Minor Response Research Articles

The effect of cannabis toxicity on a model microbiome bacterium epitomized by a panel of bioluminescent E. coli

The world acceptance of medical cannabis slowly widens. Cannabinoids are known as the main therapeutic active compounds in the cannabis plant, yet their bioactive physiological effects are still unknown. In this study, the mode of action of nine selected cannabinoids was examined using a bioluminescent bacterial panel, as well as the extracts of six different cannabis varieties and cannabinoids standards artificial mixtures. The bacterial panel was composed of genetically modified E. coli bacteria that is commonly found in the gut microbiome, to which a lux operon was added to various stress promoters. The panel was exposed to the cannabinoids in order to identify bacterial defense mechanism, via the aforementioned specific stress types response. This enables the understanding of the toxicity mode of action of cannabinoids. From all the tested cannabinoids, only delta-9-tetrahydrocannabinol (THC) and delta-9-tetrahydrocannabinolic acid A (THCA) produced a genotoxic effect, while the other tested cannabinoids, demonstrated cytotoxic or oxidative damages. Unlike pure cannabinoids, cannabis plant extracts exhibited mostly genotoxicity, with minor cytotoxicity or oxidative stress responses. Moreover, cannabinoids standards artificial mixtures produced a different response patterns compared to their individual effects, which may be due to additional synergistic or antagonistic reactions between the mixed chemicals on the bacterial panel. The results showed that despite the lack of cannabigerol (CBG), cannabidivarin (CBDV), cannabinol (CBN), and cannabichromene (CBC) in the artificial solution mimicking the CN6 cannabis variety, a similar response pattern to the cannabinoids standards mixture was obtained. This work contributes to the understanding of such correlations and may provide a realistic view of cannabinoid effects on the human microbiome.

Wilm's Tumor 1-guided preemptive treatment with hypomethylating agents for molecular relapse of AML and MDS after allogeneic transplantation.

Hypomethylating agents (HMA) for relapsed acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) after allogeneic transplantation (allo-SCT) are most effective when used at the stage of molecular relapse. As Wilm's Tumor 1 (WT1)- expression has proven to serve as broadly applicable, sensitive and specific minimal residual disease (MRD) marker, we measured WT1-expression in 35 AML and MDS patients using a standardized assay for the guidance of therapy with HMA and donor lymphocyte infusions (DLI). Molecular relapse was detected in median 168 days post-transplant prompting therapy with a median of six HMA cycles and at least one DLI (n = 22, 63%). Hereby, 13 patients (37%) achieved major response (=MRD- complete remission [CR]), and 7 patients (20%) achieved minor response (=MRD+ CR), whereas 15 patients (43%) progressed into hematologic relapse. Two-year overall survival (OS) rate was 35% including 11 patients (31%) with ongoing MRD- remission for a median of 21 months. Patients with the major response after six cycles had significantly better OS suggesting that those not achieving MRD negativity after six cycles are candidates for alternative therapies. Combining MRD-monitoring of WT1-expression and preemptive therapy with HMA and DLI appears as a practicable and efficient approach for imminent relapse after allo-SCT.

Response to trametinib treatment in progressive pediatric low-grade glioma patients

IntroductionA hallmark of pediatric low-grade glioma (pLGG) is aberrant signaling of the mitogen activated protein kinase (MAPK) pathway. Hence, inhibition of MAPK signaling using small molecule inhibitors such as MEK inhibitors (MEKi) may be a promising strategy.MethodsIn this multi-center retrospective centrally reviewed study, we analyzed 18 patients treated with the MEKi trametinib for progressive pLGG as an individual treatment decision between 2015 and 2019. We have investigated radiological response as per central radiology review, molecular classification and investigator observed toxicity.ResultsWe observed 6 partial responses (PR), 2 minor responses (MR), and 10 stable diseases (SD) as best overall responses. Disease control rate (DCR) was 100% under therapy. Responses were observed in KIAA1549:BRAF- as well as neurofibromatosis type 1 (NF1)-driven tumors. Median treatment time was 12.5 months (range: 2 to 27 months). Progressive disease was observed in three patients after cessation of trametinib treatment within a median time of 3 (2–4) months. Therapy related adverse events occurred in 16/18 patients (89%). Eight of 18 patients (44%) experienced severe adverse events (CTCAE III and/or IV; most commonly skin rash and paronychia) requiring dose reduction in 6/18 patients (33%), and discontinuation of treatment in 2/18 patients (11%).ConclusionsTrametinib was an active and feasible treatment for progressive pLGG leading to disease control in all patients. However, treatment related toxicity interfered with treatment in individual patients, and disease control after MEKi withdrawal was not sustained in a fraction of patients. Our data support in-class efficacy of MEKi in pLGGs and necessity for upfront randomized testing of trametinib against current standard chemotherapy regimens.

177Lu-DOTATATE therapy in metastatic/inoperable pheochromocytoma-paraganglioma.

Introduction:177Lu-DOTATATE-based peptide receptor radionuclide therapy (PRRT) is a promising therapy for metastatic and/or inoperable pheochromocytoma and paraganglioma (PPGL). We aim to evaluate the efficacy and safety of and identify predictors of response to 177Lu-DOTATATE therapy in metastatic and/or inoperable PPGL.Methods:This retrospective study involved 15 patients of metastatic or unresectable PPGL, who received 177Lu-DOTATATE PRRT therapy. Clinical, biochemical (plasma-free normetanephrine), and radiological (anatomical and functional) responses were compared before and after the last therapy.Results:A total of 15 patients (4 PCC, 4 sPGL, 5 HNPGL, 1 PCC + sPGL, 1 HNPGL + sPGL) were included. The median duration of follow up was 27 (range: 11–62) months from the start of PRRT. Based on the RECIST (1.1) criteria, progressive disease was seen in three (20%), stable disease in eight (53%), partial response in one (7%), and minor response in three (20%) and controlled disease in 12 (80%). On linear regression analysis the presence of PGL (P= 0.044) and baseline SUVmax >21 (P < 0.0001) were significant positive predictors of early response to PRRT. Encouraging safety profiles were noted with no long term nephrotoxicity and hematotoxicity.Conclusion:177Lu-DOTATATE therapy is an effective and safe modality of treatment for patients with metastatic/inoperable PPGL. Although it is not prudent to withhold PRRT in metastatic PPGL with baseline SUVmax < 21, baseline SUVmax >21 can be used to predict early response to PRRT.

Trametinib for the treatment of recurrent/progressive pediatric low-grade glioma.

Pediatric low-grade gliomas (pLGGs) are the most common CNS tumor of childhood and comprise a heterogenous group of tumors. Children with progressive pLGG often require numerous treatment modalities including surgery, chemotherapy, rarely radiation therapy and, more recently, molecularly targeted therapy. We describe our institutional experience using the MEK inhibitor, trametinib, for recurrent/progressive pLGGs. We performed a retrospective, IRB-approved, chart review of all pediatric patients treated with trametinib for recurrent/progressive pLGGs at Dana-Farber/Boston Children's Cancer and Blood Disorder Center between 2016 and 2018. Eleven patients were identified, of which 10 were evaluable for response. Median age at commencement of trametinib treatment was 14.7years (range 7.3-25.9years). Tumor molecular status included KIAA1549-BRAF fusion(n = 4), NF1 mutation(n = 4), FGFR mutation(n = 1) and CDKN2A loss (n = 1). Median number of prior treatment regimens was 5 (range 1-12). Median duration of treatment with trametinib was 19.2months (range 3.8-29.8months). Based on modified RANO criteria, best responses included partial (n = 2), minor response (n = 2) and stable disease (n = 6). Two patients remain on therapy (29.8 and 25.9months, respectively). The most common toxicities attributable to trametinib were rash, fatigue and gastrointestinal disturbance. Five patients required dose reduction for toxicities. Two patients experienced significant intracranial hemorrhage (ICH) while on trametinib. While it is unclear whether ICH was directly attributable to trametinib, therapy was discontinued. Trametinib appears to be an effective treatment for patients with recurrent/progressive pLGG. The toxicities of this therapy warrant further investigation, with particular attention to the potential risk for intracranial hemorrhage. Early phase multi-institutional clinical trials are underway.

Association between end-induction response according to the revised International Neuroblastoma Response Criteria (INRC) and outcome in high-risk neuroblastoma patients.

The 1993 International Neuroblastoma Response Criteria (INRC) were revised in 2017 to include modern functional imaging studies and methods for quantifying disease in bone marrow. We hypothesized the 2017 INRC would enable more precise assessment of response to treatment and provide superior prognostic information compared with the 1993 criteria. High-risk (HR) neuroblastoma patients from two institutions in Chicago diagnosed between 2006 and 2016 were identified. Patients were assessed post induction chemotherapy via the 1993 and 2017 INRC and classified as responder(≥mixed response [MXR] or≥minor response [MR], respectively) or nonresponder(<MXR or<MR). Event-free survival (EFS) and overall survival (OS) for responders versus nonresponders were determined from end induction and stratified by Cox regression. Patients with progressive disease at end induction were eliminated from the EFS analyses but included in the OS analysis. The 1993 criteria classified 52 of the 60 HR patients as responders, whereas 54 responders were identified using the 2017 criteria (Spearman correlation r=0.82, P<0.001). No statistically significant difference in EFS was observed for responders versus nonresponders using either criteria (P=0.48 and P=0.08). However, superior OS was observed for responders (P=0.01) using either criteria. Both criteria were sensitive in identifying responders among those with good outcomes. The specificity to identify nonresponders among those with poor outcomes was poor. In HR neuroblastoma, end-induction response defined by the 1993 or 2017 INRC is associated with survival. Larger cohorts are needed to determine if the 2017 INRC provides more precise prognostication.

A multicenter, open‐label, phase II study of tirabrutinib (ONO/GS‐4059) in patients with Waldenström’s macroglobulinemia

Tirabrutinib is a second‐generation Bruton’s tyrosine kinase inhibitor with greater selectivity than ibrutinib. Here, we conducted a multicenter, phase II study of tirabrutinib in patients with treatment‐naïve (Cohort A) or with relapsed/refractory (Cohort B) Waldenström’s macroglobulinemia (WM). Patients were treated with tirabrutinib 480 mg once daily. The primary endpoint was major response rate (MRR; ≥ partial response). Secondary endpoints included overall response rate (ORR; ≥ minor response), time to major response (TTMR), progression‐free survival (PFS), overall survival (OS), and safety. In total, 27 patients (18 in Cohort A; 9 in Cohort B) were enrolled. The median age was 71 y, and the median serum immunoglobulin M level was 3600 mg/dL. Among the patients, 96.2% had the MYD88L265P mutation. MRR and ORR were 88.9% and 96.3%, respectively (Cohort A: MRR, 88.9%; ORR, 94.4%; Cohort B: MRR, 88.9%; ORR, 100%). Median TTMR was 1.87 mo. PFS and OS were not reached with a median follow‐up of 6.5 and 8.3 mo for Cohorts A and B, respectively. The most common adverse events (AEs) were rash (44.4%), neutropenia (25.9%), and leukopenia (22.2%), with most AEs classified as grade 1 or 2. Grade ≥ 3 AEs included neutropenia (11.1%), lymphopenia (11.1%), and leukopenia (7.4%). No grade 5 AEs were noted. All bleeding events were grade 1; none were associated with drug‐related atrial fibrillation or hypertension. Although the follow‐up duration was relatively short, the study met the primary endpoint. Therefore, tirabrutinib monotherapy is considered to be highly effective for both untreated and relapsed/refractory WM with a manageable safety profile. (JapicCTI‐173646).

Prevalidation of an ELISA for Detection of a New Clinical Entity: Leishmania donovani-Induced Cutaneous Leishmaniasis.

Human leishmaniasis which is considered a neglected tropical parasitic disease presents in three main clinical forms (i.e., cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), and visceral leishmaniasis (VL)) that are mainly determined by its causative species. Leishmania donovani, the most virulent and visceralizing parasite, is increasingly reported to cause CL in many countries in the world. Although CL is generally not considered to evoke a humoral immune response except for a nonrobust and a variable response in minority of cases, VL is associated with a clear strong humoral response. However, humoral response in L. donovani-induced CL has not been well evaluated before. A suitable serology-based assay is an essential primary step in such a study. An indirect enzyme-linked immunosorbent assay (ELISA) based on Leishmania promastigote crude antigen (Ag) was designed and optimized in order to utilize in further serological studies on this new clinical entity. Optimization included quantification of crude Ag, checkerboard titration method for determination of optimal concentrations for coating Ag, human sera and secondary antibody (Ab) with suitable coating buffer, blocking buffer, and incubating temperatures. The selected coating buffer was 0.02 M phosphate buffer, pH 6.8, and the blocking buffer was 2% fetal bovine serum with 0.01 M phosphate-buffered saline. At least 1 μg of crude Ag was required for coating the ELISA plate, while 1 : 1000 serum was used as primary Ab. The optimized concentration of secondary Ab was 1 : 64000 which might be altered according to manufacturer recommendations. The assay specificity was pre-evaluated using sera (n = 20 from each category) from confirmed CL patients and controls (other skin diseases which mimic CL, other systemic diseases that mimic VL, nonendemic healthy controls, and endemic healthy controls). This procedure described an optimization procedure of an ELISA technique for detection of anti-Leishmania antibodies in patients with L. donovani caused CL.

Treatment of bullous pemphigoid in Chinese patients with Tripterygium wilfordii Hook F.

Tripterygium wilfordii Hook F (TwHF) is a traditional Chinese herb used in many medicinal applications, but the treatment of bullous pemphigoid (BP) with TwHF has never been reported. The aim of this study was to evaluate the efficacy and safety of TwHF in BP patients. A retrospective study was performed from January 2015 to September 2019 in the Department of Dermatology, Peking Union Medical College Hospital. A total of 10 patients with mild to moderate BP and treated with TwHF were enrolled in the study with 10 mild or moderate BP patients treated with systemic glucocorticoid randomly selected as controls. In the TwHF group, a major response was seen in seven patients, a minor response in one and no response was seen in two patients. In the glucocorticoid group, a major response was seen in nine patients and a minor response in one patient. Two patients experienced treatment failure. The time to disease control in the TwHF group (34 ± 11 days) was longer as compared to the glucocorticoid group (18 ± 8 days, P < .05). Ten patients relapsed during the follow-up period. The adverse events in the TwHF group were lower than those in the glucocorticoid group (13 vs 19). Low-dose TwHF may be effective and safe for treating mild and moderate BP.

Time- and Dose-Resolved Proteome of PM2.5-Exposure-Induced Lung Injury and Repair in Rats.

In recent years, airborne fine particulate matter (PM2.5) is drawing more public attention due to its various physicochemical features and causing pathological harm, as proven by epidemiological and clinical studies. However, the mechanism of PM2.5-exposure-induced lung injury has not been fully characterized. Here, we established a PM2.5-induced rat injury model for both short-term and long-term exposures at different concentrations. We employed the Fast-seq technique to profile 6316 proteins and the catTFRE approach to profile 387 transcription factors (TFs) in the lung tissue. In short-term exposure, we elucidated gradually upregulated proteins enriched in response to oxidative stress, phagosome, and the extracellular matrix (ECM)-receptor interaction pathway. Long-term exposure mainly showed the immune response pathway to be consisting of increased lymphocytes and cytokines. Intriguingly, we found that immune-related proteins were recoverable during short-term exposure. During the process of PM2.5 exposure, upregulated proteins presented dose-dependence in the lung, including stress response at low dose, minor immune response at middle dose, and severe inflammatory response at high dose. This data set provides a rich resource to facilitate the understanding of PM2.5-induced lung damage and repair mechanism.

Evaluation of Lanthanide-Doped Upconverting Nanoparticles for in Vitro and in Vivo Applications.

Because of their unique physicochemical properties, lanthanide-doped upconverting nanoparticles (Ln-UCNPs) have exceptional potential for biological applications. However, the use in biological systems is hampered by the limited understanding of their bionano interactions. Our multidisciplinary study has generated these insights through in-depth and quantitative analyses. The Ln-UCNPs examined here are spherical, monodisperse, and stable in aqueous environments. We show that Ln-UCNPs were associated with HeLa (cervical cancer) and LLC-PK1 (renal proximal tubule) cells and were nontoxic over a wide concentration range. Multiple biomarkers were assessed to monitor the cellular homeostasis in Ln-UCNP-treated cells. To this end, we evaluated the nuclear lamina, nucleoli, and nuclear transport factors. Single-cell analyses quantified the impact on Nrf2 and NF-κB, two transcription factors that control stress and immune responses. Moreover, we measured Ln-UCNP-induced changes in the abundance of molecular chaperones. Collectively, in vitro studies confirmed that Ln-UCNPs are nontoxic and trigger minor cellular stress responses. This lack of toxicity was verified in vivo, using the model organism Caenorhabditis elegans. The compatibility with biological systems prompted us to assess Ln-UCNPs as potential contrast agents for magnetic resonance imaging. We demonstrated that the Ln-UCNPs examined here were especially suitable as T2 contrast agents; they clearly outperformed the clinically used Gadovist. Taken together, our interdisciplinary work provides robust evidence for the nontoxicity of Ln-UCNPs. This sets the stage for the translation of Ln-UCNP for use in complex biological systems.

Serum sCD40L levels are increased in patients with psoriatic arthritis and are associated with clinical response to apremilast.

The pathogenesis of psoriatic arthritis (PsA) involves several pathways, including the CD40/CD40L signaling which promotes the release of multiple cytokines. Transmembrane CD40L is also released in soluble form (sCD40L) and phosphodiesterase 4 (PDE4) seems to be involved in its cleavage. We aimed to investigate whether apremilast, a PDE4 inhibitor, could modify circulating levels of sCD40L in PsA patients, and the possible associations of these changes with clinical response. Consecutive PsA patients starting apremilast in routine clinical practice were prospectively observed. Disease Activity of Psoriatic Arthritis (DAPSA), Psoriasis Area Severity Index (PASI), Leeds Enthesitis Score (LEI) and serum samples were collected at baseline and at 6months. Samples were run in a Bio-Plex ProTM plate for sCD40L. To investigate the association of sCD40L level with DAPSA based minor response, low disease activity (LDA) and/or remission at 6months of treatment, multivariate logistic regression models with backward selection (P<0·05) were built. We studied 27patients (16 of 27 women, 59·6%) with PsA and mean age [±standard deviation (s.d.)] of 58·4±10years. A significant reduction of the mean values of DAPSA, LEI and PASI was detected at 6months. Mean serum levels of sCD40L decreased from baseline 5364±2025pg/ml to 4412±2629 at 6months (P=0·01). Baseline DAPSA [odds ratio (OR)=0·80, 95% confidence interval (CI)=0·65-0·98] and sCD40L (OR=1·001, 95% CI=1·0001-1·0027) were independently associated with DAPSA LDA/remission at 6months. In PsA patients, sCD40L levels decrease upon apremilast treatment and might predict short-term clinical response to apremilast.

Can salicylic acid modulate biochemical, physiological and population alterations in a macrophyte species under chemical stress by diclofenac?

Salicylic acid (SA) is a pharmaceutical drug that may exert toxic effects by its own; however, simultaneous exposure of plants to SA and to other substances, often results in the significant changes in the patterns of toxic response/resistance to these other sources of chemical stress. Thus, the aim of this work was to investigate the capacity of SA of modulating Lemna minor responses co-exposed to the pharmaceutical drug, diclofenac - DCF. To attain this objective, L. minor was exposed for 7 days, to DCF alone, and to combinations of DCF with SA. After exposure, biochemical, physiological and population endpoints were analyzed as follows: catalase (CAT) and glutathione S-transferases (GSTs) activities, pigments content (chlorophyll a (Chl a), b (Chl b) and total (TChl), carotenoids (Car) and [Chl a]/[Chl b] and [TChl]/[Car] ratios), and growth specific rate, fresh weight and root length. Single exposures to DCF were capable of causing effects in all analyzed endpoints. However, co-exposure of DCF with SA partially reverted these effects. Finally, we may suggest that SA is capable to prevent the toxicity of DCF in macrophytes, by modulating the toxic response of exposed plants.

Phase I trial of lorlatinib in patients with ALK-driven refractory or relapsed neuroblastoma: A New Approaches to Neuroblastoma Consortium study.

10504 Background: Lorlatinib, a potent ALK inhibitor, exerts unprecedented activity against neuroblastoma (NB) derived xenografts harboring common crizotinib-resistant ALK mutations, leading to a first in child phase I study. Methods: R/R NB patients (pts) &gt; 12 months, with ALK mutations/amplification and prior ALK inhibitor (ALKi) treatment were eligible. Lorlatinib was administered in 28-day courses (C). For pts &lt; 18 years, 5 dose levels (DL) (45, 60, 75, 95, 115 mg/m2/day) were assessed. DL5 (115 mg/m2/day) expansion is enrolling (cohort A1). For patients &gt; 18 years, two DL (DL3a the adult RP2D of 100 mg/day and DL4a at 150mg/day) were assessed (cohort A2). Primary endpoint was dose-limiting toxicity (DLT) during C1 and neurocognitive toxicity through C2. Blood samples for circulating tumor DNA (ctDNA) were matched to radiologic restaging. Results: From 9/2017 to 1/2019, 33 eligible patients enrolled (13 with prior ALKi therapy), with median age (range) 5.5 years (2-17) on A1, 21.5 years (15-50) on A2. In A1, 3 pts each enrolled onto DL1-3, with no DLT’s. 5/10 pts enrolled on DL4, with no DLT’s. 1/3 on DL5 had a DLT of grade 3 diarrhea, with expansion ongoing. In cohort A2, 5 patients enrolled at 100 mg/day with no DLT’s; 6 enrolled at 150 mg/day, with one DLT (grade 4 reversible psychosis). Most common treatment-related adverse events were weight gain (90%, grade 1-3), hyperlipidemia (90%, grade 1-3), concentration/memory impairment (23%, grade 1-2), peripheral neuropathy (13%; grade 1-2, A2 only), and peripheral edema (10%; grade 1, A2 only). Lorlatinib steady state exposure at DL3 and DL4 was in the range of exposures seen in adult lung cancer patients at the 100 mg and 200 mg DLs. In A1, 1/18 had partial response (PR), 3/18 had minor responses (MR), and 4/18 had stable disease (SD). Of pts with MR, 2/3 had PR of soft tissue and 1/3 had complete response (CR) by MIBG. In A2 pts, 1/10 had CR, 3/10 PR, and 3/10 MR; Notably, 2/3 with PR had CR by MIBG. Of the pts with MR, one had PR and one CR by MIBG. Responses occurred across dose levels, ALK mutations, and in ALKi pre-treated pts with median courses of 2 (1-24) on A1 and 10.5 (2-28) on A2. Serial ctDNA results showed mutant ALK variant allele frequency trajectories that correlated with clinical response and emergence of novel ALK mutations in cis that corresponded with disease progression. Conclusions: Inhibition of ALK-driven NB with lorlatinib occurs with manageable toxicity and objective anti-tumor activity. Prospective ctDNA allows for monitoring of disease and evolution of resistance. Clinical trial information: NCT03107988.

CD68+ tumor-associated myeloid cells as the target of adenosine-induced gene products and predictor of response to adenosine blockade with ciforadenant (cifo) in renal cell cancer (RCC).

5025 Background: Adenosine in the tumor microenvironment (TME) is immunosuppressive and may play a role in resistance to immunotherapy. We described an adenosine induced gene expression signature (AS, Fong, Cancer Disc 2020) that correlates with response to therapy with cifo, an adenosine A2A receptor antagonist, as monotherapy or in combination with atezolizumab in refractory RCC. These genes express chemokines that signal through CCR2 and CXCR2 to recruit myeloid cells including immunosuppressive tumor associated-M2 macrophages, which are thought to mediate resistance to anti-PD(L)1 treatment. We now identify tumor infiltrating CD68+ myeloid cells as the effector cell for adenosine mediated immunosuppression. Methods: 82 RCC pts have been treated in an ongoing Phase 1/1b trial evaluating cifo (100mg po bid) monotherapy or combination with atezolizumab (840mg IV q 2 weeks). Tumor biopsies, obtained at screening and on therapy, are available for analysis in 32 pts to date. RNA expression was measured in tumors using Nanostring. Immunohistochemistry (IHC) for CD68 was performed on biopsies with CD68+ tumors defined as &gt; 4% tumor area containing CD68+ cells. Results: Pt characteristics are median age 63; median prior therapies 3, with 72% failing prior anti-PD(L)1. Gene expression of M2 markers consisting of CD68 (p = 0.0008) and CD163 (p = 0.03) was higher in baseline samples from AS+ compared to AS- pts. By IHC, 10 pts had CD68+ cells infiltrating the tumor; 9 of 10 AS+. Tumor regression was observed in 6 of 10 CD68+ pts (N = 3 monotherapy and 3 combination) including 4 partial responses (PR, RECIST). No PRs and 2 minor responses were seen in 22 pts who were CD68- (p &lt; 0.005). Median time to progression was not reached for CD68+ vs 2 mo for CD68-. Paired biopsies showed a significant reduction in infiltrating CD68+ cells (p = 0.03) with treatment including 2 of 2 evaluable PRs. Conclusions: Adenosine immunosuppression is mediated by M2 macrophages, which can be reversed by cifo. Enumerating tumor infiltrating CD68+ cells may be a valuable biomarker for identifying pts that will respond to adenosine blockade. Clinical trial information: NCT02655822 .

Phase I, first-in-human study of AbGn-107, a novel antibody-drug conjugate (ADC), in patients with gastric, colorectal, pancreatic or biliary cancers.

e16771 Background: AbGn-107 is an ADC directed against AG-7 antigen, a Lewis A-like glycol-epitope expressed in 24-61% of gastric (G), colorectal (CRC), pancreatic (PDA), and biliary (BIL) cancers. Based on promising antitumor activity of AbGn-107 in both in vitro and in vivo preclinical studies, we performed a Phase Ia trial in patients with the aforementioned GI malignancies. Methods: Standard 3+3 dose escalation was used. Key eligibility included locally advanced or metastatic G, CRC, PDA, or BIL cancer, previously treated, ECOG PS 0-1; positive AG-7 expression was not required. Two dosing intervals were tested: AbGn-107 administered i.v. Q4 weeks (at doses ranging from 0.1-1.2 mg/kg) and Q2 weeks (at doses from 0.8-1.0 mg/kg). Dose limiting toxicities (DLT) were based on grade 3/4 hematologic and non-heme AEs occurring during the initial 4-week rx window. Patients were treated until disease progression or unacceptable toxicity, with tumor assessments Q8 weeks. 1o objectives: safety and MTD; 2o objectives: PK, immunogenicity, and efficacy defined by ORR (RECIST 1.1). Results: 35 patients were enrolled across 6 dose levels (median age 61.5 yo (range 40 – 81); G (0)/CRC (12)/PDA (20)/BIL (3); median # lines of prior rx = 3 (range 1-7). Safety: 5 patients experienced Grade 3 or 4 neutropenia, all at higher dose levels, inc. 1 episode of febrile neutropenia. Other frequent drug-related AEs, mostly grade 1/2, inc. fatigue (29%), nausea (20%), and diarrhea (14%). DLTs included grade 4 CK elevation (n = 1) at 0.8 mg/kg Q4W and grade 3 arthralgias (n = 1) at 1.2 mg/kg Q4W. Based on safety profile and PK data, 1.0 mg/kg Q2W was selected as the dose schedule for cohort expansion phase. Efficacy: Median duration of treatment = 56 days (range, 8 – 225 days). Six pts have demonstrated a minor response by RECIST (range, -1.3 to -21.1%); 4 pts (all PDA) have had durable dz control &gt; 180 days. Conclusions: Overall, AbGn-107 appears well-tolerated with encouraging prelim signs of efficacy in unselected pts with heavily pre-treated advanced GI cancers. Updated safety and efficacy data will be provided at the time of the meeting for the cohort expansion phase of this study (currently open across multiple sites in U.S. and Taiwan), in which subjects with G, CRC, PDA, and BIL cancers are pre-screened for high levels of AG-7 tumor expression. Clinical trial information: NCT02908451 .

Vorasidenib (VOR; AG-881), an inhibitor of mutant IDH1 and IDH2, in patients (pts) with recurrent/progressive glioma: Updated results from the phase I non-enhancing glioma population.

2504 Background: Isocitrate dehydrogenase 1 and 2 mutations (m IDH1/2) occur in approximately 70% and 4% of low-grade gliomas (LGGs), respectively, promoting oncogenesis via increased production of D-2-hydroxyglutarate. In this ongoing phase 1 trial, VOR, a potent, oral, reversible, brain-penetrant, first-in-class dual inhibitor of mIDH1/2, is being evaluated in advanced m IDH1/2 solid tumors, including gliomas. Safety and preliminary results were presented previously (Mellinghoff et al., J Clin Oncol 2018). Here, we report updated data for the non-enhancing glioma pt population. Methods: Pts with recurrent/progressive m IDH1/2 glioma received VOR daily (continuous 28-day cycles). Key eligibility criteria included: ≥18 years; histologically or cytologically confirmed glioma with documented m IDH1/2; ECOG 0-2; and evaluable disease by RANO-LGG criteria. Dose escalation cohorts enrolled using a Bayesian logistic regression model (BLRM) escalation guided by the overdose control (EWOC). Tumor response was evaluated by MRI every 8 weeks using RANO-LGG criteria by local assessment. Results: As of 28 Nov 2019, 22 pts with non-enhancing glioma had received VOR and 8 (36%) remain on treatment. M/F, 8/14; grade 2/3, 17/5; median age, 47 years; m IDH1/2, 20/1; 1p19q intact, 9/22; median (range) number of prior systemic therapies, 2 (1–4). Common (≥5 pts) treatment-emergent adverse events (AEs) of any grade and regardless of causality included increased ALT/AST (63.6%/59.1%), headache (45.5%), nausea (40.9%), neutropenia (31.8%), fatigue and hyperglycemia (27.3% each), and seizures and decreased white blood cell count (22.7% each). Transaminase elevations were grade 1 in severity at dose levels &lt; 100mg and were less frequent (5 [38.5%] of 13 pts). Three subjects had related grade ≥3 AEs; 2 discontinued due to AEs. Objective response rate was 13.6% (1 partial response, 2 minor responses), and 17 (77.3%) pts achieved stable disease. 60.5% of pts were progression free and alive at 24 months. Conclusions: In this previously treated population with non-enhancing glioma, VOR was associated with a favorable safety profile. The study results also show encouraging preliminary activity within that population, with PFS duration extending to 24 months or longer in 60% of participants. A global randomized phase 3 study of VOR in grade 2 non-enhancing glioma pts who have had surgery only is currently enrolling (NCT04164901). Clinical trial information: NCT02481154 .

Personalized multimodality therapy (ICT) with immune checkpoint inhibitors (ICI), chemotherapy (CT), and targeted treatment (TT), in advanced/refractory cancer.

e15150 Background: Therapy for advanced/refractory malignancies is associated with poor prognosis. The combination of ICI and CT has been shown in lung and several other cancers to be superior to CT alone. Since ICI, CT, and TT have a convergent efficacy with divergent toxicity, the combination was evaluated in the treatment of these diseases. Initial evaluation was reported in JCO. 2019 37.15 suppl. e14254. Methods: Treatment was highly personalized and based on diagnosis, prior therapy, and eligibility for TT. Genomic profiling was done to determine TT. ICI included pembrolizumab in 14, nivolumab in 8, and atezolizumab in 2. Chemotherapy was given in 28-day cycles. 23 received multiple agents. 17 received platinum, 11 taxanes. TT included erlotinib in 6, bevacizumab in 6, cetuximab in 2, everolimus 2, and 8 received others. From 04/2016 to 12/2019, 24 patients, median (M) age 62 (27-78) received ICT; 15 females, 9 males. Tumor type: lung 9, pancreas 4, colon 2, glioblastoma multiforme 2, melanoma 2, stomach 1, cervix 1, cholangiocarcinoma 1, thymoma 1, Hodgkin's lymphoma 1. 18 patients had prior therapy, M2 (1-11), of them 6 had ICI and 5 TT. Response evaluation was based on PET scan. Tumor regression occurred after the first cycle. Results: All patients responded. 12 (50%) achieved CR, M14 months (3-32+); 11 (45.8%) had PR, M5+ months (1+ - 20+); and 1 minor response 1+ month. CR + PR was 95.8%. All 3 patients with lung cancer and metastases to brain, achieved CR in brain. Of 3 patients with advanced gastrointestinal cancer, 2 achieved CR and 1 achieved more than 95% reduction in disease. Tolerance was reasonable. No unexpected side effects were noted. Adverse events were primarily hematologic and febrile events/infection. Conclusions: Personalized ICT combination in advanced/refractory and diverse cancer diagnoses is associated with more than 95% response rate. In particular, it was effective in primary and metastatic CNS disease.

Atezolizumab plus stereotactic ablative therapy for medically inoperable patients with early-stage non-small cell lung cancer.

9011 Background: Stereotactic ablative radiation therapy (SABR) is the standard-of-care for medically inoperable, early stage non-small cell lung cancer (NSCLC), but regional and distant failures remain problematic. Based on our in vivo data showing synergy between radiation and immune checkpoint inhibitors (ICI) and the known efficacy and mild toxicity profile of ICI in NSCLC, we conducted a phase I study to determine the maximum tolerated dose of neoadjuvant, concurrent, and adjuvant atezolizumab with SABR for early stage NSCLC patients (pts). Methods: Eligible pts had histologically confirmed T1-3 NSCLC with at least one feature predictive of increased recurrence risk: diameter ≥1 cm, SUV ≥6.2 on PET, or moderately/poorly differentiated histology, were medically inoperable or refused surgery and had a Zubrod PS ≤2. Patients received 6 cycles of atezolizumab. A 3+3 dose finding design was employed with 3 dose levels: 3 mg/kg, 10 mg/kg, and 1200 mg flat dosing. SABR was delivered starting cycle 3 to 50 Gy over 4-5 fractions. Dose limiting toxicity (DLT) was assessed during the first 9 weeks. Results: 20 pts were enrolled, 15 pts in the dose finding and 5 pts at the recommended phase II dose (RP2D). Patient factors: MedIan age 77; 45% male, 85% smoking history, 85% PS 0-1 and 35% squamous. One pt on dose level 2 had a DLT – a grade 3 rash. Atezolizumab 1200 mg flat dosing was the RP2D. Grade 3 pneumonitis was not observed. Partial responses after 2 cycles were seen in 3/17 evaluable pts (18%) and 1 pt had a minor response. No patient progressed on treatment. PD-L1 expression was 0% 8/13 (62%), &gt;1% - 50% 4/13 (31%), &gt;50% 1/13 (8%) in pts with sufficient tissue. Of 5 pts with PD-L1 expression 3 (60%) were responders and 1 (12.5%) of 8 pts with 0% PD-L1 expression responded. Multi-plex Quantitative Immunofluorescence (QIF) using a T cell activation panel demonstrated to correlate with ICI response was performed on 9 samples (including 2 responders, 1 minor responder). The CD3 QIF score was &gt; two-fold higher in the responders compared to non-responders, and the levels of proliferating and activated T cells were likewise &gt; two-fold higher. Comprehensive stool and serial blood analyses have been completed. Correlative endpoints will be reported along with additional efficacy outcomes. Conclusions: Atezolizumab plus SABR is feasible, safe and shows an efficacy signal in medically inoperable early stage NSCLC. This combination will be tested in a randomized phase III trial SWOG/NRG S1914. Funding: This work was supported by the DOD CDMRP W81XWH-15-2-0063 and Genentech. Clinical trial information: NCT02599454.

Randomized phase II trial of MIBG versus MIBG/vincristine/irinotecan versus MIBG/vorinostat for relapsed/refractory neuroblastoma: A report from the New Approaches to Neuroblastoma Therapy Consortium.

10500 Background: 131I-metaiodobenzylguanidine (MIBG) remains one of the most active agents for neuroblastoma. It is not clear if putative radiation sensitizers improve upon this activity. The primary aim of this trial was to identify the MIBG treatment regimen with highest response rate among: MIBG monotherapy (Arm A); MIBG/Vincristine/Irinotecan (Arm B); MIBG/Vorinostat (Arm C). The secondary aim was to compare toxicity across arms. Methods: We conducted a multicenter, randomized phase II trial. Patients 1-30 years with relapsed/refractory high-risk neuroblastoma were eligible with at least one MIBG-avid site and adequate autologous stem cells (ASCs). All patients received MIBG 18 mCi/kg on Day 1 and ASC on day 15. Patients on Arm A received only MIBG; patients on Arm B also received vincristine (2 mg/m2) IV on Day 0 and irinotecan (50 mg/m2) IV daily on Days 0-4; patients on Arm C also received vorinostat (180 mg/m2) orally once daily on days -1 to 12. The primary endpoint was response after one course according to NANT response criteria. The trial was designed as a pick-the-winner study with a maximum of 105 eligible and evaluable patients to ensure an 80% chance that the arm with highest response rate is selected, if that response rate is at least 15% higher than the other arms. Results: 114 patients enrolled. Three patients were ineligible and 6 eligible patients never received MIBG, leaving 105 eligible and evaluable patients (36 Arm A; 35 Arm B; and 34 Arm C; 55 boys; median age 6.5 years). 9 patients had received prior MIBG monotherapy, 65 prior irinotecan, and 7 prior vorinostat. After one course, the response rates (Partial Response or better) on Arms A, B, and C were 17% (95% CI 7-33%), 14% (5-31%), and 32% (18-51%). An additional 4, 4, and 7 patients met NANT Minor Response criteria [partial response in one disease category (e.g., bone marrow) and stable disease in other categories] on Arms A, B, and C, respectively. On Arms A, B, and C, rates of any grade 3+ non-hematologic toxicity were 19%, 49% and 32%; rates of grade 3+ diarrhea were 0%, 11%, 0%; and rates of grade 3+ febrile neutropenia were 6%, 11%, and 0%. Conclusions: The combination of vorinostat/MIBG had the highest response rate, with manageable toxicity. Vincristine and irinotecan do not improve the response rate to MIBG and are associated with increased toxicity. These data provide response rates for MIBG monotherapy in a contemporary patient population assessed with current response criteria. Clinical trial information: NCT02035137.