179O - Combination of olaparib, durvalumab and fulvestrant in patients with advanced ER-positive, HER2-negative breast cancer harboring homologous recombination repair (HRR) deficiency or microsatellite instability (MSI): Results of the international phase II DOLAF trial

Background

BRCA germline pathogenic variants (PV) ordefects in other genes involved in HRR or MSI have been associated with sensitivity to PARP inhibitors in metastatic breast cancer (mBC). Studies suggested synergy between immune checkpoint blockade and PARP inhibition. The ER-pathway also remains a key target in this setting.

Methods

We evaluated the combination of olaparib, durvalumab and fulvestrant in ER+/HER2- mBC and either somatic or germline PV in genes of the HRR pathway, or MSI status. Patients (pts) had received 1 prior line of endocrine therapy, including a CDK4/6 inhibitor and ≤ 1 line of chemotherapy for mBC. The primary objective was the progression-free survival rate at 24 weeks (24w PFSR). With a two-stage Simon design, the null hypothesis was a PFSR ≤ 50% among the first 149 evaluable pts. Secondary endpoints included safety, progression-free survival (PFS), overall survival (OS) and objective response rate (ORR).

Results

552 pts were screened and 172 included. gBRCA1/2 were the most frequent mutated HRR genes (n=67; 39%) followed by ATM/ATR (16%), FANCA (12%), PALB2 (9%) and CHEK2 (6%). With a median follow-up of 24.6 months, 24w PFSR was 66% (95% CI: 58.2 – 73.6) in the 154 evaluable pts and 76% [95%CI: 63.4-86.4] in gBRCAm pts. Median PFS was 9.3 months (95%CI: 7.5-12.7), 12.6 months (95%CI: 8.2-16.7), and 9.0 months (95%CI: 6.7 – 11.2) in the whole, gBRCAm and non-gBRCAm populations respectively. ORR was 41% (95%CI: 33.3-49.0). Median OS was 30 months (95% CI: 26.6-NE). Most common adverse events (AE) of any grade were nausea (64%) and asthenia (53%). 33.9% of pts presented at least one AE of grade ≥ 3, the main being anemia (9%). 6 pts stopped all the drugs due to AE. No toxicity warning was encountered.

Conclusions

In patients with ER+/HER2- mBC and molecular abnormalities predicting sensitivity to PARP inhibitors, the efficacy of a combination of olarapib, durvalumab and fulvestrant as 2d to 3rd line treatment compares well to current standards and has an acceptable toxicity profile (NCT04053322).

Clinical trial identification

EudraCT 2018-003832-57.

Legal entity responsible for the study

Unicancer.

Funding

AstraZeneca.

Disclosure

S. Guiu: Financial Interests, Institutional, Invited Speaker: Lilly; Financial Interests, Institutional, Expert Testimony: Pfizer. J. Balmaña: Financial Interests, Personal, Invited Speaker: AstraZeneca; Financial Interests, Institutional, Other, Educational programs: AstraZeneca -MSD; Financial Interests, Institutional, Invited Speaker: AstraZeneca, MedSir. P. Follana: Financial Interests, Personal, Invited Speaker: GSK, Eisai, MSD; Financial Interests, Personal, Expert Testimony: CLOVIS, Novartis; Financial Interests, Personal, Advisory Board: AZ; Financial Interests, Personal, Other, Congress invitation: Gilead. A. Gonçalves: Financial Interests, Institutional, Advisory Board: AstraZeneca, Novartis, MSD, innate pharma, Parexel, Gilead; Financial Interests, Institutional, Invited Speaker: Novartis, Roche, MSD, AstraZeneca, Daiichi Sankyo; Other, travel accommodation meeting registration: Mylan; Other, travel accommodation meeting registration: Novartis; Other, travel, accommodation, meeting registration: Roche, Menarini. J. Frenel: Financial Interests, Personal, Advisory Board: Pfizer, Novocure, Pierre Fabre, Eisai, Seagen, Gilead; Financial Interests, Personal, Invited Speaker: GSK, Amgen, Eisai; Financial Interests, Institutional, Advisory Board: Exact Science, Lilly, Daiichi Sankyo, AstraZeneca, Clovis Oncology; Financial Interests, Institutional, Invited Speaker: Novartis, MSD; Financial Interests, Invited Speaker: AstraZeneca, Seagen, MSD, Daiichi Sankyo; Non-Financial Interests, Principal Investigator: Novartis, Lilly, AstraZeneca, Pfizer, Daiichi Sankyo, MSD. E.G.C. Brain: Financial Interests, Personal, Invited Speaker, Webinars, optimized endocrine therapy for older breast cancer patients: Eli Lilly; Financial Interests, Personal, Advisory Board, Palbociclib and older breast cancer patients: Pfizer; Financial Interests, Personal, Invited Speaker, Symposium HER2+ MAO conference 03/21: Seagen; Financial Interests, Personal, Invited Speaker, ELEVATE 10/2021 and ABC 11/2021 meeetings: Pfizer; Financial Interests, Personal, Other, IDMC DESTINY 05: DAIICHI; Financial Interests, Personal, Advisory Board, GCSF and FN in older patients: SANDOZ; Financial Interests, Personal, Advisory Board, Underserved Patients Populations with breast cancer, advisory board: Pfizer; Financial Interests, Personal, Invited Speaker, Management of older patients with cancer, series of seminars in Canada for HCP: Pfizer; Financial Interests, Personal, Invited Speaker, Symposium during SIOG annual meeting 1/11/2023: Daiichi; Financial Interests, Personal, Invited Speaker, RWD in myeloma and older patients, Prohgress, 17/11/2023: Takeda; Financial Interests, Personal, Invited Speaker, TIBCS, Taipei, older patients with breast cancer, 21/09/2023: Pfizer; Financial Interests, Personal, Invited Speaker, Series of lectures in Montreal/Quebec on breast cancer management in older ones, 09-13/10/2023: Pfizer; Financial Interests, Personal, Advisory Board, Elacestrant and BC, 13/03/2023: Menarini; Financial Interests, Personal, Invited Speaker, 29/03/2023 symposium during SFH annual meeting, RWD and older patients: Incyte; Financial Interests, Institutional, Invited Speaker, APPALACHES study EORTC 1745: Pfizer; Financial Interests, Institutional, Invited Speaker, TOUCH study (IBCSG 55/GERICO study): Pfizer; Financial Interests, Institutional, Invited Speaker, DEESTINY 09: Daiichi Sankyo; Financial Interests, Institutional, Invited Speaker, DESTINY 06: Daiichi Sankyo; Financial Interests, Institutional, Invited Speaker, SERENA 06: AstraZeneca. A. Mailliez: Financial Interests, Institutional, Invited Speaker: AstraZeneca, MSD, Novartis, Roche; Financial Interests, Personal, Invited Speaker: Pierre Fabre, OSEUS, Seagen, Pfizer, Daiichi Sankyo; Financial Interests, Personal, Expert Testimony: GSK. E. Curtit: Financial Interests, Personal, Advisory Board, Advisory board on QoL in breast cancer Nov 2021Advisory board: Novartis SAS; Financial Interests, Personal, Invited Speaker, Speaker in: Novartis, AstraZeneca; Financial Interests, Personal, Advisory Board, AstraZeneca Board, Jul 2022: AstraZeneca; Financial Interests, Personal, Advisory Board, Board: Exact Sciences; Financial Interests, Personal, Invited Speaker, Speaker in Exact Sciences Symposium at: Exact Sciences; Financial Interests, Personal, Invited Speaker, WebTV from: Daiichi; Financial Interests, Institutional, Research Grant, Research Grant: to assess the immunological effect of everolimus (Cohort with 100 patients treated by everolimus): Novartis; Financial Interests, Institutional, Funding, I am currently asking a funding for a project (French Databsis of patients who benefited from OncotypeDX signature), but the project is not yet validated: Exact Sciences; Non-Financial Interests, Principal Investigator, I am PI in 3 academic translational trials: University Hospital Besançon, France; Other, I received a grant (36 k€) from the Nuovo Soldati foundation in 2021 to allow me to go to the CHUV in Lausanne, Suisse, for a year as part of a mobility experience: Nuovo-SoldatiFoundation. F. Dalenc: Non-Financial Interests, Principal Investigator: Roche, AstraZeneca, Gilead, Novartis. J. Canon: Financial Interests, Institutional, Research Grant: Roche. T. Bachelot: Financial Interests, Personal, Advisory Board: Novartis, AstraZeneca, Pfizer, Seagen, Daiichi Sankyo; Financial Interests, Institutional, Advisory Board: Lilly; Financial Interests, Institutional, Research Grant: Novartis, Roche, AstraZeneca, Seagen, Pfizer; Financial Interests, Personal, Invited Speaker: Roche; Financial Interests, Institutional, Invited Speaker: AstraZeneca; Non-Financial Interests, Principal Investigator: Roche, AstraZeneca. S. Delaloge: Financial Interests, Institutional, Advisory Board: Novartis, Sanofi, Gilead; Financial Interests, Institutional, Invited Speaker: Pfizer, Roche Genentech, BMS, Sanofi; Financial Interests, Institutional, Advisory Board, ad board: Besins Healthcare; Financial Interests, Institutional, Invited Speaker, ESMO symposium: Gilead; Financial Interests, Institutional, Advisory Board, scientific board: Elsan; Non-Financial Interests, Member of Board of Directors, Société Française de Sénologie et Pathologie Mammaire: SFSPM; Non-Financial Interests, Principal Investigator, H2020 funding: European Commission. All other authors have declared no conflicts of interest.