O’Shaughnessy, Joyce

Abstract Background: A recent exploratory subgroup analysis pooling data from over 1000 patients (pts) in MONARCH 2 (final analysis) and MONARCH 3 (interim analysis) demonstrated that pts with clinical characteristics that predict for worse outcome (e.g. liver metastases, progesterone receptor [PgR]-negative status, high-grade tumors) received the largest benefit from the addition of abemaciclib to endocrine therapy (ET). There is also interest in determining the extent to which abemaciclib improves progression-free survival (PFS) in pts with favorable prognostic factors (e.g. bone-only disease, long treatment-free interval [TFI]). Here we present an update of the subgroup analyses of the MONARCH 3 study using data from the preplanned final PFS analysis. Methods: Enrollment criteria and study designs were previously described (Sledge et al. J Clin Oncol. 2017; Goetz et al. J Clin Oncol. 2017). An exploratory pooled analysis was conducted using data from MONARCH 2 (NCT02107703) and the MONARCH 3 (NCT02246621) preplanned final PFS analysis to identify significant prognostic factors regardless of therapy received. Using the updated MONARCH 3 data, PFS and objective response rate (ORR) (in pts with measurable disease) were examined within the prognostic subgroups that had been previously identified as being statistically significant. Additionally, subpopulation treatment effect pattern plot (STEPP) methodology was used to evaluate the association between TFI following adjuvant ET and outcomes of NSAI alone or with abemaciclib. Results: Assessment of clinical factors from MONARCH 2 and MONARCH 3 (final PFS data) confirmed that the following factors remained significantly prognostic regardless of treatment received: bone-only disease, liver metastases, tumor grade, PgR status, and ECOG performance status. In MONARCH 3, prognosis was poor in pts with liver metastases, PgR-negative tumors, and high-grade tumors. While all subpopulations benefited from the addition of abemaciclib to ET regardless of prognosis, pts with these three poor prognostic factors received substantial benefit from abemaciclib, with PFS hazard ratios (HR) ranging from 0.4 to 0.5 and with differential improvement in ORR typically >30%. Furthermore, STEPP analysis of TFI (on the MONARCH 3 pts who had received adjuvant ET) demonstrated that pts who had a shorter TFI had a worse prognosis and received relatively greater benefit from abemaciclib plus NSAI than did pts with a longer TFI. Patients with bone-only disease or a long TFI also received benefit from abemaciclib, but to a relatively lesser extent (HR ranging from approximately 0.6 to 0.8). Conclusions: This exploratory analysis of the preplanned final PFS data from MONARCH 3 confirms previous findings that pts with poor prognostic factors may receive relatively greater benefit from the addition of abemaciclib to ET. Citation Format: Joyce O'Shaughnessy, Matthew P. Goetz, George W. Sledge, Miguel Martin, Yong Lin, Tammy Forrester, Ian C. Smith, Angelo Di Leo, Stephen Johnston. The benefit of abemaciclib in prognostic subgroups: An update to the pooled analysis of MONARCH 2 and 3 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT099.

Abstract Background: Abemaciclib is an orally administered, selective inhibitor of cyclin-dependent kinases 4 & 6 that is dosed on a twice daily continuous schedule. Abemaciclib has demonstrated clinical efficacy with a generally tolerable safety profile in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer in combination with fulvestrant in MONARCH 2 (NCT02107703) and in combination with non-steroidal aromatase inhibitors (NSAI) in MONARCH 3 (NCT02246621). These analyses were conducted to evaluate if patient and disease characteristics may better inform in whom and when abemaciclib should be initiated to define optimal treatment strategies. Methods: MONARCH 2 and 3 enrolled patients with HR+, HER2- advanced breast cancer. In MONARCH 2, patients whose disease had progressed while receiving endocrine therapy were treated with abemaciclib/placebo plus fulvestrant. In MONARCH 3, patients were treated with abemaciclib/placebo plus NSAI as initial therapy for advanced disease. An exploratory pooled analysis of the two studies was performed to determine significant prognostic factors. Efficacy results (progression-free survival [PFS] and objective response rate [ORR] in patients with measurable disease) were examined for patient subgroups corresponding to each of the identified significant prognostic factors. Subpopulation treatment effect pattern plot (STEPP) methodology was performed to examine the association between treatment-free interval (TFI) following adjuvant endocrine therapy and outcomes of endocrine therapy alone or in combination with abemaciclib in MONARCH 3. Results: Analyses of clinical factors in over 1000 patients confirmed the following to have prognostic value: bone-only disease, liver metastases, tumor grade, progesterone receptor (PgR) status, and ECOG performance status. Prognosis was poor in patients with liver metastases, PgR-negative tumors, and high-grade tumors. While all subpopulations benefited from the addition of abemaciclib to endocrine therapy regardless of prognosis, substantial benefit of abemaciclib was observed in poor prognosis subgroups, characterized by large increases in PFS (hazard ratios = 0.4 to 0.5) and ORR (over 30%). In addition, STEPP analysis of TFI on a subset of the MONARCH 3 population showed that patients with the shortest TFI appeared to have a poorer prognosis and received more benefit from the addition of abemaciclib compared to patients with longer TFI. Conclusions: This exploratory analysis has provided data that could help optimize treatment strategies by identifying that patients with poor prognostic factors may receive greater benefit from the addition of abemaciclib to endocrine therapy. Citation Format: Goetz MP, O'Shaughnessy J, Sledge Jr. GW, Martin M, Lin Y, Forrester T, Mockbee C, Smith IC, Di Leo A, Johnston S. The benefit of abemaciclib in prognostic subgroups: An exploratory analysis of combined data from the MONARCH 2 and 3 studies [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr GS6-02.

Abstract Background: The need remains for novel agents that prolong survival and/or improve QOL in women with aBC. EP is a long-acting topoisomerase 1 inhibitor engineered to produce sustained exposure to irinotecan and its active metabolite SN38. Given previous efficacy seen in an earlier phase II trial in MBC, EP 145 mg/m2 every 3 weeks was compared to TPC (one of 7 single-agent regimens) in the randomized phase 3 BEACON study (NCT01492101). As reported at ASCO 2015 (abstract 1001), EP prolonged median overall survival by 2.1 months, although this did not reach statistical significance (12.4 vs 10.3 months; HR 0.87, p=0.08). Grade ≥ 3 adverse events were significantly less common with EP (48% vs 63% with TPC, p<0.001). We now present results of the QOL analyses. Methods: Patients completed validated health-related QoL (HRQoL) questionnaires, EORTC QLQ-C30 (version 3.0) and breast cancer-specific QLQ-BR23, pretreatment and every 8 weeks until progression, death or withdrawal of consent. Questionnaires were scored according to the EORTC manual. For each scale, raw scores were standardized via a linear transformation to a range from 0 to 100. Absolute scores and changes from baseline were analyzed longitudinally and categorically using a 5-point difference calculated by treatment group. Comparisons between treatment groups were conducted to evaluate the differences in global health status, functional scores and symptoms over time. Results: The majority of patients who were randomized (total: 733/852 [86%], EP: 378/429 [88%], TPC: 355/423 [84%]) completed at least one post-baseline HRQoL questionnaire. In the EORTC QLQ-C30, grade ≥ 3 AEs significantly impacted HRQoL measured by global health status and 5 additional functional domains. Of the six domains, compared to TPC in a longitudinal analysis, EP was statistically superior in the mean treatment effect through Week 32 in global health status p=0.02 and physical functioning scale p=0.01. EP was also numerically superior in all other scales. In EORTC QLQ-C30 and BR-23, a total of 13 symptoms were measured and categorically analyzed. There were no treatment differences in 7 of 13 symptom scales. EP was associated with worsening of 3 symptom scales: appetite loss, nausea/vomiting, and diarrhea. TPC was associated with worsening of 2 symptom scales: dyspnea and systemic side effects. Conclusions: In the phase 3 BEACON trial comparing EP to TPC, the more favorable toxicity profile of EP resulted in an improvement in global health status and physical function (results of the symptom scales confirmed the different toxicities of the two arms). EP remains a promising investigational therapy for aBC. Citation Format: Cortes J, Awada A, Perez EA, Rugo HS, Twelves C, Im S-A, Zhao C, Hoch U, Ney J, Hannah AL, O'Shaughnessy J. Impact of treatment on quality of life (QOL) in the BEACON study, a randomized phase III trial of etirinotecan pegol (EP) versus treatment of physician's choice (TPC) in patients (pts) with advanced breast cancer (aBC) whose disease has progressed following anthracycline (A), taxane (T) and capecitabine (C). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-11-08.

Purpose This phase III study compared the efficacy and safety of bevacizumab (BV) when combined with several standard chemotherapy regimens versus those regimens alone for first-line treatment of patients with human epidermal growth factor receptor 2–negative metastatic breast cancer. Patients and Methods Patients were randomly assigned in 2:1 ratio to chemotherapy plus BV or chemotherapy plus placebo. Before random assignment, investigators chose capecitabine (Cape; 2,000 mg/m 2 for 14 days), taxane (Tax) -based (nab-paclitaxel 260 mg/m 2 , docetaxel 75 or 100 mg/m 2 ), or anthracycline (Anthra) -based (doxorubicin or epirubicin combinations [doxorubicin/cyclophosphamide, epirubicin/cyclophosphamide, fluorouracil/epirubicin/cyclophosphamide, or fluorouracil/doxorubicin/cyclophosphamide]) chemotherapy administered every 3 weeks. BV or placebo was administered at 15 mg/kg every 3 weeks. The primary end point was progression-free survival (PFS). Secondary end points included overall survival (OS), 1-year survival rate, objective response rate, duration of objective response, and safety. Two independently powered cohorts defined by the choice of chemotherapy (Cape patients or pooled Tax/Anthra patients) were analyzed in parallel. Results RIBBON-1 (Regimens in Bevacizumab for Breast Oncology) enrolled 1,237 patients (Cape cohort, n = 615; Tax/Anthra cohort, n = 622). Median PFS was longer for each BV combination (Cape cohort: increased from 5.7 months to 8.6 months; hazard ratio [HR], 0.69; 95% CI, 0.56 to 0.84; log-rank P < .001; and Tax/Anthra cohort: increased from 8.0 months to 9.2 months; HR, 0.64; 95% CI, 0.52 to 0.80; log-rank P < .001). No statistically significant differences in OS between the placebo- and BV-containing arms were observed. Safety was consistent with results of prior BV trials. Conclusion The combination of BV with Cape, Tax, or Anthra improves clinical benefit in terms of increased PFS in first-line treatment of metastatic breast cancer, with a safety profile comparable to prior phase III studies.

Abstract BackgroundRIBBON-1, a Phase III, multicenter, randomized, placebo-controlled trial in patients with previously untreated MBC was designed to evaluate the efficacy and safety of adding bevacizumab (B) to chemotherapy regimens including capecitabine (Cape; n=615); a taxane (T; n=307), or an anthracycline (Anth; n=315) compared with chemotherapy alone. Pre-specified analyses of progression-free survival PFS) in the Cape and pooled T/Anth cohorts, the primary endpoints of the study were increased upon addition of B. In the Cape cohort, median PFS increased from 5.7 to 8.6 mo (HR=0.69, p-value=0.0002) and in the T/Anth cohort, it increased from 8.0 to 9.2 mo (HR=0.64; p-value&lt;0.0001).MethodsRECIST was used to determine objective response rate (ORR). Patients without a post-baseline tumor assessment were considered non-responders. The primary analysis for the ORR and the duration of response was performed using only patients with measurable disease at baseline. ORR was formally compared between the two treatment arms using the Mantel-Haenszel Chi-squared test, using the randomization stratification factors. Fisher's exact test was also performed. Clinical benefit rate (CBR) was defined as the proportion of patients with a complete or partial response or with stable disease at Week 24. Exploratory analyses of CBR and time to response are provided here. Summary statistics of time to response at Week 9 will be presented as will the final analysis of the secondary endpoint of overall survival.ResultsAnalyses of ORR and CBR are provided in the following table. CapeTaxaneAnth PL (n=206)B (n=409)PL (n=104)B (n=203)PL (n=103)B (n=212)Patients with measurable disease, n (%)161 (78.2)325 (61.1)85 (81.7)161 (79.3)92 (89.3)184 (86.8)ORR, %23.635.435.350.340.252.2CR, n (%)1 (0.6)7 (2.2)3 (3.5)4 (2.5)2 (2.2)3 (1.6)PR, n (%)37 (23.0)108 (33.2)27 (31.8)77 (47.8)35 (38.0)93 (50.5)Difference between arms, %11.815.012.0p-value, unstratified0.00940.030.073Duration of ORMedian, mo7.29.28.68.46.08.1HR (95% CI)0.61 (0.39–0.96)0.75 (0.45–1.27)0.53 (0.34–0.83)Log-rank p-value0.03260.2840.0047Clinical benefit rate*, %47.164.365.471.969.980.7p-value, unstratified&lt;0.00010.240.04CR+PR at Week 9, %20.229.438.354.544.451.1B=bevacizumab, cape=capecitabine, CI=confidence interval, HR=hazard ratio, OR=objective response, PL=placebo, T/Anth=taxane/anthracycline.*For randomized patients.ConclusionsIn patients with HER2-negative MBC, the addition of bevacizumab to capecitabine, taxane or anthracycline chemotherapy induces more responses and those responses occur more rapidly. For capecitabine and anthracycline the addition of bevacizumab leads to objective responses that last longer. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6084.

AbstractThis article reviews progress in chemopreventive drug development, especially data and concepts that are new since the 2002 AACR report on treatment and prevention of intraepithelial neoplasia. Molecular biomarker expressions involved in mechanisms of carcinogenesis and genetic progression models of intraepithelial neoplasia are discussed and analyzed for how they can inform mechanism-based, molecularly targeted drug development as well as risk stratification, cohort selection, and end-point selection for clinical trials. We outline the concept of augmenting the risk, mechanistic, and disease data from histopathologic intraepithelial neoplasia assessments with molecular biomarker data. Updates of work in 10 clinical target organ sites include new data on molecular progression, significant completed trials, new agents of interest, and promising directions for future clinical studies. This overview concludes with strategies for accelerating chemopreventive drug development, such as integrating the best science into chemopreventive strategies and regulatory policy, providing incentives for industry to accelerate preventive drugs, fostering multisector cooperation in sharing clinical samples and data, and creating public-private partnerships to foster new regulatory policies and public education.