Purpose To examine the effectiveness of hyperthermic intravesical chemotherapy (HIVEC™) with mitomycin-C (MMC) for patients with intermediate-high-risk non-muscle invasive bladder cancer (NMIBC). Materials and methods From November 2010 to April 2015, 40 patients with intermediate-high-risk NMIBC received HIVEC™ treatment with a Combat BRS system. Of these patients, 24 received neoadjuvant HIVEC™ treatment (eight weekly instillations) before a transurethral resection of the bladder (TURBT) and 16 received adjuvant HIVEC™ treatment post-TURBT (four instillations weekly + six monthly). The pathological response of each tumour was evaluated after the neoadjuvant treatment. Recurrence rates and adverse effects were evaluated in both groups. Results A total of 40 patients completed the induction therapy: 24 patients received the Neoadjuvant HIVEC™ treatment. Of these patients, 15 (62.5%) showed a complete response. Eight patients (33.3%) showed a partial response, and one patient (4.1%) showed no response at all. The 4-year cumulative incidence of recurrence was 20.8%. The adjuvant HIVEC™ treatment was given to 16 patients. The 2-year cumulative incidence of recurrence was 12.5% for this group. The incidence and severity of side effects were slightly lower in the adjuvant group than in the neoadjuvant group. However, the difference was not statistically significant (p < 0.3). Most of the side effects were low grade and had virtually no effect on the treatment plan, and 97% of patients completed all of the HIVEC™ instillations scheduled. Conclusions The recirculation of hyperthermic MMC using Combat's HIVEC™ treatment is safe and effective and is capable of achieving good success rates in both neoadjuvant and adjuvant settings. This treatment seems to be appropriate for NMIBC intermediate-high-risk patients who cannot tolerate or have contraindications for standard BCG therapy or in cases in which there are supply issues or shortages of BCG.

1037 Background: MCLA-128 (zenocutuzumab) is an ADCC-enhanced humanized bispecific antibody targeting HER2 and HER3 and potently blocking HER3-ligand induced receptor dimerization. Upregulation of Her2:Her 3 pathway is a means of resistance to ET in HR+ breast cancer, indicating a potential role for MCLA-128. In preclinical studies, the combination of MCLA-128 with ET in breast cancer xenografts outperformed single drug treatments. The current study explores the use of MCLA-128 to rescue pts with ET-resistant MBC who have progressed on a CDK4/6i. Methods: This phase II, open-label trial planned for up to 40 evaluable women with HR+, HER2 low (IHC 1+/IHC 2+ with negative FISH) MBC, who had progressed on a CDK4/6i and up to 3 lines of ET, who had received ≤ 2 chemotherapy regimens in the metastatic setting. Pts received MCLA-128 (750 mg, 2h IV, flat dose) q3w combined with last ET on which the pt had previously progressed immediately prior to study entry. Disease control rate (DCR; RECIST 1.1, per investigator), best overall response (BOR), overall response rate (ORR), safety, and PK, are evaluated. Data cut off was 14Nov2019. Results: 48 pts were treated, all of whom had progressed on a CDK4/6i. Pts had received a median 2 prior ET lines (range 1-5) and 1 line (range 1-3) of chemotherapy. Pts had a median number of 3 metastatic sites (range 1-6) and 42 (88%) had visceral involvement. Among 42 pts evaluable for efficacy, DCR was 45% (90% CI 32-59) with 2 pts having unconfirmed PR and 19 pts SD as BOR. Common related AEs (all grades; G3-4) were asthenia/fatigue (27%; 2%), diarrhea (25%; 0), nausea (21%; 0). No clinically significant LVEF decline was seen. At the end of cycle 1, mean trough level of MCLA-128 was 15.5 µg/mL, and mean terminal half-live was 102 h (n = 19-21). Data on the primary endpoint, clinical benefit rate at 24 weeks, and biomarkers will be provided. Conclusions: The addition of MCLA-128 to the last line of ET showed clinical activity after ET+CDK4/6i failure and a favorable safety profile. Clinical trial information: NCT03321981 .

No abstract

No abstract

Background: ATR is a critical regulator of the cellular response to replication stress; it signals DNA damage repair, mediated through homologous recombination. Many cancers depend on ATR to survive DNA damage. M6620 is a potent, selective inhibitor of ATR that augments the anticancer activity of cisplatin in preclinical triple-negative breast cancer (TNBC) models. Given the high prevalence of TP53 mutations in TNBC and limited platinum responsiveness in patients lacking a BRCA1/2 mutation, this study was designed to evaluate the safety and efficacy of M6620 in combination with cisplatin in an expansion cohort of patients with BRCA1/2 wild-type advanced/metastatic TNBC. Methods: Eligible patients had advanced/metastatic ER-, PR-, and HER2- breast cancer with 0-2 prior non–platinum-based therapies and measurable disease per RECIST 1.1. First line patients were eligible if relapse occurred ≥3 months after prior (neo)adjuvant chemotherapy. Of a maximum 50 patients planned for enrollment, ≥30 were required to have BRCA1/2 germline wild-type status and basaloid molecular subtype tumors on central testing. Patients received intravenous cisplatin 75 mg/m2 on day 1 with intravenous M6620 140 mg/m2 on days 2 and 9 of each 21-day cycle. In patients intolerant of cisplatin or at investigator's discretion, cisplatin could be switched to carboplatin AUC 5 with M6620 90 mg/m2. Results: At the time of abstract submission, 35 female patients were enrolled in this study; 18 patients with confirmed BRCA1/2 wild-type and basaloid metastatic TNBC who received ≥1 cycle of study drug and had ≥1 baseline scan and ≥1 on-treatment scan at the time of the data cut were included in the primary efficacy analysis. Median progression-free survival (PFS) was 4.1 months (90% CI, 1.6-6.9 months). PFS was ≥ 6 months in 2 patients and ≥ 3 months in 8 patients. Preliminary unconfirmed objective response [complete response or partial response (PR)] was observed in 38.9% (90% CI, 19.9%-60.8%) of patients. All 7 patients with preliminary objective response had PR as best overall response; the longest duration of response was 183 days. Response was ongoing in 4 patients with PR at the time of data cutoff. Grade ≥3 related treatment-emergent adverse events occurred in 16 of 35 patients: neutropenia (n=8), anemia (n=5), vomiting (n=4), nausea (n=3), and, in 1 patient each, thrombocytopenia, neutrophil count decreased, platelet count decreased, hypokalemia, generalized weakness, rigors, and acute kidney injury. Conclusions: Combination of M6620 and cisplatin shows encouraging antitumor activity and tolerability in patients with advanced/metastatic TNBC. The study is ongoing; updated safety and efficacy results will be presented. Citation Format: Telli ML, Lord S, Dean E, Abramson V, Arkenau H-T, Murias C, Becerra C, Tang R, Penney MS, Pollard J, Conboy G, Fields SZ, Shapiro G, Tolaney SM. ATR inhibitor M6620 (formerly VX-970) with cisplatin in metastatic triple-negative breast cancer: Preliminary results from a phase 1 dose expansion cohort (NCT02157792) [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 OT2-07-07.

Approved CDK4/6 inhibitors have demonstrated significant improvements in progression free survival when combined with fulvestrant in patients with HR+/HER2- advanced breast cancer, though limited by neutropenia and gastrointestinal side effects. Lerociclib is a potent selective CDK4/6 inhibitor with a differentiated PK/PD profile from currently approved CDK4/6 inhibitors that has demonstrated clinical proof-of-concept (Phase 1b data ASCO 2018). This Phase 1b/2a study assesses lerociclib dose escalation in combination with 500 mg fulvestrant using a 3+3 design followed by dose expansion in patients with metastatic or locally advanced HR+/HER2- breast cancer that had progressed following endocrine therapy. Up to two prior chemotherapies in Phase 1b and one prior in Phase 2a in the advanced setting are allowed. Prior fulvestrant was excluded for all patients; prior CDK4/6 inhibitors were excluded in Phase 2a only. Lerociclib is administered daily without a drug holiday. The objectives are to evaluate DLTs, safety, tolerability, PK, and tumor response and to determine the recommended dose and schedule (QD or BID) of lerociclib administered with fulvestrant for randomized trials. The BID dosing regimen demonstrated optimal safety, tolerability, and antitumor activity. To date, 35 patients (6 patients @ 100 mg BID, 9 patients @ 150 mg BID, 17 patients @ 200 mg BID, and 3 patients @ 250 mg BID) with mean age of 54 years, ECOG of 0 (86%) or 1 (14%), and a median of two prior anticancer therapies in the advanced setting have received lerociclib + fulvestrant for up to 804 days. A dose proportional increase in drug exposure has been observed. The most common lerociclib-related adverse events were neutropenia (63%), leukopenia (57%), nausea (37%), anemia (29%), diarrhea (20%), and thrombocytopenia (20%). The rates of lerociclib-related Grade 3 and Grade 4 neutropenia were 29% and 9%, respectively. Following an initial decline, ANC plateaued beginning at week 4. There were no reports of Grade 3 or greater nausea, vomiting, or diarrhea. One DLT of dose interruption due to Grade 2 fatigue and nausea was observed at 200 mg BID. There have been no reports of venous thromboembolism, QT prolongation or drug-induced liver injury. Twenty patients were evaluable for tumor response based on RECIST v1.1. Five patients (25%) had a confirmed PR; 8 patients (40 %) had stable disease; 6 patients (30 %) had PD. The CBR (CR + PR + SD ≥ 24 weeks) was 67% (12 of 18 patients either had SD at the week 24 tumor assessments or achieved an objective response). A population PK/PD/efficacy model was developed, and simulation data are concordant with existing clinical results. Additional patients are being enrolled at 150 mg BID and 200 mg BID, and updated data will be presented. Lerociclib, dosed BID with no drug holiday, has a favorable safety profile with low rates of gastrointestinal AEs and Grade 3/4 neutropenia, as well as encouraging antitumor activity in patients with HR+/HER2- advanced breast cancer. Phase 2b is ongoing to confirm the BID dose (150 mg or 200 mg) for randomized clinical trials. Clinical trial information: NCT02983071. Citation Format: Iurie Bulat, Marina Maglakelidze, Carmen Murias, Boris Krastev, Richard D Baird, Andrew M Wardley, Rebecca Roylance, Adrian Crijanovschi, Maia Gogiladze, Yili Pritchett, Amy McCullough, Chao Li, Jessica A Sorrentino, Rajesh Malik, Andrew P Beelen. Dose escalation and expansion study of lerociclib (G1T38), an oral CDK4/6 inhibitor, dosed with no drug holiday in combination with fulvestrant in patients with HR+/HER2- advanced breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-19-17.

4530 Background: ICIs demonstrated improved overall survival (OS) in heavily pre-treated mGOJ/GC pts. Pts selection exclusively based on PD-L1 tissue expression appears to be suboptimal, despite data from subgroup analyses of KEYNOTE trials. Strong rationale suggests a potential predictive role of inflammatory biomarkers in ICIs treated mGOJ/GC pts. Methods: Ten systemic inflammatory markers [platelets, monocytes, neutrophil/lymphocyte ratio (NLR), platelets-lymphocyte ratio, lymphocytes, sum of mononuclear cells, albumin, lactate dehydrogenase, c-reactive protein (CRP) and serum globulin] were retrospectively analyzed at baseline in 57 mGOJ/GC pts with unknown PD-L1 status treated in second-line with ICIs, and correlated with OS. Least Absolute Shrinkage and Selection Operator (LASSO) method was used to select variables (preliminarily subject to optimal coding using HR smoothed curves for OS) with the highest prognostic value. Selected variables were then analyzed in a multivariate Cox Regression Model and used to build a GIPI nomogram. Results: NLR and CRP taken as continuous variables and albumin categorized as < vs > 30 g/dL were found as the most meaningful independent predictors of OS and used to build the GIPI nomogram. Nomogram-based lowest (l), mid-low, mid-high and highest (h) risk quartiles were associated with median(m)OS of 14.9, 7.1, 5.6 and 2.1 months (mos), respectively [HR of l vs h 4.94, p 0.0002]. By optimally dichotomizing CRP and NLR, pts with one or more of the following risk factors: NLR >6, CRP >15 mg/L, albumin <30 g/dL (n: 29) had a mOS of 3.9 mos vs 14.2 mos of pts with no risk factor (n: 28) (HR 2.48, p 0.001). Conclusions: GIPI, combining NLR, CRP and Albumin, is the first inflammatory index with a significant prognostic value in mOGJ/GC pts receiving second-line ICIs. Its implementation in correlation with PD-L1 expression in the present cohort is ongoing. GIPI merits validation in independent cohorts and prospective clinical trials.

No abstract