Abstract OT2-01-02: The SMILE Study: A phase II trial of onapristone in combination with fulvestrant for patients with ER-positive and HER2-negative metastatic breast cancer after progression on endocrine therapy and CDK 4/6 inhibitors

Background Antiprogestins, including selective progesterone receptor (PgR) modulators (SPRMs) that act as PgR antagonists, are a promising class of therapeutics for overcoming endocrine resistance including in patients who develop activating estrogen receptor alpha (ESR1) mutations after prior endocrine therapy (ET). The SMILE study is a multi-institutional phase II clinical trial to determine the efficacy and safety of an antiprogestin, onapristone in combination with fulvestrant as second-line therapy for patients with ER+,PgR+/-, HER2 -metastatic breast cancer (MBC). Methods Patients with locally advanced or MBC who progress on ≥2 lines of prior therapy with ET as a single agent or in combination with CDK4/6 inhibitors, mTOR inhibitors and one line of chemotherapy in the metastatic setting are eligible. Other criteria include ECOG performance status ≤ 2, measurable disease per RECIST 1.1 criteria, adequate organ function, availability of an archived tumor biopsy block confirming the diagnosis of MBC, optional biopsy at disease progression on trial, and optional 18F-fluorofuranylnorprogesterone (18F-FFNP) PET/CT imaging. Ovarian suppression is allowed. Prior ET with tamoxifen or aromatase inhibitor therapy in the adjuvant or metastatic setting is allowed. Patients with prior exposure to fulvestrant, antiprogestins, or CDK inhibitors in the adjuvant setting are ineligible. Following consent, all subjects will receive fulvestrant at the recommended dosing schedule plus onapristone 50 mg orally, twice daily, until disease progression, unacceptable toxicity, or discontinuation for any other reason. Using the Simon Two-Stage design, a total of 39 patients will be enrolled over two years from 6-8 sites within Wisconsin Oncology Network (WON); study enrollment began in November 2021. In the first stage of the trial, thus far, nine patients were accrued who are tolerating the trial regimen well with no reported toxicities or serious events. The safety monitoring is planned when the cohort size reaches eleven patients, and interim analysis at 21 patients; if ≥2 responses are observed, then 18 additional subjects will be enrolled in the second stage. This design yields a one-sided type I error rate of 5% if the ORR is 7% and power of 80% when the combination’s true response rate is 20%. The primary objective is to evaluate the objective response rate; secondary objectives include safety and tolerability, progression-free survival, disease control rate, and duration of response. Other correlates include optional functional imaging of PgR binding with 18F-FFNP PET/CT and biomarker analysis (ER, total PgR, HER2, Ki67, CD24, CD44, LDH1, KLF4, CK 5/6, PhosphoSer294-PgR on tissue samples, ESR1 mutations, and circulating tumor DNA analysis).

Citation Format: Sailaja Kamaraju, Amy Fowler, Lubna N. Chaudhary, Mark Burkard, Thomas Giever, Robert N Hegeman, Michele Pipp-Dahm, Yee Chung Cheng, Carol Lange, Julie M. Jorns, Amy Stella, Nauman Siddiqui, Luke Zurbriggen, Saurabh Rajguru, Sergey Tarima, Deepika Sriram, Janet Retseck, Hallgeir Rui, Tarek Sahmoud, Kari B. Wisinski. The SMILE Study: A phase II trial of onapristone in combination with fulvestrant for patients with ER-positive and HER2-negative metastatic breast cancer after progression on endocrine therapy and CDK 4/6 inhibitors [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT2-01-02.

Abstract OT2-01-04: ELONA: An open-label, phase 1b-2 study of elacestrant, in combination with onapristone in patients with estrogen receptor-positive, progesterone receptor-positive, HER2-negative advanced or metastatic breast cancer

Objectives: The addition of a CDK 4/6 inhibitors to endocrine therapy, in the first or second line setting, provides a significant improvement in progression free survival (PFS), and in some cases in overall survival (OS), with a tolerable toxicity profile. Regardless, most patients experience disease progression on these agents and ultimately develop endocrine resistance, thus, emphasizing the critical need for novel treatments. Elacestrant showed a statistically significant improvement in PFS when compared to standard of care endocrine therapy after progression on CDK4/6 inhibitors in combination with endocrine therapy (Bidard et al, 2022). Onapristone is a type I antiprogestin which prevents the progesterone receptor (PgR) from dimerizing and blocks ligand-induced protein kinase-mediated phosphorylation of the PgR. The clinical anticancer activity of onapristone, in immediate release formulation, has been previously documented in patients with hormone therapy-naïve (Robertson et al, 1999) or tamoxifen-resistant (Jonat et al, 2002) breast cancer (BC). More recently, onapristone, in extended release formulation, was evaluated in doses up to 50 mg BID in a phase 1 trial that enrolled 52 heavily pretreated patients with metastatic solid tumors, with no dose limiting toxicity observed. Among the 20 breast cancer patients enrolled, 7 (35%) had stable disease (Cottou et al, 2018). Methods: ELONA is a phase 1b/2, open-label, multicenter study. The phase 1b portion of the study will assess the safety, pharmacokinetics (PK), pharmacodynamics, and preliminary efficacy of elacestrant plus onapristone to determine the combinations’ recommended phase 2 dose. The primary endpoint of the phase 2 part of the trial is objective response rate and secondary endpoints will include safety, duration of response, clinical benefit rate, PFS, and OS, in addition to pharmacodynamics markers using ctDNA. Eligible patients are pre-, peri- and post-menopausal women and men aged ≥18 years with ER+/PgR+,HER2- tumors and an Eastern Cooperative Oncology Group performance status ≤2 with at least one measurable lesion at baseline, as per RECIST version 1.1. Prior therapy in the metastatic setting includes at least one anti-hormonal therapy in combination with a CDK4/6i. No prior chemotherapy regimen in the metastatic setting is allowed. The phase 1b dose-escalation portion of the study will evaluate dose-limiting toxicities (DLTs) of the combination in up to 4 cohorts of 6 patients each.

Citation Format: Erika Hamilton, Lajos Pusztai, Hatem H. Soliman, Sara Hurvitz, Krzysztof Grzegorzewski, Nassir Habboubi, Priya Marreddy, Tarek Sahmoud, Nuhad Ibrahim. ELONA: An open-label, phase 1b-2 study of elacestrant, in combination with onapristone in patients with estrogen receptor-positive, progesterone receptor-positive, HER2-negative advanced or metastatic breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT2-01-04.

Abstract GS3-01: GS3-01 EMERALD phase 3 trial of elacestrant versus standard of care endocrine therapy in patients with ER+/HER2- metastatic breast cancer: Updated results by duration of prior CDK4/6i in metastatic setting

Background: In patients (pts) with ER+/HER2− metastatic breast cancer (MBC) following progression on prior endocrine and CDK4/6i therapy, the EMERALD trial demonstrated significantly prolonged progression-free survival (PFS) and a manageable safety profile for elacestrant versus standard of care endocrine therapy (SoC). Benefit was observed in all pts and in pts with ESR1 mutant MBC (ESR1-mut). EMERALD is the only oral SERD monotherapy pivotal trial where all pts were pretreated with CDK4/6 inhibitor (CDK 4/6i). Here, we examine the impact of duration of prior CDK4/6i on PFS.

Methods: EMERALD (NCT03778931) is a randomized, open-label, phase 3 trial that enrolled pts with ER+/HER2- MBC who previously had 1-2 lines of endocrine therapy, mandatory CDK4/6i, and ≤1 chemotherapy; prior treatment with fulvestrant was allowed. Patients were randomized 1:1 to elacestrant (400 mg orally daily) or SoC (investigator’s choice of aromatase inhibitor or fulvestrant). If randomized to the control arm, patients who received prior fulvestrant were to receive an aromatase inhibitor, and vice versa. If two CDK4/6i were used in the metastatic setting (n=40), the cumulative duration was calculated.

Results: A total of 478 pts were randomized (228 with ESR1-mut) between Feb 2019 – Oct 2020 (n=239, elacestrant; n=239, SoC). Overall survival was not yet mature, as of September 2nd 2022. Updated PFS results show statistically significant results in favor of elacestrant, both in all pts and in pts with ESR1-mut. The duration of prior CDK4/6i in the metastatic setting was positively associated with PFS, the longer the duration of prior CDK4/6i in the metastatic setting (n=465), the longer the PFS on elacestrant versus SoC (Table 1).

Updated safety data were consistent with previously reported results. Most of the adverse events (AEs), including nausea, were grade 1 and 2, and only 3.4% and 0.9% of the pts discontinued trial therapy because of an AE on elacestrant and SoC, respectively. A low percentage of pts received an antiemetic; 8.0%, 3.7%, and 10.3%, on elacestrant, fulvestrant, and AI, respectively. No hematological safety signal was observed and none of the patients in either of the two treatment arms had sinus bradycardia.

Conclusions: EMERALD is the first phase 3 trial to demonstrate a significant PFS improvement versus SoC in all pts and in the subgroup with ESR1 mutations in pts with ER-positive/HER2-negative MBC with 1-2 prior lines of endocrine treatment ± one line of chemotherapy. Elacestrant demonstrated longer PFS versus SOC that was positively associated with the duration of prior treatment with CDK4/6i, which was more pronounced in pts with ESR1-mut MBC. In this 2nd and 3rd line setting, elacestrant was well tolerated with significantly longer PFS versus SoC, highlighting its potential role as a therapeutic option for pts with ER+/HER2- MBC.

Table 1: PFS estimates in the elacestrant and SoC arms based on different cut-off points for the duration of prior CDK4/6i.

Citation Format: Aditya Bardia, Francois-Clement Bidard, Patrick Neven, Guillermo Streich, Alberto J. Montero, Frederic Forget, Marie-Ange Mouret-Reynier, Joo Hyuk Sohn, Donatienne Taylor, Kathleen K. Harnden, Hung Khong, Judit Kocsis, Florence Dalenc, Patrick Dillon, Sunil Babu, Simon Waters, Ines Deleu, Jose Angel García-Sáenz, Emilio Bria, Marina Elena Cazzaniga, Philippe Aftimos, Javier Cortés, Giulia Tonini, Tarek Sahmoud, Nassir Habboubi, Krzysztof Grzegorzewski, Virginia Kaklamani. GS3-01 EMERALD phase 3 trial of elacestrant versus standard of care endocrine therapy in patients with ER+/HER2- metastatic breast cancer: Updated results by duration of prior CDK4/6i in metastatic setting [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS3-01.

Abstract OT2-01-03: ELEVATE: A phase 1b/2, open-label, umbrella study evaluating elacestrant in various combinations in women and men with metastatic breast cancer (mBC)

Background: Elacestrant demonstrated significantly prolonged progression-free survival (PFS) and a manageable safety profile compared with standard of care endocrine therapy in the phase 3 EMERALD trial that enrolled patients with estrogen-receptor positive (ER+)/HER2− mBC following disease progression on prior endocrine and cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) therapy. Benefit was observed in the overall population and in patients with ESR1 mutations. Combining elacestrant with targeted agents utilized in combination with endocrine therapy in mBC is of therapeutic interest. Methods: ELEVATE is a phase 1b/2 trial designed to evaluate the combination of elacestrant with alpelisib, everolimus, palbociclib, abemaciclib, or ribociclib. Eligible patients (pts) are women or men with ER+/HER2− locally advanced or mBC, measurable disease per RECIST v1.1 or ≥1 lytic or mainly lytic bone lesion, ECOG PS ≤1, no inflammatory breast cancer or uncontrolled central nervous system metastases, in addition to treatment-arm specific eligibility criteria as detailed below. In the phase 1b portion, pts who have received prior aromatase inhibitor (AI) and CDK4/6i will be enrolled in three 6-patient cohorts for each combination except abemaciclib (under study in a separate trial). Patients will receive elacestrant with the targeted agent at reduced or full doses. The primary endpoint of phase 1b is to determine the recommended phase 2 dose for each combination. Secondary endpoints are safety, pharmacokinetics, pharmacodynamics, and efficacy (objective response rate [ORR], duration of response [DoR], clinical benefit rate [CBR], PFS, and overall survival [OS]). The phase 2 portion will enroll 5 separate arms: A) pts with PIK3CA mutation(s) and prior AI + CDK4/6i: alpelisib + elacestrant, n=50; B) pts with prior AI + CDK4/6i: everolimus + elacestrant, n=50; C) pts with prior AI + CDK4/6i: abemaciclib or ribociclib (investigator’s [inv] choice) + elacestrant, n=60 (30 per combination); D) pts with prior AI only (no CDK4/6i): palbociclib, abemaciclib or ribociclib (inv choice) + elacestrant, n=90 (n=30 per combination); E) pts with no prior systemic therapy: palbociclib or ribociclib (inv choice) + elacestrant, n=90 (n=45 per combination). No prior fulvestrant or chemotherapy is allowed in any arm and no more than 2 prior hormonal therapies are permitted in arms A-D. Prior therapy restrictions apply to the mBC setting or within 12 months of adjuvant therapy. The primary endpoint for the phase 2 portion is the estimation of PFS at 6 months in arms A, B, and C and at 12 months in arms D and E. Secondary endpoints will include ORR, DoR, CBR, PFS, OS, and safety. The Kaplan-Meier method will be used to estimate PFS. Descriptive statistics will be used to evaluate response and safety.

Citation Format: Hope Rugo, Aditya Bardia, Javier Cortés, Giuseppe Curigliano, Erika Hamilton, Sara Hurvitz, Sibylle Loibl, Simona Scartoni, Tarek Sahmoud, Krzysztof Grzegorzewski, Nassir Habboubi, Joyce O’Shaughnessy. ELEVATE: A phase 1b/2, open-label, umbrella study evaluating elacestrant in various combinations in women and men with metastatic breast cancer (mBC). [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT2-01-03.

Covalent ERα Antagonist H3B-6545 Demonstrates Encouraging Preclinical Activity in Therapy-Resistant Breast Cancer

Nearly 30% of patients with relapsed breast cancer present activating mutations in estrogen receptor alpha (ERα) that confer partial resistance to existing endocrine-based therapies. We previously reported the development of H3B-5942, a covalent ERα antagonist that engages cysteine-530 (C530) to achieve potency against both wild-type (ERαWT) and mutant ERα (ERαMUT). Anticipating that the emergence of C530 mutations could promote resistance to H3B-5942, we applied structure-based drug design to improve the potency of the core scaffold to further enhance the antagonistic activity in addition to covalent engagement. This effort led to the development of the clinical candidate H3B-6545, a covalent antagonist that is potent against both  ERαWT/MUT, and maintains potency even in the context of ERα C530 mutations. H3B-6545 demonstrates significant activity and superiority over standard-of-care fulvestrant across a panel of ERαWT and ERαMUT palbociclib sensitive and resistant models. In summary, the compelling preclinical activity of H3B-6545 supports its further development for the potential treatment of endocrine therapy-resistant ERα+ breast cancer harboring wild-type or mutant ESR1, as demonstrated by the ongoing clinical trials (NCT03250676, NCT04568902, NCT04288089).

SUMMARY

H3B-6545 is an ERα covalent antagonist that exhibits encouraging preclinical activity against CDK4/6i naïve and resistant ERαWT and ERαMUT tumors.

Abstract P1-17-03: H3B-6545 in combination with palbociclib in women with metastatic estrogen receptor-positive (ER+), human epidermal growth factor receptor 2 (HER2)-negative breast cancer, phase 1b study

Background: H3B-6545, a novel Selective ERα Covalent Antagonist (SERCA), inactivates both mutant and wild-type ERα by targeting cysteine 530 and enforcing antagonist conformation. It demonstrated a manageable safety profile and single-agent antitumor activity in heavily pretreated ER+, HER2- mBC patients (pts) (Hamilton et al, ASCO, 2021). Methods: The study aims at determining the recommended phase II doses of the combination of H3B-6545 and palbociclib in pts with ER+, HER2- mBC. Other endpoints include safety, pharmacokinetics, and preliminary efficacy. The escalation phase enrolls pts with at least 2 prior therapies in the metastatic setting. Up to one prior chemotherapy and up to one prior CDK4/6 inhibitor are allowed. Each cohort enrolled 6 pts to ensure availability of sufficient PK data. During the first cycle, H3B-6545 was added to palbociclib on day 9. Dose-limiting toxicities (DLTs) were assessed during the first 28 days starting from the 1st day of adding H3B-6545 to palbociclib (cycle 1 day 9 to cycle 2 day 8). Both drugs were started on day 1 of each of the subsequent cycles. Results: As of June 15, 2021, 14 pts were enrolled: 7 in Cohort 1 (H3B-6545 300 mg QD and palbociclib 100 mg QD) and 7 in Cohort 2 (H3B-6545 300 mg QD and palbociclib 125 mg QD). Median age was 61 years (range: 28-75 years), ECOG performance status was 0 in 7 pts (50%) and 1 in 7 pts (50%) and 9 pts (64%) had lung and/or liver metastases. Median number of prior therapies in the metastatic setting was 3 (range: 1-6). Prior therapy in the metastatic setting included fulvestrant (93%), CDK4/6 inhibitors (79%), aromatase inhibitors (64%), and chemotherapy (29%). One pt in each Cohort was not evaluable for dose limiting toxicity (DLT) assessment and no DLTs were observed in the first 2 Cohorts. Seven pts discontinued study treatment because of progression and 1 pt discontinued due to diagnosis of a second primary cancer during the first cycle. Non-hematological grade 2 or higher adverse events (AE), irrespective of causality, reported in ≥2 pts were: nausea, vomiting, abdominal pain, and bone pain, each observed in 2 pts (14%). Gr. 1 and 2 sinus bradycardia were reported in 6 (43%) and 1 pts (7%), respectively. One pt (7%) had grade 1 QT prolongation. No grade 4 AEs or treatment-related deaths were reported. For hematology and chemistry laboratory abnormalities: gr. 3 and 4 neutropenia in 7 pts (50%) and 2 pts (14%), respectively, gr. 3 thrombocytopenia in 1 pt (7%), gr. 3 anemia in 2 pts (14%). Grade 2 decrease in estimated glomerular filtration rate was observed in 7 pts (50%), all reported irrespective of causality. Co-administration of palbociclib had no meaningful impact on H3B-6545 exposure (15% and 21% increase in geometric means of AUC and Cmax, respectively). Co-administration of H3B-6545 modestly increased palbociclib exposure (49% and 36% increase in geometric means of AUC and Cmax, respectively). Among 6 response-evaluable pts in Cohort 1, 2 pts (33%) had confirmed partial responses and 4 pts (67%) had stable disease. Both responding pts received prior therapy with a CDK4/6 inhibitor and fulvestrant. Cohort 2 efficacy data is not yet mature. Recruitment is currently ongoing in Cohort 3 (H3B-6545 450 mg QD and palbociclib 125 mg QD). Conclusions: The combination of H3B-6545 (up to 300 mg dose) and palbociclib (up to 125 mg dose) was well-tolerated and demonstrated preliminary anti-tumor activity in heavily pretreated pts with ER+, HER2- mBC. ClinicalTrials.gov Identifier: NCT04288089.

Citation Format: Stephen Johnston, Timothy J Pluard, Judy S Wang, Erika P Hamilton, Dejan Juric, Catherine R Scholz, Elizabeth Hnitecki, Sara Dar, Lei Gao, Lisa Cantagallo, Manav Korpal, Jianjun Alan Xiao, Lihua Yu, Tarek Sahmoud, Antonio Gualberto. H3B-6545 in combination with palbociclib in women with metastatic estrogen receptor-positive (ER+), human epidermal growth factor receptor 2 (HER2)-negative breast cancer, phase 1b study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-17-03.

Abstract OT2-16-01: The SMILE study: A phase 2 trial of onapristone in combination with fulvestrant for patients with ER+ and HER2- metastatic breast cancer after progression on endocrine therapy and CDK4/6 inhibitors

Background Antiprogestins, including selective progesterone receptor (PgR) modulators (SPRMs) that act as PgR antagonists, are a promising class of therapeutics for overcoming endocrine resistance including in patients who develop activating estrogen receptor 1 (ESR1) mutations after prior endocrine therapy (ET). The SMILE study (NCT04738292) is a multi-institutional phase II clinical trial to determine the efficacy and safety of an antiprogestin, onapristone in combination with fulvestrant as second-line therapy for patients with ER+,PgR+, HER2 -metastatic breast cancer (MBC). Methods Patients with locally advanced or MBC who progress on ≥2 lines of prior therapy with ET as a single agent or in combination with CDK4/6 inhibitors, mTOR inhibitors and one line of chemotherapy in the metastatic setting are eligible. Other criteria include ECOG performance status ≤ 2, measurable disease per RECIST 1.1 criteria, adequate organ function, availability of an archived tumor biopsy block confirming the diagnosis of MBC, optional biopsy at disease progression on trial, and optional 18F-fluorofuranylnorprogesterone (18F-FFNP) PET/CT imaging. Ovarian suppression is allowed. Prior ET with tamoxifen or aromatase inhibitor therapy in the adjuvant or metastatic setting is allowed. Patients with prior exposure to fulvestrant, antiprogestins, or CDK inhibitors in the adjuvant setting are ineligible. Following consent, all subjects will receive fulvestrant at the recommended dosing schedule plus onapristone 50 mg orally, twice daily, until disease progression, unacceptable toxicity, or discontinuation for any other reason. Using the Simon Two-Stage design, a total of 39 patients will be enrolled over two years from 6-8 sites within Wisconsin Oncology Network (WON). In the first stage of the trial, 21 subjects will be enrolled; if ≥2 responses are observed, then 18 additional subjects will be enrolled in the second stage. This design yields a one-sided type I error rate of 5% if the ORR is 7% and power of 80% when the combination's true response rate is 20%. The primary objective is to evaluate the objective response rate; secondary objectives include safety and tolerability, progression-free survival, disease control rate, and duration of response. Other correlates include optional functional imaging of PgR binding with 18F-FFNP PET/CT and biomarker analysis (ER, total PgR, HER2, Ki67, CD24, CD44, LDH1, KLF4, CK 5/6, PhosphoSer294-PgR on tissue samples, ESR1 mutations, and circulating tumor DNA analysis). The study was approved in January 2021, and enrollment is active at the time of this submission.

Citation Format: Sailaja Kamaraju, Amy Fowler, Chung Yee Cheng, Lubna N Chaudhary, John Burfeind, Janet Retseck, Amye J Tevaarwerk, Mark Burkard, Elisavet Paplomata, Amanda M Parkes, Julie M Jorns, Sergey Tarima, Douglas Yee, Hallgeir Rui, Carol Lange, Tarek Sahmoud, Kari B Wisinski. The SMILE study: A phase 2 trial of onapristone in combination with fulvestrant for patients with ER+ and HER2- metastatic breast cancer after progression on endocrine therapy and CDK4/6 inhibitors [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT2-16-01.

Phase 1b study of H3B-6545 in combination with palbociclib in women with metastatic estrogen receptor–positive (ER+), human epidermal growth factor receptor 2 (HER2)-negative breast cancer

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Background: H3B-6545, a highly Selective ERα Covalent Antagonist (SERCA), inactivates both wild-type and mutant ERα by targeting cysteine 530 and enforcing a unique antagonist conformation. At the dose of 450 mg daily, H3B-6545 has a manageable safety profile and demonstrated preliminary single-agent antitumor activity in heavily pretreated ER+, HER2- mBC patients (Hamilton et al, San Antonio Breast Cancer Symposium, 2020). Methods: The study evaluates the safety, pharmacokinetics (PK), and efficacy of H3B-6545 in combination with palbociclib in patients with ER+, HER2- metastatic breast cancer (MBC). The escalation phase enrolls patients with 2 or more prior therapies in the metastatic setting. Up to one prior chemotherapy and up to one prior CDK4/6 inhibitor were allowed. Results: As of January 31, 2021, 10 patients were enrolled; 7 in Cohort 1 (H3B-6545 300 mg QD and palbociclib 100 mg QD) and 3 in Cohort 2 (H3B-6545 300 mg QD and palbociclib 125 mg QD). One patient in Cohort 1 was not evaluable for dose limiting toxicity (DLT) assessment and no DLT was observed in the 6 evaluable patients. One patient discontinued study treatment because of progression and no patients discontinued study treatment due to adverse events (AE). Grade 3 or 4 neutropenia and thrombocytopenia were observed in 4 patients and 1 patient, respectively. One patient had grade 3 hypercalcemia, generalized muscle weakness, hypophosphatemia, fall, and anemia and one patient had grade 3 lipase increase. Four patients had grade 1 bradycardia or sinus bradycardia (asymptomatic) 1 patient had grade 2 sinus bradycardia (symptomatic, no intervention required). Preliminary PK analysis suggested no clinically relevant drug-drug interactions between H3B-6545 and palbociclib, to be confirmed with data from additional cohorts. Recruitment is currently ongoing in Cohort 2. Updated results will be presented. Conclusions: H3B-6545, in combination with palbociclib, was well-tolerated. Clinical trial information: NCT04288089.

Relative bioavailability of H3B-6545 tablets versus capsules and drug-drug interaction between H3B-6545 and pantoprazole

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Background: H3B-6545 is a selective, orally available, small molecule antagonist of the estrogen receptor (ER), covalently binding to a cysteine residue at position 530 of both wild-type and the constitutively active mutant ERα proteins. H3B-6545 demonstrated preliminary clinical antitumor activity in breasts cancer patients in phase 1b/2. Methods: This was an open-label phase 1 study to evaluate the relative bioavailability of H3B-6545 from a tablet formulation compared to capsules, and the effect of pantoprazole on the pharmacokinetics of H3B-6545, in healthy post-menopausal women. Subjects were randomized (1:1 ratio) to a combined crossover and fixed sequence 3 periods treatment: A single oral dose (SOD) of 450 mg H3B-6545 fasted on day 1 (capsules or tablets), followed by a 4-day washout; A SOD of 450 mg H3B-6545 fasted on day 5 (crossover formulation from the first period), followed by a 4-day washout; daily oral doses of 40 mg pantoprazole on days 9 to 15 with coadministration of a SOD of 450 mg H3B-6545 (tablets) on day 15. Results: A total of 16 subjects were enrolled and received at least one dose of H3B-6545 and 15 subjects completed all 3 periods. One subject assigned to the tablet/capsule treatment sequence withdrew from the study due to subject decision on day 13 (Period 3), following completion of Period 1 (H3B-6545 tablet) and Period 2 (H3B-6545 capsule). Following a SOD of H3B-6545 capsules alone, tablets alone, or tablets at steady-state QD of pantoprazole, H3B-6545 geometric mean Cmax was about 1070, 1120 and 1330 ng/mL, respectively, AUC was about 16600, 17500 and 18300 ng.h/mL, respectively, half-life was about 11.0, 11.0 and 10.2 hours, respectively, and the median Tmax was about 3.0, 4.0, and 2.0 hours post dose, respectively. The ratio (capsule/tablet) of Cmax and AUC was both about 0.95; steady-state pantoprazole QD increased H3B-6545 Cmax by 20% with no change in AUC. Nine subjects (56.3%) reported at least 1 TEAE during the study with constipation being the most common (43.8%); all TEAEs were mild in severity. There were no SAEs reported. Conclusions: Plasma PK of H3B-6545 is similar between tablets and capsules, and in the absence or presence of pantoprazole. Concurrent use of gastric acid reducers had a minimal effect on H3B-6545 exposure and was not considered clinically meaningful.

Abstract PS12-15: Pharmacokinetics of H3B-6545 in patients with locally advanced or metastatic estrogen receptor-positive HER2 negative breast cancer (ER+ and HER2- BC)

RATIONALE: Addition of CDK 4/6 inhibitors to endocrine therapy has become standard for patients (pts) with ER+ and HER2- BC with improvements in overall survival. However, acquired resistance to front-line therapy is inevitable, and response to later-line therapy is poor. H3B-6545 is a selective, orally available, small molecule covalent antagonist of the estrogen receptor (ERα). H3B-6545 binds covalently to a cysteine residue at position 530 of both wild-type and the constitutively active mutant ERα proteins. H3B-6545 demonstrated significant antitumor activity in multiple PDX breast cancer models, including those with mutated ESR1 (the gene encoding ERα). A phase I-II study was conducted to explore the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics, and efficacy of this agent in advanced ER+ and Her2- breast cancer pts (NCT03250676). METHODS: PK samples in phase I were obtained at day 1 and day 15 of cycle 1 (Predose, 0.5, 1, 2, 4, 6, 8, 10, and 24 h post dose) and sparse PK samples were collected in the phase II part of the trial. For pts enrolled in the food effect sub-study of phase II, plasma samples were collected during cycle 1 on day 15 and day 22 (Predose, 0.5, 1, 2, 4, 6, 8, 10, and 24 h post dose). Nonlinear mixed effect model (NONMEM) was applied for development of population PK models to fit H3B-6545 plasma concentration data with NONMEM® version 7.4 software. R was used for data management, visualization and statistical summaries. RESULTS: This phase I-II trial enrolled 47 pts in phase I part and 83 pts in the phase II part at the recommended phase II dose of 450 mg QD as of May 15, 2020. The 1180 plasma concentrations of H3B-6545 from a total of 103 pts at doses of 100-600 mg available as of January 15, 2020 were included in this analysis, with the following characteristics [n or (median, min-max) unit]: race (n=91/5/1/6 for White/Black/Asian/others), age (62.5, 31-81) yrs, body weight (79.5, 49-140) Kg, BMI (26.9, 17.6-45.6) Kg/m2, albumin (40, 29-52) g/dL, ALP (88.5, 39-917) IU/L, ALT (28, 10-193) IU/L, AST (36.5, 13-259) IU/L, bilirubin (8.6, 1.7-25.7) µM and creatinine clearance (112, 49.5-389) mL/min. The median number of prior therapy in the metastatic setting was 3 (range: 1 - 10). Out of 103 patients, 32 pts received treatment with a single high-fat meal to test food effect on PK over a randomized crossover design. H3B-6545 plasma concentrations were best described with a one compartment disposition PK model, plus a combined first- and zero-order parallel absorption and lag time. The estimated apparent clearance (CL/F) and volume of distribution (V/F) were 31 L/h and 422 L, respectively, with a typical terminal half-life of about 10 hours. H3B-6545 was absorbed fast, with a typical tmax of about 4 hours. A moderate to high variability (40-60%) was identified in major PK parameters (CL/F, V/F, bioavailability [F1]). A high-fat meal increased bioavailability by approximately 45% and prolonged tmax, roughly from 4 hours to 6 hours post dose. No significant effect was identified from other covariates: age, body weight, race, albumin, AST, ALP, ALT, bilirubin and creatinine clearance. CONCLUSIONS: H3B-6545 PK profiles in breast cancer patients were well described by a one-compartment disposition model with no significant effect of demographics, liver and renal function. When administered with a high fat meal, H3B-6545 exposure was modestly increased.

Citation Format: Oneeb Majid, Jianjun Alan Xiao, Tarek Sahmoud, Sanae Yasuda, Lisa Cantagallo, Erika P Hamilton, Timothy Pluard, Dejan Juric, Antonio Gualberto, Ziad Husseiin. Pharmacokinetics of H3B-6545 in patients with locally advanced or metastatic estrogen receptor-positive HER2 negative breast cancer (ER+ and HER2- BC) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS12-15.

Abstract PS12-23: Development of H3B-6545, a first-in-class oral selective ER covalent antagonist (SERCA), for the treatment of ERaWT and ERaMUT breast cancer

Mutations in the ligand-binding domain of estrogen receptor alpha (ERα) are detected in up to 30% of patients (pts) who have relapsed or progressed during endocrine therapy. By favoring the agonistic conformation in ERα, these hotspot mutations promote ligand-independent activation of ERα and confer partial resistance to ER-directed therapies. Of the various hotspot mutations, Y537S is the most constitutively active, promotes the greatest resistance phenotype to current endocrine therapies, and is associated with the worst prognosis relative to other ERα mutations. The fact that current ER-directed therapies have limited activity in the ERα mutant setting emphasizes the critical need to develop the next generation of high affinity ER antagonists that can overcome the aberrant activity of mutant ERα.

H3B-6545 is a first-in-class selective ERα covalent antagonist (SERCA) which inactivates both wild-type and mutant ERα by irreversibly engaging cysteine-530. Biophysical and biochemical analyses confirm the long residence time achieved by covalent binding, and cellular analyses confirm the selectivity and single-digit nanomolar potency of H3B-6545 across a panel of ERαWT and ERαMUT breast cancer cell lines. H3B-6545 as a monotherapy demonstrates superior anti-tumor activity relative to fulvestrant across a set of CDK4/6 inhibitor naïve ERαWT and ERαY537S cell line-derived xenograft (CDX)/patient-derived xenograft (PDX) models, with regressions being noted in both the ERαWT and ERαMUT settings. Furthermore, H3B-6545 continues to demonstrate single agent activity in CDK4/6 inhibitor-resistant ERαWT and ERαY537S PDX models, in which fulvestrant fails to demonstrate significant anti-tumor activity. Lastly, improved activity and duration of response are noted when H3B-6545 is combined with several targeted therapies, including CDK4/6 inhibitors palbociclib and abemaciclib across a range of ERαWT and ERαY537S CDX/PDX models.

The phase I-II trial (NCT03250676) enrolled 130 heavily pretreated pts with ER+, HER2- metastatic breast cancer, including 12 pts harboring high allele frequency clonal ESR1 Y537S circulating tumor DNA (ctDNA). Median number of prior therapy in the metastatic setting was 3 (range: 1-10). Consistent with the preclinical data, H3B-6545 demonstrated promising clinical activity among these pts with clonal Y537S mutations, with a median progression free survival of 7.3 months and an overall response rate of 25% (3 confirmed partial responses).

In summary, these compelling preclinical data coupled with emerging clinical activity in heavily pretreated poor prognosis pts support further development of H3B-6545 as monotherapy or combination treatment.

Citation Format: Manav Korpal, Craig Furman, Xiaoling Puyang, Zhaojie Zhang, Zhenhua Wu, Deepti Banka, Subhasree Das, Benoit Destenaves, Lei Gao, Erika Hamilton, Ming-Hong Hao, Sean Irwin, Stephen Johnston, Jaya J Joshi, Dejan Juric, Amy Kim, Tuong-Vi Nguyen, Marc Pipas, Timothy Pluard, Victoria Rimkunas, Nathalie Rioux, Joanne Schindler, Peter Smith, Michael Thomas, John Wang, Judy S Wang, Markus Warmuth, Huilan Yao, Shihua Yao, Lihua Yu, Frédéric H Vaillancourt, David M Bolduc, Nicholas A Larsen, GuoZhu Zheng, Sudeep Prajapati, Tarek Sahmoud, Antonio Gualberto, Ping Zhu. Development of H3B-6545, a first-in-class oral selective ER covalent antagonist (SERCA), for the treatment of ERaWT and ERaMUT breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS12-23.

Evaluation of Clinical Efficacy of New Medical Treatments in Advanced Colorectal Cancer. Results of a Workshop Organized by the Eortc Gitccg

During the last few years several factors have contributed to an increasing change in the medical treatment of advanced colorectal cancer. Among them are the more general acceptance of the impact of chemotherapy on quality of life and survival in first as well as in second-line treatment, the introduction of new drugs and the definition of novel endpoints which can roughly be defined as “patient benefit”. For this reason the European Organization for Research and Treatment of Cancer (EORTC) Gastrointestinal Tract Cancer Cooperative Group (GITCCG) felt it was appropriate to organize a workshop with experts from different countries and national groups to discuss in depth several aspects concerning the treatment of patients with advanced colorectal cancer.

Abstract P1-10-08: Development of a first-in-class oral selective ERα covalent antagonist (SERCA) for the treatment of ERαWT and ERαMUT breast cancer

Mutations in estrogen receptor alpha (ERα) are detected in up to 30% of breast cancer patients who have relapsed during endocrine therapy. ERα mutations functionally confer resistance to existing classes of endocrine therapies, likely through gaining constitutive activity. The fact that current ER-directed therapies are only partially effective in the ERα mutant setting, and that a significant proportion of resistant breast cancer metastases continue to remain dependent on ERα signaling for growth/survival, highlights the critical need to develop the next generation of ERα antagonists that can overcome aberrant ERα activity. Using structure-based drug design approaches we have identified a novel class of ERα antagonist referred to as Selective ERα Covalent Antagonist (SERCA) that inactivate both wild-type and mutant ERα by targeting a unique cysteine residue that is not conserved among other steroid hormone receptors. Biophysical, biochemical and cellular analyses confirm the covalent mechanism of action, specific binding to ER and selective inhibition of ERα-dependent transcription of SERCAs. H3B-6545 is a highly selective SERCA that potently antagonizes wild-type and mutant ERα in biochemical and cell based assays demonstrating increased potency over standard of care and other experimental agents. In vivo, H3B-6545 shows superior efficacy to fulvestrant in the MCF-7 xenograft model with once daily oral dosing, achieving maximal antitumor activity at doses >10x below the maximum tolerated dose in mice. In addition, H3B-6545 shows superior antitumor activity to both tamoxifen and fulvestrant in patient derived xenograft models of breast cancer carrying estrogen receptor mutations. In summary, H3B-6545 is a first-in-class, orally available and selective ER covalent antagonist with a compelling pre-clinical profile that is being developed for the treatment of ERα positive breast cancer.

Citation Format: Korpal M, Puyang X, Furman C, Zheng GZ, Banka D, Wu J, Zhang Z, Thomas M, Mackenzie C, Yao H, Rimkunas V, Kumar P, Caleb B, Karr C, Subramanian V, Irwin S, Larsen N, Vaillancourt F, Nguyen T-V, Davis A, Chan B, Hao MH, O'Shea M, Prajapati S, Agoulnik S, Kuznetsov G, Kumar N, Yu Y, Lai G, Hart A, Eckley S, Fekkes P, Bowser T, Joshi JJ, Selvaraj A, Wardell S, Norris J, Smith S, Reynolds D, Mitchell L, Wang J, Yu L, Kim A, Rioux N, Sahmoud T, Warmuth M, Smith PG, Zhu P. Development of a first-in-class oral selective ERα covalent antagonist (SERCA) for the treatment of ERαWT and ERαMUT breast cancer [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 P1-10-08.

H3B-8800-G0001-101: A first in human phase I study of a splicing modulator in patients with advanced myeloid malignancies

TPS7075

Background: Dysregulated mRNA splicing is important in tumorigenesis and in resistance to cancer therapy. Somatic heterozygous mutations in core spliceosome genes (e.g. SF3B1, SRSF2, U2AF1) have been reported at high frequencies in patients with myelodysplastic syndromes (MDS), acute myeloid leukemia (AML), and chronic myelomonocytic leukemia (CMML). These mutations confer a change of function resulting in aberrant mRNA splicing that, in preclinical models, results in defects in hematopoietic cell development and myelodysplasia. Recurrent mutations in the spliceosome of patients with malignancies suggests importance in disease pathogenesis. Cells bearing splicing mutations depend on wild-type spliceosome function, suggesting the spliceosome as a therapeutic target. In vitro data indicate preferential induction of apoptosis (measured by caspase 3/7 activation) in SF3B1-mutant cells following treatment with the SF3B1 modulator H3B-8800. H3B-8800 inhibits growth in human AML cell lines, including those with mutations in U2AF1, SRSF2 or SF3B1. Oral administration of H3B-8800 modulates splicing and induces antitumor activity in xenograft leukemia models expressing mutant core spliceosome components. Methods: This study explores the safety of H3B-8800 in patients with myeloid cancers. Dose escalation (Cohort A) follows a 3+3 design with a starting dose of 1 mg daily for 5 consecutive days every 14 days in a 28 day cycle. Cohort A is open to patients with MDS, AML or CMML, irrespective of spliceosome mutations. In parallel to dose escalation, up to 6 patients with mutations of interest may be enrolled at doses determined to be safe in Cohort A (Cohort B). After determining the recommended phase 2 dose, 4 expansion cohorts will enroll patients with: (1) International Prognostic Scoring System (IPSS) low/int-1 risk MDS with SF3B1 mutations, (2) IPSS low/intermediate risk-1 MDS with mutations in SRSF2, U2AF1, or ZRSR2, (3) high/intermediate risk-2 MDS or AML, and (4) CMML; 3 and 4 having mutations in SF3B1, SRSF2, U2AF1, or ZRSR2. The first cohort enrolled 3 patients and the trial is currently enrolling patients at the second dose level. Clinical trial information: NCT02841540.

Efficacy of everolimus with exemestane versus exemestane alone in Asian patients with HER2-negative, hormone-receptor-positive breast cancer in BOLERO-2

BACKGROUND

The addition of mTOR inhibitor everolimus (EVE) to exemestane (EXE) was evaluated in an international, phase 3 study (BOLERO-2) in patients with hormone-receptor-positive (HR(+)) breast cancer refractory to letrozole or anastrozole. The safety and efficacy of anticancer treatments may be influenced by ethnicity (Sekine et al. in Br J Cancer 99:1757-62, 2008). Safety and efficacy results from Asian versus non-Asian patients in BOLERO-2 are reported.

METHODS

Patients were randomized (2:1) to 10 mg/day EVE + EXE or placebo (PBO) + EXE. Primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival, response rate, clinical benefit rate, and safety.

RESULTS

Of 143 Asian patients, 98 received EVE + EXE and 45 received PBO + EXE. Treatment with EVE + EXE significantly improved median PFS versus PBO + EXE among Asian patients by 38 % (HR = 0.62; 95 % CI, 0.41-0.94). Median PFS was also improved among non-Asian patients by 59 % (HR = 0.41; 95 % CI, 0.33-0.50). Median PFS duration among EVE-treated Asian patients was 8.48 versus 4.14 months for PBO + EXE, and 7.33 versus 2.83 months, respectively, in non-Asian patients. The most common grade 3/4 adverse events (stomatitis, anemia, elevated liver enzymes, hyperglycemia, and dyspnea) occurred at similar frequencies in Asian and non-Asian patients. Grade 1/2 interstitial lung disease occurred more frequently in Asian patients. Quality of life was similar between treatment arms in Asian patients.

CONCLUSION

Adding EVE to EXE provided substantial clinical benefit in both Asian and non-Asian patients with similar safety profiles. This combination represents an improvement in the management of postmenopausal women with HR(+)/HER2(-) advanced breast cancer progressing on nonsteroidal aromatase inhibitors, regardless of ethnicity.

Safety and efficacy of everolimus with exemestane vs. exemestane alone in elderly patients with HER2-negative, hormone receptor-positive breast cancer in BOLERO-2

BACKGROUND

Postmenopausal women with hormone receptor-positive (HR(+)) breast cancer in whom disease progresses or there is recurrence while taking a nonsteroidal aromatase inhibitor (NSAI) are usually treated with exemestane (EXE), but no single standard of care exists in this setting. The BOLERO-2 trial demonstrated that adding everolimus (EVE) to EXE improved progression-free survival (PFS) while maintaining quality of life when compared with EXE alone. Because many women with HR(+) advanced breast cancer are elderly, the tolerability profile of EVE plus EXE in this population is of interest.

PATIENTS AND METHODS

BOLERO-2, a phase III randomized trial, compared EVE (10 mg/d) and placebo (PBO), both plus EXE (25 mg/d), in 724 postmenopausal women with HR(+) advanced breast cancer recurring/progressing after treatment with NSAIs. Safety and efficacy data in elderly patients are reported at 18-month median follow-up.

RESULTS

Baseline disease characteristics and treatment histories among the elderly subsets (≥ 65 years, n = 275; ≥ 70 years, n = 164) were generally comparable with younger patients. The addition of EVE to EXE improved PFS regardless of age (hazard ratio, 0.59 [≥ 65 years] and 0.45 [≥ 70 years]). Adverse events (AEs) of special interest (all grades) that occurred more frequently with EVE than with PBO included stomatitis, infections, rash, pneumonitis, and hyperglycemia. Elderly EVE-treated patients had similar incidences of these AEs as did younger patients but had more on-treatment deaths.

CONCLUSION

Adding EVE to EXE offers substantially improved PFS over EXE and was generally well tolerated in elderly patients with HR(+) advanced breast cancer. Careful monitoring and appropriate dose reductions or interruptions for AE management are recommended during treatment with EVE in this patient population.

Health-related quality of life and disease symptoms in postmenopausal women with HR(+), HER2(-) advanced breast cancer treated with everolimus plus exemestane versus exemestane monotherapy

OBJECTIVE

Everolimus (EVE)+exemestane (EXE; n = 485) more than doubled median progression-free survival versus placebo (PBO) + EXE (n = 239), with a manageable safety profile and no deterioration in health-related quality-of-life (HRQOL) in patients with hormone-receptor-positive (HR(+)) advanced breast cancer (ABC) who recurred or progressed on/after nonsteroidal aromatase inhibitor (NSAI) therapy. To further evaluate EVE + EXE impact on disease burden, we conducted additional post-hoc analyses of patient-reported HRQOL.

RESEARCH DESIGN AND METHODS

HRQOL was assessed using EORTC QLQ-C30 and QLQ-BR23 questionnaires at baseline and every 6 weeks thereafter until treatment discontinuation because of disease progression, toxicity, or consent withdrawal. Endpoints included the QLQ-C30 Global Health Status (QL2) scale, the QLQ-BR23 breast symptom (BRBS), and arm symptom (BRAS) scales. Between-group differences in change from baseline were assessed using linear mixed models with selected covariates. Sensitivity analysis using pattern-mixture models determined the effect of study discontinuation on/before week 24. Treatment arms were compared using differences of least squares mean (LSM) changes from baseline and 95% confidence intervals (CIs) at each timepoint and overall.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov: NCT00863655.

MAIN OUTCOME MEASURES

Progression-free survival, survival, response rate, safety, and HRQOL.

RESULTS

Linear mixed models (primary model) demonstrated no statistically significant overall difference between EVE + EXE and PBO + EXE for QL2 (LSM difference = -1.91; 95% CI = -4.61, 0.78), BRBS (LSM difference = -0.18; 95% CI = -1.98, 1.62), or BRAS (LSM difference = -0.42; 95% CI = -2.94, 2.10). Based on pattern-mixture models, patients who dropped out early had worse QL2 decline on both treatments. In the expanded pattern-mixture model, EVE + EXE-treated patients who did not drop out early had stable BRBS and BRAS relative to PBO + EXE.

KEY LIMITATIONS

HRQOL data were not collected after disease progression.

CONCLUSIONS

These analyses confirm that EVE + EXE provides clinical benefit without adversely impacting HRQOL in patients with HR(+) ABC who recurred/progressed on prior NSAIs versus endocrine therapy alone.

A phase 2 study of everolimus combined with trastuzumab and paclitaxel in patients with HER2-overexpressing advanced breast cancer that progressed during prior trastuzumab and taxane therapy

Increased activation of the PI3K/Akt/mTOR pathway is a common factor in putative mechanisms of trastuzumab resistance, resulting in dysregulation of cell migration, growth, proliferation, and survival. Data from preclinical and phase 1/2 clinical studies suggest that adding everolimus (an oral mTOR inhibitor) to trastuzumab plus chemotherapy may enhance the efficacy of, and restore sensitivity to, trastuzumab-based therapy. In this phase 2 multicenter study, adult patients with HER2-positive advanced breast cancer resistant to trastuzumab and pretreated with a taxane received everolimus 10 mg/day in combination with paclitaxel (80 mg/m² days 1, 8, and 15 every 4 weeks) and trastuzumab (4 mg/kg loading dose followed by 2 mg/kg weekly), administered in 28-day cycles. Endpoints included overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety. Fifty-five patients were enrolled; one remained on study treatment at the time of data cutoff. The median number of prior chemotherapy lines for advanced disease was 3.5 (range 1–11). The ORR was 21.8 %, the clinical benefit rate was 36.4 %, the median PFS estimate was 5.5 months (95 % confidence interval [CI]: 4.99–7.69 months), and the median OS estimate was 18.1 months (95 % CI: 12.85–24.11 months). Hematologic grade 3/4 adverse events (AEs) included neutropenia (25.5 % grade 3, 3.6 % grade 4), anemia (7.3 % grade 3), and thrombocytopenia (5.5 % grade 3, 1.8 % grade 4). Nonhematologic grade 3/4 AEs included stomatitis (20.0 %), diarrhea (5.5 %), vomiting (5.5 %), fatigue (5.5 %), and pneumonia (5.5 %), all grade 3. These findings suggest that the combination of everolimus plus trastuzumab and paclitaxel is feasible, with promising activity in patients with highly resistant HER2-positive advanced breast cancer. This combination is currently under investigation in the BOLERO-1 phase 3 trial.

Everolimus for previously treated advanced gastric cancer: results of the randomized, double-blind, phase III GRANITE-1 study

PURPOSE

The oral mammalian target of rapamycin inhibitor everolimus demonstrated promising efficacy in a phase II study of pretreated advanced gastric cancer. This international, double-blind, phase III study compared everolimus efficacy and safety with that of best supportive care (BSC) in previously treated advanced gastric cancer.

PATIENTS AND METHODS

Patients with advanced gastric cancer that progressed after one or two lines of systemic chemotherapy were randomly assigned to everolimus 10 mg/d (assignment schedule: 2:1) or matching placebo, both given with BSC. Randomization was stratified by previous chemotherapy lines (one v two) and region (Asia v rest of the world [ROW]). Treatment continued until disease progression or intolerable toxicity. Primary end point was overall survival (OS). Secondary end points included progression-free survival (PFS), overall response rate, and safety.

RESULTS

Six hundred fifty-six patients (median age, 62.0 years; 73.6% male) were enrolled. Median OS was 5.4 months with everolimus and 4.3 months with placebo (hazard ratio, 0.90; 95% CI, 0.75 to 1.08; P = .124). Median PFS was 1.7 months and 1.4 months in the everolimus and placebo arms, respectively (hazard ratio, 0.66; 95% CI, 0.56 to 0.78). Common grade 3/4 adverse events included anemia, decreased appetite, and fatigue. The safety profile was similar in patients enrolled in Asia versus ROW.

CONCLUSION

Compared with BSC, everolimus did not significantly improve overall survival for advanced gastric cancer that progressed after one or two lines of previous systemic chemotherapy. The safety profile observed for everolimus was consistent with that observed for everolimus in other cancers.

BOLERO-2: Efficacy and safety of first-line everolimus plus exemestane in advanced breast cancer

152

Background: In the BOLERO-2 study, progression-free survival (PFS) was significantly longer with the combination of everolimus and exemestane (EVE + EXE) compared with placebo and exemestane (PBO + EXE; hazard ratio = 0.45; p < .0001). Consistent efficacy results were observed in all subgroup analyses, such as in patients with visceral metastases and patients with disease recurrence during/after adjuvant therapy. This analysis of BOLERO-2 examines the efficacy of EVE + EXE in the subgroup of patients who received treatment immediately after recurrence during adjuvant therapy (i.e., as first-line therapy in the advanced setting). Methods: BOLERO-2 enrolled patients with hormone receptor–positive (HR+) advanced breast cancer with disease recurrence or progression after prior nonsteroidal aromatase inhibitors and compared EVE (10 mg/d) + EXE (25 mg/d) vs PBO + EXE. The primary end point was PFS by local investigator review. Results: A total of 137 patients received first-line EVE + EXE (n = 100) or PBO + EXE (n = 37) in the advanced setting. Of these patients, 74% of the EVE + EXE arm and 76% of the PBO + EXE arm had recurred after adjuvant endocrine therapy plus chemotherapy; 26% and 24%, respectively, had recurred after adjuvant endocrine therapy alone. Also, approximately 20% of patients entered the trial after recurring during or within 12 months of adjuvant therapy (21% EVE + EXE vs 16% PBO + EXE). The EVE + EXE group had significantly longer PFS compared with the PBO + EXE group (11.50 vs 4.07 months, respectively; hazard ratio = 0.39; 95% confidence interval, 0.25-0.62). Median PFS remained longer with EVE + EXE versus PBO + EXE, regardless of whether chemotherapy was included with the prior adjuvant hormonal therapy. Similar results were obtained from the analyses based on central review. The safety profile was consistent with the known profiles of each agent. Conclusions: EVE + EXE prolonged PFS in patients with HR+ advanced breast cancer who received treatment as first-line therapy. These results support the combination of EVE + EXE in patients with recurrence after adjuvant therapy. The recently initiated BOLERO-4 study is also evaluating the efficacy of EVE as a first-line therapy in patients with HR+ advanced breast cancer. Clinical trial information: NCT00863655.

Patient-reported physical, emotional, and social functioning in advanced breast cancer: Insights from BOLERO-2

155

Background: The phase III BOLERO-2 study at 18 months’ median follow-up showed that everolimus (EVE) + exemestane (EXE) significantly improved progression-free survival (PFS) vs EXE alone in 724 patients with hormone receptor–positive (HR+) advanced breast cancer (ABC) with recurrence/progression during/after nonsteroidal aromatase inhibitor (NSAI) therapy. A higher rate of grade 3/4 adverse events was noted with EVE + EXE but was not associated with deterioration in quality of life (QOL) based on the EORTC QLQ-C30 Global Health Status scale. Additional patient-reported post hoc analyses of QOL are reported herein. Methods: During BOLERO-2, QOL (EORTC QLQ-C30 and QLQ-BR23) was assessed at baseline and q 6 wk thereafter until progression or discontinuation. Physical, emotional, and social functioning subscales of QLQ-C30 were analyzed. Time to definitive deterioration (TTD) was defined based on either a 5% (protocol-specified) or a 10-point (more stringent) decrease from baseline for each subscale and analyzed by Kaplan-Meier methods. The difference between treatments was assessed by a log-rank test stratified by randomization factors. Results: QLQ-C30 compliance was >80% at week 48. Among the 3 protocol-specified QLQ-C30 subscales, analyses based on a 5% decrease in QOL showed a longer TTD for both physical and emotional functioning in the EVE + EXE group vs EXE alone (log-rank p = 0.0120 and p = 0.0277, respectively). The TTDs for social functioning were similar in both treatment arms (log-rank p = 0.3374). Analyses based on a 10-point decrease indicated a longer TTD for physical functioning in the EVE + EXE group (15.2 mo) vs EXE alone (9.7 mo; log-rank p = 0.0211). The TTDs for emotional and social functioning were similar between EVE + EXE and EXE alone: 13.9 vs 13.8, respectively (log-rank p = 0.4023), and 11.5 vs 9.5, respectively (log-rank p = 0.2507). Conclusions: The treatment goal for ABC is to maximize clinical benefit with minimal negative effects on QOL. These additional BOLERO-2 QOL analyses confirmed that the more than doubling of PFS with EVE + EXE was accompanied by maintained physical, emotional, and social functioning compared with EXE alone in patients with HR+ ABC progressing after NSAI. Clinical trial information: NCT00863655.

Correlation of molecular alterations with efficacy of everolimus in hormone-receptor–positive, HER2-negative advanced breast cancer: Results from BOLERO-2

142

Background: Everolimus (EVE) plus exemestane (EXE) more than doubled progression-free survival (PFS) while maintaining quality of life vs EXE alone in postmenopausal women with hormone receptor–positive (HR+), HER2-negative (HER2–) advanced breast cancer (BOLERO-2 phase III; NCT00863655). PFS benefit was seen in all clinically defined subgroups. We evaluated genetic variations of a broad panel of cancer-related genes and explored their correlations with EVE benefit. Methods: Exon sequence and gene copy number variations were analyzed in 182 cancer-related genes by next-generation sequencing (NGS). Correlations with PFS were evaluated using univariate and multivariate Cox models. Results: NGS data (>250x coverage) were successfully generated from archival tumor specimens from 227 patients (NGS population, 157 in EVE + EXE arm and 70 in EXE arm) whose baseline characteristics and clinical outcome were comparable to the trial population (PFS HR = 0.40 and 0.45, respectively). The treatment benefit of EVE + EXE over EXE was maintained in the subgroups defined by each of the 9 genes with a mutation rate >10% (e.g., PIK3CA, FGFR1, CCND1) or when less frequently mutated genes (e.g., PTEN, AKT1) were included in their respective pathways. Patients with 0 or 1 genetic alteration in PI3K or FGFR pathways or CCND1 had a greater treatment effect from EVE (HR = 0.27, 95% CI 0.18-0.41, adjusted by covariates, in 76% of the NGS population), indicating the value of these pathways for predicting sensitivity to EVE in this setting. Conclusions: This is the first global registration trial in which efficacy-predictive biomarkers were explored by correlating broad genetic variations with clinical efficacy. The preliminary results suggest that a large subgroup of patients (76%), defined by minimal genetic variations in the PI3K or FGFR pathways or CCND1, derives the most benefit from EVE therapy (HR = 0.27 vs 0.40 for the full NGS population). These exploratory results and their implication in understanding the interplay of multiple pathways in tumor cells and testing new hypotheses for targeted combination therapies in HR+/HER2– BC will be further investigated. Clinical trial information: NCT00863655.

Correlation of molecular alterations with efficacy of everolimus in hormone receptor–positive, HER2-negative advanced breast cancer: Results from BOLERO-2

LBA509

Background: Everolimus (EVE) plus exemestane (EXE) more than doubled progression-free survival (PFS) while maintaining quality of life vs EXE alone in postmenopausal women with hormone-receptor positive (HR+), HER2-negative (HER2-) advanced breast cancer (BOLERO-2 phase III; NCT00863655). PFS benefit was seen in all clinically defined subgroups. We evaluated genetic variations of a broad panel of cancer-related genes and explored their correlations with EVE benefit. Methods: Exon sequence and gene copy number variations were analyzed in 182 cancer-related genes by next-generation sequencing (NGS). Correlations with PFS were evaluated using both univariate and multivariate Cox models. Results: NGS data (>250x coverage) were successfully generated from archival tumor specimens from 227 patients (NGS population, 157 and 70 in EVE+EXE and EXE arms, respectively) whose baseline characteristics and clinical outcome were comparable with the trial population (PFS HR = 0.40 and 0.45, respectively). The treatment benefit of EVE+EXE over EXE is maintained in the subgroups defined by each of the nine genes with a mutation rate >10% (eg, PIK3CA, FGFR1, and CCND1), or when less frequently mutated genes (eg, PTEN, AKT1) were included in their respective pathways. Patients with no or only 1 genetic alteration in PI3K or FGFR pathways, or CCND1, had a greater treatment effect from EVE (HR = 0.27, 95% CI 0.18-0.41, adjusted by covariates, in 76% of the NGS population), indicating the value of these pathways for predicting sensitivity/resistance to EVE in this setting. Conclusions: This is the first global registration trial in which efficacy-predictive biomarkers were explored by correlating broad genetic variations with clinical efficacy. It demonstrated the feasibility of applying large-scale NGS and subsequent correlative analysis to such trials. The observations suggest that a large subgroup of patients (76%), defined by minimal genetic variations in the PI3K or FGFR pathways, or CCND1, derives the most benefit from EVE therapy (HR = 0.27 vs 0.40 for the full NGS population). These exploratory results and their implication in understanding the interplay of multiple pathways in tumor cells and testing new hypotheses for targeted combination therapies in HR+/HER2- BC will be further investigated. Clinical trial information: NCT00863655.

Effect of visceral metastases on the efficacy and safety of everolimus in postmenopausal women with advanced breast cancer: subgroup analysis from the BOLERO-2 study

BACKGROUND

Everolimus (EVE; an inhibitor of mammalian target of rapamycin [mTOR]) enhances treatment options for postmenopausal women with hormone-receptor-positive (HR(+)), human epidermal growth factor receptor-2-negative (HER2(-)) advanced breast cancer (ABC) who progress on a non-steroidal aromatase inhibitor (NSAI). This is especially true for patients with visceral disease, which is associated with poor prognosis. The BOLERO-2 (Breast cancer trial of OraLEveROlimus-2) trial showed that combination treatment with EVE and exemestane (EXE) versus placebo (PBO)+EXE prolonged progression-free survival (PFS) by both investigator (7.8 versus 3.2 months, respectively) and independent (11.0 versus 4.1 months, respectively) central assessment in postmenopausal women with HR(+), HER2(-) ABC recurring/progressing during/after NSAI therapy. The BOLERO-2 trial included a substantial proportion of patients with visceral metastases (56%).

METHODS

Prespecified exploratory subgroup analysis conducted to evaluate the efficacy and safety of EVE+EXE versus PBO+EXE in a prospectively defined subgroup of patients with visceral metastases.

FINDINGS

At a median follow-up of 18 months, EVE+EXE significantly prolonged median PFS compared with PBO+EXE both in patients with visceral metastases (N=406; 6.8 versus 2.8 months) and in those without visceral metastases (N=318; 9.9 versus 4.2 months). Improvements in PFS with EVE+EXE versus PBO+EXE were also observed in patients with visceral metastases regardless of Eastern Cooperative Oncology Group performance status (ECOG PS). Patients with visceral metastases and ECOG PS 0 had a median PFS of 6.8 months with EVE+EXE versus 2.8 months with PBO+EXE. Among patients with visceral metastases and ECOG PS ≥1, EVE+EXE treatment more than tripled median PFS compared with PBO+EXE (6.8 versus 1.5 months).

INTERPRETATION

Adding EVE to EXE markedly extended PFS by ≥4 months among patients with HR(+) HER2(-) ABC regardless of the presence of visceral metastases.

Clinical management and resolution of stomatitis in BOLERO-2

558

Background: In BOLERO-2, adding everolimus (EVE) to exemestane (EXE) more than doubled progression-free survival without affecting quality of life vs EXE alone in postmenopausal women with hormone-receptor–positive advanced breast cancer who had recurrence or progression on/after nonsteroidal aromatase inhibitor therapy. Although mTOR inhibitors are generally well tolerated, stomatitis is one of their most clinically relevant and potentially dose-limiting toxicities (Sonis Cancer2010). The incidence, grade, and clinical course of stomatitis among patients (pts) participating in the BOLERO-2 study are described. Methods: Pts were randomized 2:1 to receive EVE+EXE or placebo (PBO)+EXE. Stomatitis incidence, severity, consequent dose interruptions/adjustments, study drug discontinuations, and time to resolution were recorded. Results: The median duration of EVE+EXE treatment exposure was 30 wk (range, 1-123 wk). Stomatitis (any grade) occurred more frequently with EVE+EXE than with PBO+EXE (59% vs 12%, respectively). Grade 3 stomatitis occurred in 8% vs 1% of pts receiving EVE+EXE vs PBO+EXE, respectively; no grade 4 was reported. Onset of grade ≥2 stomatitis after treatment initiation was earlier in the EVE+EXE arm vs the PBO+EXE arm: median time was 15d vs 24d, respectively. In the EVE+EXE arm, 97% of pts with grade 3 stomatitis (n=38) improved to ≤1 after a median of 13 d. Complete resolution was observed in 82% of these pts after a median of 38 d. In the PBO+EXE arm, all pts with grade 3 stomatitis (n=2) improved to ≤1 after a median of 18 d. Complete resolution was observed after a median of 29 d. Overall, 24% of pts in the EVE+EXE arm required dose interruptions/adjustments vs 1% of pts in the PBO+EXE arm, and 3% of pts (n=13) discontinued EVE+EXE vs <1% of pts (n=1) discontinuing PBO+EXE, all related to stomatitis. Conclusions: The BOLERO-2 data foster a new era of combining targeted and endocrine therapies. In the study, treatment-emergent stomatitis was of mild to moderate intensity, occurred shortly after treatment initiation, and was generally reversible. Most incidents were successfully managed with palliative interventions and temporary dose modifications. Oral hygiene and other preventive measures are recommended. Clinical trial information: NCT00863655.

Phase III, randomized, double-blind, placebo-controlled multicenter trial of daily everolimus plus weekly trastuzumab and vinorelbine in trastuzumab-resistant, advanced breast cancer (BOLERO-3)

505

Background: Everolimus (EVE) is an inhibitor of mammalian target of rapamycin (mTOR), a protein kinase central to a number of signaling pathways regulating cell growth and proliferation. Data from preclinical and phase 1/2 clinical studies indicated that adding EVE to trastuzumab (TRAS) plus chemotherapy may restore sensitivity to and enhance efficacy of human epidermal growth factor receptor 2 (HER2)-targeted therapy. The international BOLERO-3 phase 3 study is being conducted to evaluate the addition of EVE to TRAS plus vinorelbine. Methods: Adult women with HER2+ advanced breast cancer and who received prior taxane therapy and experienced recurrence or progression on TRAS were randomized 1:1 to receive either EVE or placebo (5 mg/day) in combination with weekly TRAS and vinorelbine (25 mg/m2). The primary endpoint is progression-free survival (PFS). Secondary endpoints included overall survival, response rate, clinical benefit rate, safety, quality of life, and pharmacokinetics. Final analysis will be conducted after approximately 417 PFS events. Results: The trial accrued 569 patients between October 2009 and May 2012. Previous therapy included TRAS (100%), a taxane (100%), and lapatinib (28%). The median age was 54 years, and 76% of patients had visceral metastases, 5% had stable brain metastases, 56% had hormone-receptor–positive disease, 33% had Eastern Cooperative Oncology Group performance status of 1 or 2, and 41% had 3 or more metastatic sites. The median number of prior chemotherapy lines in the metastatic setting was 1. As of February 4, 2013, a total of 396 PFS events were reported. Conclusions: Final PFS analysis will be performed in early May 2013; primary and secondary efficacy endpoints will be presented. Clinical trial information: NCT01007942.

Frequent LOH of CYP2D6 in ER+ breast cancer determined by next-generation sequencing (NGS)

534

Background: The role of CYP2D6 genetic variation in predicting response to tamoxifen in ER+ breast cancer is a subject of ongoing debate. There has been great variability in approaches to both genotyping and phenotyping, and in particular many investigators have extracted DNA from breast cancer samples rather than peripheral blood. We hypothesized that CYP2D6 gene copy number alterations are common in ER+ breast cancer, affecting genotype results, and used NGS to characterize CYP2D6 in patients with ER+ disease. Methods: CYP2D6 sequencing was performed as part of a comprehensive NGS profile of cancer-related genes for 261 predominantly relapsed and metastatic ER+ breast cancer FFPE specimens. Sequence data were resolved into genotypes according to the * allele nomenclature. Tumor LOH was determined at CYP2D6, and its error impact on genotyping methods was estimated. To assess biological significance, the prevalence of CYP2D6 alleles and LOH in ER+ disease was compared against a control set of 99 ER- tumors. Results: CYP2D6 allele frequencies in our full cohort (ER+, 261; ER-, 99) were consistent with prior studies; 64.4%, 16.8%, 9.0% vs. 63.1%, 17.2%, 7.0% for *1/*2, *4, and *41 respectively, and 1%-2% for the rarer alleles *9, *10, and *5. The rate of CYP2D6 LOH was higher in ER+ disease (41% vs. 26%, p<0.01), with all excess arising from copy-loss (as opposed to copy-neutral) changes (22% vs. 7%, p<0.002). The estimated impact of LOH on germline genotype assessment from tumor was considerable; an assay sensitive at >20% minor allele frequency (e.g., Sanger sequencing) can misclassify >10% of heterozygotes, leading to significant Hardy-Weinberg disequilibrium (e.g., p=8.3x10-8 for *4). Interestingly, an enrichment of reduced or non-functional CYP2D6 alleles in ER+ samples was observed (61% vs. 47%, p<0.03). Conclusions: Our results demonstrate the distorting effect of extensive LOH on genotype assessment of CYP2D6 in breast cancer. Therefore, tumor DNA should not be routinely used for determination of germline 2D6 genotype, although it appears possible to use NGS. The apparent association between reduced function CYP2D6 alleles and ER+ breast cancer in our dataset requires further investigation.

Incidence, management, and resolution of noninfectious pneumonitis in BOLERO-2

561

Background: The BOLERO-2 trial showed that adding everolimus (EVE) to exemestane (EXE) more than doubled progression-free survival (PFS) without reducing quality of life versus placebo (PBO) + EXE alone in postmenopausal women with hormone-receptor–positive (HR+), HER2-negative (HER2–) advanced breast cancer (ABC) progressing on/after nonsteroidal aromatase inhibitor (NSAI) therapy. Although generally well tolerated, mTOR inhibitors such as EVE have been associated with noninfectious pneumonitis (NIP). Methods: Patients (pts) were randomized 2:1 to receive EVE+EXE or PBO+EXE. Incidence and severity of NIP, consequent dose interruptions/adjustments, study drug discontinuations, and time to resolution were recorded. Results: Median duration of exposure to EVE was 24 weeks with median dose intensity of 8.6 mg/d. Pulmonary adverse events (AEs) of any grade (NIP, interstitial lung disease, lung infiltration, pneumonia, or pulmonary fibrosis) were recorded in 97 of 482 pts (20%) in the EVE+EXE arm versus 1 of 238 pts (<1%) in the PBO+EXE arm. Of these, 16% of pts (77 of 482) in the EVE+EXE arm versus 0 in the PBO+EXE arm had a diagnosis consistent with NIP. In the EVE+EXE arm, grade 1 (no symptoms), grade 2 and 3 NIP occurred in 7%, 6% and 3% of pts, respectively, and no grade 4 events were reported. Complete resolution of NIP to grade ≤1 was recorded for all but 4 pts for whom NIP was still observed at last follow-up before study discontinuation. Overall, in the EVE+EXE arm, NIP was recorded as the reason for dose interruption and treatment discontinuation in 7.5% and 5.6% of pts, respectively. Conclusions: Data from BOLERO-2 support the combination of EVE and EXE to significantly prolong PFS in postmenopausal women with HR+, HER2– ABC progressing on/after NSAI. The incidence of NIP in this study was generally consistent with reports from other oncology settings, was of mild to moderate severity, and was generally reversible with appropriate interventions and temporary dose modifications. Patient and healthcare provider education for early diagnosis and management of NIP are highly recommended. Clinical trial information: NCT00863655.

Correlation of molecular alterations with efficacy of everolimus in hormone-receptor–positive (HR+), HER2-negative advanced breast cancer: Preliminary results from BOLERO-2

LBA509

The full, final text of this abstract will be available at abstract.asco.org at 7:30 AM (EDT) on Monday, June, 3, 2013, and in the Annual Meeting Proceedings online supplement to the June 20, 2013, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Monday edition of ASCO Daily News.

BOLERO-6: Phase II study of everolimus plus exemestane versus everolimus or capecitabine monotherapy in HR+, HER2- advanced breast cancer

TPS660

Background: Everolimus (EVE), an orally bioavailable inhibitor of the mammalian target of rapamycin (mTOR), has shown clinical activity as monotherapy and in combination with endocrine therapy (ET) in hormone-receptor–positive (HR+; estrogen and/or progesterone receptors) advanced breast cancer (ABC). In a pivotal phase 3 trial in patients with HR+ ABC progressing on ET, EVE + exemestane (EXE) significantly prolonged median progression-free survival (PFS) vs EXE alone per local (7.8 vs 3.2 months; log-rank P<.0001) or central (11.0 months for EVE+EXE vs 4.1 months for EXE alone; log-rank P<.0001) assessment. Capecitabine, an orally administered fluoropyrimidine carbamate indicated as monotherapy in paclitaxel and/or anthracycline-refractory ABC, has shown clinical benefit in patients with HR+, human epidermal growth factor receptor 2-negative (HER2-) ABC. The BOLERO-6 study in patients with HR+, HER2- ABC progressing on prior anastrozole or letrozole will compare PFS following EVE+EXE combination therapy vs EVE or capecitabine monotherapy. Methods: In this multicenter, open-label, randomized, 3-arm, phase 2 study, 300 patients will be randomized to receive either EVE (10 mg/d) + EXE (25 mg/d) combination therapy, or EVE (10 mg/d) alone, or capecitabine (1,250 mg/m2twice daily for 14 d/3-wk cycle) alone, until disease progression. Patients will be stratified based on the presence of visceral disease. Key eligibility criteria include age ≥18 years, postmenopausal status; histologic or cytologic confirmation of estrogen-receptor–positive, HER2- ABC; radiologic or objective evidence of recurrence or progression on prior aromatase inhibitors; Eastern Cooperative Oncology Group (ECOG) performance status ≤2. The primary endpoint is PFS with EVE+EXE vs EVE, based on local radiologic assessment (Response Evaluation Criteria in Solid Tumors [RECIST] 1.1). The key secondary endpoint is PFS with EVE+EXE vs capecitabine. Other secondary endpoints include overall survival, objective response rate, clinical benefit rate, safety, quality of life, and patient satisfaction with treatment. Enrollment will start in Q1 2013. Estimated study completion in Q1 2015. Clinical trial information: NCT01783444.

Patient-reported physical, emotional, and social functioning in advanced breast cancer: Insights from BOLERO-2

553

Background: The phase 3 BOLERO-2 study at 18 months’ median follow-up showed that everolimus (EVE) + exemestane (EXE) significantly improved progression-free survival (PFS) vs EXE alone in 724 hormone-receptor–positive (HR+) advanced breast cancer (ABC) patients with recurrence/progression during/after nonsteroidal aromatase inhibitor (NSAI) therapy. A higher rate of grade 3/4 adverse events was noted with EVE + EXE, but was not associated with deterioration in quality of life (QOL) based on the EORTC QLQ-C30 Global Health Status scale. Additional patient-reported post hoc analyses of QOL are reported herein. Methods: During BOLERO-2, QOL (EORTC QLQ-C30 and QLQ-BR23) was assessed at baseline and q 6 wk thereafter until progression or discontinuation. Physical, emotional, and social functioning subscales of QLQ-C30 were analyzed. Time to definitive deterioration (TTD) was defined based on either a 5% (protocol specified) or 10-point (more stringent) decrease from baseline for each subscale and analyzed by Kaplan-Meier methods. The difference between treatments was assessed by a log-rank test stratified by randomization factors. Results: QLQ-C30 compliance was > 80% at week 48. Among the 3 protocol-specified QLQ-C30 subscales, analyses based on a 5% decrease in QOL showed a longer TTD for both physical and emotional functioning in the EVE + EXE group vs EXE alone (log-rank P = .0120 and P = .0277, respectively). The TTD for social functioning was similar in both treatment arms (log-rank P = .3374). Analyses based on a 10-point decrease indicated a longer TTD for physical functioning in the EVE + EXE group (15.2 mo) vs EXE alone (9.7 mo; log-rank P = .0211). The TTDs for emotional and social functioning were similar between EVE + EXE and EXE alone: 13.9 vs 13.8, respectively (log-rank P = .4023), and 11.5 vs 9.5, respectively (log-rank P = .2507). Conclusions: The treatment goal for ABC is to maximize clinical benefit with minimal negative effects on QOL. These additional BOLERO-2 QOL analyses confirmed that the more than doubling of PFS with EVE + EXE was accompanied by maintained physical, emotional, and social functioning compared with EXE alone in patients with HR+ ABC progressing after NSAI. Clinical trial information: NCT00863655.

Health-related quality of life of patients with advanced breast cancer treated with everolimus plus exemestane versus placebo plus exemestane in the phase 3, randomized, controlled, BOLERO-2 trial

BACKGROUND

The randomized, controlled BOLERO-2 (Breast Cancer Trials of Oral Everolimus) trial demonstrated significantly improved progression-free survival with the use of everolimus plus exemestane (EVE + EXE) versus placebo plus exemestane (PBO + EXE) in patients with advanced breast cancer who developed disease progression after treatment with nonsteroidal aromatase inhibitors. This analysis investigated the treatment effects on health-related quality of life (HRQOL).

METHODS

Using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) questionnaire, HRQOL was assessed at baseline and every 6 weeks thereafter until disease progression and/or treatment discontinuation. The 30 items in 15 subscales of the QLQ-C30 include global health status wherein higher scores (range, 0-100) indicate better HRQOL. This analysis included a protocol-specified time to definitive deterioration (TDD) analysis at a 5% decrease in HRQOL versus baseline, with no subsequent increase above this threshold. The authors report additional sensitivity analyses using 10-point minimal important difference decreases in the global health status score versus baseline. Treatment arms were compared using the stratified log-rank test and Cox proportional hazards model adjusted for trial stratum (visceral metastases, previous hormone sensitivity), age, sex, race, baseline global health status score and Eastern Cooperative Oncology Group performance status, prognostic risk factors, and treatment history.

RESULTS

Baseline global health status scores were found to be similar between treatment groups (64.7 vs 65.3). The median TDD in HRQOL was 8.3 months with EVE + EXE versus 5.8 months with PBO + EXE (hazard ratio, 0.74; P = .0084). At the 10-point minimal important difference, the median TDD with EVE + EXE was 11.7 months versus 8.4 months with PBO + EXE (hazard ratio, 0.80; P = .1017).

CONCLUSIONS

In patients with advanced breast cancer who develop disease progression after treatment with nonsteroidal aromatase inhibitors, EVE + EXE was associated with a longer TDD in global HRQOL versus PBO + EXE.

Everolimus for angiomyolipoma associated with tuberous sclerosis complex or sporadic lymphangioleiomyomatosis (EXIST-2): a multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND

Angiomyolipomas are slow-growing tumours associated with constitutive activation of mammalian target of rapamycin (mTOR), and are common in patients with tuberous sclerosis complex and sporadic lymphangioleiomyomatosis. The insidious growth of these tumours predisposes patients to serious complications including retroperitoneal haemorrhage and impaired renal function. Everolimus, a rapamycin derivative, inhibits the mTOR pathway by acting on the mTOR complex 1. We compared the angiomyolipoma response rate on everolimus with placebo in patients with tuberous sclerosis or sporadic lymphanioleiomyomatosis-associated angiomyolipomata.

METHODS

In this double-blind, placebo-controlled, phase 3 trial, patients aged 18 years or older with at least one angiomyolipoma 3 cm or larger in its longest diameter (defined by radiological assessment) and a definite diagnosis of tuberous sclerosis or sporadic lymphangioleiomyomatosis were randomly assigned, in a 2:1 fashion with the use of an interactive web response system, to receive oral everolimus 10 mg per day or placebo. The primary efficacy endpoint was the proportion of patients with confirmed angiomyolipoma response of at least a 50% reduction in total volume of target angiomyolipomas relative to baseline. This study is registered with ClinicalTrials.gov number NCT00790400.

RESULTS

118 patients (median age 31·0 years; IQR 18·0–61·0) from 24 centres in 11 countries were randomly assigned to receive everolimus (n=79) or placebo (n=39). At the data cutoff, double-blind treatment was ongoing for 98 patients; two main reasons for discontination were disease progression (nine placebo patients) followed by adverse events (two everolimus patients; four placebo patients). The angiomyolipoma response rate was 42% (33 of 79 [95% CI 31–53%]) for everolimus and 0% (0 of 39 [0–9%]) for placebo (response rate difference 42% [24–58%]; one-sided Cochran-Mantel-Haenszel test p<0·0001). The most common adverse events in the everolimus and placebo groups were stomatitis (48% [38 of 79], 8% [3 of 39], respectively), nasopharyngitis (24% [19 of 79] and 31% [12 of 39]), and acne-like skin lesions (22% [17 of 79] and 5% [2 of 39]).

INTERPRETATION

Everolimus reduced angiomyolipoma volume with an acceptable safety profile, suggesting it could be a potential treatment for angiomyolipomas associated with tuberous sclerosis.

FUNDING

Novartis Pharmaceuticals.

Effect of everolimus on bone marker levels and progressive disease in bone in BOLERO-2

BACKGROUND

Breast Cancer Trials of Oral Everolimus 2 (BOLERO-2), a phase III study in postmenopausal women with estrogen receptor-positive breast cancer progressing despite nonsteroidal aromatase inhibitor therapy, showed statistically significant benefits with adding everolimus to exemestane. Moreover, in preclinical studies, mammalian target of rapamycin inhibition was associated with decreased osteoclast survival and activity. Exploratory analyses in BOLERO-2 evaluated the effect of everolimus on bone marker levels and progressive disease in bone.

METHODS

Patients were treated with exemestane (25mg/day) and randomized (2:1) to everolimus (10mg/day; combination) or placebo (exemestane only). Exploratory endpoints included changes in bone turnover marker levels vs baseline and progressive disease in bone, defined as unequivocal progression of a preexisting bone lesion or the appearance of a new bone lesion.

RESULTS

Baseline disease characteristics were well balanced between arms (N = 724); baseline bisphosphonate use was not (43.9% combination vs 54.0% exemestane only). At a median of 18 months of follow-up, median progression-free survival (primary endpoint) was statistically significantly longer with the combination vs exemestane only (Cox proportional hazard ratio = 0.45, 95% confidence interval = 0.38 to 0.54; log-rank, 1-sided P < .0001). Bone marker levels at 6 and 12 weeks increased with exemestane only, as expected, but decreased with the combination. The cumulative incidence rate of progressive disease in bone was lower in the combination arm. Bone-related adverse events occurred with similar frequency in both arms (3.3% combination vs 4.2% exemestane only).

CONCLUSION

These exploratory analyses suggest that everolimus has beneficial effects on bone turnover and progressive disease in bone in patients receiving exemestane for hormone receptor-positive breast cancer progressing during/after nonsteroidal aromatase inhibitor therapy.

Efficacy and safety of everolimus for subependymal giant cell astrocytomas associated with tuberous sclerosis complex (EXIST-1): a multicentre, randomised, placebo-controlled phase 3 trial

BACKGROUND

Tuberous sclerosis complex is a genetic disorder leading to constitutive activation of mammalian target of rapamycin (mTOR) and growth of benign tumours in several organs. In the brain, growth of subependymal giant cell astrocytomas can cause life-threatening symptoms--eg, hydrocephalus, requiring surgery. In an open-label, phase 1/2 study, the mTOR inhibitor everolimus substantially and significantly reduced the volume of subependymal giant cell astrocytomas. We assessed the efficacy and safety of everolimus in patients with subependymal giant cell astrocytomas associated with tuberous sclerosis complex.

METHODS

In this double-blind, placebo-controlled, phase 3 trial, patients (aged 0-65 years) in 24 centres in Australia, Belgium, Canada, Germany, the UK, Italy, the Netherlands, Poland, Russian Federation, and the USA were randomly assigned, with an interactive internet-response system, in a 2:1 ratio to oral everolimus 4·5 mg/m(2) per day (titrated to achieve blood trough concentrations of 5-15 ng/mL) or placebo. Eligible patients had a definite diagnosis of tuberous sclerosis complex and at least one lesion with a diameter of 1 cm or greater, and either serial growth of a subependymal giant cell astrocytoma, a new lesion of 1 cm or greater, or new or worsening hydrocephalus. The primary endpoint was the proportion of patients with confirmed response--ie, reduction in target volume of 50% or greater relative to baseline in subependymal giant cell astrocytomas. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00789828.

FINDINGS

117 patients were randomly assigned to everolimus (n=78) or placebo (n=39). 27 (35%) patients in the everolimus group had at least 50% reduction in the volume of subependymal giant cell astrocytomas versus none in the placebo group (difference 35%, 95% CI 15-52; one-sided exact Cochran-Mantel-Haenszel test, p<0·0001). Adverse events were mostly grade 1 or 2; no patients discontinued treatment because of adverse events. The most common adverse events were mouth ulceration (25 [32%] in the everolimus group vs two [5%] in the placebo group), stomatitis (24 [31%] vs eight [21%]), convulsion (18 [23%] vs ten [26%]), and pyrexia (17 [22%] vs six [15%]).

INTERPRETATION

These results support the use of everolimus for subependymal giant cell astrocytomas associated with tuberous sclerosis. Additionally, everolimus might represent a disease-modifying treatment for other aspects of tuberous sclerosis.

FUNDING

Novartis Pharmaceuticals.

BOLERO-2: Health-related quality-of-life (HRQoL) in metastatic breast cancer patients treated with everolimus and exemestane versus exemestane

125

Background: BOLERO-2, a phase III study, randomized 724 patients with hormone-receptor–positive metastatic breast cancer, who had recurrence or progression on/after prior nonsteroidal aromatase inhibitor therapy, to everolimus (EVE) + exemestane (EXE) or EXE + placebo. A preplanned 12-mo median time interim analysis demonstrated that EVE + EXE significantly improved progression-free survival (PFS) vs EXE + placebo, but EVE + EXE resulted in a higher rate of grade 3-4 toxicity. Per-protocol patients reported HRQoL data are limited; here we report on additional post hoc analyses of these outcomes. Methods: Using the EORTC QLQ-C30 questionnaire, HRQoL was assessed at baseline and every 6 weeks thereafter until progression. QLQ-C30 consists of 30 items combined into 15 subscales, including a Global Health Status (GHS), where higher scores (range, 0-100) indicate better HRQoL. Analysis included a protocol-specified time to definitive deterioration (TTD) analysis at a 5% decrease in QoL relative to baseline, with no subsequent increase above this threshold. We report additional sensitivity analyses using 10-point minimally important difference (MID) decreases in QLQ-C30 score relative to baseline. Treatment arms were compared using a stratified log-rank test and a Cox proportional hazards model adjusted for trial stratum (visceral metastases and previous hormone sensitivity), age, sex, race, baseline score, ECOG performance status, prognostic risk factors, and treatment history. Results: Baseline QLQ-C30 GHS scores were not statistically significantly different across treatment groups (64.7 vs 65.3; difference –0.7 [95% CI, –4.3-3.0]). Median TTD in HRQoL was 7.0 mo (95% CI, 5.6-8.3) for EVE + EXE vs 5.6 (95% CI, 4.2-7.0) for EXE (p = .0792). Adjusted HR (0.80) approached significance (95% CI, 0.63-1.02). At the 10-point MID, median TTD for EVE + EXE was 9.7 mo (95% CI, 8.3-11.2) vs 8.4 mo (95% CI, 6.3-12.5) for EXE. Adjusted HR was 0.90 (95% CI, 0.69-1.18). Conclusions: These additional analyses from the BOLERO-2 study demonstrate that in addition to significantly improving PFS, EVE + EXE does not compromise HRQoL.

Effects of everolimus (EVE) on disease progression in bone and bone markers (BMs) in patients (pts) with bone metastases (mets)

102

Background: BOLERO-2, a multinational, double-blind, placebo-controlled, phase III study in postmenopausal women with estrogen-receptor–positive breast cancer (BC) refractory to nonsteroidal aromatase inhibitors (NSAIs), showed significant clinical benefits with the addition of EVE to exemestane (EXE) (Baselga J et al. NEJM2011 Epub). As bone resorption is an important factor in BC mets, it is interesting to study bone-related effects of EVE. In preclinical studies, mTOR inhibition was associated with decreased osteoclast survival and activity. Exploratory analyses in BOLERO-2 evaluated the effects of EVE vs placebo (PBO) on BM levels and BC progression in bone in pts with bone mets at baseline. Methods: Eligible pts were treated with EXE (25 mg once daily) and randomized (2:1) to EVE (10 mg once daily) or PBO. Bone turnover markers (BMs) were exploratory endpoints analyzed at 6 and 12 wks after treatment initiation and included bone-specific alkaline phosphatase, amino-terminal propeptide of type I collagen, and C-terminal cross-linking telopeptide of type I collagen. Progressive disease in bone (PDB) was defined as worsening of a preexisting bone lesion or a new bone lesion. Results: Baseline disease characteristics, including bone mets at baseline (n = 370, 76% EVE vs n = 184, 77% PBO), were well balanced between arms (N = 724), and baseline bisphosphonate use was not (44% EVE vs 55% PBO). At 12.5 mo median follow-up, progression-free survival (primary endpoint), overall response rate, and clinical benefit rate (p < 0.0001, all) were significantly higher with EVE (n = 485) vs PBO (n = 239). BM levels at 6 and 12 wks increased vs baseline with PBO but decreased with EVE. The cumulative incidence rate of BC PBD was lower for EVE vs PBO at day 60 (3.03% vs 6.16%, respectively), and this trend was sustained beyond 6 months. Updated results will be presented. All bone-related adverse events reported were grade 1-2 and occurred with similar frequency in EVE (2.9%)- and PBO (3.8%)-treated patients. Conclusions: Exploratory analyses from BOLERO-2 suggest that adding EVE has beneficial effects on bone turnover and BC progression in bone in pts receiving EXE therapy for NSAI-refractory BC.

Safety of everolimus for women over age 65 with advanced breast cancer (BC): 12.5-month follow-up of BOLERO-2

104

Background: Postmenopausal women with estrogen-receptor–positive (ER+) BC who relapse/progress on a nonsteroidal aromatase inhibitor (NSAI) are usually treated with the steroidal AI exemestane (EXE), but there is no currently approved treatment for this indication. The BOLERO-2 trial showed that adding everolimus (EVE), an oral inhibitor of mammalian target of rapamycin (mTOR), to EXE significantly improved clinical benefit beyond that of EXE alone (Hortobagyi et al, SABCS 2011, Abstract S3-7). As many women with advanced BC are elderly, the tolerability profile of EVE + EXE in this population is of interest. Methods: BOLERO-2 is a phase III, randomized trial comparing EVE (10 mg once daily) vs placebo (PBO), both plus EXE (25 mg once daily), in postmenopausal women with advanced ER+ BC progressing or recurring after NSAIs. Safety data with a focus on elderly patients are reported at 12.5 months’ median follow-up. Results: Baseline disease characteristics, age, and prior cancer therapy were well balanced between treatment arms (N = 724). At 12.5 months’ median follow-up, the addition of EVE to EXE significantly improved progression-free survival in patients <65 (HR, 0.37; p < .05) or ≥65 years of age (HR, 0.56; p < .05). Adverse events (AEs) of special interest (all grades) occurring more frequently with EVE vs PBO (overall study population) included stomatitis (66.6% vs 11.3%), infection (50.4% vs 25.2%), rash (44.0% vs 8.4%), pneumonitis (18.7% vs 0.4%), and hyperglycemia (15.4% vs 2.5%). Elderly EVE-treated patients (≥65 years) had similar or marginally lower incidence of stomatitis (52.1%), rash (32.3%), pneumonitis (14.6%), and hyperglycemia (12.5%) compared with the overall population. Grade 3-4 AEs in patients ≥70 years of age (n = 161) reported only among patients receiving EVE (n = 118) included fatigue (10.2%), anemia (10.2%), hyperglycemia (8.5%), stomatitis (7.6%), dyspnea (6.8%), pneumonitis (5.1%), neutropenia (3.4%), and hypertension (3.4%). Conclusions: Adding EVE to EXE was well tolerated in the overall population and in elderly patients with advanced BC; grade 3-4 AEs were uncommon and manageable. Overall, AEs were consistent with the known safety profile of EVE.

Everolimus for postmenopausal women with advanced breast cancer: Updated results of the BOLERO-2 phase III trial

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Background: Current treatment options for postmenopausal patients with estrogen-receptor–positive breast cancer (BC) who relapse or progress on a nonsteroidal aromatase inhibitor (NSAI) are limited. The BOLERO-2 trial supports the activity of everolimus (EVE; an oral mammalian target of rapamycin [mTOR] inhibitor) added to the steroidal aromatase inhibitor exemestane (EXE) to prolong progression-free survival (PFS) in this patient population. Long-term PFS and survival data are awaited. Methods: BOLERO-2 is a phase 3, double-blind, randomized, international trial comparing EVE (10 mg once daily) + EXE (25 mg once daily) vs. placebo (PBO) + EXE in postmenopausal women with advanced estrogen-receptor–positive BC progressing or recurring after NSAIs (letrozole or anastrozole). Patients were randomized (2:1) to EVE + EXE or PBO + EXE. The primary endpoint was PFS by local investigator assessment. Main secondary endpoints included centrally assessed PFS, overall survival (OS), safety, bone turnover, and overall response rate. Results: Baseline disease characteristics including tumor burden and prior cancer therapy were well balanced between treatment arms (N = 724). Median PFS was doubled and response rates were consistently improved with EVE + EXE (n = 485) vs PBO + EXE (n = 239) in interim analyses. Median PFS by local assessment was ~3 mo with PBO + EXE vs 6.9 mo (hazard ratio [HR], 0.43; P < .0001) and 7.4 mo (HR, 0.44; P < .0001) with EVE + EXE at 7.5 mo and 12.5 mo follow-up, respectively. Fewer deaths were reported with EVE + EXE (17.2%) vs PBO + EXE (22.7%) at 12.5 mo follow-up. Safety profiles were consistent with previous reports for mTOR inhibitors. PFS data including 528 events (protocol-specified final analysis), and updated OS and safety data will be presented. Conclusions: Adding EVE to EXE markedly prolonged PFS in patients with NSAI-refractory advanced estrogen-receptor–positive BC. There were fewer deaths among patients receiving EVE, and further follow-up will evaluate the effect of EVE on OS.