Antitumor Benefit Research Articles

Regorafenib dose escalation therapy for patients with refractory metastatic colorectal cancer (RECC Study).

116 Background: Regorafenib, a multi-kinase inhibitor, significantly improved overall survival in previously treated metastatic colorectal cancer (mCRC) patients in the phase 3 CORRECT trial. Despite its significant benefits, various toxicities such as hand-foot skin reaction (HFSR), fatigue, and liver dysfunction have limited regorafenib use. The toxicities occur soon after treatment initiation, typically within the first cycle, and later improve. Although the standard daily dose of regorafenib is 160 mg, physicians have adopted various dosing regimens in clinical practice, indicating the need to optimize the dosing strategy to maintain the antitumor benefits. The ReDOS study demonstrated the effectiveness of a weekly dose-escalating strategy (WDES) of regorafenib starting with a lower daily dose. We conducted the phase II RECC study to evaluate the safety and efficacy of WDES for regorafenib in an Asian population. Methods: Patients with sufficient organ function who had previously received more than two lines of chemotherapy were included. Regorafenib was started at 80 mg/day and escalated to 120 mg/day in Week 2 and 160 mg/day in Week 3 if no severe drug-related toxicities were observed. The primary endpoint was progression-free survival (PFS) and secondary endpoints were time to treatment failure (TTF), response rate (RR), overall survival (OS), and safety. Tumor response and progression were assessed radiologically every 8 weeks. Results: From March 2017 to November 2018, 57 eligible patients were enrolled and all started regorafenib at 80 mg/day. Thirty-five patients (61%) were subsequently escalated to 120 mg/day and 16 (28%) to 160 mg/day. Forty patients (70.2%) finished Cycle 2 at 8 weeks. Only 8 patients (14%) discontinued treatment because of adverse events. The median PFS was 1.9 months, RR was 0%, and disease control rate was 32%. The most frequent adverse event ≥grade 3 was hypertension (17.5%), followed by HFSR (14%). No treatment-related deaths occurred. Conclusions: Regorafenib dose escalation was well tolerated with PFS similar to that reported in the CORRECT study, indicating that WDES may represent an option for regorafenib administration. Clinical trial information: UMIN000028933.

Cannabidiol-from Plant to Human Body: A Promising Bioactive Molecule with Multi-Target Effects in Cancer.

Cannabis sativa L. is a plant long used for its textile fibers, seed oil, and oleoresin with medicinal and psychoactive properties. It is the main source of phytocannabinoids, with over 100 compounds detected so far. In recent years, a lot of attention has been given to the main phytochemicals present in Cannabis sativa L., namely, cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC). Compared to THC, CBD has non-psychoactive effects, an advantage for clinical applications of anti-tumor benefits. The review is designed to provide an update regarding the multi-target effects of CBD in different types of cancer. The main focus is on the latest in vitro and in vivo studies that present data regarding the anti-proliferative, pro-apoptotic, cytotoxic, anti-invasive, anti-antiangiogenic, anti-inflammatory, and immunomodulatory properties of CBD together with their mechanisms of action. The latest clinical evidence of the anticancer effects of CBD is also outlined. Moreover, the main aspects of the pharmacological and toxicological profiles are given.

A Sphingosine-1-Phosphate Modulator Ameliorates Polycystic Kidney Disease in Han:SPRD Rats

Background: Inflammation plays an important role in polycystic kidney disease (PKD). Cordyceps sinensis, a prized ­Chinese medicinal herb, exerts anti-tumor, anti-inflammatory and anti-metastatic effects and benefits patients with kidney diseases. The aim of this study was to test the efficacy of FTY720, an immunosuppressant derived from C. sinensis, in a rat cystic kidney disease model, and explore its underlining mechanism. Methods: Male wild type and Cy/+ Han:SPRD rats were treated with FTY720 at 3 and 10 mg/kg/day for 5 weeks and 12 weeks by gavage. Blood and kidney were collected for functional, morphological, RNA, and protein analysis. Results: Inflammation is activated in Cy/+ Han:SPRD rats. Inflammatory cytokines including interleukin 6 and tumor necrosis factor alpha were upregulated and inflammation-related pathways were activated, such as nuclear factor κB and signal transducer and activator of transcription 3 (STAT3) pathways. Furthermore, the bioactive sphingolipid mediator sphingosine-1-phosphate (S1P), a regulator of inflammation, was accumulated in the Cy/+ Han:SPRD rats. FTY720 significantly reduced cyst growth and delayed disease progression by reducing the accumulation of S1P, thereby inhibiting inflammatory responses. Conclusion: FTY720 treatment reduced the expression of inflammatory cytokines and attenuated the activation of NK-κB and STAT3 pathways in Cy/+ Han:SPRD rats. It suggests that FTY720 may serve as a therapeutic agent for clinical autosomal dominant PKD treatment.

A novel intraperitoneal therapy for gastric cancer with DFP-10825, a unique RNAi therapeutic targeting thymidylate synthase, in a peritoneally disseminated xenograft model.

PurposeIn advanced gastric cancer, peritoneal dissemination is a life‐threatening mode of metastasis. Since the treatment options with conventional chemotherapy remain limited, any novel therapeutic strategy that could control such metastasis would improve the outcome of treatment. We recently developed a unique RNA interference therapeutic regimen (DFP‐10825) consisting of short hairpin RNA against thymidylate synthase (TS shRNA) and cationic liposomes. The treatment with DFP‐10825 has shown remarkable antitumor activity in peritoneally disseminated human ovarian cancer–bearing mice via intraperitoneal administration. In this study, we expanded DFP‐10825 to the treatment of peritoneally disseminated gastric cancer.MethodsDFP‐10825 was administered intraperitoneally into mice with intraperitoneally implanted human gastric cancer cells (MKN45 or NCI‐N87). Antitumor activity and host survival benefits were monitored. Intraperitoneal distribution of fluorescence‐labeled DFP‐10825 was monitored in this MKN45 peritoneally disseminated mouse model.ResultsIntraperitoneal injection of DFP‐10825 suppressed tumor growth in two peritoneally disseminated cancer models (MKN45 and NCI‐N87) and increased the survival time of the MKN45 model without severe side effects. Throughout the treatment regimen, no significant body weight loss was associated with the administration of DFP‐10825. Interestingly, after intraperitoneal injection, fluorescence‐labeled DFP‐10825 retained for more than 72 hours in the peritoneal cavity and selectively accumulated in disseminated tumors.ConclusionsIntraperitoneal injection of DFP‐10825 demonstrated effective antitumor activity without systemic severe adverse effects via the selective delivery of RNAi molecules into disseminated tumors in the peritoneal cavity. Our current study indicates that DFP‐10825 could become an alternative option to improve the outcomes of patients with peritoneally disseminated gastric cancer.

Secreted amphiregulin promotes vincristine resistance in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer. Despite advances in surgery, radiotherapy and chemotherapy, the overall 5‑year survival rate of patients with OSCC has not significantly improved. In addition, the prognosis of patients with advanced‑stage OSCC remains poor. Therefore, it is necessary to develop novel therapeutic modalities. Vincristine (VCR), a naturally occurring vinca alkaloid, is a classical microtubule‑destabilizing agent and is widely used in the treatment of a number of cancers. Despite the proven antitumor benefits of VCR treatment, one of the major reasons for the failure of treatment is drug resistance. Changes in the tumor microenvironment are responsible for cross‑talk between cells, which may facilitate drug resistance in cancers; secreted proteins may promote communication between cancer cells to induce the development of resistance. To identify the secreted proteins involved in VCR resistance, conditioned media was obtained, and an antibody array was conducted to screen a comprehensive secretion profile between VCR‑resistant (SAS‑VCR) and parental (SAS) OSCC cell lines. The results showed that amphiregulin (AREG) was highly expressed and secreted in SAS‑VCR cells. Pretreatment with exogenous recombinant AREG markedly increased drug resistance against VCR in OSCC cells, as assessed by an MTT assay. Colony formation, MTT and western blot assays were performed to investigate the effects of AREG knockdown on VCR sensitivity. The results indicated that AREG expression can regulate VCR resistance in OSCC cells; overexpression of AREG increased VCR resistance in parental cells, whereas AREG knockdown decreased the VCR resistance of resistant cells. In addition, it was also demonstrated that the glycogen synthase kinase‑3β pathway may be involved in AREG‑induced VCR resistance. These findings may provide rationale to combine VCR with blockade of AREG‑related pathways for the effective treatment of OSCC.

Medical findings of nasopharyngeal carcinoma patients and anti-tumor benefits of formononetin

Epidemiologically, a malignancy of nasopharyngeal carcinoma (NPC) is endemic in worldwide, characterized with high invasiveness and lethality. Formononetin (FN), an anti-tumor bioactive component, is found to exert anti-proliferative activity against NPC cells. However, the invasive pharmacological activities of FN against NPC have not yet been investigated. In this study, the human NPC data and samples were used for further assays. In addition, a human cell line of CNE2 was used to evaluate the anti-invasive effects of formononetin and the underlying mechanism. As results, advanced NPC patients were diagnosed through validation of blood tumor markers and medical images, and the results showed increased Lamin A/C and cytokeratin 19 (CK19) expressions in carcinomatous sections. In experimental study in vitro, FN-treated CNE2 cells exhibited inhibited cellular proliferation, promoted cell apoptosis, and decreased would healing process, reduced cellular migratory capability, respectively. Furthermore, FN-treated CNE2 cells resulted in down-regulated expressions of b-cell lymphoma-2 (Bcl-2), extracellular regulated protein kinases1/2 (ERK1/2), Lamin A/C and CK19 in a dose-dependent manner, while intracellular Bax expression was elevated. Taken together, these clinical findings elucidate invasive characteristics of human NPC samples. Further, the anti-proliferative and invasive benefits of FN were achieved through suppression of cellular ERK1/2 pathway and inactivation of intracellular Lamin A/C signaling in NPC cells.

Abstract 5024: Treatment with synthetic RIG-I agonist triphosphate RNA leads to local and systemic anti-tumor effects in a mouse melanoma tumor model

Abstract RIG-I is a highly important cytosolic pattern recognition receptor (PRR) involved in sensing RNA virus infection and inducing interferon (IFN) production. RIG-I’s natural ligand, triphosphate RNA (ppp-RNA), is proposed to be a valuable addition to the growing arsenal of cancer immunotherapy treatment options. This study validates the use of intratumoral treatment with synthetic RIG-I agonist ppp-RNA for the therapy of human cancer, with melanoma as potential entry indication amenable to intratumoral treatment. Firstly, we demonstrate that RIG-I expression is closely correlated to cellular and cytokine immune activation in a wide variety of tumor types. Secondly, cellular models of human melanoma confirm susceptibility of cancer cells to ppp-RNA treatment, revealing unexpected heterogeneity between cell lines in their selectivity for RNA features, including sequence, secondary structures and presence of triphosphate. Cellular RNA treatment responses (type I IFN, FasR, MHC-I, cytotoxicity) were demonstrated to be RIG-I dependent using RIG-I KO cells. Thirdly, we show that ppp-RNA treatment of a mouse melanoma tumor model, leads to significant local and systemic anti-tumor effects and survival benefits, associated with a type I IFN response, tumor cell apoptosis and innate and adaptive immune cell activation. For the first time, we demonstrate systemic presence of tumor antigen specific CTLs following treatment with RIG-I agonist. Overall our study demonstrates that ppp-RNA or analogs thereof have the potential to play an important role for cancer treatment in the next wave of immunotherapy. However, potential challenges in the generation and formulation of potent RIG-I agonists remain to be solved. Citation Format: Mike W. Helms, Eric Parmantier, Kerstin Jahn-Hofmann, Felix Gnerlich, Lars König, Christiane Metz-Weidmann, Monika Braun, Gabriele Dietert, Kaj Grandien, Joachim Theilhaber, Hui Cao, Tim Wagenaar, Max Schnurr, Stefan Endres, Dmitri Wiederschain, Sabine Scheidler, Simon Rothenfusser, Bodo Brunner. Treatment with synthetic RIG-I agonist triphosphate RNA leads to local and systemic anti-tumor effects in a mouse melanoma tumor model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5024.

Abstract CT122: Randomized assessment of cisplatin dose interval for ototoxicity in the treatment of locally advanced squamous cell carcinoma of the head and neck undergoing curative concurrent chemoradiotherapy (RADIO)

Abstract Background: Recently reported randomized clinical trials (RCTs) have confirmed the importance of concurrent cisplatin in the curative treatment of HPV-related oropharynx cancer treated with definitive radiotherapy (RT) (Mehanna ESMO 2018, Trotti ASTRO 2018). However, the optimal cisplatin dose and schedule in this setting remain unclear. Concurrent high-dose cisplatin (HDC) given every 3 weeks is considered standard but associated with increased risks of infection, vomiting and nephrotoxicity (Szturz 2018). Cisplatin-associated hearing loss (CAHL) has been less well studied. Noronha et al (2018) reported less permanent deafness but inferior cancer outcomes with weekly cisplatin at a dose of 30 mg/m2 compared to HDC. However, meta-analysis of RCTs shows no difference in mortality with weekly compared to HDC (Szturz 2018). RCT results to date suggest a minimum total dose of 200 mg/m2 cisplatin be delivered at a minimum dose of 40 mg/m2 per week for optimal anticancer effect. Weekly cisplatin schedule, MATE1 polymorphisms (SNPs), absence of COMT SNPs and lower cochlear RT dose independently predict lower CAHL risk (Teft 2019). We hypothesize that if there is a small incremental antitumor benefit of HDC in oropharyngeal cancer patients who are expected to be cured, it is offset by the negative quality of life (QoL) impact of permanent hearing loss. This RCT was designed to confirm reduced ototoxicity with weekly compared to q3weekly cisplatin when combined with RT, quantitate effects on hearing-related QoL, and validate pharmacogenomic risk factors. Methods: This randomized clinical trial will be conducted at two comprehensive cancer centres in Ontario, Canada and is open to enrollment. 100 patients will be stratified by tumor HPV status and randomized (1:1) to receive cisplatin either 100 mg/m2 IV q21days for 3 doses (control arm) or 40 mg/m2 IV weekly (experimental arm) during RT. Eligible patients will have squamous cell carcinoma of the oral cavity, oropharynx, larynx, nasal cavity, hypopharynx or unknown primary site planned for IMRT + cisplatin with curative intent after assessment by a multidisciplinary team, and must be deemed suitable for HDC by the treating medical oncologist. Patients with prior head or neck RT, baseline hearing impairment or known/suspected nasopharyngeal cancer are ineligible. RT will be once daily IMRT 5 days weekly to total dose of 70 Gy/35F (64 Gy/30F if postoperative). The trial is powered to evaluate co-primary endpoints of hearing-related QoL (by HHIA & HHIE) and CAHL grade 2 or greater (CTCAE 4.03) at 1 year. Secondary endpoints include: need for amplification, tinnitus, health-related QoL, and grade 3 or worse neuropathy and neuropathy all at 1 year. Overall and progression-free survival, locoregional control, and cost-effectiveness will also be assessed. Citation Format: Eric Winquist, Brandon Meyers, Greg Pond, Sebastien Hotte, Morgan Black, Christina Parker, Anthony Nichols, David Palma, Richard Kim, Sara Kuruvilla. Randomized assessment of cisplatin dose interval for ototoxicity in the treatment of locally advanced squamous cell carcinoma of the head and neck undergoing curative concurrent chemoradiotherapy (RADIO) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT122.

Abstract 4723: Combinatorial efficacy of anti-PD1 treatment and selective histone deacetylase 6 (HDAC6) inhibition in chronic lymphocytic leukemia (CLL)

Abstract A suppressive microenvironment allows CLL B cells to avoid immune surveillance. Coinhibitory antigens, anti-inflammatory cytokines and skewed immune populations support malignancy and contribute to poorer immune responses in CLL patients. Novel approaches to counter immunosuppression are therefore being explored. The HDAC family of proteins epigenetically regulate immune-related pathways in cancer and may be noteworthy immunomodulatory targets. In addition to the recognized role of HDACs in cell survival, HDACi may alter inflammatory status of immune and tumor cells. We have previously reported that HDAC6 regulates IL-10 transcription, and is responsible for T cell anergy in murine and human APCs. IL-10 is secreted by CLL B cells and is thought to influence immunosuppression. Therefore, we hypothesized that HDAC6i could reverse immunosuppression in CLL for antitumor benefit. The purpose of this study was to determine 1) the effects of selective HDAC6i on CLL immune biology and 2) whether combination with HDAC6i could improve efficacy of anti-PD1 for CLL therapy. To accomplish these aims, the euTCL1 and euTCL1/HDAC6KO adoptive transfer models of murine CLL were utilized. ACY738 (selective HDAC6i) was administered orally in chow at 25mpk daily. Anti-PD1 was administered intraperitoneally 3x per week at 3mpk. CLL surface antigens were analyzed via flow cytometry. Functional mixed lymphocyte assays were performed ex vivo, measuring IFNg production, and Th1/Th2 factors were examined via qRT-PCR in CLL T cells. Early PD-L1 expression on B cells correlated to CLL burden in euTCL1 mice. Post ACY738 treatment, euTCL1 B cells downregulated expression of PD-L1 and plasma IL-10. In addition, PD-1 and CTLA4 was decreased on CD4+, CD8+, Tregs and effector memory T cells. Splenic T cells from ACY738 mice upregulated TBET and downregulated GATA3, indicative of a less exhausted phenotype. Subsequently, euTCL1 B cells were treated ex vivo with ACY738 and cocultured with T cells. T cell activation (IFNg production) was increased after coculture with treated B cells compared to control B cells. We then hypothesized that ACY738 could be rationally be combined with anti-PD1 mAb for CLL treatment. Mice treated with anti-PD1 accumulated fewer CD5+ B cells, confirming that PD-1/PD-L1 blockade demonstrated anti-CLL benefit. Strikingly, combination of ACY738 and anti-PD1 further delayed the growth of CLL cells compared to either single agent. Consistently, anti-PD1 treatment in euTCL1/HDAC6KO mice further delayed CLL development. In conclusion, we report here that HDAC6i can reinvigorate CLL T cells, and combination of HDAC6i with anti-PD1 increased anti-CLL efficacy in vivo. This work provides evidence that this combination could be clinically investigated to simultaneously reduce tumor burden and improve immune function in CLL patients. Citation Format: Kamira Maharaj, John Powers, Alex Achille, Eva Sahakian, Javier Pinilla-Ibarz. Combinatorial efficacy of anti-PD1 treatment and selective histone deacetylase 6 (HDAC6) inhibition in chronic lymphocytic leukemia (CLL) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4723.

PRINT: Prostate cancer intensive, non-cross reactive therapy for CRPC—Early observations of feasibility and efficacy.

310 Background: Optimal sequencing of approved therapeutic agents in mCRPC is not known. The standard approach, is to treat until resistance then switch. The PRINT trial explores the efficacy of treating mCRPC with a rapidly-cycling, non-cross reactive regimen as a way to more effectively treat an intrinsically heterogeneous disease, to delay or prevent drug resistance, and minimize treatment toxicity. Methods: Patients were treated with 3 consecutive treatment modules, each of 12 weeks' duration: 1. abiraterone acetate 1000 mg PO daily and prednisone 5 mg PO BID; 2. cabazitaxel 20 mg/m2 IV and carboplatin AUC 4 IV q3 weeks; 3. enzalutamide 160 mg PO daily and radium-223 50 kBq/kg IV q4 weeks (in those with bone metastases). After completion of this 9 month regimen, patients are followed on ADT alone. Primary endpoint is PSA or radiographic time to disease progression. Results: From 3/2017 to 10/2018, 28 of 40 planned men with mCRPC were enrolled, 19 (67.9%) with bone metastases. PSA response rates ( > 90%/ > 50%), compared to baseline, following each treatment module: 1. 50%/78.6%; 2. 50%/92.7%; 3. 64.39%/92.7%. Currently, 14 patients have completed the study regimen with median follow up of 3.6 months, 8 of whom continue without any additional therapy. Of the patients evaluable for primary endpoint, median time to PSA progression is 96+ days (95% CI 82-110+ days). The regiment was well tolerated, grade 3/4 adverse effects include: hyperglycemia (17.9%), diarrhea (7.1%), anemia (3.6%), fatigue (3.6%), neutropenia (3.6%), thrombocytopenia (3.6%). Measurable response and molecular correlate data will be presented. Conclusions: Treatment of mCRPC with a rapidly-cycling non-cross reactive regimen is feasible, demonstrates significant antitumor benefits, and is well tolerated. Further follow up will determine if PRINT delays progression compared with standard approaches. Clinical trial information: NCT02903160.

Combination Therapy Using Ruxolitinib and Oncolytic HSV Renders Resistant MPNSTs Susceptible to Virotherapy.

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft-tissue sarcomas resistant to most cancer treatments. Surgical resection remains the primary treatment, but this is often incomplete, ultimately resulting in high mortality and morbidity rates. There has been a resurgence of interest in oncolytic virotherapy because of encouraging preclinical and clinical trial results. Oncolytic herpes simplex virus (oHSV) selectively replicates in cancer cells, lysing the cell and inducing antitumor immunity. We previously showed that basal interferon (IFN) signaling increases interferon-stimulated gene (ISG) expression, restricting viral replication in almost 50% of MPNSTs. The FDA-approved drug ruxolitinib (RUX) temporarily resets this constitutively active STAT signaling and renders the tumor cells susceptible to oHSV infection in cell culture. In the studies described here, we translated our in vitro results into a syngeneic MPNST tumor model. Consistent with our previous results, murine MPNSTs exhibit a similar IFN- and ISG-mediated oHSV-resistance mechanism, and virotherapy alone provides no antitumor benefit in vivo However, pretreatment of mice with ruxolitinib reduced ISG expression, making the tumors susceptible to oHSV infection. Ruxolitinib pretreatment improved viral replication and altered the oHSV-induced immune-mediated response. Our results showed that this combination therapy increased CD8+ T-cell activation in the tumor microenvironment and that this population was indispensable for the antitumor benefit that follows from the combination of RUX and oHSV. These data suggest that JAK inhibition prior to oncolytic virus treatment augments both oHSV replication and the immunotherapeutic efficacy of oncolytic herpes virotherapy.

Patient Co-Morbidity Profile Should Drive PI3K Inhibitor Selection for Relapsed Follicular Lymphoma

Background: Idelalisib (Zydelig®, IDELA), an oral agent, and copanlisib (Aliqopa®, COPA), an intravenous agent, are the only B-cell receptor pathway targeting agents approved for treatment of follicular lymphoma (FL). Both agents target PI3Kδ while COPA also targets PI3Kα. These drugs received accelerated approvals, and overall response rates in their respective phase 2 trials were comparable. Safety profiles may be impacted by distinct kinase inhibitory profiles, delivery method, and dosing. Given similar response rates with these agents, the administration schedule and safety profile become important considerations. A challenge is the appropriate regimen choice to maximize anti-tumor benefit while limiting treatment-emergent adverse events (TEAEs) or exacerbation of pre-existing co-morbidities. Objective: To compare the safety profiles of IDELA and COPA to determine which drug may be more suitable for select patient populations. Methods: We selected key AEs for analysis based on the "Highlights of Prescribing Information" in each drug9s United States package insert (USPI) to assess the incidence of TEAEs in patients receiving COPA or IDELA. Using the Safety Analysis Set for patients with iNHL treated with IDELA (N=163, median duration of treatment [mDoT] 27 weeks) and TEAEs reported for patients with FL and other hematological malignancies treated with COPA (Aliqopa® USPI [N=168, mDoT 22 weeks], Dreyling et al., J. Clin. Oncol. 2017; 35:3898 [N=142, mDoT 22 weeks], and Dreyling et al., Blood. 2017; 130:2777 [N=142, mDoT 26 weeks]), we ascertained the most common TEAEs, compared the incidence of specific TEAEs (estimate difference in proportions, Fisher9s exact test), and assessed the effect of pre-existing conditions on IDELA- and COPA-mediated AEs. Results: All grade (aGr) and grade 3/4 (Gr3/4) diarrhea and transaminitis were significantly more common in IDELA-treated patients, and aGr and Gr3/4 hyperglycemia (blood glucose >160 mg/dL and >250 mg/dL, respectively) and hypertension (systolic blood pressure [SBP] >120 mmHg; diastolic blood pressure [DBP] > 80 mmHg and SBP > 160 mmHg; DBP > 100 mmHg, respectively) were significantly more common in COPA-treated patients (Figs. 1 and 2). The incidences of aGr and Gr3/4 infection, neutropenia, and pneumonitis were similar in IDELA- and COPA-treated patients. IDELA-treated patients with pre-existing diabetes mellitus or hyperglycemia experienced more Gr3/4 hyperglycemia than IDELA-treated patients without either diagnosis (7.1% vs. 0%, p=0.0286), but at rates lower than in COPA-treated patients (10.7% vs. 53.6%, p Conclusion: Pre-existing co-morbidities and the nature of emergent therapy-associated side effects (including type, severity, and duration [transient vs. chronic]) may impact PI3K inhibitor choice for the treatment of relapsed FL. Findings in this analysis suggest that for patients with pre-existing diabetes mellitus or hypertension, IDELA may be a more appropriate option. For patients at increased risk for diarrhea-related complications, COPA may be a more appropriate option. IDELA-treated patients should be followed closely for diarrhea and should be monitored routinely for hepatotoxicity regardless of hepatic status at treatment initiation. Patients treated with either compound should be followed closely for infection, neutropenia, and pneumonitis. Disclosures Ye:Gilead Sciences, Inc.: Employment, Equity Ownership. Xing:Gilead Sciences: Employment. Roudet:Gilead Sciences, Inc.: Employment. Ruzicka:Gilead Sciences, Inc.: Employment. Dreyling:Bayer: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Research Funding; Mundipharma: Consultancy, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria; Acerta: Consultancy; Sandoz: Consultancy. Zinzani:Janssen: Honoraria, Speakers Bureau; Gilead: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Speakers Bureau; Astra Zeneca: Speakers Bureau; Bayer: Membership on an entity9s Board of Directors or advisory committees; Verastem: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Speakers Bureau; Bayer: Membership on an entity9s Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Celltrion: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Speakers Bureau; TG Pharmaceuticals: Honoraria, Membership on an entity9s Board of Directors or advisory committees; PFIZER: Honoraria, Membership on an entity9s Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Speakers Bureau; TG Pharmaceuticals: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity9s Board of Directors or advisory committees; SERVIER: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Speakers Bureau; MSD: Honoraria, Speakers Bureau; Takeda: Membership on an entity9s Board of Directors or advisory committees; PFIZER: Honoraria, Membership on an entity9s Board of Directors or advisory committees. Gopal:Teva: Research Funding; Asana: Consultancy; Incyte: Consultancy; Merck: Research Funding; Aptevo: Consultancy; Janssen: Consultancy, Research Funding; Spectrum: Research Funding; Takeda: Research Funding; BMS: Research Funding; Pfizer: Research Funding; Seattle Genetics: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; Brim: Consultancy.

Abstract B42: The properties of ex vivo expanded γδ T cells provide for the rational use of combination therapies

Abstract Cell-based immunotherapies have relied mainly on the use of αβ T cells or dendritic cells, and technologies to expand and engineer these cells have resulted in potent antitumor products. Although the use of adaptive immunocompetent cells has advanced more rapidly than innate immune cells, such as natural killer or γδ T cells, these alternative cellular products can provide equivalent antitumor activity. However, the methods to expand clinically relevant innate cell products are not as advanced as those for other immunocompetent cells, such as αβ T cells. We have developed a safe and efficient method for expanding, storing, and genetically engineering γδ T cells, and have focused on the use of these ex vivo expanded cells to treat pediatric neuroblastoma. γδ T cells are an attractive candidate for cell-based products because their antitumor activity is directly cytolytic to tumor cells, in part, due to their receptors NKG2D and CD16. NKG2D facilitates the innate recognition of stress-induced ligands such as MICA/B and UL-16 binding proteins (ULBP), and CD16 enables mechanisms of antibody-dependent cellular cytotoxicity (ADCC). We have developed a serum-free expansion protocol using apheresis products from healthy donors and from neuroblastoma patients. γδ T cells from all starting products can be expanded to greater than 70% of the culture within 12-14 days. These γδ T cells are cytotoxic against K562 cells, which has become our standard for which to compare the various expansion products, and 5 human derived neuroblastoma cell lines. We have tested several freezing media and developed a method using serum-free conditions between days 12-14 of expansion, resulting in equivalent cytotoxicity by cells pre- and post-freezing while maintaining greater than 70% viability post-thaw. We also show that our expansion protocol results in γδ T cells that are greater than 90% positive for surface expression of the receptors NKG2D and CD16. Therefore, we are using these cells in combination treatments that include standard chemotherapy regimens for relapsed neuroblastoma patients, i.e., temozolomide (TMZ), and the monoclonal antibody dinutuximab. We have shown that stress antigens such as MICA/B and ULBP2/5/6 are upregulated in vitro on IMR5 cells for 6 hours after a 1-hour exposure to TMZ. Further, combining patient-expanded γδ T cells that express CD16 with a GD2-specific antibody, dinutuximab, induces 30% increased neuroblastoma cell death compared to γδ T cells alone. To test the in vivo effectiveness of 12-day expanded, frozen, and thawed cells, we injected NSG male and female mice with 5 x 106 IMR5 cells subcutaneously. After a palpable 125-mm3 tumor was established, we began treatment with various combinations of γδ T cells, dinutuximab, and TMZ. These ongoing studies show that γδ T cells alone do not provide an antitumor benefit, but tumor regression is achieved when incorporating γδ T cells into dinutuximab and TMZ treatment regimens. This advantage is only observed at lower TMZ doses, whereas at higher TMZ doses, >60 mg/kg, chemotherapy dominates the antitumor effect. Overall, these studies show that a safer, serum-free expanded γδ T cell product can be produced, which can be stored frozen without affecting the cytotoxic properties. The expression of NKG2D and CD16 on the expanded cells allows for the development of combination therapies using cytotoxic chemotherapy agents and antibody-based treatments. The combination of γδ T cells, TMZ, and dinutuximab can provide a rational advancement for treating pediatric neuroblastoma patients, and we hypothesize that this combination therapy is preferred over high-dose chemotherapy regimens because it can reduce treatment-related toxicities and provide a multifaceted immunotherapeutic approach to neuroblastoma treatment. Citation Format: Jaquelyn T. Zoine, Kathryn S. Sutton, Kristopher A. Knight, Kelly C. Goldsmith, Christopher B. Doering, H. Trent Spencer. The properties of ex vivo expanded γδ T cells provide for the rational use of combination therapies [abstract]. In: Proceedings of the AACR Special Conference: Pediatric Cancer Research: From Basic Science to the Clinic; 2017 Dec 3-6; Atlanta, Georgia. Philadelphia (PA): AACR; Cancer Res 2018;78(19 Suppl):Abstract nr B42.

Abstract 1678: Integrated genomics and histology based studies of triple negative breast cancer identify ICOS as potential target for therapeutic intervention

Abstract ICOS (Inducible CO-Stimulator of T cells) is a co-stimulatory molecule expressed primarily on T lymphocytes. ICOS was prioritized as a target of interest based on nonclinical and clinical data that identified ICOS as a potentially key molecule in providing optimal anti-tumor benefit following anti-CTLA-4 therapy. We are developing JTX-2011, an ICOS agonist antibody that is designed to generate an anti-tumor immune response through stimulation of T effector cells and preferential reduction of intratumoral T regulatory (Treg) cells. In preclinical mouse tumor models, efficacy of an ICOS agonist was greatest in tumors with the highest levels of intra-tumoral ICOS, suggesting a potential predictive biomarker approach for clinical development. In assessing ICOS expression across multiple tumor types at both the RNA and protein level, we have identified triple negative breast cancer (TNBC) as a potential indication for an ICOS-targeted immunotherapy approach. Integrated analysis of RNA, DNA and clinical data from the Cancer Genome Atlas (TCGA) was performed to understand the context in which ICOS is expressed. Additionally, ICOS levels were assessed by IHC in human tumor samples from an orthogonal data set. IHC and RNA analyses revealed a dynamic range of ICOS expression across indications and identified a subpopulation of breast cancer tumors enriched for high ICOS expression. Further analysis of both IHC and RNA data sets revealed that the triple negative subtype has higher enrichment of ICOS expression than other breast cancer subtypes. ICOS levels were correlated to gene signatures of immune infiltrate as well as other clinical attributes and molecular markers. There was a correlation between ICOS, ICOS signature, PD-L1 and IFNγ signatures. We then assessed TNBC samples obtained pre and post-neoadjuvant treatment to further understand the impact of chemotherapy on the tumor microenvironment. This included analysis of ICOS and PD-L1 protein expression as well as assessment of tumor-infiltrating immune cell subsets. While the distribution of certain immune cell subsets differed in pre and post-treatment samples, the expression of ICOS remained consistent. Based on these data, a TNBC cohort, enriched for the ICOS IHC biomarker, is included in the Phase 2 portion of the ICONIC study that is designed to assess the potential for a combination of JTX-2011 with a PD-1 checkpoint in this difficult to treat patient population. Citation Format: Heather A. Hirsch, Tong Zi, Rachel Fontana, Yun Wu, Jason Reeves, Alexander Needham, Edward Stack, David Lee, Emma Lees, Deborah A. Law, Elizabeth Trehu, Elizabeth A. Mittendorf. Integrated genomics and histology based studies of triple negative breast cancer identify ICOS as potential target for therapeutic intervention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1678.

Shining light on advanced NSCLC in 2017: combining immune checkpoint inhibitors.

The treatment landscape has changed since the immune checkpoint inhibitors were approved in the treatment of non-small cell lung cancer (NSCLC). Although the promising clinical benefit from programmed death-1/programmed death ligand-1 (PD-1/PD-L1) inhibitors was observed in the second or subsequent line treatment of patients who progressed on chemotherapy, it has a long way for single PD-1/PD-L1 inhibitor to move forward to the frontline without a predictive biomarker. Tumor response is far from satisfactory without selection and primary or acquired resistance to PD-1/PD-L1 inhibitors hampered their utility. Therefore, it is crucial to determine a strategy that can optimize the application of immune checkpoint inhibitors and increase the numbers of the responders. Multiple combination approaches based on PD-1/PD-L1 inhibitors are designed and aimed to boost anti-tumor response and benefit a broader population. In this review, we will integrate the updated clinical data to highlight the four most promising combination strategies in advance NSCLC: combination of checkpoint inhibition with chemotherapy, anti-angiogenesis, immunotherapy and radiotherapy. We further discuss the issues needed to be addressed and perspectives in the context of "combination era".

Phosphatidylserine targeting antibody in combination with tumor radiation and immune checkpoint blockade promotes anti-tumor activity in mouse B16 melanoma

Abstract Phosphatidylserine (PS) is a phospholipid that is exposed on surface of apoptotic cells, some tumor cells and tumor endothelium. It has been shown to promote immunosuppressive signals in the tumor microenvironment. Radiation therapy (RT) is an effective focal treatment of primary solid tumors, but is less effective in treating metastatic solid tumors as a monotherapy. There is evidence that RT induces immunogenic tumor cell death and enhances tumor-specific T cell infiltration in treated tumors. In this study, we show that irradiation of B16 melanoma causes an increase in PS expression on the surface of viable tumor and immune infiltrates. We subsequently examined the effects of combining RT with an antibody that targets PS (mch1N11) and immune checkpoint blockade (anti-PD-1) in B16 melanoma. We found that treatment with mch1N11 synergizes with RT to improve anti-tumor activity and overall survival in tumor bearing mice. In addition, the triple combination of mch1N11, RT and anti-PD-1 treatment displayed even greater anti-tumor and survival benefit. Analysis of immune responses in the tumors of treated animals revealed a shift towards a pro-inflammatory M1 phenotype after treatment with RT and mch1N11. In addition, analysis of the adaptive immune response revealed an increase in antigen-specific CD8 T cell infiltration in the tumors as well as increased activation, effector function and differentiation in the triple combination therapy. This finding highlights the potential of combining these agents to improve outcome in patients with advanced-stage cancer and may inform the design of future clinical trials.

Anticancer activity of the intraperitoneal-delivered DFP-10825, the cationic liposome-conjugated RNAi molecule targeting thymidylate synthase, on peritoneal disseminated ovarian cancer xenograft model.

IntroductionPeritoneal disseminated ovarian cancer is one of the most difficult cancers to treat with conventional anti-cancer drugs and the treatment options are very limited, although an intraperitoneal (ip) paclitaxel has shown some clinical benefit. Therefore, treatment of peritoneal disseminated ovarian cancer is a highly unmet medical need and it is urgent to develop a new ip delivered drug regulating the fast DNA synthesis.MethodsWe developed a unique RNAi molecule consisting of shRNA against the thymidylate synthase (TS) and a cationic liposome (DFP-10825) and tested its antitumor activity and PK profile in peritoneally disseminated human ovarian cancer ascites models by the luciferase gene-transfected SCID mice. DFP-10825 alone, paclitaxel alone or combination with DFP-10825 and paclitaxel were administered in an ip route to the tumor-bearing mice. The TS expression level was measured by conventional RT-PCR. The anti-tumor activity and host survival benefit by DFP-10825 treatment on tumor-bearing mice were observed as resulting from the specific TS mRNA knock-down in tumors.ResultsDFP-10825 alone significantly suppressed the growth of SKOV3-luc tumore ascites cells and further extended the survival time of these tumor-bearing mice. Combination with the ip paclitaxel augmented the antitumor efficacy of DFP-10825 and significantly prolonged the survival time in the tumor-bearing mice. Short-hairpin RNA for TS (TS shRNA) levels derived from DFP-10825 in the ascetic fluid were maintained at a nM range across 24 hours but not detected in the plasma, suggesting that TS shRNA is relatively stable in the peritoneal cavity, to be able to exert its anti-tumor activity, but not in blood stream, indicating little or no systemic effect.ConclusionCollectively, the ip delivery of DFP-10825, TS shRNA conjugated with cationic liposome, shows a favorable antitumor activity without systemic adverse events via the stable localization of TS shRNA for a sufficient time and concentration in the peritoneal cavity of the peritoneally disseminated human ovarian cancer-bearing mice.

Lipase-Triggered Water-Responsive "Pandora's Box" for Cancer Therapy: Toward Induced Neighboring Effect and Enhanced Drug Penetration.

Insufficient drug release as well as poor drug penetration are major obstacles for effective nanoparticles (NPs)-based cancer therapy. Herein, the high aqueous instability of amorphous calcium carbonate (ACC) is employed to construct doxorubicin (DOX) preloaded and monostearin (MS) coated "Pandora's box" (MS/ACC-DOX) NPs for lipase-triggered water-responsive drug release in lipase-overexpressed tumor tissue to induce a neighboring effect and enhance drug penetration. MS as a solid lipid can prevent potential drug leakage of ACC-DOX NPs during the circulatory process, while it can be readily be disintegrated in lipase-overexpressed SKOV3 cells to expose the ACC-DOX core. The high aqueous instability of ACC will lead to burst release of the encapsulated DOX to induce apoptosis and cytotoxicity to kill the tumor cells. The liberated NPs from the dead or dying cells continue to respond to the ubiquitous aqueous environment to sufficiently release DOX once unpacked, like the "Pandora's box", leading to severe cytotoxicity to neighboring cells (neighboring effect). Moreover, the continuously released free DOX molecules can readily diffused through the tumor extracellular matrix to enhance drug penetration to deep tumor tissue. Both effects contribute to achieve elevated antitumor benefits.

The outcome of checkpoint inhibitor therapy in patients with cancer and solid organ transplant: A systematic review of the literature.

41 Background: Solid organ transplant recipients have been excluded from Checkpoint inhibitors (CPI) clinical trials because of the concern of allo-immunity and possible organ rejection. Methods: We searched 5 databases through September 2017. Studies describing the use of CPI to treat cancer in solid organ transplant Patients (pts), and provided detailed description of each case were included. Results: Sixteen publications met inclusion criteria, reporting on 19 cases. Median age of pts was 59 (14-77) yrs and 74% were male. Cancer types included melanoma (n=11), cutaneous squamous cell carcinoma (ca) (n=3), non-small cell lung ca and hepatocellular ca (n=2 each), and duodenal ca (n=1). Median time to start CPI after organ transplant was 11 (1-25) yrs. Nivolumab (nivo) was used in 53%, ipilimumab (ipi) in 26%, and pembrolizumab (pem) in 21%. Most pts were maintained on low dose prednisone (≤ 10 mg), mTOR inhibitors, and other immunosuppressives prior to initiating CPI. Graft rejection occurred in 10 of 19 pts (7/12 kidney, 2/5 liver, and 1/2 heart transplants), 90% after receiving anti PD-1, and CPI was discontinued. Median time to rejection was 21 (5-60) days, and obtained biopsies were suggestive of a T-cell mediated rejection process. Only a cardiac transplant recipient with a bioposy proven cellular rejection after nivo, had improved ejection fraction after pulse steroids. Aside from rejection no other immune related adverse events (irAEs) reported. Nivo re-challenge was recommended for a kidney recipient 12 weeks after the rejection process, and the pt had partial tumor response but remained on hemodialysis. Of the 9 pts who had no rejection, 4 had irAEs (hepatitis, colitis, pneumonitis, and dermatitis), including 3 who required high-dose steroids with subsequent improvement, and the remaining 5 pts did not experience any irAEs. Clinical benefit rate was 57% of all pts. Two pts with liver transplants died within 1 month of nivo treatment secondary to acute liver rejection, and 2 others died because of progressive cancer. Conclusions: CPI seem to be associated with high rate of rejection. Multi-institutional collaborative studies are warranted to enhance our understanding of the pathogenesis and plan optiomal therapy that maintain graft tolerance without dampening antitumor clinical benefits.

Enhancing CAR T cell persistence through ICOS and 4-1BB costimulation.

Successful tumor eradication by chimeric antigen receptor-expressing (CAR-expressing) T lymphocytes depends on CAR T cell persistence and effector function. We hypothesized that CD4+ and CD8+ T cells may exhibit distinct persistence and effector phenotypes, depending on the identity of specific intracellular signaling domains (ICDs) used to generate the CAR. First, we demonstrate that the ICOS ICD dramatically enhanced the in vivo persistence of CAR-expressing CD4+ T cells that, in turn, increased the persistence of CD8+ T cells expressing either CD28- or 4-1BB-based CARs. These data indicate that persistence of CD8+ T cells was highly dependent on a helper effect provided by the ICD used to redirect CD4+ T cells. Second, we discovered that combining ICOS and 4-1BB ICDs in a third-generation CAR displayed superior antitumor effects and increased persistence in vivo. Interestingly, we found that the membrane-proximal ICD displayed a dominant effect over the distal domain in third-generation CARs. The optimal antitumor and persistence benefits observed in third-generation ICOSBBz CAR T cells required the ICOS ICD to be positioned proximal to the cell membrane and linked to the ICOS transmembrane domain. Thus, CARs with ICOS and 4-1BB ICD demonstrate increased efficacy in solid tumor models over our current 4-1BB-based CAR and are promising therapeutics for clinical testing.