Introduction. The presence of a germinal BRCA mutation occurs in 3–4% of all breast cancer (BC) patients with various biological subtypes, but significantly with a high frequency in patients with a triple negative biological subtype (in 10–20% of cases). For the treatment of patients with HER2-negative metastatic breast cancer associated with gBRCA mutation, the effectiveness of biologically targeted drugs from the group of PARP inhibitors (olaparib and talazoparib) has been proven.Purpose. Comparison of the results of our experience with the use of talazoparib in patients with HER2-gBRCA+ + mBC with the data of the EMBRACA registration study.Materials and methods. As part of the multicenter compassionate use program (CUP) with the support of Pfizer, 24 patients with HER2-negative metastatic gBRCA-associated mutation metastatic breast cancer (HER2-gBRCA+ breast cancer) received biologically targeted therapy with the PARP inhibitor talazoparib at a standard oral dose of 1 mg per day for vital indications . The average age of patients with HER2-gBRCAm+ breast cancer was 50 years (29–90 years).Results. Objective response (OR) was registered in 29% of cases, disease control (OR+stabilization) – in 71% of cases. The median progression-free survival (PFS) was 6.5 months (95% CI [3–10]). Objective response, disease control, and median PFS were evaluated depending on the biological subtype, the number of lines of previous therapy, and the presence of platinum-containing agents in the anamnesis.Objective response and disease control were evaluated depending on the biological subtype: in patients with ER+HER2-mBC versus patients with triple negative subtype, OR was 33% vs 22%, and disease control was 83% vs 61%, respectively. In the presence of < 3 vs ≥ 3 lines of therapy for metastatic disease in the anamnesis, OR was 31% vs 12.5%, disease control – 75% vs 50% of cases, respectively. In the presence or absence of platinum-containing agents in the anamnesis, OR was observed in 22% vs 33% of cases, and disease control – 67% vs 67%, respectively.In patients with the luminal subtype versus patients with the triple negative subtype, the PFS was 9 months vs 5 months, respectively (HR = 0.705; 95% CI [0.231–2.147]; p = 0.5208). Median PFS in the presence of <3 vs ≥3 lines of therapy for metastatic disease in the anamnesis was 9 months vs 4 months, respectively (HR = 4,216; 95% CI [1,334–13,327]; p = 0.0056). In the presence or absence of platinum-containing agents in previous lines of therapy 5 months vs 9.5 months, respectively (HR =1.484; 95% CI [0.48–4.582]; p = 0.4750).During the treatment with talazoparib adverse events of the 3rd-4th grades were observed in 5 patients (20,8%). These include moderate and severe anemia in 3 patients (12.5%), thrombocytopenia in 1 patient (4%), and neutropenia in 1 patient (4%). The majority of patients (79,5%), which received talazoparib, did not require dose adjustment. The need to reduce the dose to 0.75 mg was noted in 3 patients (12.5%), to 0.5 mg – in 2 patients (8%). Hemotransfusion was performed in 3 patients. For effective therapy safety management regular monitoring of blood parameters is necessary.Conclusion. Thus, targeted therapy with talazoparib is an effective treatment option for HER2-gBRCA+ mBC.

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Currently, 6 months of perioperative or adjuvant chemotherapy (ACT) is a standard treatment option after radical surgical removal of metachronous metastases in patients with metastatic colorectal cancer (CRC). Data show that ACT improves relapse-free survival in such patients, although no difference in overall survival rate was observed. We perform a systematic review to evaluate the efficacy of adjuvant chemotherapy after radical resection of metachronous metastases in CRC.

e13035 Background: EMPOWER trial demonstrated the benefit of eribulin administrated post CD4/6i in patients (pts) with HR+ HER2-negative (HR+HER2-) metastatic breast cancer (MBC). There are several important limitations to this trial: > 60% of pts were stage IV at the time of treatment initiation, eribulin used in late lines (2L only in 30% pts) and follow-up data were immature. Current study aimed to provide additional data on the real-world effectiveness and safety of eribulin monotherapy in this setting. Methods: Observation study of eribulin monotherapy in standard regimen enrolled 54 pts (median age 56; range 29-79 years) with HR+ HER2- MBC received at least one dose of eribulin post CDK 4/6i in metastatic settings; 24% pts had de novo metastatic BC, 76% - recurrent BC; 77% received palbociclib, 21% ribociclib, 2% both drugs; 49% pts received CDK4/6i with fulvestrant and 51% with AI. CDK4/6i was used: 49% pts in 1L, 36% in 2L, 16% in 3L. Median DOR of CDK4/6i treatment was 9.07 months (range 2-38). 94% pts received anthracyclines and taxanes, eribulin was used in 2L in 60%, 30% in 3L, 8% in 4L, 2% in 5L. The most common sites of metastases (Mts) were bones (78%), liver (73%), lung (56%) and brain (8%); visceral Mts were seen in 90% pts. Median follow-up – 11,5 months (range 3-36). Results: Median cycles of eribulin therapy was 10,5 (range 1-44); objective response rate was seen in 24%, stabilization - 67%, progression - in 9%. Median PFS was 10.0 months, there were no significant differences in the different subgroups (visceral/no visceral; recurrent/de novo BC; age; CDK4/6i as 1L vs 2L, fulvestrant vs AI), p > 0,05. Median PFS was higher in pts with lung Mts vs non-lung (24 vs 9,1 months, p = 0.056). Most common AEs all grades were neutropenia (26%), anemia (9%), asthenia (9%), polyneuropathy (11.1%). AE did not affect the effectiveness of eribulin (p = 0.648). Dose reduction was in 19% pts and did not affect the effectiveness of eribulin (p = 0.612). At median follow-up of 11.5 months, 92.5% of patients still alive. Conclusions: As post-CDK4/6i therapy, eribulin in HR+HER2- MBC pts was effective and well tolerated, regardless of age, line of CDK4/6, CDK 4/6i combination partner. Patients with metastasis to the lung have better mPFS. Results in this real-world population of pts with HR+HER2- MBC were consistent with the EMPOWER study, and support administration of eribulin in 2-3 lines as an effective option for post-CD4/6i pts.

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