Single-agent Cohort Research Articles

Inotuzumab ozogamicin combined with chemotherapy in pediatric B-cell precursor CD22+ acute lymphoblastic leukemia: results of the phase IB ITCC-059 trial.

Inotuzumab ozogamicin (InO) is a CD22-directed antibody conjugated with calicheamicin. The phase IB of the ITCC-059 trial tested InO combined with chemotherapy in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Relapsed /refractory CD22+ BCP-ALL pediatric patients were enrolled. The primary objective was to establish the recommended phase II dose (RP2D). Secondary objectives included preliminary efficacy and tolerability. InO was combined with 1.5 mg/m2 of vincristine (days 3, 10, 17, 24), 20 mg/m2 of dexamethasone (2 5-day blocks, then amended), and intrathecal therapy. A rolling-6 design was used testing InO from 0.8 to 1.8 mg/m2/cycle. Between May 2020 and April 2022, 30 patients were treated, and 29 were evaluable for dose limiting toxicities (DLT). At 1.1 mg/m2/cycle, two of four patients had DLT (liver toxicity). InO was de-escalated to 0.8 mg/m2/cycle (N=6) without DLT while awaiting a protocol amendment to reduce dexamethasone dose to 10 mg/m2. Post amendment, InO was re-escalated to 1.1 mg/m2/cycle (N=6, 1 DLT), then to 1.4 mg/m2/ cycle (N=3, no DLT), and finally to 1.8 mg/m2/cycle (N=7, 1 DLT). Three additional patients were treated in an expansion cohort. The pooled response rate was 80% (24/30; 95% confidence interval [CI]: 61.4-92.3) and, among responders, 66.7% achieved minimal residual disease negativity. The RP2D of InO combined with vincristine, dexamethasone and intrathecal therapy was declared at 1.8 mg/m2/cycle (1.5 mg/m2/cycle after remission) in a fractioned schedule. This combination showed a response rate similar to the single agent cohorts of this trial, with liver toxicity issues at the initial higher dexamethasone dose (clinicaltrials gov. Identifier: NTR5736).

Synergistic Growth Inhibition of NPM1 Mutant AML PDX By Combined Therapy with BCL-2 Inhibitor Venetoclax (ABT-199) and Menin Inhibitor DS-1594b In Vivo

Introduction: Mixed-lineage-leukemia (MLL) translocations are prevalent in hematologic malignancies, resulting in aggressive leukemias resistant to standard therapies and low 5-year survival rates. These translocations lead to the production of MLL fusion proteins that promote leukemia development by enhancing proliferation, inhibiting hematopoietic differentiation, and driving leukemogenesis. Acute myeloid leukemia (AML), an aggressive blood cancer with a grim prognosis, particularly in elderly patients, frequently involves mutations in the nucleophosmin (NPM1) gene. Importantly, the interaction between Menin, MLL, and MLL fusion proteins play a crucial role in the pathogenesis of AML, both with MLL rearrangements (MLLr) and in leukemias carrying NPM1 mutations. Inhibition of the Menin-MLL interaction using novel Menin inhibitors has demonstrated efficacy in pre-clinical and clinical studies for both AML subsets. In this study, we investigate the effectiveness of the novel Menin-MLL inhibitor DS-1594b, developed by Daiichi Sankyo Co. Ltd., in combination with the BCL-2 antagonist venetoclax (ABT-199), in a patient-derived xenograft (PDX) model of NPM1-mutated acute leukemia. We have previously reported synergistic lethality and differentiation-inducing effects of this drug combination in both AML cell lines and primary leukemia samples in vitro (Ciaurro et al., Blood 2022). Our findings shed light on the potential of this therapeutic combination for the targeted treatment of AML with NPM1 mutations. Methods: NSG mice (female, 8-10 weeks old) were purchased from Jackson Laboratory. Mice were inoculated via the tail vein with NPM1m PDX/luc/GFP (3×10 6 cells). Once leukemia engraftment was confirmed by bioluminescent imaging mice were randomized in 4 groups: vehicle, ABT199, DS-1594b alone, and combination. After 12 days drugs were administered as follows: DS1594b at a dosage of 50 mg/kg by oral gavage for 4 weeks; ABT-199 at a dosage of 50 mg/kg by oral gavage for 2 weeks and 100mg/kg for the other 2 weeks. NSG mice were euthanized by CO 2 inhalation at the endpoint of the study in accordance with IACUC protocols. BM and spleens were harvested in a sterile environment and flushed in HBSS with 1% FBS. For CyTOF data spleen cells were initially barcoded and stained with metal-conjugated antibodies according to Fluidigm's protocols and samples were analyzed by CyTOF (Helios) Mass Cytometer. Results: New in vitro data confirmed synergistic lethality on additional AML cell lines and demonstrated upregulation of PARP-C and Caspase3-C apoptosis pathways using western blot analysis. Further, additional 3 primary AML patient samples showed additive or synergistic growth inhibition when treated with combination of drugs. In the in vivo experiment with NPM1m PDX/luc/GFP AML PDX model, we found that co-treatment with DS-1594b and venetoclax for four weeks resulted in a greater reduction in AML burden compared to treatment with either agent alone or a vehicle control as shown by Bioluminescence imaging. Moreover, weight of mice in the combo group was not significantly affected, while mice lost weight in vehicle and in single agent cohort due to rapid disease progression. The survival curve clearly demonstrated the benefits of the combination treatment, with the DS-1594b group having modest anti-tumor efficacy, and the combination group showing the greatest efficacy (Fig. 1A). To study the effects on cell differentiation, we used CyTOF technique, which allowed us to analyze a complete panel of 30 markers. We found two populations of cells, which we named populations (pop) 3 and pop 4, that were enriched in the group treated with the combination of drugs compared to the control group (Fig 1B). These populations of cells had higher levels of expression of CD33 and CD38, which are well-known markers of cellular differentiation. Conclusions: In this study, we present the in vivo effectiveness of DS-1594b in combination with venetoclax in a PDX model of NPM1-mutated AML. Moreover, the combination treatment exhibits differentiation-inducing effects, which contribute to its therapeutic effectiveness, and was safe. Overall, our findings strongly indicate that the combination of DS-1594b and venetoclax exhibits promising anti-leukemic activity in vivo and holds potential as a therapeutic strategy for AML patients with mtNPM1 mutations.

Phase 1/1b study of SY-5609, a selective and potent CDK7 inhibitor, in advanced solid tumors and in 2L/3L pancreatic ductal adenocarcinoma (PDAC) in combination with gemcitabine +/- nab-paclitaxel.

3080 Background: SY-5609 is an oral, highly selective and potent noncovalent inhibitor of CDK7, a key regulator of cell cycle progression and transcription. In this Phase 1 FIH study (NCT04247126), the single agent (SA) continuous daily dosing (CDD) regimen maximum tolerated dose (MTD) was 3 mg/day. Subsequently, enhanced tolerability was demonstrated using an intermittent 7 day on/7 day off (7/7) schedule at higher dose levels (Sharma 2021). SY-5609 preclinical data and early clinical activity provided the rationale for evaluating SY-5609 + gemcitabine (gem) +/- nab-paclitaxel (np) in PDAC. Herein, we present data from the ongoing SA dose escalation and SY-5609 + gem +/- nab-paclitaxel (np) safety lead-ins (SLIs). Methods: The 7/7 schedule was used to further evaluate SA escalation in pts with select solid tumors. In the PDAC combination SLIs, SY-5609, starting with a dose of 4 mg, is escalated using the 7/7 schedule in combination with biweekly gem (1000 mg/m2) +/- np (125 mg/m2). Evaluations included safety, clinical activity (RECIST v1.1), PK, and induction of peripheral blood PD marker POLR2A (Papadopoulos 2020). Results: As of 13 Jan 2023, 87 pts have been enrolled (70 SA, 14 SY-5609 + gem, 3 SY-5609 + gem/np), including 30 pts across the 4, 5, 6, 7, and 10 mg SA 7/7 cohorts included in the safety summary. MTD for the 7/7 schedule has not been reached. The 15 mg SA cohort is now enrolling. Most SA 7/7 AEs were low-grade; AEs included (>20%) nausea, diarrhea, fatigue, anorexia, and thrombocytopenia. No new safety signals were observed in the SY-5609 4 mg and 5 mg + gem and SY-5609 4 mg + gem/np cohorts; 1 pt (SY-5609 5 mg + gem) had a DLT of Gr3 diarrhea. The 10 mg + gem cohort is now enrolling. Most SY-5609 + gem +/- np AEs were low grade. AEs in the SLIs were consistent with the safety profile of either SY-5609 or gem +/- np and included (>20%) fatigue, anorexia, nausea, abdominal pain, and constipation. In the SA cohorts (response-evaluable, n=29), 100% (3/3) of pts in the 10 mg 7/7 cohort had stable disease (SD) as the best response, compared to 19% (5/26) SD rate in 4 to 7 mg SA 7/7 cohorts. Disease control rate in the combination SLIs (response-evaluable, n=11) was 45% (5/11), including 1 confirmed partial response (4 mg + gem) in a patient with liver metastases who had a reduction in CA 19-9 from 60,357 U/mL to 968 U/mL, and SD in 4 pts (3 in 5 mg + gem, 1 in 4 mg + gem/np). SA and SLI PK data support an emerging exposure-activity relationship. POLR2A PD marker data from SA and SLI cohorts correlate with exposure. Conclusions: To date, intermittent dosing of SY-5609 on the 7/7 schedule has acceptable tolerability alone and in combination with gem +/- np. Encouraging preliminary clinical activity and the emerging exposure-activity relationship supports the ongoing escalation of SY-5609 in SA and combination SLI cohorts; updated results will be presented. Clinical trial information: NCT04247126 .

Abstract CT029: Phase Ib study of GDC-6036 in combination with cetuximab in patients with colorectal cancer (CRC) with KRAS G12C mutation

Abstract Background: GDC-6036 is an oral, highly potent and selective KRAS G12C inhibitor that demonstrated anti-tumor activity in patients with KRAS G12C-positive advanced solid tumors, including CRC. In a previously reported single-agent cohort, GDC-6036 achieved a best response of partial response or complete response in 35% (19/55) of patients, with a confirmed overall response rate (ORR) of 24% (13/55 patients) in KRAS G12C-positive CRC patients (Desai et. al., ESMO 2022). EGFR blockade may sensitize tumors to KRAS G12C inhibition and the combination of an anti-EGFR antibody (cetuximab) with a KRAS G12C inhibitor showed greater anti-tumor activity than single-agent KRAS G12C inhibition in preclinical models (Amodio et. al., 2020). Methods: In an ongoing Phase I study (NCT04449874), patients with advanced or metastatic KRAS G12C-positive CRC were administered GDC-6036 (200-400 mg orally once a day) with cetuximab (400 mg/m2 intravenously initially, then 250 mg/m2 weekly) until intolerable toxicity or disease progression. Endpoints included safety (NCI-CTCAE v5), pharmacokinetics (PK), and preliminary anti-tumor activity (RECIST v1.1). Results: As of the clinical data cut-off date of 21 Nov 2022, 29 patients (enrolled by 07 Oct 2022) had received GDC-6036 and cetuximab. The median lines of prior metastatic therapy was 2 (range 1-8) and the median time on study treatment was 5.2 (range 1.4-11.2) months. All patients experienced at least one treatment-related adverse event (TRAE); the most common TRAEs (≥15%) were rash (grouped terms), diarrhea, nausea, vomiting, dry skin, and paronychia. Grade 3-4 TRAEs occurred in 11 patients (38%). Five patients (17%) experienced at least one serious AE, none of which were treatment-related (including 2 patients who died of CRC progression during the safety follow-up). AEs led to GDC-6036 modifications (interruptions and/or reductions) in 13 (45%) patients, dose reduction in 3 (10%) patients, and no patients discontinued due to AEs. Eleven patients discontinued from study treatment (10 due to disease progression and 1 due to physician’s discretion). The PK profile of GDC-6036 (400 mg once a day) was similar in combination with cetuximab when compared with single-agent. A partial response was achieved in 66% (19/29) of patients, with a confirmed ORR of 62% (18/29 patients). Conclusions: GDC-6036 in combination with cetuximab demonstrated a manageable safety profile and promising clinical activity. These data support that the addition of anti-EGFR therapy to GDC-6036 may lead to robust clinical benefit in patients with KRAS G12C-positive CRC. Citation Format: Jayesh Desai, Sae-Won Han, Jong-Seok Lee, Einat Shacham-Shmueli, Erminia Massarelli, Andrés Cervantes, Elena Garralda, Alejandro Falcon, Wilson H. Miller, Eelke Gort, Thomas Karasic, Salvatore Siena, Rafal Stec, Laura Medina, Luis Paz-Arez, Angelo Delmonte, Adrian Sacher, Hans Prenen, Martin Forster, Tae Won Kim, Matthew G. Krebs, Rasha Cosman, Yoonha Choi, Sandhya Mandlekar, Mark T. Lin, Kenneth K. Yau, Julie Chang, Stephanie Royer-Joo, Neekesh V. Dharia, Jennifer L. Schutzman, Manish Patel. Phase Ib study of GDC-6036 in combination with cetuximab in patients with colorectal cancer (CRC) with KRAS G12C mutation [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 CT029.

Phase 1a/1b study design of the novel STING agonist, immune-stimulating antibody-conjugate (ISAC) TAK-500, with or without pembrolizumab in patients with advanced solid tumors.

TPS2690 Background: Tumor resistance to immune checkpoint inhibitors (CPIs), including pembrolizumab, is common. Suggested mechanisms of resistance include reduced interferon (IFN) signaling, immune escape, and immunosuppressive tumor phenotypes. Innate immune cell stimulation in the tumor microenvironment may be a potential pathway to overcome this resistance. Stimulator of interferon genes (STING) is a cytosolic protein critical for initiation of type-1 IFN-dependent innate immunity. TAK-500 is a novel ISAC comprising a STING agonist (based on TAK-676, which is currently in phase 1 clinical trials [NCT04420884, NCT04879849]), an IgG1 anti-cysteine-cysteine chemokine receptor 2 (CCR2) antibody, and a self-immolating maleimide-containing protease-cleavable peptide linker. CCR2-expressing myeloid cells, including tumor associated macrophages (TAMs), promote immune evasion in part by reducing infiltration of CD8+ T cells into the tumor microenvironment. As such, TAK-500 has the potential to mitigate CPI resistance in solid tumors via targeted STING activation of tumor-infiltrating CCR2-expressing myeloid cells, thus leading to stimulation of innate and adaptive immunity within the tumor microenvironment through three potential mechanisms of action: activation of IFN signaling, reprogramming of CCR2-expressing myeloid cells to an inflammatory phenotype, and blockade of suppressive TAM recruitment. Methods: Adult patients with a diagnosis of locally advanced or metastatic gastroesophageal adenocarcinoma, pancreatic adenocarcinoma, hepatocellular carcinoma, non-squamous non-small cell lung cancer, squamous cell carcinoma of the head and neck, mesothelioma or triple-negative breast cancer are eligible. All patients must have progressive disease while on, or be intolerant to, all current standard therapies. Approximately 106 patients in total will be enrolled to the dose escalation and expansion cohorts. In the dose escalation phase, intravenous (IV) TAK-500 will be administered over the range 8–480 µg/kg on day 1 of every 21-day cycle (Q3W) to establish the pharmacologically active dose (PAD) range. An additional escalation cohort of patients will receive TAK-500 + IV pembrolizumab 200 mg Q3W, starting at a dose of TAK-500 that is 1–2 dose levels below the lowest PAD range established in the single agent cohort. Dose escalation in both cohorts will be guided by Bayesian Optimal Interval design. In the dose expansion phase, only the combination of TAK-500 + pembrolizumab will be evaluated. Primary objectives of this study are safety and tolerability; secondary objectives include determination of the PAD range, the recommended phase 2 dose, pharmacokinetics, pharmacodynamics, and antitumor activity of TAK-500 as a single agent and in combination with pembrolizumab. Clinical trial information: NCT05070247.

A phase 1 dose-escalation and expansion-cohort study of the oral CDK7 inhibitor XL102 as a single-agent and in combination therapy in patients (pts) with advanced solid tumors.

TPS3176 Background: XL102 is an orally bioavailable, selective, and covalent small-molecule inhibitor of cyclin-dependent kinase 7 (CDK7). CDK7 is a serine/threonine kinase that is overexpressed in multiple tumor types. CDK7 controls cell cycle progression via the phosphorylation of CDKs (1, 2, 4, and 6) and regulates transcription through phosphorylation of RNA polymerase II. XL102 induced cell death in various cancer cell lines and caused tumor regression in multiple human tumor cell line to mouse xenograft tumor models. Here, we present the study design of an ongoing phase 1 trial in pts with advanced solid tumors, including hormone receptor-positive breast cancer (HR+BC), triple-negative breast cancer (TNBC), epithelial ovarian cancer (EOC), and metastatic castration-resistant prostate cancer (mCRPC). Methods: This first-in-human, open-label, phase 1 trial (NCT04726332) consists of a dose-escalation stage and a disease-specific cohort expansion stage. In the dose-escalation stage (modified interval 3+3 design), a maximum tolerated dose and/or recommended dose (MTD/RD) of XL102 will be established (primary endpoint) for use alone (solid tumors) and then for use in combination with standard dose fulvestrant (HR+BC) or abiraterone/prednisone (mCRPC); dose escalation will require ̃36 pts for the single-agent cohort and ̃15 pts for each combination cohort. Pts enrolled in the dose-escalation stage must have an unresectable or metastatic tumor for which available therapies are intolerable, ineffective, or do not exist. Upon determining the MTD/RD for each regimen, the cohort-expansion stage will enroll according to Simon’s Two-Stage Minimax design, assuming a power of 80% and one-sided α of 15%, for single-agent XL102 (HR+BC, TNBC, EOC, and mCRPC) and XL102 in combination therapy (HR+BC and mCRPC); the expansions will enroll ̃36 pts for each single-agent cohort and ̃44 pts for each combination cohort. Pts enrolled in the expansion stage must have measurable disease per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1), adequate organ function, and exposure to prior therapy, with specific therapy requirements based on the disease cohort. The primary endpoint of the expansion stage is objective response rate (ORR) of XL102 alone and in combination therapy as assessed by investigator per RECIST v1.1. Secondary endpoints are safety, tolerability, and pharmacokinetics. Exploratory endpoints include duration of response (DOR) and progression-free survival (PFS) as assessed by the investigator per RECIST v1.1, overall survival, and correlation of tumor and blood biomarkers with response. ORR, DOR, and PFS may also be assessed by blinded independent radiology committee in selected expansion cohorts. The study began enrolling pts in February 2021 and is ongoing. Total enrollment is estimated to be up to 298 pts. Clinical trial information: NCT04726332.

Contribution of Bcl-2 Inhibitor Venetoclax Toward Anti-CD19 CAR T Cell Efficacy in Relapsed/Refractory Diffuse Large B Cell Lymphoma

IntroductionClinical outcomes of anti-CD19 chimeric antigen receptor T-cell (CAR-T CD19) therapy for the treatment of relapsed/refractory Diffuse Large B Cell lymphoma (r/r DLBCL) must be improved, as patients undergoing CAR-T CD19 therapy can expect a cure rate of only 41% and a median survival of just 6.3 months if unresponsive. Of patients presenting with naïve DLBCL, 35% will advance to third-line treatment with CAR-T CD19 therapy. Poor clinical responses to CAR-T CD19 therapy and a small window of survival for unresponsive patients highlights the critical need for improvement of CAR-T CD19 therapy in the setting of r/r DLBCL. Overexpression of anti-apoptotic Bcl-2 protein has been characterized in r/r DLBCL, and contributes to the disease's aggressive phenotype. Aberrant expression of the Bcl-2 protein proves targetable by an FDA-approved small molecule inhibitor which mimics the role of pro-apoptotic BH3 proteins, known as Venetoclax. Here, we investigate the effect of Venetoclax on CAR-T CD19 cell immunophenotype, effector function, and cytotoxicity upon co-culture with a lab-generated model of immortalized rituximab/chemo-resistant B cell lymphomas (Raji4RH) which recapitulate the resistant phenotype of r/r DLBCL seen in patients.MethodsPBMCs were isolated and activated from apheresis samples from consenting adults (healthy donors) using the Miltenyi Biotec TransACT human CD3/CD28 Kit. Cells were transduced with lentiviral vectors encoding for 2nd generation CAR constructs 24 hours post-activation. Transduced cells were cultured in RPMI media supplemented with hIL-2 (1ng/mL) and hIL-7 (10ng/mL). At day 14, cells were cultured with Raji4RH and Venetoclax in either combined or solitary cultures. Co-culture cytotoxicity assays were performed by pre-labeling target cells with permeant dye (Thermo Fisher Scientific CellTrace Blue Proliferation Kit), then incubating with CAR-T CD19 cells (GFP labeled) at various effector:target ratios and Venetoclax concentrations for 24 hours. Sample wells were stained with viability dye and acquired on BD LSR II Cytometer. CAR-T CD19 cell immunophenotype was identified following 24-hour exposure of Venetoclax to CAR T cell populations at various concentrations. Following exposure, samples were stained with viability dye, CD3, CD4, CD8, CD45RA, CD45RO, CD62L, CCR7, CD25, and CD95. Frequencies of T REG, T Central Memory, T naive, and T Stem Cell Memory populations were calculated. CAR-T CD19 cell effector function was elucidated by activating (24 hours), then exposing CAR-T CD19 cells to concentrations of Venetoclax for 24 hours. Brefeldin A was added to culture for the remaining 4 hours of incubation. Cells were collected and stained intracellularly for IFNγ, Perforin, and Granzyme B; and extracellularly for CD3, CD4, and CD8. Sample acquisition for effector function assay was performed on BD LSRII Cytometer.ResultsConcurrent in vitro CAR-T CD19 administration and Venetoclax exposure significantly increases Raji4RH cell death as opposed to single agent cohorts. CAR-T CD19 cell viability is unaffected by Venetoclax at concentrations which confer synergy, and a predominantly CD8+ population is favored. Finally, Venetoclax appears to significantly increase the frequency of T N/T SCM and T CM within exposed cultures, while affording a 21% decrease in T REG frequency. Additionally, the notable increase in T N/T SCM and T CM phenotypes following exposure to Venetoclax did not arise as a consequence of decreased cellular viability.ConclusionThe combination of Venetoclax exposure and αCD19 CAR T cell administration demonstrates synergy when employed in the context of rituximab-resistant lymphoma cells, which may be explained by the effect of the BH3 mimetic's exposure on CAR-T CD19 cell immunophenotype. The ability to manipulate Bcl-2 protein expression within CAR-T CD19 cells affords insight into the role that the Bcl-2 family pathway plays within CAR-T CD19 cell biology. In addition to answering fundamental questions of CAR T cell biology, the combination of Venetoclax and CAR-T CD19 therapy may provide a solution to the observed clinical gap, in which CAR-T CD19 therapy alone cures less than half of all patients who advance to this third line treatment regimen. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

15 First-line platinum-based chemotherapy combined with PD-1/PD-L1 inhibitors (ICI) prevents hyperprogression in non-small cell lung cancer (NSCLC) patients by reducing circulating immature neutrophils

BackgroundHyperprogression (HPD) has been described in ≃14–26% of NSCLC patients upon single-agent ICI1 and has not been reported upon ICI and platinum-based chemotherapy (PCT) combinations. Both high circulating neutrophils2 and senescent T-cells3 correlated with HPD, however the exact neutrophils-T-cells interplay and the role of specific neutrophils subsets in driving HPD is unknown.MethodsNSCLC patients treated with 1st line ICI as single-agent or in combination with PCT were assessed for HPD and circulating neutrophils’ phenotype. HPD required 3 assessment (2 before ICI, 1 upon ICI) and was defined as delta tumor growth rate (TGR) (TGR upon ICI – TGR before ICI) >50% and/or TGR ratio (TGR upon ICI/TGR before ICI) ≥2. Circulating low density neutrophils (LDNs) subtypes were assessed by flow cytometry on peripheral blood mononuclear cells (PMBCs). LDNs were defined as CD66b+CD15+ cells among CD11b+ PBMCs. Immature subtypes were defined as CD10- LDNs. T-cells were isolated from healthy donors and cocultured with patients‘ LDNs to characterize the neutrophils-T-cells interplay. LDNs subtypes were isolated from patients and treated in-vitro with cisplatin to assess cell death.Results46 NSCLC patients were treated with single-agent ICI and 17 with PCT+ICI (table 1). In the ICI single-agent cohort, PD and HPD occurred in 21 (41%) and 4 (9%) patients. Before ICI start, HPD patients had significantly higher median% of circulating immature CD10- LDNs neutrophils [43.5 (min 29.5; max 82.6) vs 10.3 (min 0.1; max 79.4), p=0.01] compared to PD patients (figure 1). In the ICI-PCT cohort no HPD was reported. 5 patients had baseline CD10- LDNs ≥ 43.5% (median% of CD10- LDNs in HPD patients upon single-agent ICI), 2 of them had stable disease and 3 PD upon ICI-PCT. In these 5 patients, CD10- LDNs significantly decreased during ICI-PCT compared to what observed in HPD patients upon single-agent ICI [median variation -43.4 (min -67.6, max -31.6) vs +6.9 (min -33, max +44), p= 0.03] (figure 2). After 7 days of coculture with T-cells, immature CD10- LDNs significantly reduced T-cells survival and promoted a T-cell senescent phenotype (CD28 loss, CD57 gain) impairing T-cells proliferation and increasing IFN-gamma production (figure 3). Cisplatin treatment significantly increased necrotic cell death among CD10- LDNs compared to CD10+ LDNs (figure 4).Abstract 15 Table 1Patients characteristics in the single-agent ICI and PCT+ICI cohortsAbstract 15 Figure 1Patterns of response, progression and hyperprogression to single-agent ICI and correlation with mature (CD10+) or immature (CD10-) LDNs’ subtypesAbstract 15 Figure 2Neutrophils dynamic variation upon treatment (5 patients with high baseline CD10- LDNs and PD/SD to chemo-ICI vs 4 patients with HPD upon single-agent ICI)Abstract 15 Figure 3Mature (CD10+) and immature (CD10-) LDNs in coculture with T-cells from an healthy donor differently influence CD8 and CD4 T-cells survival, proliferation, IFN-gamma production and expression of a senescent (CD28- CD57+) phenotype.Abstract 15 Figure 4Cisplatin in-vitro treatment at different concentration (1 uM and 5 uM) increases necrotic (7AAD expression) cell death preferentially of immature (CD10-) rather than mature (CD10+) LDNsConclusionsHigher baseline immature CD10- LDNs impair T-cell survival and promote T-cell senescence being a circulating biomarker of HPD upon single-agent ICI. The addition of PCT prevents HPD by inducing immature neutrophils cell death.ReferencesFerrara R, Mezquita L, Texier M, Lahmar J, Audigier-Valette C, Tessonnier L, et al. Hyperprogressive disease in patients with advanced non-small cell lung cancer treated with pd-1/pd-l1 inhibitors or with single-agent chemotherapy. JAMA Oncol 2018;4:1543–52. https://doi.org/10.1001/jamaoncol.2018.3676Kim Y, Kim CH, Lee HY, Lee S-H, Kim HS, Lee S, et al. Comprehensive clinical and genetic characterization of hyperprogression based on volumetry in advanced non-small cell lung cancer treated with immune checkpoint inhibitor. J Thorac Oncol 2019;14:1608–18. https://doi.org/10.1016/j.jtho.2019.05.033Ferrara R, Naigeon M, Auclin E, Duchemann B, Cassard L, Jouniaux JM, et al. Circulating T-cell immunosenescence in advanced non-small cell lung cancer patients treated with single agent PD-1/PD-L1 inhibitors or platinum-based chemotherapy. Clin Cancer Res 2020. https://doi.org/10.1158/1078-0432.CCR-20-1420.Ethics ApprovalPatients blood was obtained after signature of informed consent and within an observational prospective study (INT 22_15) approved by local Institutional Ethical Committee.

Abstract 1669: Immunometabolism of circulating neutrophils in hyperprogressive disease (HPD) upon first-line PD-1/PD-L1 inhibitors (ICI) alone or in combination with platinum-based chemotherapy (PCT) in non-small cell lung cancer (NSCLC) patients (pts)

Abstract Background: HPD has been described in 14-26% of NSCLC pts upon single agent ICI and correlates with poor survival. Currently, HPD occurrence has not been explored upon ICI-PCT and biomarkers of HPD are lacking. Although high circulating neutrophils (Ns) correlated with HPD in NSCLC pts, the role of specific Ns subsets is unknown. Methods: NSCLC pts treated with 1st line ICI as single agent or in combination with PCT were assessed for HPD and circulating Ns' phenotype. Tumor response was evaluated by RECIST 1.1. HPD required 3 assessment (2 before ICI, 1 upon ICI) and was defined as delta tumor growth rate (TGR) (TGR upon ICI - TGR before ICI) >50% and/or TGR ratio (TGR upon ICI/TGR before ICI) ≥2. Circulating low density Ns (LDNs) subtypes were assessed by flow cytometry (FC) on peripheral blood mononuclear cells (PBMCs). LDNs were defined as CD66b+CD15+ cells among CD11b+ PBMCs. Immature subtypes were defined as CD10- LDNs. Fatty acids (FA) (bodipy-palmitate) uptake was assessed by FC. T-cells of healthy donors were isolated and activated in vitro with CD3/CD28 beads in presence or not of pts' Ns to characterize their interplay. Results: Of 63 NSCLC pts, 22% had PD-L1 on tumor cells ≥50%. In the ICI single agent cohort (N=46), PD and HPD occurred in 21 (41%) and 4 (9%) pts, respectively. Before ICI start, HPD pts had significantly higher median percentage (%) of circulating immature CD10- LDNs [43.5 (min 29.5; max 82.6) vs 10.3 (min 0.1; max 79.4), p=0.01] compared to PD pts. In the ICI-PCT cohort (N=17), PD occurred in 4 (23%) pts, no HPD was reported. 5 pts had baseline CD10- LDNs ≥ 43.5% (median % of CD10- LDNs in HPD pts upon single agent ICI), 2 of them had SD and 3 PD upon ICI-PCT. In these 5 pts, CD10- LDNs significantly decreased during ICI-PCT compared to what observed in HPD pts during single agent ICI [median variation -43.4 (min -67.6, max -31.6) vs +6.9 (min -33, max +44), p= 0.03]. CD10- LDNs did not impair T-cells proliferation and IFNγ production, measured after 7 days of coculture but significantly reduced T-cell survival compared to CD10+LDNs. Baseline metabolic profile assessment showed that immature CD10- LDNs had a predominant lipid metabolism with a higher FA uptake [bodipy-palmitate mean florescence intensity (MFI) ± standard deviation (SD): 46754±11562] compared to lymphocytes [bodipy-palmitate MFI ±SD: 11542±405]. Conclusion: Higher baseline immature CD10- LDNs is a circulating biomarker of HPD upon single agent ICI. The addition of PCT prevents HPD reducing the immature Ns subset. The FA metabolism of immature LDNs does not affect T-cells proliferation/activation but reduces T-cells survival, suggesting that these two processes are differently regulated and that immature Ns reduce T-cells life span by metabolic competition. Citation Format: Roberto Ferrara, Elena Jachetti, Giuseppina Calareso, Marta Brambilla, Giuseppe Lo Russo, Claudia Proto, Arsela Prelaj, Diego Signorelli, Giulia Galli, Alessandro De Toma, Mario Occhipinti, Sara Manglaviti, Alice Labianca, Monica Ganzinelli, Sestina Maria Spanò, Giuliano Molino, Antonia Martinetti, Francesca Gabriella Greco, Marta Bini, Teresa Beninato, Filippo de Braud, Mario Paolo Colombo, Marina Chiara Garassino, Sabrina Sangaletti. Immunometabolism of circulating neutrophils in hyperprogressive disease (HPD) upon first-line PD-1/PD-L1 inhibitors (ICI) alone or in combination with platinum-based chemotherapy (PCT) in non-small cell lung cancer (NSCLC) patients (pts) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1669.

A phase 1/2 open-label study of KY1044, an anti-ICOS antibody with dual mechanism of action, as single agent and in combination with atezolizumab, in adult patients with advanced malignancies.

2624 Background: KY1044, is a fully human IgG1 anti ICOS antibody designed to stimulate Teffs and to deplete ICOS high Tregs in the tumor microenvironment. Methods: Patients with advanced/metastatic malignancies received escalating doses of KY1044 as a single agent and in combination with atezolizumab 1200 mg by IV infusion every 3 weeks until disease progression or unacceptable toxicity. Dose escalation was guided by a modified toxicity probability interval design. The primary objective was to determine safety, tolerability, and maximum tolerated dose. Cohorts that were tolerated were later enriched with more subjects. AEs were classified according to CTCAE v5 and efficacy measures performed according to RECIST v1.1 every 8 weeks for the first 16 weeks and then every 12 weeks. Results: As of 16-Dec-2020, a total of 103 patients have been enrolled in the study (38 patients as monotherapy in 6 cohorts at doses ranging from 0.8 to 240 mg and 65 in combination with atezolizumab in 5 cohorts at doses 0.8 – 80 mg). 63% and 55% of patients received ≥4 prior anti-cancer therapies in the single agent and combination cohorts, respectively. All cohorts were completed without DLTs during the first 21 days of treatment. In the KY1044 single agent cohorts, 47.4% of patients experienced treatment-related AEs (TRAEs), all were grades 1 or 2. In the combination cohorts, TRAEs were observed in 58% of patients. Most of the TRAEs were grade 1 or 2 apart from 8 TRAEs that were ≥grade 3 occurring in <8% of patients. Infusion-related reactions, pyrexia and lymphopenia were the most commonly occurring TRAEs in ≥10% of patients. TRAE leading to dose interruptions occurred in 1 patient in the single agent cohort and in 4 patients in the combination cohort. Only 1 patient discontinued treatment due to myositis that was considered related to the combination. Preliminary KY1044 PK data from 69 patients agree with the PK model predictions. Median treatment duration for all enrolled patients was 9 weeks. Treatment duration ≥16 weeks was observed in 24% (9/38) and 27% (17/64) patients in the single agent and combination cohorts, respectively. Five objective responses, including 1 CR in triple negative breast cancer (TNBC) and 4 PRs in TNBC, head and neck squamous cell carcinoma, penile and pancreatic cancer were observed. Four of the 5 responding patients were still on treatment at the data cut, with 3 patients on treatment for >43 weeks (range 45 to 66 weeks). Conclusions: KY1044 is well tolerated as single agent and in combination with atezolizumab. Objective responses have been observed in this phase 1 part of the study. The phase 1 expansion and phase 2 part of the study is ongoing. Clinical trial information: NCT03829501.

Intratumoral OH2, an oncolytic herpes simplex virus 2, in patients with advanced solid tumors: a multicenter, phase I/II clinical trial

BackgroundOH2 is a genetically engineered oncolytic herpes simplex virus type 2 designed to selectively amplify in tumor cells and express granulocyte-macrophage colony-stimulating factor to enhance antitumor immune responses. We investigated...

Identification of transcriptomic determinants to predict the efficacy of anti-EGFR treatment of colorectal cancer patients.

130 Background: It is now well known that in colorectal cancer (CRC) activating mutations in KRAS, NRAS, and BRAF confer resistance to anti-EGFR therapy. However, only ~ 40% of patients with RASWT (KRASWT/NRASWT/BRAFWT) tumors respond to therapy. We have used transcriptomic data in addition to somatic mutations to decipher intrinsic resistance mechanisms and identify novel biomarkers of anti-EGFR response in CRC. Methods: The transcriptomic profiles of metastatic CRC patients treated with the anti-EGFR drug cetuximab plus chemotherapy (n = 193) or as a single agent (n = 80) were retrospectively obtained from two independent clinical cohorts (Okita et al., 2018; & Khambata-Ford et al., 2007). Tumor samples were further divided into RASWT and RASMut groups and subsequently in four consensus molecular subtypes (CMS) based on their transcriptomic profile. The transcriptomic profiles of cetuximab treated CRC cell lines (n = 148, Medico et al., 2015) and PDX models (n = 230, Bertotti et al., 2015) were used for validation. Results: In RASWT population of cetuximab plus chemotherapy cohort, the disease control rates (DCR) observed for cetuximab in the second line were 92% (33/36) for CMS2 and 83% (15/18) for CMS4 tumors relative to 50% (2/4) and 59% (13/22) for CMS1 and CMS3 respectively (Chi-square test p-value = 0.037). Similarly, in cetuximab single agent cohort, the DCR were 0% (0/4), 68% (15/22), and 29% (5/17) for CMS1, CMS2, and CMS4, respectively (Chi-square test p-value = 0.029). In the preclinical study of 148 CRC cell lines, 60% (12/20) of CMS2 cell lines with RASWT genes were sensitive to cetuximab, versus no sensitive cell lines from other CMS (CMS1 = 0/4; CMS3 = 0/5; CMS4 = 0/12). In the PDX study, 84% (11/13) of CMS2 tumor showed clinical benefit, followed by CMS4 with 75% (6/8) in RASWT group (CMS1 = 2/5; CMS3 = 2/4). Gene Set Enrichment Analysis (GSEA) of tumor tissue samples identified that Myc (NES = 1.32, FDR = 0.3), E2F (NES = 2.24, FDR = 0.02), and mTOR (NES = 1.54, FDR = 0.1) pathways were active in the cetuximab refractory RASWT CMS2 patients relative to cetuximab sensitive tumors. Similarly, these pathways were also activated (FDR ≤ 0.05) in cetuximab resistant RASWT cell lines and PDX models, suggesting that preclinical models are appropriate for testing of potential therapeutic combinations to overcome resistance to anti-EGFR therapy. Conclusions: Resistance to anti-EGFR therapy in extended RASWT CRC tumors is mediated in part by transcriptional activation and can be predicted by consensus molecular subtype (CMS) and quantifying transcriptional states of Myc, E2F, and mTOR pathway gene sets.

Real-world survival outcomes of heavily pretreated patients with refractory HR+, HER2\u2212metastatic breast cancer receiving single-agent chemotherapy\u2014a comparison with MONARCH 1

PurposeIn MONARCH 1 (NCT02102490), single-agent abemaciclib demonstrated promising efficacy activity and tolerability in a population of heavily pretreated women with refractory HR+, HER2− metastatic breast cancer (MBC). To help interpret these results and put in clinical context, we compared overall survival (OS) and duration of therapy (DoT) between MONARCH 1 and a real-world single-agent chemotherapy cohort.MethodsThe real-world chemotherapy cohort was created from a Flatiron Health electronic health records-derived database based on key eligibility criteria from MONARCH 1. The chemotherapies included in the cohort were single-agent capecitabine, gemcitabine, eribulin, or vinorelbine. Results were adjusted for baseline demographics and clinical differences using Mahalanobis distance matching (primary analysis) and entropy balancing (sensitivity analysis). OS and DoT were analyzed using the Kaplan–Meier method and Cox proportional hazards regression.ResultsA real-world single-agent chemotherapy cohort (n = 281) with eligibility criteria similar to the MONARCH 1 population (n = 132) was identified. The MONARCH 1 (n = 108) cohort was matched to the real-world chemotherapy cohort (n = 108). Median OS was 22.3 months in the abemaciclib arm versus 13.6 months in the matched real-world chemotherapy cohort with an estimated hazard ratio (HR) of 0.54. The median DoT was 4.1 months in MONARCH 1 compared to 2.9 months in the real-world chemotherapy cohort with HR of 0.76.ConclusionsThis study demonstrates an approach to create a real-world chemotherapy cohort suitable to serve as a comparator for trial data. These exploratory results suggest a survival advantage and place the benefit of abemaciclib monotherapy in clinical context.

OP0205 PHASE I STUDY OF D-0120, A NOVEL URAT1 INHIBITOR IN CLINICAL DEVELOPMENT FOR HYPERURICEMIA AND GOUT

Background:D-0120 is a novel oral selective uric acid transporter (URAT1) inhibitor being developed for the treatment of hyperuricemia and gout by blocking the reabsorption of uric acid (UA) within the renal proximal tubule, thereby reducing serum uric acid concentrations. As a novel URAT1 inhibitor, D-0120 is anticipated to have more potent serum UA reducing effect than the approved URAT1 inhibitor lesinurad, but with less toxicity and wider therapeutic window. The pharmacological potential of D-0120 for the treatment of hyperuricemia and gout was demonstrated in preclinical studies. The results of the in vitro hURAT1 expressed CHO cell model showed that the inhibitory activity of D-0120 is 150-fold more potent than lesinurad and slightly more potent than verinurad.Objectives:The purpose of this dose escalation study is to evaluate the safety and tolerability of D-0120 in multiple ascending doses in healthy volunteer, to characterize the pharmacokinetics (PK) of D-0120 and to assess pharmacodynamic (PD) effects and determine the drug-drug interaction (DDI) effect of febuxostat and D-0120 in healthy volunteers.Methods:This is a randomized, double blind, multiple ascending doses Phase I study of D-0120 in healthy volunteers conducted at one site. Thirty-two healthy eligible volunteers with serum uric acid level ≥ 4.5 mg/dL but within normal range at screening were enrolled and dosed with D-0120 within 4 different single agent cohorts for a period of 7 days. Each cohort had 8 subjects randomized at 3:1 ratio for D-0120:placebo. A fifth cohort of 8 healthy eligible volunteers were enrolled and dosed with 5 mg of D-0120 in combination with 40 mg of febuxostat over a period of 9 days. Evaluation of safety, PK and PD was conducted at various timepoints while the patients were in confinement. Further safety evaluation took place on Day 14. A Safety Review Committee reviewed safety, PK and PD data for each cohort of D-0120 dose level (2.5 mg, 5 mg, 10 mg, 20 mg) as well as when D-0120 5 mg was combined with 40 mg febuxostat. PK evaluation for multiple dose parameters included AUC0-τ, Cmax, Cmin, Tmax and Fl.Results:Dose escalation of D-0120 from 2.5 mg/day to 20 mg/day was completed without any dose limiting toxicities. Most AEs occurred during the study were mild to moderate in severity and did not require any treatment before resolution. There was no SAE and no dose reduction during the treatment period. The pharmacokinetic (PK) evaluation of ascending dose levels of D-0120 suggested a dose proportional increase in drug exposure and there was no significant change of PK profile between Day 1 and Day 7 of dosing. For pharmacodynamic (PD) evaluation, the serum uric acid (UA) levels before and after D-0120 dosing was evaluated on multiple days. The UA reduction effect achieved maximum at about 4-8 hours after dosing and the effect lasted for at least 24 hours. After the 7-day dosing period, the mean percentage of UA reduction from baseline showed an increasing trend as the dose level increased.More detailed safety, PK and PD data from multiple D-0120 dose cohorts and D-0120/febuxostat combination cohort will be presented at the meeting.Conclusion:The oral daily administration of a novel URAT1 inhibitor, D-0120, in healthy volunteers for 7 days was well tolerated at dose levels from 2.5 mg/day to 20 mg/day. The PK profile demonstrated a dose proportional increase. D-0120 administration for 7 days resulted in significant reduction of serum UA levels. Further evaluation of this novel agent in longer treatment period and in patients with hyperuricemia and/or gout is warranted.

Melflufen plus dexamethasone in relapsed and refractory multiple myeloma (O-12-M1): a multicentre, international, open-label, phase 1–2 study

Multiple myeloma is an incurable haematological malignancy, representing over 10% of haematological cancers in the USA. We did a phase 1-2 study of melflufen and dexamethasone in patients with relapsed and refractory multiple myeloma to determine the maximum tolerated dose of melflufen and to investigate its safety and efficacy. We did a multicentre, international, dose-confirmation and dose-expansion, open-label, phase 1-2 study in seven centres in the USA and Europe. Eligible patients were aged 18 years or older, had relapsed and refractory multiple myeloma, had received two or more previous lines of therapy (including lenalidomide and bortezomib), were refractory to their last line of therapy, and had an Eastern Cooperative Oncology Group performance status of 2 or less. In phase 1, patients received an intravenous infusion of melflufen at 15 mg, 25 mg, 40 mg, or 55 mg for 30 min on day 1 in 21-day cycles plus oral dexamethasone 40 mg weekly and did not receive melflufen as a single agent. Melflufen was also tested in a single-agent cohort late in phase 2 in a small number of patients at the maximum tolerated dose identified in phase 1. In phase 2, patients were enrolled at the maximum tolerated dose in the melflufen plus dexamethasone in the combination cohort.. The phase 1 primary objective was to determine the maximum tolerated dose. The phase 2 primary objective was to evaluate overall response rate and clinical benefit rate. This primary analysis was done per protocol, in the all-treated and efficacy-evaluable population (defined as patients who received at least two doses of melflufen and who had a response assessment after baseline). The single-agent melflufen cohort was closed on October 6, 2016, as per the recommendation by the data safety monitoring committee on the basis of interim data suggesting greater activity in the melflufen plus dexamethasone cohort. The study is completed but survival follow-up is ongoing. This study is registered with ClinicalTrials.gov, NCT01897714. Patients were enrolled between July 4, 2013, and Dec 31, 2016: 23 patients in phase 1 and 58 in phase 2, including six patients from phase 1 treated at the maximum tolerated dose of melflufen 40 mg plus weekly dexamethasone. In phase 2, 45 patients were given a combination of melflufen plus dexamethasone and 13 patients were given single-agent melflufen. In phase 1, the established maximum tolerated dose was 40 mg of melflufen in combination with dexamethasone. No dose-limiting toxicities were observed in the first three dose cohorts (15 mg, 25 mg, and 40 mg). The highest dose cohort tested (55 mg) exceeded the maximum tolerated dose because four of six patients experienced grade 4 neutropenia with grade 4 thrombocytopenia also occurring in three of these patients; therefore, the planned highest dose of 70 mg was not tested. In phase 2, patients treated with combination therapy achieved an overall response rate of 31% (14 of 45 patients; 95% CI 18-47) and clinical benefit rate of 49% (22 of 45; 34-64) in the all-treated population, and 41% (14 of 34; 25-59) and 65% (22 of 34; 47-80) in the efficacy-evaluable population. In the phase 2 single-agent cohort, the overall response rate was 8% (one of 13 patients; 0·2-36·0) and the clinical benefit rate was 23% (three of 13; 5-54). Among the 45 patients given melflufen plus dexamethasone during phase 2, the most common grade 3-4 adverse events were clinically manageable thrombocytopenia (28 [62%] patients) and neutropenia (26 [58%]), and non-haematological toxicity was infrequent. 24 serious adverse events were reported in 17 (38%) of 45 patients, most commonly pneumonia (five [11%]). The most common grade 3-4 adverse events that occurred in the phase 2 single-agent cohort of 13 patients were neutropenia (nine [69%]) and thrombocytopenia (eight [62%]). Nine patients experienced serious adverse events in the single-agent cohort, most commonly thrombocytopenia (two [15%]). There were three deaths from adverse events within 30 days of treatment that were possibly related to treatment: one in the 25 mg cohort in phase 1 (due to bacteraemia) and two in the phase 2 combination cohort (one due to neutropenic sepsis and one due to Escherichia coli sepsis), each in the setting of progressive disease. These data show that melflufen is active in patients with relapsed and refractory multiple myeloma and tolerable in most patients. These results show the feasibility of this regimen and support the initiation of additional clinical studies of melflufen in multiple myeloma, both in combination with dexamethasone as well as in triplet regimens with additional classes of drugs. Oncopeptides AB.

Rapid and Durable Responses with the SYK/JAK Inhibitor Cerdulatinib in a Phase 2 Study in Relapsed/Refractory Follicular Lymphoma-Alone or in Combination with Rituximab

Rapid and Durable Responses with the SYK/JAK Inhibitor Cerdulatinib in a Phase 2 Study in Relapsed/Refractory Follicular Lymphoma-Alone or in Combination with Rituximab

Abstract P6-18-19: Real-world survival of heavily pretreated patients with refractory HR+, HER2- metastatic breast cancer receiving single-agent chemotherapy - A comparison with MONARCH 1

Abstract Background In MONARCH 1 (NCT02102490), abemaciclib demonstrated promising single-agent activity and tolerability in a population of heavily pretreated women with refractory HR+, HER2- metastatic breast cancer (MBC).1 Confirmed objective response rate (ORR) was 19.7% (95% CI: 13.3, 27.5) and at 18 months minimum follow-up median overall survival (OS) was 22.3 months. Due to the single-arm trial design of MONARCH 1, there is a need to view these results in clinical context relative to available treatment options. This study compared the OS results of abemaciclib in MONARCH 1 vs that in a real-world single-agent chemotherapy cohort with similar patient and disease characteristics. Methods MONARCH 1 study design and key eligibility criteria were previously described.1 The real-world cohort was based on Flatiron Health electronic health records-derived, nationally representative (USA-based) database comprising patient-level structured and unstructured data, curated via technology-enabled abstraction, for patients with MBC between January 1, 2011 through February 28, 2018. A real-world single-agent chemotherapy cohort was created based on the key eligibility criteria of MONARCH 1 and included patients diagnosed with HR+, HER2- MBC who received single-agent chemotherapy (eribulin, capecitabine, gemcitabine, or vinorelbine) following 1-2 prior chemotherapy regimens in the metastatic setting, had an ECOG PS of 0-1, and no prior CDK4 & 6 therapy. The index date was the start of the eligible single-agent chemotherapy, and patients were followed from the index date until date of death, loss to follow-up, or end of the database, whichever occurred earlier. OS results were adjusted using 2 methods (Mahalanobis distance matching and entropy balancing with bootstrapping) to account for baseline demographic and clinical differences between the real-world and trial cohorts. Results A real-world cohort (n=281) with eligibility criteria similar to the MONARCH 1 population (n=132) was identified. A subsequent matching based on Mahalanobis distance was performed to match MONARCH 1 population (n=108) with the real-world cohort (n=108). The matched cohorts demonstrated similar patient and disease characteristics. Median OS was 22.3 months in the abemaciclib arm vs 13.6 months in the matched cohort with an estimated hazard ratio (HR) of 0.54 (95% CI: 0.37, 0.77). Results of a sensitivity analysis performed using entropy balancing were consistent with an adjusted median OS of 12.7 months in the real-world cohort (n=281)with HR of 0.57 (95% CI from bootstrapping: 0.44, 0.78). Conclusion Methodological advances to adjust for potential biases, and improvements in data quality, have evolved enabling the ability to leverage a real-world cohort as an external comparator arm. This study demonstrates the ability to create a real-world chemotherapy cohort suitable to serve as a comparator for MONARCH 1. These exploratory results suggest a survival advantage and adequately place the clinical benefit of abemaciclib monotherapy in clinical context. References Dickler et al, CCR 2017 Citation Format: Rugo H, Dieras V, Cortes J, Patt D, Wildiers H, O'Shaughnessy J, Zamora E, Yardley DY, Carter GC, Sheffield KM, Li L, Andre VA, Derbyshire RE, Li XI, Frenzel M, Huang Y-J, Dickler MN, Tolaney SM. Real-world survival of heavily pretreated patients with refractory HR+, HER2- metastatic breast cancer receiving single-agent chemotherapy - A comparison with MONARCH 1 [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-19.

Azacitidine and Romidepsin Synergize to Induce Expression of Cancer Testes Antigens (CTA) and Shift Peripheral T-Cell Lymphoma (PTCL) Cell Lines Toward a Th1-like Phenotype

Introduction: The PTCL appear to be exquisitely sensitive to epigenetic modifiers, including histone deacetylase inhibitors and hypomethylating agents. While the PTCL harbor recurring mutations in genes controlling CpG methylation, including TET2, IDH2 and DNMT3, it is not clear these genetic events portend sensitivity to these classes of drugs. In preclinical models of PTCL, HDACi and HMA exhibit marked class synergy in vivo and in vitro. Early Phase 1 and 2 experiences have confirmed compelling activity across the PTCL, with exceptionally high response rates in patients with angioimmunoblastic T-cell lymphoma. While the precise mechanism of synergy is under investigation, it is clear these drugs can induce a host of immunological effects on both the tumor cell proper as well as the host. We present details of these class effects in models of PTCL.Methods: We have explored combinations of azacitidine and romidepsin in a panel of 6 TCL cell lines. The cell viability was accessed and synergy was calculated using Excess Over Bliss modeling to determine the efficacy of the combination. We then performed RNAseq analysis on 4 TCL lines. We confirmed the protein expression of multiple targets using western blot to confirm to results obtained from sequencing. TCL lines were exposed to combination for 96 hours, supernatant was collected and assayed for proliferative properties using isolated PBMCs from healthy donors and anti-CD3/anti-CD28 beads.Results: The combination of azacitidine and romidepsin were potently synergic across all 6 cell lines. Determination of DNA methylation revealed a decrease in %MdC, as a function of concentration. A supervised analysis of the RNAseq revealed almost all of the genes perturbed by the single agent treatments were enhanced by the combination. There were 1215 genes affected by combination treatment with a p-value ≤0.05; 921 of the genes were not found in either single agent cohort. Of the 1215 genes, 936 were upregulated and 279 genes were downregulated. A gene set enrichment analysis (GSEA) of the RNAseq data displayed a significant down regulation in multiple genes involved in cholesterol biosynthesis in the combination, for example, HMGCR (-2.1 FC), FDPS (-2 FC) and IDI1 (-1.8 FC). The RNAseq analysis revealed a marked increase in expression levels in a variety cancer/testis antigens (CTA) that were most amplified by the combination, such as PRAME (4.9 FC) and MAGE-A1 (11.3 FC). As single agents, azacitidine alone was capable of inducing minor expression of some targets while romidepsin did not affect any. There was a radical change in genes involved in viral/interferon response and immune response observed in RNAseq. The expression of a handful of interleukins and interferons associated with viral/interferon and immune responses were induced by single agent azacitidine and amplified the most by the combination, such as IF16 (1.4 FC aza, 2.8 FC combo), IL18 (3.4 FC combo), IL34 (2.4 FC aza, 3.7 FC combo) and IL26 (5.2 combo FC). Noticeably, single agent romidepsin (3 FC) and the combination (6 FC) augmented the expression of CD274 (PD-L1).Most drastically intensified from this subset of immune response genes was TBX21 (6.9 FC) expression that was induced by the combination. We see from a western blot that the combination induces maximum protein expression levels of T-bet (transcription factor encoded by TBX21) in 4/6 TCL cell lines. STAT4, known to interact with T-bet to promote Th1-differentiation, protein expression was confirmed to increase with combination treatment in 4/6 TCL cell lines. Enhanced proliferation was seen when PBMCs were cultured with conditioned medium from 4 different TCL lines treated with the combination.Conclusions: The generated data presents a strong justification for the use of combination in addition to an immune checkpoint inhibitor, such as a PD-1/PD-L1 inhibitor. With the emergence of members of CTA family becoming a developing marker in immunotherapy, it is of absolute importance to narrow down the possible targets induced by combination therapy. Here we identify two members of the family that are uniquely expressed as a result from exposure to the combination. Interestingly, the combination is also able to induce a Th1-like phenotype that is often associated with a favorable prognosis. These data suggest that azacitidine and romidepsin in TCL is a promising platform treatment that undeniably proves itself advantageous in preclinical models. DisclosuresO'Connor:Seattle Genetics: Research Funding; ADC Therapeutics: Research Funding; Celgene: Research Funding.

Adjuvant treatment of resectable biliary tract cancer with cisplatin plus gemcitabine: A prospective single center phase II study

BackgroundBiliary tract cancer (BTC) is a dismal disease, even after curative intent surgery. We conducted this prospective, non-randomized phase II study to evaluate the feasibility and efficacy of cisplatin and gemcitabine as adjuvant treatment in patients with resected BTC.MethodsPatients initially received gemcitabine 1000 mg/m2 alone on days 1, 8 and 15 every 28-days for a total of six cycles (single agent cohort), and after protocol amendment a combination therapy with gemcitabine 1000 mg/m2 and cisplatin 25 mg/m2 on days 1 and 8 was administered every 21 days for a total of eight cycles (combined regimen cohort). Treatment was planned to start within eight weeks after curative intent resection. Adverse events, disease-free survival and overall survival were assessed.ResultsOverall 30 patients were enrolled in the study from August 2008 and last patient was enrolled at 2nd December 2014. The follow-up of the patients ended at 31st December 2016. The first 9 patients received single-agent gemcitabine. The interim analysis met the predefined feasibility criteria and, from September 2010 on, the second group of 21 patients received the combination of cisplatin plus gemcitabine. In the single-agent cohort with gemcitabine the median relative dose intensity (RDI) was 100% (IQR 88.3–100). Patients treated with the combination cisplatin-gemcitabine received an overall median RDI of 100% (IQR 50–100) for cisplatin and 100% (IQR 75–100) for gemcitabine respectively. The most significant non-hematological adverse events (grade 3 or 4) were fatigue (20%), infections during neutropenia (10%), and two cases of biliary sepsis (7%). Abnormal liver function was seen in 10% of the patients. One patient died due to infectious complications during treatment with cisplatin and gemcitabine. The median disease-free survival (DFS) was 14.9 months (95% CI 0–33.8) with a corresponding 3-year DFS of 43.1 ± 9.1%. The median overall survival (OS) was 40.6 months (95% CI 18.8–62.3) with a 3-year OS of 55.7 ± 9.2%. No statistically significant differences in survival were seen between the two treatment cohorts.ConclusionAdjuvant chemotherapy with gemcitabine with or without cisplatin was well tolerated and resulted in promising survival of the patients.Trial registrationThe study was retrospectively registered on 25th June 2009 at clinicaltrials.gov (NCT01073839).

A Phase 1 and 2 study of Filanesib alone and in combination with low‐dose dexamethasone in relapsed/refractory multiple myeloma

Filanesib (ARRY-520) is a highly selective inhibitor of kinesin spindle protein, which has demonstrated preclinical antimyeloma activity. This open-label Phase 1/2 study determined the maximum tolerated dose of Filanesib administered on Days 1 and 2 of 14-Day Cycles in patients with multiple myeloma (MM) and included expansion cohorts with and without dexamethasone (40 mg/week). Patients in the dose-escalation (N = 31) and Phase 2 single-agent (N = 32) cohorts had received prior bortezomib as well as prior thalidomide and/or lenalidomide. Patients in the Phase 2 Filanesib plus dexamethasone cohort (N = 55) had received prior alkylator therapy and had disease refractory to lenalidomide, bortezomib, and dexamethasone. Prophylactic filgrastim was incorporated during dose escalation and was used throughout Phase 2. Patients in each cohort had received a median of ≥6 prior therapies. The most common dose-limiting toxicities were febrile neutropenia and mucosal inflammation. In Phase 2, Grade 3 and 4 cytopenias were reported in approximately 50% of patients. Nonhematologic toxicities were infrequent. Phase 2 response rates (partial responses or better) were 16% (single agent) and 15% (Filanesib plus dexamethasone). All responding patients had low baseline levels of α1-acid glycoprotein, a potential selective biomarker. Filanesib 1.50 mg/m2 /day administered with prophylactic filgrastim has a manageable safety profile and encouraging activity in heavily pretreated patients This study is registered at www.clinicaltrials.gov as NCT00821249. Cancer 2017;123:4617-4630. © 2017 American Cancer Society.