Prior Lines Of Chemotherapy Research Articles

A phase III study of lurbinectedin alone or in combination with irinotecan vs investigator's choice (topotecan or irinotecan) in patients with relapsed small cell lung cancer (SCLC; LAGOON trial).

TPS8613 Background: Lurbinectedin is a novel synthetic chemical entity that acts as an inhibitor of oncogenic transcription and is active in tumors addicted to transcription. A phase II Basket trial (NCT02454972) in patients with small cell lung cancer (SCLC) treated with lurbinectedin in the second-line setting showed overall response rate (ORR) of 35.2% and median duration of response (DoR) of 5.3 months, with durable responses (43.0% ≥ 6 months). Based on these results, lurbinectedin was granted accelerated approval by the US FDA. An ongoing phase I/II trial (NCT02611024) is evaluating the lurbinectedin/irinotecan combination. Preliminary results showed ORR of 62% and median DoR of 5.7 months (2020 World Conference on Lung Cancer) warranting expansion to 100 patients. These results have supported the conduction of a phase III trial (LAGOON - NCT05153239). Methods: LAGOON is a randomized phase III clinical trial evaluating two experimental arms (lurbinectedin alone, 3.2 mg/m2 D1 q3wk, or lurbinectedin 2 mg/m2 D1 plus irinotecan D1, D8 q3wk) versus Investigator’s Choice (topotecan D1-5 q3wk or irinotecan D1 q3wk according to label) as control arm in relapsed SCLC patients. Approximately 705 patients will be enrolled. Central randomization will be implemented (1:1:1 ratio). Stratification will be done according to chemotherapy-free interval (CTFI) after first line (sensitive vs. resistant); prior anti-PD-(L)1; baseline central nervous system (CNS) involvement; lactate dehydrogenase value, and Investigator’s preference for the Control Arm. Main inclusion criteria include age ≥ 18 years, confirmed SCLC diagnosis, one prior line of platinum-containing chemotherapy with/without anti-PD-(L)1, and CTFI ≥ 30 days. Patients with CNS metastases can participate if pretreated and radiologically stable for at least 4 weeks. Main exclusion criteria include platinum-naïve patients, patients pretreated with more than one prior chemotherapy regimen (including platinum re-challenge), and prior treatment with lurbinectedin, trabectedin, PM14, or topoisomerase I inhibitors. An Independent Data Monitoring Committee will oversee the conduct of the study. An Independent Review Committee will provide the patient’s response at each tumor assessment endpoint to determine the best patient’s response and the date of objective response or progression/censoring according to RECIST v.1.1. Clinical trial information: NCT05153239 .

Luveltamab tazevibulin (STRO-002), an anti-folate receptor alpha (FolRα) antibody drug conjugate (ADC), safety and efficacy in a broad distribution of FolRα expression in patients with recurrent epithelial ovarian cancer (OC): Update of STRO-002-GM1 phase 1 dose expansion cohort.

5508 Background: Luveltamab tazevibulin (luvelta) is a novel FolRα-targeting ADC with a stable cleavable linker and a 3-aminophenyl hemiasterlin warhead (DAR of 4) that induces cytotoxic and immunologic cell death. Using site-specific conjugation technology, luvelta is designed to target a broad range of FolRα expressing OC. STRO-002-GM1 is a global phase 1 study evaluating luvelta in patients with relapsed OC. We provide updated data from the initial ovarian expansion cohort. Methods: The study enrolled advanced OC pts who had progressive platinum resistant (PROC) after 1-3 prior lines or platinum sensitive disease after 2-3 prior lines of platinum chemotherapy. Pts were randomized 1:1 to received luveltamab at 4.3 or 5.2 mg/kg given IV every 3 weeks until disease progression. Prophylactic corticosteroid eyedrops were not required/administered. FolRα expression was not required for study entry but was analyzed retrospectively in archival tissue using the FOLR1 IHC assay (Ventana Medical Systems). The scoring paradigm assessed percentage of cells with any intensity expression (TPS). TPS >25% was selected for further analysis. Results: 44 pts were enrolled (23 pts at 4.3 mg/kg and 21 pts at 5.2 mg/kg). For pts with a TPS >25% (n=35), the median prior lines of therapy was 2.5 (range 1-3), 69% had prior bevacizumab treatment, and 83% prior PARP inhibitor treatment. Investigator assessed efficacy data for pts with a TPS >25% are presented in the table. The most common grade ≥ 3 treatment emergent adverse events (TEAEs) included neutropenia (70.5%), arthralgia (18.2%), and anemia (13.6%). G3/4 neutropenia had a higher incidence at 5.2 mg/kg than 4.3 mg/kg (76% vs 65%); most notable for G4 neutropenia (52% vs 22%). 1 pt at each dose level had febrile neutropenia. TEAEs led to dose delay in 80% of pts with a higher incidence at 5.2 mg/kg (95% vs. 65%). TEAEs led to dose reduction in 61% of pts with a higher incidence at 5.2 mg/kg (76% vs. 48%). 1 pt had a G5 sepsis with G4 neutropenia. Neutropenia, arthralgia and anemia were managed with standard medical treatment and dose reductions. Conclusions: These dose expansion data confirm activity of luvelta at starting doses ranging from 4.3-5.2 mg/kg in recurrent OC with FolRα expression as low as TPS>25% and supports further clinical study in this population. The global phase 2/3 REFRaME registration study will evaluate luvelta in PROC pts with TPS >25%. Clinical trial information: NCT03748186 . [Table: see text]

A phase II study of olaparib and durvalumab in patients with IDH-mutated cholangiocarcinoma.

4099 Background: IDH1/2 mutations (m) occur in approximately 25% of cholangiocarcinomas (CCAs) (20% intrahepatic, < 5% extrahepatic) and result in the accumulation of R-2-hydroxyglutarate (R2HG). R2HG, suppresses homologous recombination repair and as a result IDH1/2m are hypothesized to predict PARP inhibitor sensitivity. PARP inhibition upregulates PD-L1 and the combination is thought to be synergistic. We conducted a phase II trial of olaparib with durvalumab for patients with IDH-mutated cholangiocarcinoma. Methods: Patients with advanced IDHm CCA were enrolled in this phase II open-label study (NCT03991832). Patients received olaparib 300 mg twice daily continuously and durvalumab 1500 mg IV every 4 weeks. Simon’s optimal two-stage design was used, with an interim analysis planned for efficacy. 10 patients were accrued in the first stage, with a plan for expansion if ≥2 responses were observed. The primary objective was to determine the overall response rate (RECIST 1.1) and disease control rate (DCR). Secondary objectives included progression-free survival, overall survival, and safety of the olaparib and durvalumab combination. Results: 10 patients with IDH1m were enrolled in this study between January 2020-August 2021. Median age was 63.5 years (range 49-78), and 50% were female. All patients had a baseline ECOG PS of 0-1. 40% of patients had prior surgical resections and subsequently developed recurrent disease. 20% of patients had ³2 lines of prior chemotherapy, with 90% receiving prior platinum. Median duration of treatment was 1.95 months (range 1.8-13.5). There were no treatment-related grade 3-4 toxicities. Any grade toxicities included fatigue (100%), nausea (60%), anemia (20%), hypothyroidism (20%), elevated liver enzymes (20%). We did not observe any complete or partial responses. The DCR was 30% with 3 patients demonstrating stable disease. One patient remained on treatment for 13.5 months, and was eventually taken off study due to clinical progression. The median PFS was 1.97 months (95% CI 1.73-3.93). Given that no responses were seen in the initial 10 patients, the study did not proceed to Stage 2. Conclusions: While the combination of olaparib and durvalumab was well-tolerated, this study was discontinued after Stage I due to lack of efficacy. IDH1/2m may not induce a BRCAness phenotype and further correlative studies are planned to evaluate this. Clinical trial information: NCT03991832 .

CRI-CCTG-0003/IND.240: An immunotherapy platform study in platinum-resistant high grade serous ovarian cancer (IPROC).

TPS5617 Background: Identifying new treatments for patients with platinum-resistant high grade serous ovarian cancer (HGSC) is a priority. Although several biological features of HGSC suggest inherent immunogenicity, immunotherapy has had limited efficacy to date. IPROC is an adaptive platform trial designed to evaluate multiple immunotherapy combinations selected and informed by an expert panel. IPROC accommodates both biomarker-agnostic and biomarker-directed combinations. Protocol and sub study specific translational studies are conducted on archived diagnostic tissue and serial prospective blood and tumor sample collection. Methods: IPROC is an open-label, multi center, phase II platform trial. Eligibility includes HGSC histology; progression within 6 months of the last platinum regimen; <1 prior line of chemotherapy for platinum resistant disease (unlimited prior lines for platinum sensitive); prior treatment with immunotherapy allowed (provided not discontinued for toxicity), ECOG 0/1. Patients must be willing and able to undergo study procedures. The primary endpoint is ORR (RECIST1.1). Secondary endpoints include iRECIST ORR, RECIST/iRECIST progression free and overall survival and safety. Exploratory objectives include whole exome sequencing and immune profiling of tumor and blood samples to identify biomarkers and new immunotherapy strategies/combinations for future evaluation. Tumor biopsy occurs at baseline, cycle 2 and progression (voluntary) with blood and plasma collected at each cycle and on progression. All sub studies use Simon 2-stage design with 10 patients (pts) enrolled in each stage. At the end of stage 1, in the absence of response, a modified cohort based on biomarker selection may be created through protocol amendment. In each substudy a null hypothesis that the objective response rate (ORR) is ≤5% is tested against a one-sided alternative that the ORR is ≥ 25%. A combination would be accepted as active if ≥4/20 pts respond with α=0.02 and power of 0.76. As of January 19, 2023, 2 sub studies are open and 12 patients have accrued. Sub study A is evaluating the combination of durvalumab and BA3011, a conditionally active anti-AXL humanized monoclonal antibody (IgG1) conjugated to monomethyl auristatin E (MMAE) in AXL overexpressing HGSC. Sub study B is evaluating durvalumab plus BA3021, a CAB anti-receptor tyrosine kinase orphan receptor 2 (ROR2) humanized monoclonal antibody (IgG1) conjugated to MMAE in ROR2 overexpressing HGSC. Further sub studies are planned (NCT04918186). Clinical trial information: NCT04918186 .

Biomarker analysis of phase II pembrolizumab maintenance treatment after chemotherapy response in patients with HER2-negative inflammatory breast cancer and triple-negative breast cancer.

1105 Background: Accumulating toxicities make indefinite chemotherapy unfeasible for many patients with metastatic/recurrent HER2-negative inflammatory breast cancer (IBC) or triple-negative breast cancer (TNBC). We conducted a single-arm phase II trial of pembrolizumab monotherapy to determine the efficacy of maintenance immunotherapy in patients with metastatic HER2-negative aggressive breast cancer and to identify biomarkers correlated with disease control. Methods: The study enrolled patients who had a complete response, partial response, or stable disease after a minimum of 3 cycles of chemotherapy for metastatic TNBC/IBC regardless of PD-L1 expression between 2015 and 2022. Pembrolizumab was administered at 200 mg every 3 weeks until disease progression, intolerable toxicity, or 2 years of exposure to the drug. The primary endpoint was the 4-month disease control rate (DCR), and the secondary endpoint was progression-free survival (PFS). Correlative studies were performed to determine associations between clinical response, and immune profiling consisting of T-cell clonality, immunophenotyping, and dendritic cell (DC) function with blood collected at baseline and after 2 cycles of pembrolizumab treatment. Results: Of 43 treated patients, 11 had metastatic IBC and 32 had TNBC. The median number of prior lines of chemotherapy for metastatic disease was 1. During a median follow-up of 11.4 months, 33 patients had progressive disease and 25 were deceased. The 4-month DCR was 58.1% (95% CI: 43.4%-72.9%) and the median PFS was 4.8 months (95% CI: 3.0-7.1 months). The median PFS of the metastatic IBC group (2.2 months) and TNBC group (4.8 months) did not differ significantly ( p = .12). Thirty-one patients discontinued treatment due to progressive disease rather than toxicity. Observed toxicities were consistent with the known profile of pembrolizumab. Correlative blood studies showed availability of PD-1 on CD8 T cells decreased on therapy. T-cell exhaustion markers 2B4, CTLA4, and TIM3 decreased in patients who had therapeutic benefit, while LAG3 increased in patients without benefit. During therapy, ex vivo cytokine synthesis (IL-6/IL-12/TNFα) by DCs was superior in patients who benefited from therapy and increased from pretreatment samples. High T-cell clonality at baseline predicted response to immunotherapy (10.4 vs 3.6 months, p = .04). Additionally, patients exhibiting the greatest clinical benefit also had a significant increase in T-cell clonality over the course of therapy (20% vs 5.9% mean increase, p = .04). Conclusions: Increased T-cell clonality and DC activity, along with reductions in T-cell exhaustion, were associated with prolonged disease control following pembrolizumab maintenance therapy, achieving acceptable disease control with manageable toxicity. Clinical trial information: NCT02411656 .

Clinical outcomes of patients with metastatic breast cancer treated with eribulin: A real-world evidence study from China.

e13126 Background: Eribulin is a novel synthetic analog of halichondrin B that acts as a microtubule inhibitor and inhibits the G2-M growth phase. Eribulin was approved for metastatic breast cancer (MBC) based on the landmark phase 3 EMBRACE trial (Cortes et al, Lancet 2011; NCT00388726); however, only a small number of Asian patients were included in that trial. Therefore, in this real-world study, we retrospectively assessed the clinical outcomes of Chinese patients with MBC who received eribulin. Methods: Adult patients with MBC who received eribulin as several lines of therapy were retrospectively analyzed. Socio-demographic, clinical, pathology, imaging, and therapy records were reviewed. Progression-free survival (PFS) and tumor response were evaluated. Results: A total of 85 patients were included. The median age was 45 years (range, 21–63). Eribulin was used as a first, second, third, and fourth or more chemotherapy agent in 13 (15.3%), 16 (18.8%), 11 (12.9%) and 45 (52.9%) of patients with MBC, respectively. Eribulin was monotherapy in 32.9% of patients; eribulin plus anti-HER2 targeted therapy was used in 9.4% of patients; eribulin plus immunotherapy was used in 5.9% of patients; eribulin plus other chemotherapy was used in 36.5% of patients, and eribulin plus antiangiogenic therapy was used in 9.4% of patients. The objective response rate (ORR) was 28.2% overall. By number of lines of therapy, the first-line ORR was 38.5% and the second-line ORR was 37.5%. On subgroup analysis, ORR of patients with liver metastasis and lung metastasis was 43.9% and 38.6 %, respectively. By molecular classification, the ORR of patients with HR+/HER2− disease was 66.7%; among patients with HER2+ disease, 32.6%; and among patients with triple-negative BC, 13.3%. The 6-month PFS rate was 33.6% overall. By number of lines of therapy, the 6-month PFS rate among patients who received eribulin as first-line treatment was 67.7% and among patients who received eribulin as second-line treatment, 38.3%. Among patients who received eribulin monotherapy, the 6-month PFS rate was 21.4% and among patients who received eribulin combination therapy, 41.2%. No adverse reactions related to neutrophils were reported. Conclusions: This real-world retrospective study suggests that eribulin was effective in Chinese patients with MBC with a range of prior lines of chemotherapy, supporting the use of eribulin in the treatment of Chinese patients with MBC.

LEONARDA-1: Phase III randomized study of lerociclib plus fulvestrant in patients with HR+, HER2- locally advanced or metastatic breast cancer that has progressed on prior endocrine therapy.

1017 Background: Lerociclib (GB491), a novel oral CDK4/6 inhibitor with continuously daily dosing, which has demonstrated anti-tumor response and a differentiated safety & tolerability profile in previous clinical trials. The LEONARDA-1 study assessed the efficacy of lerociclib and fulvestrant in endocrine-resistant advanced BC. Methods: This is a randomized, double-blind, placebo-controlled phase III study assessing lerociclib in combination with fulvestrant in pre/peri-menopausal or postmenopausal, HR+, HER2- locally advanced or metastatic BC patients (pts) who had relapsed or progressed on prior endocrine therapy (ET). Eligible patients were allowed one prior line of chemotherapy for metastatic disease. Pre-/peri-menopausal pts also received goserelin. Pts were randomized 1:1 to receive lerociclib (150mg po bid, d1-28, q4w) or placebo (P) plus fulvestrant (F). The primary endpoint was investigator-assessed progression-free survival (PFS) based on RECIST v1.1. Secondary endpoints included PFS (assessed by BICR), overall survival (OS), response assessment, safety and tolerability, pharmacokinetic (PK) profile. Results: By December 2nd 2022 as data cut-off date, 275 pts were randomized, 137 to receive lerociclib + F and 138 to P + F. Median follow-up time was 7.36 months (range, 0.03-11.93+) for lerociclib + F vs 7.33 months (range, 0.03-11.27) for P + F. Baseline characteristics were well balanced (The median age was 54 years and 53.5 years, 41.6%% and 44.9% were Pre/peri-menopausal, 64.2% and 62.3% had visceral disease, 24.8% and 26.1% were primary resistant to prior ET, 28.5% and 29.0% received one line of chemotherapy for metastatic disease, respectively). At the time of cut-off date, 125 PFS events were observed with a median PFS of 11.07 months for lerociclib + F and 5.49 months for P + F (HR: 0.458; 95% CI: 0.317, 0.661, P< 0.001 by log-rank test). In patients with measurable disease (n=240, 87.3%), the ORR was significantly higher in lerociclib + F 26.9% (2.5% complete response [CR]) vs 9.9% (0% CR) for P + F. Consistent benefit from lerociclib was seen in pre/peri-menopausal and postmenopausal subjects. The most common adverse events (AEs) for lerociclib + F versus P + F were neutropenia (90.5% vs. 4.3%), leucopenia (86.9% vs. 6.5%), anemia (34.3% vs. 10.1%), thrombocytopenia (19.7% vs. 3.6%), and diarrhea (19.7% vs. 3.6%). Grade 3 or 4 neutropenia was reported in 46.7% pts on lerociclib + F (G3: 41.6%, G4: 5.1%) vs 0% pts on P + F. There was no case of ≥Grade3 diarrhea reported. The discontinuation rate due to AEs was 0.7% on lerociclib + F and 0% on P + F. Serious AEs were reported for 5.8% and 8.0%, respectively. Conclusions: Lerociclib at 150mg twice daily plus fulvestrant significantly improved PFS and ORR and demonstrated a favorable tolerable safety profile in pts with HR+ / HER2- endocrine-resistant advanced BC. Clinical trial information: NCT05054751 .

Efficacy of immune checkpoint inhibitors in microsatellite unstable/mismatch repair-deficient advanced pancreatic adenocarcinoma: An AGEO European Cohort.

4148 Background: Immune checkpoint inhibitors (ICI) have been approved for the use in solid tumors with MSI/dMMR. Nevertheless, the outcome of patients (pts) with MSI/dMMR pancreatic ductal adenocarcinoma (PDAC) seems poorer when compared to other malignancies. This multi-institutional analysis aimed to assess the efficacy and tolerability of ICIs in a large real-world cohort of pts with MSI/dMMR PDAC. Methods: Retrospective data were collected for pts with MSI/dMMR PDAC treated with ICIs from February 2016 to May 2022 in 16 different centers across Europe and Israel. Progression-free survival (PFS) and overall survival (OS) were calculated from the start of treatment, and objective response (OR) and disease control rate (DCR) were measured according to RECIST V1.1. Results: We identified 31 pts with metastatic MSI/dMMR PDAC. The mean age was 62.1 years (range: 37-82), 45.1% were female and ECOG PS status was predominantly 0 or 1 (83.9%). At the time of ICI treatment 1 pt had locally advanced and 30 had metastatic disease. MSH2/MSH6 deficiency (def) was found in 9 cases, MLH1/PMS2 def in 7, MSH 6 def in 4, MSH 2 def in 3, PMS2 def in 3 and MLH1/MSH6/PMS2 def and, a CpG highland methylator phenotype in 1 pt. MMR status was not available in 4 pts. Germline mutation testing was performed in 20/31 pts (64.5%) and Lynch syndrome was diagnosed in 8 pts (45%). Nineteen pts received pembrolizumab, 8 received nivolumab, 1 received lodapolimab and 3 received ipilimumab/nivolumab (ipi/nivo). The mean number of prior lines of chemotherapy was 1.5 (range 0-4). Among the 31 pts in this analysis, 15 (48,4%) had an OR (3: complete response and 12 partial response) and 6 (19,3%) had stable disease, resulting in a DCR of 67.7%. Ten pts had disease progression (PD) (32.3%). Median PFS was 26.7 months and median OS was not reached with median follow-up (FU) of 18 months. Median duration of response was not reached (95%CI:24.1-NR). Analysis of all responders, with a follow up of 12 months or more (n:14), showed that 100% of them maintained their response. In addition 71% of the pts of this cohort are still alive with a median time of follow up since the diagnosis of metastatic disease of 39.9 months. After ICIs discontinuation, 6 pts received chemotherapy. One pt who had PD after 15 months of pembrolizumab switched to ipi/nivo and achieved a CR. Immunotherapy was generally well tolerated; No Grade 3-5 adverse events (AEs) were reported and no therapy discontinuation due an adverse event was observed. Conclusions: This retrospective analysis suggests that ICIs are effective and well tolerated in pts with MSI/dMMR advanced PDAC. Hence, our work supports the use of PD-1 inhibition in this group of pts with high unmet medical need.

Safety and efficacy of PIPAC in patients with ovarian cancer with peritoneal metastases: A first-in-US phase I study.

5554 Background: Epithelial ovarian cancer (EOC) is characterized by chemoresistant recurrences primarily confined to the intraperitoneal cavity, frequently leading to malignant small bowel obstructions. Intraperitoneal (IP) chemotherapy has been incorporated in EOC, but only in the first-line setting. Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a novel IP drug delivery method that optimizes tissue penetration depth and drug distribution, to treat recurrent peritoneal malignancies. Recent trials outside the U.S. demonstrated partial to stable response following PIPAC in recurrent EOC. To date, no clinical trials have been completed investigating the role of PIPAC in EOC in the United States. Methods: We performed a multicenter prospective phase I trial using IP cisplatin 10.5 mg/m2 and doxorubicin 2.1 mg/m2 via PIPAC at 6-week intervals. Patients were eligible if they had recurrent disease with peritoneal metastasis; extraperitoneal metastasis was allowed. The primary endpoint was dose-limiting toxicity (DLT). Secondary endpoints included progression free survival, PCI scoring, RECIST measurements, and quality of life (QoL). The patients with gastric and uterine cancers’ toxicity data were used but given inherent prognostic differences the treatment efficacy for these patients were not used in this analysis. Adverse event (AE) monitoring was graded using CTCAE spanning 18 weeks. Following completion of treatment (³2 PIPACs) patients were followed up every 12 weeks. QoL was measured using patient-reported assessments at 0, 6, 12, and 18 weeks. Baseline demographics were summarized. Mean change in PCI was calculated between cycle (C) 1 and 2, and cycle 2 and 3. Toxicities attributed to the surgery or PIPAC were reported with highest grade for each patient. Results: Nine heavily pretreated, recurrent patients were enrolled in the trial: 7 with platinum-resistant recurrent EOC, 1 with uterine cancer, and 1 with gastric cancer. PIPAC completion rate was 71.4%. Median age of participants was 65 years. Median prior lines of chemotherapy were 4 (range 2 - 10). No surgical complications occurred in the cohort. Two patients came off study: one for G3 abdominal pain and the other for G3 anorexia. For the EOC cohort, the median PCI reduction was -1.4% (C1 to C2) and -2.8% (C1 to C3). One low-grade serous EOC patient demonstrated a partial response based on RECIST criteria and received 6 cycles. Two EOC patients showed an initial response based on PCI reduction, but progressed following Cycle 2. Overall, QoL was stable. Conclusions: PIPAC with cisplatin/doxorubicin in platinum-resistant ovarian cancer is well tolerated. Intraperitoneal responses were seen in a subset of low-grade serous ovarian cancer patients, which may warrant further study. Heavily pretreated, platinum-resistant high-grade EOC patients derived limited intraperitoneal control from PIPAC monotherapy. Clinical trial information: NCT04329494 .

185O Trastuzumab deruxtecan (T-DXd) vs treatment of physician’s choice (TPC) in patients (pts) with HER2-low unresectable and/or metastatic breast cancer (mBC): A detailed safety analysis of the randomized, phase III DESTINY-Breast04 trial

DESTINY-Breast04 (NCT03734029) demonstrated significantly improved overall and progression-free survival (PFS) with T-DXd vs TPC in pts with HER2-low (immunohistochemistry [IHC] 1+ or IHC 2+/in situ hybridization-negative) mBC, with manageable safety. Here, we report additional safety data. Pts with centrally confirmed HER2-low mBC, treated with 1-2 prior lines of chemotherapy, were randomly assigned 2:1 to receive T-DXd or TPC. An analysis of selected treatment-emergent adverse events (TEAEs) and age (<65 vs ≥65 years [y]) was done; endpoints included time to first onset (TTO), duration of first event (DUR), and resolution. At data cutoff (January 11, 2022), median (m) treatment duration was 8.2 months (mo; range [r], 0.2-33.3) for T-DXd vs 3.5 mo (r, 0.3-17.6) for TPC. Exposure-adjusted incidence rates (EAIRs; per pt-y) for any-grade TEAEs were lower for T-DXd vs TPC (1.30 vs 2.66). mTTO and mDUR of any-grade interstitial lung disease (ILD) in pts treated with T-DXd were 129 days (d; r, 26-710 d) and 47 d (r, 13-365 d). 13 pts had adjudicated drug-related grade 1 ILD; of those pts, 6 were rechallenged with T-DXd after resolution (details to be presented). Incidence of any-grade drug-related neutropenia (NP) and febrile NP was lower for T-DXd vs TPC; subsequent granulocyte colony-stimulating factor use was 6.7% vs 19.8%. Nausea/vomiting (N/V) events in T-DXd vs TPC were 79.5% vs 35.5%. T-DXd-treated pts received more antiemetic prophylaxis (AP; 50.9%) vs TPC-treated pts (37.2%); 92.3% of T-DXd and 68.8% of TPC N/V events in AP-treated pts resolved. Incidence of any-grade drug-related TEAE was consistent between pts aged <65 y and ≥65 y. For T-DXd, incidence of grade ≥3 TEAEs and TEAEs associated with drug discontinuations (DD) was higher in pts aged ≥65 y compared to those aged <65 y; the most common TEAE associated with DD was ILD/pneumonitis. However, mPFS favored T-DXd over TPC in all patients, regardless of age. EAIR, TTO, and DUR data for selected TEAEs will be presented. T-DXd demonstrated a manageable safety profile to support its use as the new standard of care in pts with HER2-low mBC.

The Role of Immunotherapy in Advanced and Recurrent MMR Deficient and Proficient Endometrial Carcinoma

ABSTRACT The incidence of endometrial cancer has increased approximately 40% in the last decade along with a 60% increase in the number of associated deaths. Although surgery along with possible adjuvant therapy provides good results in patients with early-stage disease, patients with advanced or recurrent disease have limited options and typically undergo chemotherapy with no standard second-line therapy. Immunotherapy with checkpoint inhibitors (ICIs) is a promising option in this setting. This review aims to improve knowledge on the role of ICIs in advanced/recurrent endometrial cancer in different contexts based on molecular and genomic profiling. The DNA mismatch repair (MMR) system is a highly conserved mechanism that acts to restore DNA integrity after mismatching mistakes during replication, recombination, or iatrogenic damage. Somatic or germline mutations or epigenetic silencing can all result in possible inactivation of MMR genes, resulting in an MMR-deficient (dMMR) genotype. Short tandem repeats, called microsatellites, are repetitive DNA sequences that facilitate slippage or replication errors that are generally repaired by MMR; however, in a dMMR context, these can result in repeat mutations called microsatellite instability (MSI). The presence of MSI characterizes a hypermutable state of cell, and MSI tumors have elevated expression of the checkpoint programmed death 1 ligand (PD-L1). Microsatellite instability/dMMR testing may have potential prognostic value as a predictor of response to immunotherapy. Endometrial cancer is the solid tumor characterized by the highest prevalence of MSI−/dMMR, which is present in 30% and 13% to 30% of primary and recurrent endometrial cancer, respectively. Recently, results from the KEYNOTE-158 trial reporting on the efficacy and safety of pembrolizumab (programmed death 1 [PD-1] ICI) in patients with MSI-H/dMMR endometrial cancer who progressed after a prior line of chemotherapy showed an objective response rate of 48%, median progression-free survival of 13.1 months, and a low rate of high-grade toxicity. Results from the GARNET study reporting on the use of dostarlimab (PD-1 ICI) in dMMR advanced endometrial tumors showed that 80% of patients experienced progression-free survival of 18 months and an objective response rate of 44.7%. Several trials have examined the use of ICIs for patients with advanced endometrial carcinoma in MMR-proficient tumors; however, they seem to show a lesser effect in this setting. Results are more promising in MMR-proficient patients when ICIs are combined with other agents such as tyrosine kinase inhibitors; however, the toxicity profile is significantly worse, and efficacy remains significantly higher in the dMMR group. The KEYNOTE-775 study, a phase III randomized controlled trial, found that in patients with advanced or recurrent endometrial cancer pembrolizumab plus lenvatinib (tyrosine kinase inhibitor) increased progression-free survival (6.6 vs 3.8 months) and overall survival (17.4 vs 12 months) compared with conventional chemotherapy; however, treatment discontinuation and dose reduction occurred in 33% and 70% of patients, respectively. This review describes and evaluates the use of new lines of treatment including immunotherapy agents for advanced and recurrent endometrial cancer. Many trials are still ongoing, with several testing ICIs alone or in combination with other agents to improve safety profiles and efficacy.

PARP inhibitors (PARPi) prolongation after local therapy for oligo-metastatic progression in relapsed ovarian cancer patients

BackgroundPARP inhibitors (PARPi) have revolutionized the management of high-grade epithelial ovarian cancer (HGOC) treatment. However, a significant number of patients relapse or progress under PARPi, leading to the introduction of a new line of systemic therapy such as chemotherapy. In patients with a limited number of metastatic sites at progression, −referred to as an oligometastatic progression- a potential indication for local therapy followed by re-introduction or continuation of PARPi treatment rather than initiating a new line of chemotherapy could be proposed. However, the impact of such strategies on progression free survival (PFS) in these patients remains unknown. MethodsThis international multicenter retrospective study evaluated the efficacy of PARPi continuation or re-introduction in patients with HGOC after local treatment for oligometastatic progression. The main objective was to assess PFS under PARPi after local therapy (PFS post-LT). Secondary objectives included safety and overall survival (OS). Results74 patients were identified in 20 centers between April 2020 and November 2021. 65% of patients were BRCA mutated and 92% had received ≥2 lines of prior systemic chemotherapy before the initial introduction of PARPi. Main progression sites were lymph nodes (42%), peritoneum (27%), liver (16%), other visceral (16%) and abdominal wall (4%). Local therapies included radiotherapy (45%), surgery (43%), both (7%), percutaneous thermal ablation (4%) or chemoembolization (1%). Median PFS post-LT was 11.5 months [95% CI 7.4; 17.2]. After a median follow up of 14.8 months, 6 patients (8.1%) discontinued PARPi due to toxicity. The 1-year overall survival rate was 90.7% [95% CI 79.1; 96.0]. ConclusionsWith close to one year without progression or introduction of a new line of systemic therapy, this study reports the feasibility and potential benefit of this original strategy in patients with oligometastatic progression under PARPi.

Abstract CT263: A phase Ib dose-expansion study of porustobart, an anti-CTLA-4 heavy chain only monoclonal antibody, in combination with toripalimab in patients with advanced high-grade neuroendocrine neoplasms (NENs)

Abstract Background: Porustobart (HBM4003) is a fully human heavy chain only monoclonal antibody targeting CTLA-4. In addition to blocking the CTLA-4 pathway, porustobart was engineered to deplete Treg cells by enhanced antibody-dependent cellular cytotoxicity (ADCC) that was clinically validated. The prognosis of advanced high-grade NENs is poor without standard second line treatments. 4003.6, a multi-center phase Ib study is evaluating porustobart plus toripalimab (an anti-PD-1 antibody) in advanced high-grade NENs (NCT05167071). Methods: Patients (pts) with pretreated advanced high-grade NENs received porustobart at one of the two dose levels (0.3 mg/kg and 0.45 mg/kg) plus toripalimab 240 mg every three weeks (Q3W). The primary endpoint is objective response rate (ORR) per RECIST 1.1 by investigator. Results: As of 31 Aug 2022, 21 pts had been dosed, including 15 pts with neuroendocrine carcinoma (NEC), 3 pts with grade 3 neuroendocrine tumor (G3-NET) and 3 pts with mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN). 66.7% (14/21) pts received at least 2 prior lines of chemotherapy. Nine tested pts were all microsatellite stable (MSS). Median follow up time was 163 days for 0.3mg/kg dose group and 56 days for 0.45mg/kg dose group.Sixteen pts had post-baseline tumor assessments. The ORR and DCR were 37.5% and 62.5%, respectively. Median duration of response was not reached. For the 11 evaluable pts with NEC, the ORR and DCR were 36.4% and 72.7%, respectively. No significant difference in efficacy was observed between the two dose groups. Treatment-related adverse events (TRAEs) were reported in 100.0% (21/21) pts, and ≥Grade 3 TRAEs were reported in 33.3% (7/21) pts. In 0.3mg/kg dose group, 75% (6/8) pts received 5-16 cycles of study treatment, and 50% (4/8) pts experienced ≥Grade 3 TRAEs. In 0.45mg/kg dose group, 92.3% (12/13) pts received ≤4 cycles, and 23.1% (3/13) pts experienced ≥Grade 3 TRAEs. Most common (≥20%) TRAEs by pooled term were hepatic function abnormal, hyperthyroidism, rash, leukopenia, anaemia, pyrexia, hypothyroidism, neutrophil count decreased and thrombocytopenia. PK data indicated no potential interaction between porustobart and toripalimab. Increase of T cell proliferation were observed in the peripheral blood of all pts. Conclusions: Porustobart 0.3 mg/kg or 0.45 mg/kg plus toripalimab 240mg Q3W showed promising anti-tumor activity and an acceptable safety profile in pts with advanced high-grade NENs. Citation Format: Ming Lu, Panpan Zhang, Lin Shen, Kai Chen, Jianwei Yang, Lijie Song, Humphrey Gardner, Kedan Lin, Luyin Ding, Shuai Zhao, Yuan Geng, Jie Ding, Zailian Lu, Yedong Wang. A phase Ib dose-expansion study of porustobart, an anti-CTLA-4 heavy chain only monoclonal antibody, in combination with toripalimab in patients with advanced high-grade neuroendocrine neoplasms (NENs) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT263.

Abstract CT045: A randomized phase II trial of TG4001 plus avelumab versus avelumab alone in recurrent/metastatic (R/M) human papilloma virus (HPV)-16 positive anogenital cancers

Abstract Background: Immune checkpoint inhibitors targeting the PD1/PD-L1 axis have made a breakthrough in advanced solid tumors, leading to improved overall survival (OS) in several cancer types. However, only a minority of patients experience durable responses, requiring further development of anti-tumoral immunotherapies to overcome tumor immune escape. We hypothesized that priming the immune system with TG4001, a vaccine using the highly attenuated Modified Vaccinia virus Ankara as vector expressing the HPV16 E6 and E7 proteins (rendered non-oncogenic) and interleukin-2, would increase the clinical benefit associated with PD-L1 blockade in HPV16+ cancer patients. In the single-arm part of the trial evaluating the combination of TG4001 and avelumab in terms of response rate, the overall response rate (ORR) was 22%. Presence of liver metastases had a profound impact on outcome in terms of ORR and Progression Free Survival (PFS). In patients (pts) without liver metastases an ORR of 32% was observed versus 0% in pts with liver metastases, warranting further development of this combination in this patient population (SITC 2020, Abstract ID 793). Methods: We have designed a randomized open-label two-arms trial evaluating the efficacy of the combination of TG4001 and avelumab versus avelumab alone (NCT03260023). Eligible pts have R/M HPV-16 positive anogenital cancer including cervical, vulvar, vaginal, penile, and anal cancers with no more than one prior line of chemotherapy for R/M disease and no previous exposure to cancer immunotherapy. HPV-16 positivity is determined in a central laboratory. Patients are randomly assigned 1:1 to receive either TG4001 plus avelumab or avelumab alone. Randomization is stratified by primary tumor type (cervical, anal, genital). TG4001 is administered subcutaneously (SC) at 5 × 107 plaque forming units (pfu) Q1w for 5 weeks, Q2w until month 6 and Q12w until progressive disease and avelumab intravenously (IV) at 800 mg Q2w until progressive disease. A total of up to 140 pts are currently being recruited into two cohorts (A and B) in France, Spain, and USA. For Cohort A, consisting of pts without liver metastases at Baseline (BL), a 2-stage sample size adjustment design is used with PFS by RECIST 1.1 as primary endpoint. Plans are to accrue 120 patients following Interim Analysis and Independent Data Monitoring Committee (IDMC) review. Cohort B recruits pts with liver metastases at BL. To be eligible, hepatic disease is restricted in terms of extent and number of lesions. A total of 20 pts will be recruited and analyzed for the percentage of early progressors. Secondary endpoints include overall survival, objective response rate according to RECIST1.1, duration of response, disease control rate. Exploratory endpoints comprise analyses of blood-based parameters and tumor-based proteins and RNA expression and their impact on clinical outcomes. Citation Format: Christophe Le Tourneau, Frédéric Rolland, Amaury Daste, Philippe Cassier, Sébastien Salas, Luis Manso Sánchez, Gerardo Colon-Otero, Lauriane Eberst, Olivier Lantz, Ana Lalanne, Annette Tavernaro, Hakim Makhloufi, Kaïdre Bendjama, Maud Brandely, Jean-Pierre Delord. A randomized phase II trial of TG4001 plus avelumab versus avelumab alone in recurrent/metastatic (R/M) human papilloma virus (HPV)-16 positive anogenital cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT045.

Pembrolizumab Added to Ifosfamide, Carboplatin, and Etoposide Chemotherapy for Relapsed or Refractory Classic Hodgkin Lymphoma

To our knowledge, this is the first clinical trial designed to investigate concurrent treatment with a checkpoint inhibitor and conventional chemotherapy in relapsed or refractory classic Hodgkin lymphoma in patients destined for an autologous stem cell transplant. To evaluate the complete response rate as assessed by 18F-fluorodeoxyglucose-positron emission tomography with computed tomography (FDG-PET/CT) after salvage therapy for patients with relapsed or refractory classic Hodgkin lymphoma. A single-group, phase 2, multi-institutional nonrandomized clinical trial to evaluate the addition of pembrolizumab to ifosfamide, carboplatin, and etoposide (ICE) chemotherapy was conducted from April 20, 2017, to October 29, 2020, at 5 US sites. The 42 patients were aged 18 years or older, with an Eastern Cooperative Oncology Group Performance Status Scale score of 0 or 1 and biopsy-proven relapsed or refractory classic Hodgkin lymphoma after 1 or 2 prior lines of chemotherapy. Patients were required to be appropriate candidates for transplant, with measurable lesions detected by FDG-PET/CT. Two cycles of pembrolizumab (200 mg intravenously on day 1) with ICE chemotherapy every 21 days, followed by stem cell mobilization and collection, and then 1 cycle of pembrolizumab monotherapy followed by FDG-PET/CT response assessment. The primary end point was complete response rate detected by FDG-PET/CT, defined as a Deauville score of 3 or lower. Patients with a complete response proceeded to an autologous stem cell transplant. Secondary end points included progression-free survival, overall survival, stem cell mobilization, and neutrophil and platelet engraftment. Adverse events were monitored to assess safety. Forty-two patients were enrolled, with 37 evaluable for the primary end point. The median age was 34 years (range, 19-70 years), 25 patients were female (68%), 6 were African American (16%), and 26 were White (70%). The complete response rate for the 37 patients assessed by FDG-PET/CT imaging was 86.5% (95% CI, 71.2%-95.5%); the overall response rate was 97.3% (36 patients), with 10.8% partial responses (4 patients). New areas of FDG-PET positivity in 2 patients were biopsied, showing noncaseating granuloma in 1 case and a reactive lymph node in a second. Progression-free survival and overall survival 2-year estimates were 87.2% (32 patients; 95% CI, 77.3%-98.3%) and 95.1% (95% CI, 88.8%-100%), respectively. The addition of pembrolizumab to ICE chemotherapy did not negatively affect stem cell mobilization or collection or engraftment, similar to prior experience in this patient population and setting. Results suggest that the addition of pembrolizumab to ICE chemotherapy was well tolerated and highly effective in comparison with prior reports of chemotherapy-only regimens, supporting further investigation in patients with relapsed or refractory classic Hodgkin lymphoma eligible for an autologous stem cell transplant. ClinicalTrials.gov Identifier: NCT03077828.

Abstract OT3-26-01: CCTG MA40: DOUBLE-BLIND PLACEBO CONTROLLED PHASE III TRIAL OF FULVESTRANT AND IPATASERTIB FOR ADVANCED HER-2 NEGATIVE AND ESTROGEN RECEPTOR POSITIVE (ER+) BREAST CANCER POST FIRST LINE CDK 4/6 AND AROMATASE INHIBITOR THERAPY (FINER)

Abstract Background: The PI3K/AKT/mTOR pathway is a rational target in the metastatic disease setting for hormone receptor positive breast cancer based on preclinical and clinical data demonstrating that pathway inhibition improves outcome (Baselga 2012, Andre 2019, Jones 2019). Combining fulvestrant and AKT inhibition demonstrated efficacy in pts with HR+aBC (Howell 2022). Ipatasertib is a potent, highly selective, small-molecule inhibitor of three isoforms of serine/threonine kinase AKT. We hypothesize that Ipatasertib plus fulvestrant will improve PFS compared to fulvestrant in the second line setting post disease progression on aromatase inhibitor (AI) + CDK 4/6 inhibitor therapy. Methods: MA40 is a double blind, placebo-controlled trial in patients with hormone receptor positive, HER2-negative breast cancer with prior progression on AI plus CDK4/6 inhibitor therapy. Patients are randomized to fulvestrant/ipatasertib 400 mg po days 1-21 every 28 day or fulvestrant/placebo. The primary objective is to compare Progression Free Survival (PFS) between arms (RECIST 1.1, investigator assessed). Secondary objectives include comparisons between arms: PIK3CA/AKT1/PTEN altered cohort and non-altered cohorts; PFS by Blinded Central Radiology Review (all enrolled patients, PIK3CA/AKT1/PTEN altered and non-altered cohorts), Response rate; Duration of Response; Clinical Benefit Rate; Overall Survival; Time to Commencement of Subsequent Line of Systemic Therapy or Death; Safety and Tolerability (CTCAE version 5.0); QOL (EORTC QLQ-C30, NCI PRO-CTCAE); Economic Evaluation, (healthcare utilization and health utilities(EQ-5D-5L)). Statistical Design: Allocation 1:1 balanced for: PIK3CA/PTEN/AKT1 mutation status (ctDNA analysis using FoundationOne®Liquid Platform) (altered vs wildtype/unknown); prior treatment duration with CDK4/6 inhibitor (&amp;lt; 6 months vs &amp;gt; 6 months) and centre. Sample size is 250 to detect a benefit in PFS with the addition of ipatasertib. Eligibility Criteria: Histologically and/or cytologically confirmed ER positive and HER-2 negative breast cancer by local assessment that is advanced; postmenopausal status; clinical and/or radiographic progression during treatment with or within 28 days after discontinuation of first line of treatment with a CDK 4/6 inhibitor and an AI; only one prior line of chemotherapy in the advanced setting. Conduct to Date: Enrollment is ongoing. Supported by Hoffmann-La Roche Limited, CCS Citation Format: Stephen K. Chia, David W. Cescon, Andrew D. Redfern, Danielle Rodin, Christine Simmons, Jean-Pierre Ayoub, Haji Ibrahim Chalchal, Daniel Rayson, Moira Rushton-Marovac, Tracey Hay, Lisa Gallinaro, Bingshu Chen, Wendy Parulekar. CCTG MA40: DOUBLE-BLIND PLACEBO CONTROLLED PHASE III TRIAL OF FULVESTRANT AND IPATASERTIB FOR ADVANCED HER-2 NEGATIVE AND ESTROGEN RECEPTOR POSITIVE (ER+) BREAST CANCER POST FIRST LINE CDK 4/6 AND AROMATASE INHIBITOR THERAPY (FINER) [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 OT3-26-01.

Abstract P1-11-01: Trastuzumab deruxtecan vs treatment of physician’s choice in patients with HER2-low unresectable and/or metastatic breast cancer: Subgroup analyses from DESTINY-Breast04

Abstract Background: DESTINY-Breast04 demonstrated that the HER2 targeting antibody–drug conjugate trastuzumab deruxtecan (T-DXd) significantly prolonged progression-free survival (PFS) and overall survival (OS) vs treatment of physician’s choice (TPC) in patients (pts) with HER2-low (immunohistochemistry [IHC] 1+ or IHC 2+/in situ hybridization negative) metastatic breast cancer (mBC) in pts in the hormone receptor−positive (HR+) cohort and all pts (HR+ and HR-; median PFS, 9.9 vs 5.1 months [mo], hazard ratio: 0.50; median OS, 23.4 vs 16.8 mo, hazard ratio: 0.64; both P &amp;lt; 0.0001; Modi et al. N Engl J Med 2022). Objective response rate (ORR) with T-DXd was ≥50% across cohorts. These subgroup analyses examine pt history and disease characteristics that may correlate with response to therapy. Methods: N = 557 pts with centrally confirmed HER2-low mBC were randomized 2:1 to T-DXd or TPC. Randomization was stratified by HER2 status (IHC 1+ vs 2+), 1 vs 2 prior lines of chemotherapy, and HR+ (with vs without prior treatment with cyclin-dependent kinase 4/6 inhibitor [CDK4/6i]) vs HR−. With the exception of the PFS and OS analyses by prior CDK4/6i use, all other described efficacy analyses were assessed post-hoc. Results: Benefit of T-DXd vs TPC was consistent in pts with or without prior CDK4/6i use (Table 1). Pts with high disease burden (ie, ≥3 metastatic sites) also benefited from T-DXd vs TPC (Table 2). There was a small subgroup (n = 22) among all pts (HR+ [n = 18] and HR− disease [n = 4]) with rapid progression prior to enrollment (disease progression within 6 mo of concluding a prior course of chemotherapy in early breast cancer). T-DXd showed responses in 7/14 (50%) pts in this subgroup vs 0/8 with TPC; this subgroup also had prolonged median PFS with T-DXd vs TPC (Table 3). Efficacy data for HER2 IHC 1+ vs 2+ and prior chemotherapy subgroups will be presented. Median OS was not reached for many subgroups (insufficient events in each group [data not shown]); however, subgroups in general showed OS benefit consistent with the primary analysis. With T-DXd, rates of interstitial lung disease/pneumonitis were similar in pts with/without prior CDK4/6i use. Conclusions: T-DXd treatment for HER2-low mBC in the phase 3 study DESTINY-Breast04 showed consistent efficacy independent of disease burden, prior CDK4/6i treatment, or rapid progression status. ILD is an important identified risk and requires proactive monitoring and management. These data continue to support the use of T-DXd as the new standard of care across subgroups of pts with HER2-low mBC. Editorial Acknowledgment Under guidance of the authors, assistance in medical writing and editorial support was provided by Eileen McIver, PhD, and Soniya Patel, PhD, of ApotheCom, and was funded by Daiichi Sankyo. Funding This study was funded by Daiichi Sankyo and AstraZeneca. Table 1. Efficacy by Prior CDK4/6i Treatment in Pts With HER2-Low Breast Cancer, HR+ Cohort. Table 2. Efficacy by Disease Burdena in Pts With HER2-Low Breast Cancer, ITT. Table 3. Efficacy by Rapid Progressor Statusa in Pts With HER2-Low Breast Cancer, ITT. Citation Format: Nadia Harbeck, Shanu Modi, William Jacot, Toshinari Yamashita, Joo Hyuk Sohn, Maria Vidal, Junji Tsurutani, Naoto T. Ueno, Aleix Prat, Naoki Niikura, Binghe Xu, Hope Rugo, Konstantinos Papazisis, Javier Cortés, Ian Krop, Dhiraj Gambhire, Lotus Yung, Yibin Wang, Jasmeet Singh, David Cameron. Trastuzumab deruxtecan vs treatment of physician’s choice in patients with HER2-low unresectable and/or metastatic breast cancer: Subgroup analyses from DESTINY-Breast04 [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 P1-11-01.

Abstract P3-07-10: CCTG IND.236: A Phase 1b trial of combined CFI-402257 and weekly paclitaxel in patients with HER2-negative (HER2-) advanced breast cancer (aBC)

Abstract CCTG IND.236: A Phase 1b trial of combined CFI-402257 and weekly paclitaxel in patients with HER2-negative (HER2-) advanced breast cancer (aBC) Philippe L. Bedard, Mihaela Mates, John Hilton, Nathalie Levasseur, Arif Awan, Amirrtha Srikanthan, David Cescon, Karen Gelmon, Andrew Robinson, Nancy Drummond-Ivars, Irene Li, Laleh Rastgou, Jackie Edwards, Linda Hagerman, Siwei Zhang, Mark Bray, Lesley Seymour, Moira Rushton-Marovac, Pierre-Olivier Gaudreau Background: CFI-402257 is a selective oral inhibitor of TTK protein kinase, a critical regulator of the mitotic spindle assembly checkpoint overexpressed in breast cancer (BC). CFI-402257 monotherapy has anti-proliferative and cytotoxic activity and enhances antitumor activity of paclitaxel in BC xenograft models. Material and methods: Primary objectives were to establish safety and Recommended Phase 2 dose (RP2D) of CFI-402257 combined with weekly paclitaxel (Phase 1b) and Overall Response Rate (ORR) as per RECIST 1.1 (Phase 2). Patients with HER2- aBC with adequate organ function, PS 0-1, previously treated with &amp;gt;1 non-taxane chemotherapy, were eligible. A 3+3 design was used for Phase 1b, with dose limiting toxicities (DLTs) assessed during cycle 1 (28 days). Starting dose CFI-402257 was 84mg (DL1 = 84mg, DL2 = 112mg, DL3 = 168mg, DL4 = 210mg and DL5 = 252mg) on a 2-day on, 5-day off schedule with paclitaxel 80mg/m2 day 1, 8, 15. Safety assessments were performed weekly (CTCAE v5.0) and response every 2 cycles. A Simon 2-stage design was used for Phase 2 (stage 2 required ≥4 responses in 17 evaluable patients from stage 1). Results: 37 patients received a total of 260 cycles including all 5 dose levels. Median age was 59; 92% ER+/HER2-; 49% PS1; 22% 3 prior chemotherapy lines; 41% 4 sites of metastatic disease, and 81% had received prior CDK4/6 inhibitors. Grade 3 hematological adverse events (AEs, all dose levels) were neutropenia (70%), lymphopenia (41%) and anemia (14%). Six DLTs occurred: 5 dose-related grade 4 neutropenia and 1 febrile neutropenia. Three DLTs occurred at DL3, two at DL4, and one at DL5. Three serious AEs (two at DL3, and one at DL4) at least possibly related to treatment were seen: 2 febrile neutropenia and 1 skin infection (all grade 3). Frequent AEs (˃5%; all dose levels) considered at least possibly related to treatment were: diarrhea (38%), nausea (30%), fatigue (27%), vomiting (16%), anorexia (14%), maculo-papular rash (14%), oral mucositis (11%), alopecia (11%) and pruritus (8%). DL3 (168mg) was selected as RP2D. ORR was 3/36=8% and 1/17=5.9% in all vs Phase 2 evaluable patients, respectively. Clinical Benefit Rate (CBR; defined as complete response, partial response or stable disease ˃16 weeks in duration) was 18/33=54.6% and 10/17=58.8% in all vs Phase 2 evaluable patients, respectively. During Phase 2, the 17 evaluable patients from stage 1 did not meet pre-specified threshold for anti-tumor activity to proceed to stage 2. Conclusions: CFI-402257 and paclitaxel was well tolerated, with neutropenia as the main toxicity. DL3 (168mg) was selected as RP2D. Phase 2 ORR and CBR was 5.9% and 58.8%, respectively; during Phase 2, the 17 evaluable patients from stage 1 did not meet the pre-specified threshold for anti-tumor activity to proceed to stage 2 and the trial was closed to accrual on April 7, 2022. Final analysis and correlative analyses are ongoing. Acknowledgements: Coordinated by the CCTG. Funding supported by SU2C Canada - Canadian Cancer Society Breast Cancer Dream Team Research Funding (SU2C-AACR-DT-18-15) and OICR. CFI-402257 provided by Treadwell Therapeutics. Citation Format: Philippe Bedard, Mihaela Mates, John Hilton, Nathalie Levasseur, Arif Awan, Amirrtha Srikanthan, David W. Cescon, Karen Gelmon, Andrew Robinson, Nancy Drummond-Ivars, Irene Li, Laleh Rastgou, Jackie Edwards, Linda Hagerman, Siwei Zhang, Mark Bray, Lesley Seymour, Moira Rushton, Pierre-Olivier Gaudreau. CCTG IND.236: A Phase 1b trial of combined CFI-402257 and weekly paclitaxel in patients with HER2-negative (HER2-) advanced breast cancer (aBC) [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 P3-07-10.

Abstract OT1-03-04: Datopotamab deruxtecan (Dato-DXd), a TROP2 antibody-drug conjugate, vs investigators’ choice of chemotherapy in previously-treated, inoperable or metastatic HR+/HER2– breast cancer: TROPION-Breast01

Abstract Background: Chemotherapy is the main treatment in patients with pre-treated endocrine-resistant HR+/HER2– metastatic breast cancer, but has limited efficacy and substantial toxicities. The antibody-drug conjugate Dato-DXd consists of a humanized IgG1 mAb targeting TROP2 attached via a stable cleavable linker to a topoisomerase I (TopI) inhibitor payload. Heavily pre-treated patients with metastatic triple-negative breast cancer in the TROPION-PanTumor01 (NCT03401385) study of Dato-DXd showed a manageable safety profile and highly encouraging objective response rates (ORR by blinded independent central review [BICR]: 34% in all patients; 52% in patients treatment-naïve to TopI inhibitor-based therapies). The metastatic HR+/HER2– breast cancer cohort of TROPION-PanTumor01 has completed enrollment (n=41); data are currently maturing. Trial design: TROPION-Breast01 (NCT05104866) is an ongoing, global, phase 3, open-label, randomized trial evaluating efficacy and safety of Dato-DXd vs investigators’ choice of chemotherapy (ICC) in patients with inoperable or metastatic HR+/HER2– breast cancer. Patients (n≈700) are randomized 1:1 to Dato-DXd 6 mg/kg IV Q3W or ICC (eribulin, capecitabine, vinorelbine, or gemcitabine) until progression. Adults with an ECOG performance status of 0–1, who experienced progression on or are unsuitable for endocrine therapy, and received 1–2 prior lines of standard-of-care chemotherapy in the inoperable or metastatic setting are eligible. Monotherapy treatment with inhibitors of mTOR, PD-[L]1, CDK4/6 and PARP do not count as prior chemotherapy lines. Patients must have ≥1 measurable lesion per RECIST 1.1 and an archival or fresh formalin-fixed and paraffin-embedded tumor sample. Clinically inactive brain metastases are permitted. Dual primary endpoints are progression-free survival (PFS) by BICR, and overall survival. Secondary endpoints include PFS per investigator, ORR, disease control rate, patient-reported outcomes, and Dato-DXd pharmacokinetics and immunogenicity. Exploratory endpoints include TROP2 expression and exposure–efficacy relationship. Patients are stratified by number of prior chemotherapy lines, prior CDK4/6 inhibitor use, and region. At the time of writing 236 patients have been enrolled across 19 countries. Citation Format: Aditya Bardia, Kevin Kalinsky, Junji Tsurutani, Erika Hamilton, Joo Hyuk Sohn, Kyong Hwa Park, Yeon Hee Park, Seock-Ah Im, Keun Seok Lee, Daisy Dastur, Vincent Haddad, Sabrina Khan, Binghe Xu, Barbara Pistilli, Hope Rugo. Datopotamab deruxtecan (Dato-DXd), a TROP2 antibody-drug conjugate, vs investigators’ choice of chemotherapy in previously-treated, inoperable or metastatic HR+/HER2– breast cancer: TROPION-Breast01 [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 OT1-03-04.

Abstract OT3-11-02: SOLTI-1910: Predicting olaparib sensitivity in patients with unresectable locally advanced/metastatic HER2-negative breast cancer with BRCA1/2, PALB2, RAD51C/D mutations or HRD by the RAD51 test: RADIOLA TRIAL

Abstract Background The OlympiAD trial evaluated the PARP inhibitor (PARPi) olaparib versus a non-platinum standard chemotherapy in HER2-negative metastatic breast cancer (MBC) patients with a germline BRCA1/2 (gBRCA) mutation. Olaparib resulted in improved progression-free survival (PFS) and doubled the response rate vs chemotherapy. Nevertheless, the response rate to PARPi is 60% in the gBRCA1/2 population with MBC (current approval), suggesting a limited positive predictive value of gBRCA1/2 status. Moreover, patients with other relevant Homologous Recombination Repair defects (HRD) such as PALB2 or RAD51C/D mutation carriers, or HRD epigenetic silencing, are not captured with a gBRCA analysis. We have previoulsy shown that the functional HRD biomarker RAD51, tested in FFPE tumor samples using an optimized immunofluorescence-based assay, is associated with platinum response in early TNBC and PARPi response in preclinical BC models. We hypothesize that the RAD51 test would help to expand the clinical benefit of PARPi by predicting response to olaparib in MBC with germline/somatic BRCA1/2, PALB2 or RAD51C/D mutation and beyond. Study design RADIOLA is an open-label, single-arm, multicentre phase II study evaluating treatment with olaparib in male or female ≥18 years patients with HER2-negative MBC with ≤ two prior chemotherapy lines in two cohorts: cohort 1 (N=41) with known germline/somatic BRCA1/2, PALB2 or RAD51C/D mutation; cohort 2 (N=25) with functional HRD, namely RAD51-low score (≤10%), in wild-type/unknown mutation status at study entry. All patients will receive olaparib 300mg po BID until progression or unacceptable toxicity. Primary objective will assess, in terms of overall response rate (ORR), the capacity of the RAD51 score to predict olaparib efficacy in cohort 1. Secondary objectives include PFS, clinical benefit rate, duration of response, safety in both cohorts and ORR in cohort 2. Recruitment Recruitment (11 sites) started in March 2022. As of July 2022, 7 patients have been enrolled in Spain. Funding This study is financially supported by AstraZeneca. Citation Format: Judith Balmaña, Tomás Pascual, Alba Llop-Guevara, Pablo Tolosa, Isabel Blancas, Maria-Eva Perez-Lopez, Barbara Adamo, Iris Teruel, Jose Ponce, Marta Gonzalez, Gemma Viñas, Laura Lema, Francisco Javier Salvador, Mª Teresa Martinez, Alejandra Espinosa, Aleix Prat, Violeta Serra. SOLTI-1910: Predicting olaparib sensitivity in patients with unresectable locally advanced/metastatic HER2-negative breast cancer with BRCA1/2, PALB2, RAD51C/D mutations or HRD by the RAD51 test: RADIOLA TRIAL [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 OT3-11-02.