Therapeutic Partner Research Articles

Preclinical Therapeutic Synergy of MEK1/2 and CDK4/6 Inhibition in Neuroblastoma.

Purpose: Neuroblastoma is treated with aggressive multimodal therapy, yet more than 50% of patients experience relapse. We recently showed that relapsed neuroblastomas frequently harbor mutations leading to hyperactivated ERK signaling and sensitivity to MEK inhibition therapy. Here we sought to define a synergistic therapeutic partner to potentiate MEK inhibition.Experimental Design: We first surveyed 22 genetically annotated human neuroblastoma-derived cell lines (from 20 unique patients) for sensitivity to the MEK inhibitor binimetinib. After noting an inverse correlation with sensitivity to ribociclib (CDK4/6 inhibitor), we studied the combinatorial effect of these two agents using proliferation assays, cell-cycle analysis, Ki67 immunostaining, time-lapse microscopy, and xenograft studies.Results: Sensitivity to binimetinib and ribociclib was inversely related (r = -0.58, P = 0.009). MYCN amplification status and expression were associated with ribociclib sensitivity and binimetinib resistance, whereas increased MAPK signaling was the main determinant of binimetinib sensitivity and ribociclib resistance. Treatment with both compounds resulted in synergistic or additive cellular growth inhibition in all lines tested and significant inhibition of tumor growth in three of four xenograft models of neuroblastoma. The augmented growth inhibition was attributed to diminished cell-cycle progression that was reversible upon removal of drugs.Conclusions: Here we demonstrate that combined binimetinib and ribociclib treatment shows therapeutic synergy across a broad panel of high-risk neuroblastoma preclinical models. These data support testing this combination therapy in relapsed high-risk neuroblastoma patients, with focus on cases with hyperactivated RAS-MAPK signaling. Clin Cancer Res; 23(7); 1785-96. ©2016 AACR.

Abstract 4985: Radiation potentiates systemic anti-tumor immunity unleashed by a novel TLR9 agonist (SD-101)

Abstract Background: SD-101 is a CpG oligonucleotide-based TLR9 agonist that engages its target within early and late endosomes of plasmacytoid dendritic cells (pDCs), resulting in DC activation, robust IFN-α responses, and priming of tumor-specific T-cells. We have previously shown that local radiotherapy (RT) may also act as an immune adjuvant and thereby contribute to immune-mediated tumor rejection (J Natl Cancer Inst, 2013: 105:256-265). We hypothesized that the effects of SD-101 may be potentiated by RT and trigger immune-mediated abscopal responses, outside the irradiated field (Int. J. Radiat. Oncol. Biol. Phys., 58:862-870). Methods: BALB/c mice were inoculated s.c. with syngeneic TSA mammary tumor cells in 2 sites (primary [ipsilateral flank] and secondary [contralateral flank]) to detect abscopal responses. When tumors reached an average of 5 mm in diameter, mice were randomly assigned to 1 out of 4 treatment groups: control (untreated), SD-101, RT, or SD-101+RT. RT was delivered to primary tumors (8 Gy x3 fractions) in 3 consecutive days; secondary tumors were completely shielded from RT. SD-101 was injected into primary tumors (50 μg) three times per week starting on the last day of RT. Mice were followed for tumor growth in both the primary and secondary tumors. In a parallel experiment, mice were euthanized 10 days after initiation of therapy for immune analysis. Results: Significant growth delays (p <0.05) were observed in the primary tumors of mice treated with monotherapy (RT or SD-101), as compared to the primary tumors of the untreated controls. In contrast, no significant growth delays were observed in the secondary tumors of these mice, when compared to the secondary tumors of their untreated counterparts. The combination of SD-101+RT, however, effectively controlled the primary tumors (100% of mice exhibited complete tumor rejection) of treated mice, while significant growth delays were also observed in the secondary tumors (p <0.05), when compared to the secondary tumors of mice from the other groups. SD-101 alone or in combination with RT, induced intratumoral enrichment of CD8α+ DCs (3.02% of CD11c+ cells in SD-101-treated mice vs 1.08% in untreated mice), whereby these CD8α+ DCs preferentially expressed high levels of activation markers (CD40, CD80, and CD86). Yet, mice treated with SD-101+RT, when compared to the other groups, also demonstrated an expansion of tumor-reactive T-cells (CD8+/PD-1+) both locally and systemically (J Clin Investig 2014 124(5):2246-2259). Conclusions: Our studies support the rational use of RT as a powerful therapeutic partner to potentiate the anti-tumor effects of SD-101. Citation Format: Karsten Pilones, Jeffrey Kraynak, Sandra Demaria, Encouse Golden, Silvia Formenti. Radiation potentiates systemic anti-tumor immunity unleashed by a novel TLR9 agonist (SD-101). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4985.

Statistical Methods for Clinical Validation of Follow-On Companion Diagnostic Devices via an External Concordance Study

ABSTRACTTo date there are a number of FDA-approved companion diagnostics for use with specific corresponding therapeutic products. Hence, opportunities exist for device manufacturers to develop follow-on companion diagnostic devices. A follow-on companion diagnostic is intended to be used with the therapeutic product in the indicated patient population, as in the labeling of the comparator companion diagnostic. Thus, information provided by a follow-on companion diagnostic device is essential for the safe and effective use of the corresponding therapeutic product in the comparator companion diagnostic. However, the manufacturer of a follow-on companion diagnostic device may not have a therapeutic partner to conduct a new clinical trial, or there may lack the patient samples from the original clinical trial, where the comparator and therapeutic product were evaluated. As such, an external concordance study is conducted to assess the concordance between the comparator and the follow-on device. Difficulty and challenges arise on how to evaluate the follow-on device’s clinical performance based the agreements from an external concordance study. In this article, we will discuss the challenges and issues for the clinical validation of follow-on devices and we aim to provide some statistical methods on how to support clinical validation of follow-on companion diagnostic devices for its proposed indications for use via an external concordance study.

Abstract P6-11-08: Exploring the best therapeutic partner of triple negative breast cancers: Using different characteristics/dependent pathways of triple negative breast cancer cell lines based on subgroups

Abstract Triple negative breast cancer (TNBC) still remains as a difficult disease given the abscence of effective treatment modality, despite some success in PARP inhibition in BRCA gene mutation patients. Recently, TNBC was elucidated to be a large group of heterogenic subgroups based on their genetic/proteomic characters. Two main subgroups that consists of greater than 90% of whole TNBC include mesenchymal like (TNMBC) and basal (TNBBC) subgroups. Mesenchymal like subgroup harbor myoepithelial, epithelial-to-mesenchymal transition related phenotype, and genetic dependency on growth hormone pathway, higher sensisitivy to death receptor inducing apoptosis pathway, as well as more dependency on PI3K-Akt-mTOR pathway. In contrast, basal like subgroup harbor the characteristics that is related to a defective DNA repair system, cell cycles regulation, and interestingly - dependency on RAS-MEK pathway for their survival and growth. Given explosive enrichment of understanding such pathways and enumeration of pathway targeting inhibitors, as well as the ability of timely recognition of biomarkers in patients sample which can differentiate subgroups of TNBC- offer an attractive strategy of novel therapeutics development in this difficult to treat disease. We tested targeting both dependent pathway and core characteristics of TNBC using representative panels of each subgroups: MDA-MB-468, BRCA1KD MCF10A, HCC1937 as in TNBBC panel showed effective killing when various combination of pAkt and PI3K, mTOR inhibitors, CDK1/2 inhibitors, death receptor mediated apoptosis inducing agents were introduced in combination. In contrast TNMBC MDA-MB-231, SUM159,BT549 showed effective killing when pERK and MEK inhibitors, in combination with BMI-1 inhibitors were given. Further elucidation of mechanisms of action in each combinations will further offer the ground of proper combination in subgroups of TNBC that could be further studied in animal model, and finally in clinical development. Citation Format: Bora Lim, David T Dicker, Leah C Kline, Wafik S El-Deiry. Exploring the best therapeutic partner of triple negative breast cancers: Using different characteristics/dependent pathways of triple negative breast cancer cell lines based on subgroups [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-11-08.

For patients with rheumatic disease and hepatitis C infection: the end of interferon

Hepatitis C virus (HCV) is a global pathogen and is the cause of rare but complex rheumatic complications but more commonly exists as a challenging comorbidity for patients with existing rheumatic diseases. Until recently, the standard of care of HCV has been the use of interferon-based regimens, which not only have limited effectiveness in curing the underlying viral illness but are poorly tolerated and in patients with rheumatic diseases especially problematic given their association with a wide variety of autoimmune toxicities. Numerous and other more effective and better tolerated regimens are rapidly emerging incorporating direct acting antiviral agents that do not require the use of interferon, that is, interferon free. The potential of interferon free treatment of HCV makes screening for this comorbidity more important than ever. Rheumatologists need to be knowledgeable about these therapeutic advances and partner with hepatologists to craft the most efficacious and toxicity-free regimes possible.

Interference Of The Tumor Supportive Effects Of BCL2 and MCL1 Sensitize Malignant Plasma Cells To The Lethal Effects Of Lenalidomide and Dexamethasone Regimen: An Important Clinical Path For BCL2 Targeting Drugs

BackgroundMultiple myeloma (MM) is the second most common hematologic malignancy in the U.S. and is characterized by increased immunoglobulin production and infiltration of the bone marrow by malignant plasma cells. Myeloma cell growth is supported by both the elements present in the bone marrow microenvironment as well as deregulation of internal cellular systems associated with proliferation and apoptosis. Defective programmed cell death by BCL2 or MCL1 upregulation is observed in >80% of myeloma cases and is associated with an aggressive clinical course. Remarkably, there is no approved drug with the ability to target BCL2 or MCL1. Various strategies to mitigate the effects of increased BCL2 functionality, via small molecule inhibitors or BCL2-specific antisense oligonucleotides have been previously examined in MM. These studies revealed that 1) apart from BCL2, additional anti-apoptotic members belonging to the BCL2 family (i.e. MCL1, BCL-xL) play integral roles in maintenance of the myeloma cell phenotype, 2) drugs, which target only BCL2 offer limited therapeutic advantage and 3) given that survival factors engaged in MM are multifactorial, perhaps isolated targeting of the BCL2 pathways may not be sufficient. We therefore hypothesized that the clinical development of drugs that target various antiapoptotic BCL2 family members will require a partnership with established anti-MM regimens whose activity can potentially be further enhanced with correction of the apoptotic response system. AimSince lenalidomide and dexamethasone (LD) is an established therapy for plasma cell cancers, we investigated if the pan-BCL2 inhibitor AT-101 (BH3 mimetic), which has high binding specificity for BCL2, MCL1 and BCL-xL, can be an effective therapeutic partner to enhance anti-MM effects of LD. MethodsHuman MM (KMS11, U266, OPM2) and WM (BCWM.1) cell lines along with their corresponding bortezomib resistant (BR) clones, (KMS11/BR, U266/BR, OPM2/BR and BCWM.1/BR) which were developed in our laboratory were used in this study. For gene expression profiling, the Illumina HumanHT-12 v3 whole-genome gene expression array and Nanostring nCounter mRNA quantification assays (NanoString, Seattle, WA) were utilized. Statistical analysis was conducted using R-based packages and the MeV software (TIGR). Apoptosis was measured by annexin-v/PI staining, and mitochondrial membrane permeability (MOMP) was assessed using TMRM followed by flow cytometry. Protein profiles were ascertained by western blot. ResultsGene expression and immunoblot analysis of six plasma cell cancer models showed upregulation of various BCL2 family members, notably MCL1 and BCL-xL. In a dose-dependent manner, AT-101 was able to downregulate BCL2 and MCL1 and induced apoptotic cell death in MM and WM cells in a dose dependent manner. Tumor cell death was associated with caspase and PARP-1 cleavage accompanied by an increase in MOMP. This cytotoxic effect and BCL2 downregulation were further potentiated when AT-101 was combined with lenalidomide/dexamethasone (LDA). Nanostring nCounter mRNA quantification and IPA analysis revealed differential changes in the CCNA, FRZB, FYN, IRF1, PTPN11 genes in LDA treated cells. IPA canonical pathway analysis demonstrated the p53 signaling and the cyclins and cell cycle regulation pathways to be the most significantly activated by LDA therapy. SummaryIn summary, we describe for the first time the cellular and molecular events associated with the use of AT-101 in combination with lenalidomide/dexamethasone in preclinical models of plasma cell malignancy. This study lays the rationale for engaging and handicapping the intrinsic apoptotic system through the pan-BCL2 targeting capabilities of AT-101; thus enhancing the anti-MM effects of lenalidomide/dexamethasone. Disclosures:Foran:Celgene: Research Funding.

Enhancing Photodynamyc Therapy Efficacy by Combination Therapy: Dated, Current and Oncoming Strategies

Combination therapy is a common practice in many medical disciplines. It is defined as the use of more than one drug to treat the same disease. Sometimes this expression describes the simultaneous use of therapeutic approaches that target different cellular/molecular pathways, increasing the chances of killing the diseased cell. This short review is concerned with therapeutic combinations in which PDT (Photodynamyc Therapy) is the core therapeutic partner. Besides the description of the principal methods used to assess the efficacy attained by combinations in respect to monotherapy, this review describes experimental results in which PDT was combined with conventional drugs in different experimental conditions. This inventory is far from exhaustive, as the number of photosensitizers used in combination with different drugs is very large. Reports cited in this work have been selected because considered representative. The combinations we have reviewed include the association of PDT with anti-oxidants, chemotherapeutics, drugs targeting topoisomerases I and II, antimetabolites and others. Some paragraphs are dedicated to PDT and immuno-modulation, others to associations of PDT with angiogenesis inhibitors, receptor inhibitors, radiotherapy and more. Finally, a look is dedicated to combinations involving the use of natural compounds and, as new entries, drugs that act as proteasome inhibitors.

Abstract LB-247: A multidisciplinary phase II study of AZD2171 (cediranib), an oral pan-VEGF receptor tyrosine kinase inhibitor, in patients with recurrent glioblastoma

Abstract Targeted agents are promising new therapeutics that have entered clinical trials for glioblastoma. AZD2171 (cediranib) is a potent, oral pan-VEGF receptor tyrosine kinase inhibitor with a half-life of 20 hours compatible with once-daily dosing. A primary target of AZD2171, VEGFR2, is expressed on glioblastoma endothelium. We have demonstrated normalization of tumor vessels in recurrent glioblastoma patients administered AZD2171 on a daily basis. Normalization has rapid onset, is reversible, and is associated with alleviation of brain edema (Batchelor TT, et al. Cancer Cell 2007;11:83-95). In this Phase II study of 31 recurrent glioblastoma subjects we now report clinical outcomes, including the proportion of patients alive and progression-free at 6 months (APF6) as the primary endpoint. Secondary endpoints include radiographic response proportion; progression-free survival; and overall survival and toxicity. At this time we are presenting radiographic response data, APF6, PFS, and OS on 31 patients. Thirty patients have experienced disease progression and one patient remains in follow-up without progression. The primary and secondary endpoints are tabulated below: Radiographic Responses Partial Response (more than 50% decrease in volume) in 16/30 (56%) APF6 [95% CI] 25.8% [14.7%, 46.9%] PFS [95% CI] 117 days [88, 145] OS [95% CI] 221 days [172, 285] Only one of the first 16 patients was removed from the study due to toxicity (fatigue). Dose limiting toxicities were observed in 9/16 patients with hypertension; fatigue and diarrhea were encountered most often. There have been no intracerebral hemorrhages. AZD2171 alleviated brain edema, a major cause of morbidity in glioblastoma patients, and had a steroid-sparing effect in many of the patients enrolled. Blood biomarkers were serially assessed and it was observed that plasma VEGF, PlGF, and SDF1α were increased after treatment. Plasma PlGF and VEGF decreased upon cediranib discontinuation. Plasma bFGF and SDF1α and viable circulating endothelial cells increased when tumors escaped treatment with AZD2171. AZD2171 is a promising therapy for glioblastoma and an attractive therapeutic partner for chemotherapy or radiation.

Kinetics of response to ipilimumab (MDX-010) in patients with stage III/IV melanoma

8525 Background: Ipilimumab, a fully human monoclonal antibody that blocks cytotoxic T-lymphocyte antigen-4 (CTLA-4), enhances immune responses to tumor-associated antigens resulting in durable objective responses (OR). This abstract describes the kinetics of response after ipilimumab treatment. Methods: 5 studies (2 complete; 3 ongoing) in 269 treated patients with stage III/IV melanoma were reviewed and analyzed to determine the kinetics and duration of response after ipilimumab. Patients received ipilimumab alone or with dacarbazine, IL-2 or gp100 peptide vaccine. Ipilimumab doses ranged from 0.3–10mg/kg/dose (single or multiple). Complete and partial response (CR, PR), stable and progressive disease (SD, PD) were evaluated. Results: 41 patients (15%) had a confirmed OR at analysis. CR and PR was of late onset in some patients and occurred from ∼10–106 and ∼5–62 weeks (w) post-treatment initiation, respectively. In 28 patients onset of CR or PR occurred after >∼12w of treatment. PD preceded OR (without additional therapy) in 4 patients. In 2 patients, PD measured at ∼6w post-treatment initiation was followed by a PR at ∼12w. In 1 patient the PR changed to a CR at ∼24w and lasted for ∼188w+; the other patient maintained a PR for ∼17w. In the other 2 patients, PD at ∼12w was followed by SD at ∼17–20w and a PR after ∼30 and 62w; PRs in both patients lasted for ∼17 and 40w+, respectively. Duration of OR ranged from ∼6–187w+; ORs are ongoing in 25 patients. Late onset occurred irrespective of dose, regimen and therapeutic partner. Conclusions: Preliminary results suggest that ORs with ipilimumab may be later in onset and more durable than with traditional chemotherapy and may occur after progression. This late onset of effect likely reflects the immune-related mechanism of action of ipilimumab, and suggests that continued treatment/observation may be beneficial despite initial PD or SD. Acknowledgement: Dr. S. Rosenberg [Table: see text]

HIV‐1 Coreceptor Use in Triple‐Class Treatment–Experienced Patients: Baseline Prevalence, Correlates, and Relationship to Enfuvirtide Response

We wished to assess, in heavily treatment-experienced patients, the prevalence of and baseline characteristics associated with HIV-1 coreceptor use and their relationship to responses to enfuvirtide treatment. Samples were obtained from participants in phase 3 studies of enfuvirtide. Multiple logistic regression and analysis of covariance were performed on data for baseline coreceptor use, virological and immunological response, and changes in coreceptor use during treatment. Baseline envelopes were phenotyped for 724 patients; 50% harbored R5 strains, 48% harbored dual/mixed (D/M) strains, and 2% harbored X4 strains. D/M strains were associated with significantly lower CD4(+) cell counts but comparable viral loads, compared with R5 strains (P=.0005). Virological and immunological responses to enfuvirtide-based treatment showed no correlation with baseline coreceptor use. Changes in virus tropism from D/M to R5 strains during treatment were common, particularly in patients who received enfuvirtide (27%, vs. 14% who received no enfuvirtide; P<.05). At baseline, D/M strains were associated with lower CD4(+) cell counts but similar viral loads, compared with R5 strains, and were common across CD4(+) cell count strata. The comparable virological and immunological responses and bias toward shifts from D/M to R5 strains in patients who received enfuvirtide support its use in triple-class treatment-experienced patients and its study as a therapeutic partner for coreceptor-binding inhibitors.

The Lost Ones

SUMMARY. This is a clinical paper in that it deals with a series of patients seen for psychotherapy by a group of trainees who were supervised together. Several common characteristics emerged and four of the most typical patients are described in detail. They were all difficult to work with, had seen or were seeing many other therapists and could not use insight interpretations. They had all suffered rejection, real or imagined, from previous therapists but persisted in their search for the ideal therapeutic partner who would omnipotently remove their symptoms. The degree of their perplexity and frustration led us to look upon them as lost. Following the description of each of the patients, the paper comments on four main areas: story making and its absence; the importance to the patient of not knowing; holding; technique. We believe that every analyst has encountered such a lost one in their practice.