Tolerability and Efficacy of the Anticluster of Differentiation 47 Antibody Magrolimab Combined With Azacitidine in Patients With Previously Untreated AML: Phase Ib Results.

PURPOSE: Magrolimab is a first-in-class humanized monoclonal antibody against cluster of differentiation 47, an antiphagocytic signal used by cancer cells to evade phagocytosis. Azacitidine upregulates prophagocytic signals on AML cells, further increasing phagocytosis when combined with magrolimab. We report final phase Ib data for magrolimab with azacitidine in patients with untreated AML ineligible for intensive chemotherapy (ClinicalTrials.gov identifier: NCT03248479). PATIENTS AND METHODS: Patients with previously untreated AML, including TP53-mutant AML, received magrolimab intravenously as an initial dose (1 mg/kg, days 1 and 4), followed by 15 mg/kg once on day 8 and 30 mg/kg once weekly or every 2 weeks as maintenance. Azacitidine 75 mg/m2 was administered intravenously/subcutaneously once daily on days 1-7 of each 28-day cycle. Primary end points were safety/tolerability and proportion with complete remission (CR). RESULTS: Eighty-seven patients were enrolled and treated; 72 (82.8%) had TP53 mutations with a median variant allele frequency of 61% (range, 9.8-98.7). Fifty-seven (79.2%) of TP53-mutant patients had European LeukemiaNet 2017 adverse-risk cytogenetics. Patients received a median of 4 (range, 1-39) cycles of treatment. The most common treatment-emergent adverse events included constipation (49.4%), nausea (49.4%), and diarrhea (48.3%). Thirty (34.5%) experienced anemia, and the median hemoglobin change from baseline to first postdose assessment was -0.9 g/dL (range, -3.6 to 2.5 g/dL). Twenty-eight (32.2%) patients achieved CR, including 23 (31.9%) patients with TP53 mutations. The median overall survival in TP53-mutant and wild-type patients were 9.8 months and 18.9 months, respectively. CONCLUSION: Magrolimab with azacitidine was relatively well tolerated with promising efficacy in patients with AML ineligible for intensive induction chemotherapy, including those with TP53 mutations, warranting further evaluation of magrolimab with azacitidine in AML. The phase III randomized ENHANCE-2 (ClinicalTrials.gov identifier: NCT04778397) and ENHANCE-3 (ClinicalTrials.gov identifier: NCT05079230) studies are recruiting frontline patients with AML.

Phase Ib Study of the BET Inhibitor GS-5829 as Monotherapy and Combined with Enzalutamide in Patients with Metastatic Castration-Resistant Prostate Cancer.

PURPOSE: A phase Ib study (1604) was conducted to evaluate the safety and efficacy of GS-5829, an oral bromodomain and extraterminal inhibitor, alone and in combination with enzalutamide in metastatic castration-resistant prostate cancer (mCRPC). A phase I study (1599) in solid tumors/lymphoma was also conducted. PATIENTS AND METHODS: Men with confirmed mCRPC and disease progression despite abiraterone and/or enzalutamide treatment were enrolled in a 3 + 3 dose escalation paradigm starting at 2 mg daily with GS-5829 alone and in combination with 160 mg daily enzalutamide. The primary efficacy endpoint was nonprogression rate at week 24; secondary endpoints included prostate-specific antigen reduction from baseline, progression-free survival, and GS-5829 pharmacokinetics (PK). PK and safety were also evaluated in Study 1599. RESULTS: Thirty-one men, with a median of five prior regimens, received at least 1 dose of study drug in Study 1604. Treatment-emergent adverse events (TEAE) were reported in 94% of patients; 16% discontinued for TEAEs. There were no dose-dependent increases in the AUCtau or Cmax after once-daily administration of GS-5829 2 to 9 mg, and biomarkers CCR2 inhibition and HEXIM1 induction were increased only at higher doses of monotherapy. A high degree of interpatient variability existed across all doses in PK and pharmacodynamic parameters. The proportion with nonprogression at week 24, estimated by Kaplan-Meier model, was 25% (95% confidence interval, 10-42) for all treated patients. CONCLUSIONS: GS-5829 was generally tolerated but demonstrated limited efficacy and lack of dose proportional increases in plasma concentrations in patients with mCRPC.

A plasma-derived extracellular vesicle mRNA classifier for the detection of breast cancer.

BACKGROUND: According to the global cancer burden data released in 2020, breast cancer (BC) has become the most common cancer in the world. Similar to those of other cancers, the present methods used in clinic for diagnosing early BC are invasive, inaccurate, and insensitive. Hence, new non-invasive methods capable of early diagnosis are needed. METHODS: We applied next-generation sequencing and analyzed the messenger RNA (mRNA) profiles of plasma extracellular vesicles (EVs) derived from 14 BC patients and 6 patients with benign breast lesions. We used 3 regression models, namely support vector machine (SVM), linear discriminate analysis (LDA), and logistic regression (LR), to develop classifiers for use in making predictive BC diagnoses; and used 259 plasma samples, including those obtained from 144 patients with BC, 72 patients with benign breast lesions, and 43 healthy women, which were divided into training groups and validation groups to verify their performances as classifiers by quantitative reverse transcription polymerase chain reaction (RT-qPCR). The area under the curve (AUC) and accuracy, sensitivity, and specificity of the classifiers were cross-validated with the leave-1-out cross-validation (LOOCV) method. RESULTS: Among all combinations assessed with the 3 different regression models, an 8-mRNA combination, named EXOBmRNA, exhibited high performance [accuracy =71.9% and AUC =0.718, 95% confidence interval (CI): 0.652 to 0.784] in the training cohort after LOOCV was performed, showing the largest AUC in the SVM model. The mRNAs in EXOBmRNA were HLA-DRB1, HAVCR1, ENPEP, TIMP1, CD36, MARCKS, DAB2, and CXCL14. In the validation cohort, the AUC of EXOBmRNA was 0.737 (95% CI: 0.636 to 0.837). In addition, gene function and pathway analyses revealed that different levels of gene expression were associated with cancer. CONCLUSIONS: We developed a high-performing predictive classifiers including 8 mRNAs from plasma extracellular vesicles for diagnosing breast cancer.

Idelalisib immune-related toxicity is associated with improved treatment response.

Idelalisib is associated with increased occurrence of immune-related adverse events (irAEs). Clinical observations suggest a correlation between immune checkpoint inhibitor-induced irAEs and survival outcomes in patients with solid tumors; however, this relationship in hematologic malignancies is not well understood. In a post hoc analysis of 3 registrational trials, we explored the relationship between Grade ≥3 diarrhea/colitis and alanine/aspartate transaminase (ALT/AST) elevation incidences and efficacy endpoints in patients with indolent non-Hodgkin lymphoma (iNHL), follicular lymphoma (FL), and chronic lymphocytic leukemia treated with idelalisib. Grade ≥3 diarrhea/colitis was associated with higher overall response rate (ORR) and longer progression-free survival (PFS) for all subgroups. Grade ≥3 ALT/AST elevations were associated with improved duration of response and overall survival for all subgroups and improved ORR and PFS for patients with FL or iNHL. Our analysis in hematologic malignancies showed a trend correlating idelalisib-induced Grade ≥3 irAEs with improved efficacy.

A retrospective observational study to evaluate the clinical outcomes and routine management of patients with chronic lymphocytic leukaemia treated with idelalisib and rituximab in the UK and Ireland (RETRO-idel).

Idelalisib (IDL) is an oral first-in-class phosphatidylinositol 3-kinase delta (PI3Kδ) inhibitor approved for chronic lymphocytic leukaemia (CLL) alongside rituximab (R) since 2014. However, little data exist on routine practice. The RETRO-idel was a protocol-led, retrospective study of 110 patients [n = 27 front-line (1L)] who received IDL-R. The primary end-point was clinical overall response rate (ORR). The median (range) follow-up of the whole cohort was 30·2 (0·1-51·9) months. The median (range) age was 72 (48-89) years. Tumour protein p53-disruption was common [100% 1L, 32·5% relapsed/refractory (R/R)]. The best ORR (intention-to-treat) was 88·2% (1L 96·3%, R/R 85·5%). Overall, the median event-free survival (mEFS) was 20·3 months and time-to-next treatment was 29·2 months. The mEFS for 1L patients was 18·7 months and R/R patients was 21·7 months. The 3-year overall survival was 56·1% (95% confidence interval 45·7-65·3). IDL was discontinued in 87·3% (n = 96). More patients discontinued due to adverse events in the front-line setting (1L 63·0% vs. R/R 44·6%) and due to progressive disease in R/R patients (20·5% vs. 3·7% in 1L). Lower respiratory tract infection/pneumonia were reported in 34·5% (Grade ≥3, 19·1%), diarrhoea in 30·9% (Grade ≥3, 6·4%), and colitis in 9·1% (Grade ≥3, 5·5%). Overall, these data describe clear efficacy for IDL-R in routine practice. No new safety signals were identified, although careful management of known toxicities is required.

Retrospective Analysis of the Impact of Adverse Event-Triggered Idelalisib Interruption and Dose Reduction on Clinical Outcomes in Patients With Relapsed/Refractory B-Cell Malignancies.

BACKGROUND: Idelalisib is a phosphatidylinositol 3-kinase δ inhibitor approved for relapsed/refractory follicular lymphoma, a type of indolent non-Hodgkin lymphoma (iNHL), and chronic lymphocytic leukemia (CLL). Idelalisib-triggered adverse events (AEs) may be managed with treatment interruption and/or dose reduction, potentially extending therapy duration and increasing the likelihood of continued response. PATIENTS AND METHODS: Post hoc analyses were conducted to evaluate clinical outcomes after AE-induced idelalisib interruption for 125 patients with iNHL and 283 with CLL. RESULTS: Progression-free survival (PFS) was longer for patients with iNHL who experienced ≥ 2 interruptions versus those with 0 interruptions who discontinued idelalisib or study because of AEs (hazard ratio 0.33; P = .0212). Both PFS and overall survival were longer for patients with CLL with ≥ 2 interruptions versus 0 interruptions in those who discontinued therapy because of an AE (hazard ratio PFS 0.50, overall survival 0.41; P < .005). Clinical benefits persisted for patients with CLL who experienced treatment interruption after receiving idelalisib for ≥ 6 months. Supplementing interruption with dose reduction did not worsen clinical outcomes. However, time off therapy of ≥ 8% may diminish the clinical benefit of treatment interruption. CONCLUSION: Idelalisib interruption and dose reduction were associated with enhanced clinical outcomes for patients with relapsed/refractory iNHL or CLL who experienced an AE, supporting this management strategy when indicated.

No increased bleeding events in patients with relapsed chronic lymphocytic leukemia and indolent non-Hodgkin lymphoma treated with idelalisib.

The advent of novel B-cell receptor pathway targeting agents like ibrutinib dramatically changed management of B-cell malignancies. However, with concomitant anticoagulation (AC) and antiplatelet (AP) therapy, ibrutinib is associated with increased bleeding. This post hoc analysis aimed to determine the role of AC/AP therapy in patients with idelalisib-treated B-cell malignancies and to establish if it contributes to increased bleeding events. Data from two idelalisib trials (rituximab ± idelalisib in chronic lymphocytic leukemia [CLL] and idelalisib monotherapy in indolent non-Hodgkin lymphoma [iNHL]) were analyzed. Antithrombotic therapy was common (36%-63%), with comparable bleeding incidence across treatment groups (14%-19%; p = 0.56). Bleeding events of grade ≥3 occurred in 0.9% and 3.2% of the idelalisib-treated CLL and iNHL cohorts, respectively. Our findings demonstrate no increase in bleeding events with simultaneous AC/AP treatment and idelalisib use. Hemorrhagic risk is prevalent in these patients and an important consideration when evaluating available treatment options. ClinicalTrials.gov identifiers: NCT01539512 and NCT01282424.

Outcomes of patients with up to 6 years of follow-up from a phase 2 study of idelalisib for relapsed indolent lymphomas.

The phase 2 study of idelalisib monotherapy for indolent non-Hodgkin lymphomas (iNHLs) was completed in 2018; final efficacy and safety data with up to 6.7 years long-term follow-up are reported. Patients with iNHL refractory to both rituximab and an alkylating agent were enrolled and received 150 mg idelalisib twice daily (N = 125). Idelalisib resulted in an overall response rate of 57.6% with 34.4% continuing therapy for ≥12 months. The median progression-free survival and duration of response were 11.0 and 11.8 months for follicular lymphoma, 22.2 and 20.4 months for lymphoplasmacytic lymphoma/Waldenström's macroglobulinemia (LPL/WM), and 6.6 and 18.4 months for marginal zone lymphoma (MZL). Median overall survival after extended follow-up was 48.6 (95% CI 33.9, 71.7) months. Long-term follow-up did not reveal new safety concerns. These data indicate beneficial outcomes with longer follow-up after idelalisib for treatment of iNHL including in patients with LPL/WM and MZL.

Phase 1b study to investigate the safety and tolerability of idelalisib in Japanese patients with relapsed/refractory follicular lymphoma and chronic lymphocytic leukemia.

OBJECTIVE: Idelalisib is an orally administered, highly selective inhibitor of phosphatidylinositol 3-kinase-δ. In this phase 1b study, the safety, tolerability and pharmacokinetics of idelalisib, an oral inhibitor of phosphatidylinositol 3-kinase-δ, were evaluated in Japanese patients with relapsed or refractory indolent B-cell non-Hodgkin lymphoma. METHODS: In total, six patients (follicular lymphoma: n = 3, chronic lymphocytic leukemia: n = 3) were enrolled to receive idelalisib 150 mg twice daily. RESULTS: No dose-limiting toxicities were reported. The most common adverse events were diarrhea (n = 5), gastritis (n = 3), insomnia (n = 3) and pyrexia (n = 3). The most common ≥grade 3 adverse events were diarrhea (n = 2), increased transaminase levels (n = 2) and decreased appetite (n = 2). The maximum idelalisib plasma concentrations (Cmax) were achieved at 2.50 h (range: 1.50-4.00 h). The mean idelalisib plasma concentrations decreased over time but remained detectable in most patients at 12 h. All enrolled patients underwent efficacy evaluation by investigators, and five patients (follicular lymphoma: n = 2, chronic lymphocytic leukemia: n = 3) achieved partial response. The median duration of partial response was 14.5 months (range: 3.7-31.3 months). CONCLUSION: Idelalisib 150 mg twice daily was considered tolerable in Japanese patients with follicular lymphoma or chronic lymphocytic leukemia.(Clinical trial registration: NCT02242045).

Prognostic risk score for patients with relapsed or refractory chronic lymphocytic leukaemia treated with targeted therapies or chemoimmunotherapy: a retrospective, pooled cohort study with external validations.

BACKGROUND: Clinically validated prognostic models for overall survival do not exist for patients with relapsed or refractory chronic lymphocytic leukaemia (CLL) who are on targeted therapies. We aimed to create a prognostic model to identify high-risk individuals who do not achieve a good outcome with available targeted therapies. METHODS: In this retrospective, pooled cohort study, 2475 patients with CLL treated between June 22, 2012, and Sept 23, 2015, in six randomised trials of ibrutinib, idelalisib, and venetoclax, or at the Mayo Clinic CLL Database (MCCD) were included. Eligible patients had CLL, were previously treated, were aged 18 years or older, had ECOG performance status 0-1, and required further treatment as per the international workshop on CLL 2008 criteria. There was heterogeneity in other eligibility criteria. We evaluated 28 candidate factors known to affect the overall survival of these patients and applied univariate and multivariate analyses to derive the risk score in a training dataset (n=727) of patients treated with ibrutinib or chemoimmunotherapy. We validated the score in an internal-validation dataset (n=242) of patients treated with ibrutinib or chemoimmunotherapy and three external-validation datasets (idelalisib or chemoimmunotherapy dataset, n=897; venetoclax or chemoimmunotherapy dataset, n=389; and the MCCD [including patients treated with heterogeneous therapies], n=220), applying C-statistics as a measure of discrimination. FINDINGS: The derived model consisted of four factors (one point each; serum ß2-microglobulin ≥5 mg/dL, lactate dehydrogenase >upper limit of normal, haemoglobin <110 g/L for women or <120 g/L for men, and time from initiation of last therapy <24 months), separating patients into low (score 0-1), intermediate (score 2-3), and high risk (score 4) groups. The risk score was prognostic for overall survival in the training dataset (CS=0·74, 95% CI 0·60-0·85, log-rank p<0·0001), and in the internal-validation (CS=0·79, 0·56-0·97, log-rank p=0·0003), and all three external-validation cohorts (idelalisib or chemoimmunotherapy: CS=0·71, 0·59-0·81, log-rank p<0·0001; venetoclax or chemoimmunotherapy: CS =0·76, 0·66-0·85, log-rank p=0·014; MCCD cohort: CS=0·61, 0·56-0·66), log-rank p<0·0001). The risk score is available on Calculate by QxMD. INTERPRETATION: We present the first validated risk score to predict overall survival in patients with relapsed or refractory CLL treated with targeted therapy. The model is applicable to patients treated with all currently approved targeted therapies (ibrutinib, idelalisib, and venetoclax) and chemoimmunotherapy. This tool allows the identification of a well defined cohort of previously treated patients with CLL who are at high risk of death, and could be used in future prospective trials to test therapeutic options for these patients with an unmet clinical need. FUNDING: Lymphoma Research Foundation, Lymphoma Research Fund (Andrew D Zelenetz), and National Institutes of Health/National Cancer Institute.

Evaluation of the CLL-IPI in relapsed and refractory chronic lymphocytic leukemia in idelalisib phase-3 trials.

The CLL-IPI is a risk-weighted prognostic model for previously untreated patients with chronic lymphocytic leukemia (CLL), but has not been evaluated in patients with relapsed CLL or on novel therapies. We evaluated the CLL-IPI in 897 patients with relapsed/refractory CLL in 3 randomized trials testing idelalisib (PI3Kδ inhibitor). The CLL-IPI identified patients as low (2.2%), intermediate (12.8%), high (48.7%), and very high (36.2%) risk and was prognostic for survival (log-rank p < .0001; C-statistic 0.706). Of CLL-IPI factors, age >65, ß2-microglobulin >3.5mg/L, unmutated immunoglobulin heavy chain variable region gene, and deletion 17p/TP53 mutation were independently prognostic, but Rai I-IV or Binet B/C was not. The CLL-IPI is prognostic for survival in relapsed CLL and with idelalisib therapy. However, low/intermediate risk is uncommon, and regression parameters of individual factors in this risk-weighted model appear different in relapsed CLL. Reassessment of the weighting of the individual variables might optimize the model in this setting.

Efficacy and safety of idelalisib in combination with ofatumumab for previously treated chronic lymphocytic leukaemia: an open-label, randomised phase 3 trial.

BACKGROUND: Idelalisib, a selective inhibitor of PI3Kδ, is approved for the treatment of patients with relapsed chronic lymphocytic leukaemia (CLL) in combination with rituximab. We aimed to assess the efficacy and safety of idelalisib in combination with a second-generation anti-CD20 antibody, ofatumumab, in a similar patient population. METHODS: In this global, open-label, randomised, controlled phase 3 trial, we enrolled patients with relapsed CLL progressing less than 24 months from last therapy. Patients refractory to ofatumumab were excluded. Patients were stratified by relapsed versus refractory disease, presence or absence of del(17p) or TP53 mutation, or both, and IGHV mutated versus unmutated. We randomised patients in a 2:1 ratio using a web-based interactive system that generated a unique treatment code, and assigned patients to receive either idelalisib plus ofatumumab (oral idelalisib 150 mg twice daily continuously plus ofatumumab 300 mg intravenously in week 1, then 1000 mg intravenously weekly for 7 weeks, and every 4 weeks for 16 weeks) or ofatumumab alone (ofatumumab dosing as per the combination group, except 2000 mg was substituted for the 1000 mg dose). An independent review committee assessed response, including progressive disease, based on imaging using modified International Workshop on Chronic Lymphocytic Leukaemia 2008 criteria. The primary endpoint was progression-free survival assessed by an independent review committee in the intention-to-treat population. We did a primary analysis (data cutoff Jan 15, 2015) and an updated analysis (data cutoff Sept 1, 2015). This trial is registered with Clinicaltrials.gov, number NCT01659021. FINDINGS: Between Dec 17, 2012, and March 31, 2014, we enrolled 261 patients (median age 68 years [IQR 61-74], median previous therapies three [IQR 2-4]). At the primary analysis, median progression-free survival was 16·3 months (95% CI 13·6-17·8) in the idelalisib plus ofatumumab group and 8·0 months (5·7-8·2) in the ofatumumab group (adjusted hazard ratio [HR] 0·27, 95% CI 0·19-0·39, p<0·0001). The most frequent grade 3 or worse adverse events in the idelalisib plus ofatumumab group were neutropenia (59 [34%] patients vs 14 [16%] in the ofatumumab group), diarrhoea (34 [20%] vs one [1%]), and pneumonia (25 [14%] vs seven [8%]). The most frequent grade 3 or worse adverse events in the ofatumumab group were neutropenia (14 [16%]), pneumonia (seven [8%]), and thrombocytopenia (six [7%] vs 19 [11%] in the idelalisib plus ofatumumab group). Serious infections were more common in the idelalisib plus ofatumumab group and included pneumonia (23 [13%] patients in the idelalisib plus ofatumumab group vs nine [10%] in the ofatumumab group), sepsis (11 [6%] vs one [1%]), and Pneumocystis jirovecii pneumonia (eight [5%] vs one [1%]). 22 treatment-related deaths occurred in the idelalisib plus ofatumumab group (the most common being sepsis, septic shock, viral sepsis, and pneumonia). Six treatment-related deaths occurred in the ofatumumab group (the most common being progressive multifocal leukoencephalopathy and pneumonia). INTERPRETATION: The idelalisib plus ofatumumab combination resulted in better progression-free survival compared with ofatumumab alone in patients with relapsed CLL, including in those with high-risk disease, and thus might represent a new treatment alternative for this patient population. FUNDING: Gilead Sciences, Inc.

Neoadjuvant doxorubicin/cyclophosphamide followed by ixabepilone or paclitaxel in early stage breast cancer and evaluation of ßIII-tubulin expression as a predictive marker.

BACKGROUND: This randomized phase II trial was designed to compare the rate of pathologic complete response (pCR) induced by neoadjuvant cyclophosphamide plus doxorubicin (AC) followed by ixabepilone or paclitaxel in women with early stage breast cancer (BC). Expression of ßIII-tubulin as a predictive marker was also evaluated. PATIENTS AND METHODS: Women with untreated, histologically confirmed primary invasive breast adenocarcinoma received four cycles of AC followed by 1:1 randomization to either ixabepilone 40 mg/m2 (3-hour infusion) every 3 weeks for four cycles (n = 148) or weekly paclitaxel 80 mg/m2 (1-hour infusion) for 12 weeks (n = 147). All patients underwent a core needle biopsy of the primary cancer for molecular marker analysis prior to chemotherapy. ßIII-Tubulin expression was assessed using immunohistochemistry. RESULTS: There was no significant difference in the rate of pCR in the ixabepilone treatment arm (24.3%; 90% confidence interval [CI], 18.6-30.8) and the paclitaxel treatment arm (25.2%; 90% CI, 19.4-31.7). ßIII-Tubulin-positive patients obtained higher pCR rates compared with ßIII-tubulin-negative patients in both treatment arms; however, ßIII-tubulin expression was not significantly associated with a differential response to ixabepilone or paclitaxel. The safety profiles of both regimens were generally similar, although neutropenia occurred more frequently in the ixabepilone arm (grade 3/4: 41.3% vs. 8.4%). The most common nonhematologic toxicity was peripheral neuropathy. CONCLUSIONS: Neoadjuvant treatment of early stage BC with AC followed by ixabepilone every 3 weeks or weekly paclitaxel was well tolerated with no significant difference in efficacy. Higher response rates were observed among ßIII-tubulin-positive patients.

Biomarker analysis of neoadjuvant doxorubicin/cyclophosphamide followed by ixabepilone or Paclitaxel in early-stage breast cancer.

PURPOSE: Predictive biomarkers offer the potential to improve the benefit:risk ratio of a therapeutic agent. Ixabepilone achieves comparable pathologic complete response (pCR) rates to other active drugs in the neoadjuvant setting. This phase II trial was designed to investigate potential biomarkers that differentiate response to this agent. EXPERIMENTAL DESIGN: Women with untreated, histologically confirmed primary invasive breast adenocarcinoma received neoadjuvant doxorubicin/cyclophosphamide, followed by 1:1 randomization to ixabepilone (n = 148) or paclitaxel (n = 147). Rates of pCR were compared between treatment arms based on predefined biomarker sets: TUBB3, TACC3, and CAPG gene expression, a 20- and 26-gene expression model, MDR1 protein expression, and other potential markers of sensitivity. ßIII-tubulin protein expression is reported separately but is referred to here for completeness. All patients underwent a core needle biopsy of the primary cancer for molecular marker analysis before chemotherapy. Gene expression profiling data were used for molecular subtyping. RESULTS: There was no significant difference in the rate of pCR in both treatment arms in ßIII-tubulin-positive patients. Higher pCR rates were observed among ßIII-tubulin-positive patients than in ßIII-tubulin-negative patients. Furthermore, no correlation was evident between TUBB3, TACC3, and CAPG gene expression, MDR1 protein expression, multi-gene expression models, and the efficacy of ixabepilone or paclitaxel, even within the estrogen receptor-negative subset. CONCLUSION: These results indicate that ßIII-tubulin protein and mRNA expression, MDR1 protein expression, TACC3 and CAPG gene expression, and multigene expression models (20- and 26-gene) are not predictive markers for differentiating treatment benefit between ixabepilone and paclitaxel in early-stage breast cancer.