and consequently contribute strongly to tumor paracrine signaling.

Abstract P1-08-42: High HER2 expression correlates with response to trastuzumab and the combination of trastuzumab and lapatinib in the NeoALTTO phase III trial

Background: Expression of p95HER2, a truncated form of HER2 lacking the extracellular domain, has been associated with resistance to trastuzumab (T)-based therapy in metastatic breast cancer patients. Conversely, high levels of HER2 have been correlated with increased clinical benefit from anti-HER2 therapy in the neoadjuvant setting. In this work we correlated the expression of p95HER2 and HER2 with pathological complete response (pCR) following T, lapatinib (L) or the combination of both agents (T+L) with paclitaxel.

Methods: p95HER2 and HER2 were quantified by VeraTag® and HERmark® (Monogram Biosciences), respectively, in primary tumors of 455 patients enrolled in the phase III neoadjuvant study NeoALTTO (Baselga J. et al. Lancet, 2012). The relationship of pCR status to p95HER2 and HER2 was studied using logistic regression models, which accounted for stratification factors and treatment. Unless specified, p95HER2 and HER2 were included as log terms.

Results: p95HER2 was measurable in 283 cases (62%) and HER2 in 327 cases (72%). A positive correlation between p95HER2 and HER2 levels was found in the 274 cases (60%) where quantification of both markers was available. Increased HER2 was strongly associated with increased pCR rate in patients treated with the combination of T+L (OR 5.09, 95%CI 2.27-11.44; p&lt;0.01), with a trend observed also in the L-only arm (OR 1.88, 95% CI 0.96-3.70; p = 0.067). Overall, patients with tumors that were HER2-positive (&gt;17.8 RF/mm2) by HERmark had a higher pCR rate than those that were HER2-negative by HERmark (39% vs. 11%, respectively; p&lt;0.001). Increasing p95HER2 levels did not predict for pCR in the L or T+L arms and showed weak evidence (p = 0.073) of an increase in pCR in the T arm.

In an unplanned analysis, we examined the odds of achieving response to anti-HER2 therapy in patients with HER2 levels above and below the median (100 RF/mm2, HER2 entered as a binary covariate). HER2 levels above the median predicted a higher response rate to T (OR 3.6, 95% CI 1.2-11; p&lt;0.05) and, more significantly, to T+L (OR 6.01, 95% CI 2.51-14.4; p&lt;0.001). In particular, patients treated with T+L had a higher probability to achieve pCR compared to T alone when HER2 was above the median (T+L = 73% pCR vs. T = 43% pCR, p&lt;0.01; OR 3.74, 95% CI 1.57-8.90), but not when HER2 was below the median (T+L = 29% pCR vs. T = 19% pCR, p&gt;0.2; OR 1.84, 95% CI 0.74-4.55). When tumors were divided in hormone receptor (HR)-positive and HR-negative groups, total levels of HER2 still predicted response to T or T+L.

Conclusions: Increasing HER2 protein expression correlated with increased benefit of adding L to T compared to T alone. In tumors above the median of HER2 expression, the levels of HER2 predicted for response to both T and T+L. Our interpretation is that, in the neoadjuvant setting, the association between p95HER2 expression and response to anti-HER2 therapy is likely a consequence of the correlation between p95HER2 and total HER2 levels. HER2 expression seems to be a stronger predictor of pCR than p95HER2 for response to T, L and especially, T+L. Future studies to understand the impact of p95HER2 and HER2 expression on disease-free and overall survival following anti-HER2 therapy are warranted.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-42.

Clinical benefit of lapatinib-based therapy in patients with human epidermal growth factor receptor 2-positive breast tumors coexpressing the truncated p95HER2 receptor

PURPOSE

A subgroup of human epidermal growth factor receptor 2 (HER2)-overexpressing breast tumors coexpresses p95HER2, a truncated HER2 receptor that retains a highly functional HER2 kinase domain but lacks the extracellular domain and results in intrinsic trastuzumab resistance. We hypothesized that lapatinib, a HER2 tyrosine kinase inhibitor, would be active in these tumors. We have studied the correlation between p95HER2 expression and response to lapatinib, both in preclinical models and in the clinical setting.

EXPERIMENTAL DESIGN

Two different p95HER2 animal models were used for preclinical studies. Expression of p95HER2 was analyzed in HER2-overexpressing breast primary tumors from a first-line lapatinib monotherapy study (EGF20009) and a second-line lapatinib in combination with capecitabine study (EGF100151). p95HER2 expression was correlated with overall response rate (complete + partial response), clinical benefit rate (complete response + partial response + stable disease > or =24 wk), and progression-free survival using logistic regression and Cox proportional hazard models.

RESULTS

Lapatinib inhibited tumor growth and the HER2 downstream signaling of p95HER2-expressing tumors. A total of 68 and 156 tumors from studies EGF20009 and EGF100151 were evaluable, respectively, for p95HER2 detection. The percentage of p95HER2-positive patients was 20.5% in the EGF20009 study and 28.5% in the EGF100151 study. In both studies, there was no statistically significant difference in progression-free survival, clinical benefit rate, and overall response rate between p95HER2-positive and p95HER2-negative tumors.

CONCLUSIONS

Lapatinib as a monotherapy or in combination with capecitabine seems to be equally effective in patients with p95HER2-positive and p95HER2-negative HER2-positive breast tumors.