Subgroup analysis in patients (pts) with non-squamous (N-Sq), EGFR-wild type (wt), second/third-line NSCLC from the global phase (Ph) 3 trial DUBLIN-3 (BPI-2358-103) with the plinabulin/docetaxel (Plin/Doc) combination versus Doc alone

9090

Background: With PD-1/PD-L1 inhibitors moving to first line in NSCLC, 2nd/3rd line NSCLC is a severe unmet medical need, dominated by docetaxel-based therapies with > 40% severe neutropenia and limited survival. Plin, a novel immune-enhancing small molecule, enhances dendritic cell maturation and T-Cell proliferation. In the ITT population, the Plin/Doc combination had superior Efficacy (mOS; HR = 0.82, p = 0.0399), Safety (lower Gr3/4 AE rate/pt/year (yr); p = 0.038) and better Quality of Life (QTWiST; p = 0.026) versus (vs) standard of care (SoC) Doc alone in advanced and metastatic NSCLC pts in DUBLIN-3 (Han, ESMO 2021) who failed platinum therapy. Here we report on the N-Sq pts subgroup. Methods: DUBLIN-3(NCT02504489) was a randomized, single-blind (pts only), active controlled Ph3 study in 2nd/3rd line stage IIIB/IV, EGFR wt NSCLC pts with a measurable lesion (RECIST 1.1) in the lung, and ECOG ≤ 2, conducted in US, Australia and China. Pts (n = 559) were randomized 1:1 to Plin/Doc or Doc/Placebo (21-day (D) cycle (C)). Doc (75 mg/m2 on D1 and Plin 30 mg/m2 on D1 and D8 were given by IV infusion. A post-hoc analysis of median Overall Survival (mOS) and restricted mean survival time (RMST) from K-M curves, OS rate at 24,36 and 48 month (Mo), and grade 4 neutropenia (Gr4N) rates was performed for the N-Sq patients (n = 153 for Plin/doc and n = 178 for Doc). Results: Baseline characteristics were balanced between both groups. Primary and key secondary objectives in the ITT population were met (Han, ESMO 2021). Plin/Doc was well tolerated. Estimated Adverse Event Rate per Year [95% CI] was 1.43 [1.13,1.81] for Plin/Doc versus 2.77 [2.33,3.28] for Doc alone (p < 0.001). The median OS benefit is 2.6 months (p = 0.023). The table below summarizes the results for the N-Sq subgroup. Conclusions: The addition of Plin to Doc was superior to SoC Doc alone for efficacy and safety in the clinically relevant subgroup of non-squamous EGFR-wild type, 2nd/3rd line NSCLC pts. Clinical trial information: NCT02504489. [Table: see text]

DUBLIN-3 results on quality of life (QoL) in second/third-line EGFR-wild type NSCLC patients (pts) receiving docetaxel (Doc) with or without plinabulin (Plin) using the validated EORTC QLQ C30 and QLQ LC13 questionnaires

9091

Background: Plin, a novel immune-enhancing small molecule, enhances dendritic cell maturation and T-cell proliferation. In the ITT population, the Plin/Doc combination had superior Efficacy (mOS; p = 0.0399), Safety (Gr3/4 AE rate/pt/year; p = 0.038) and QTWiST (p = 0.026) vs standard of care (SoC) Doc alone in NSCLC pts in DUBLIN-3 (Han, ESMO 2021). Here we report DUBLIN-3 QoL results. Methods: DUBLIN-3(NCT02504489) was a randomized, single-blinded (pts only), active-controlled Ph3 study in 2nd/3rd line stage IIIB/IV, EGFR wt NSCLC pts with a measurable lesion (RECIST 1.1) in the lung, and ECOG ≤ 2, conducted in US, Australia, and China. Pts (n = 559) were randomized 1:1 to Plin/Doc or Doc/Placebo (21-day (D) cycle). Doc (75 mg/m2 on D1 and Plin 30 mg/m2 on D1 and D8 were given by IV infusion. QoL was evaluated by the validated questionnaires EORTC QLQ C30 and QLQ LC13 (which is specific for Lung Cancer), and patient-reported scores were collected at baseline and D1, D8 of each cycle (C). Results: Baseline characteristics and QLQ C30 and LC13 scores were comparable between both groups. Plin/Doc was well tolerated. Cumulative C30 sand LC13 scores were calculated for each patient. Mean (SEM) change from baseline in cumulative C30 and LC13 scores were comparable for Plin/Doc and Doc in the first 10 cycles, however separated after C10 in favor of Plin/Doc (table). LC13 items in favor of Plin/Doc vs Doc alone, were items 31 (Coughing; p < 0.05), 36 (Sore Mouth; p < 0.01), 37 (Dysphagia; p < 0.01). Conclusions: We previously reported an OS, Safety, and QTWiST benefit with Plin/Doc vs Doc alone (ESMO 2021) in EGFR wild type 2nd/3rd line NSCLC pts from DUBLIN-3. Here, we report statistically significant QoL benefits with Plin/Doc vs Doc alone, as assessed with EORTC QLQ C30 and LC13, which may be relevant to guide treatment decisions in this generally sick patient population. Clinical trial information: NCT02504489. [Table: see text]

Real-world effectiveness of prophylactic granulocyte colony-stimulating factor (G-CSF) early (week 1) and late (weeks 2-3) in the cycle for the prevention of febrile neutropenia (FN) among patients (pts) with breast cancer (BC) after high FN–risk chemotherapy (chemo)

599

Background: G-CSF mitigates chemotherapy-induced neutropenia (CIN) and reduces FN risk. G-CSF moves the nadir of absolute neutrophil count (ANC) earlier (to week 1) in the chemo cycle and shortens nadir duration (Crawford, NEJM 1991), suggesting the potential for suboptimal CIN protection early (week 1) in the chemo cycle. The relative FN risk in week 1 vs. weeks 2-3 of the cycle with G-CSF is unknown and was analyzed compared with no G-CSF in the real-world setting with high FN risk chemo. Methods: Using a database of administrative claims representing 100% of fee-for-service Medicare, we analyzed BC pts who initiated docetaxel (T), doxorubicin (A), or cyclophosphamide (C) monotherapy or combination therapy between 01/01/2015 – 12/31/2019. Sample pts included adults aged ≥ 65 years with continuous coverage in Medicare Parts A, B, and D for 6 months before and 20 days after chemo initiation. Pts were categorized as receiving vs. not receiving G-CSF therapy within 3 days after chemo. Rate of FN events starting in week 1 vs. weeks 2-3 in cycle 1 was calculated. We defined FN as an inpatient admission with a primary or secondary diagnosis of neutropenia and measured the interval between chemo initiation and FN admission. Results: Among 18,788 Medicare beneficiaries with BC treated with T, A, and/or C, 72% received G-CSF therapy. More pts receiving G-CSF were treated with ≥ 2 of T, A, and/or C compared to pts who did not receive G-CSF (71% vs. 51%). Overall FN incidence in cycle 1 was significantly lower among pts receiving G-CSF (4.0%; n=546) compared to pts not receiving G-CSF (8.8%; n=462) (p<0.0001). In pts with G-CSF, 81% (440/546) of all 1st-cycle FN events started in week 1 vs. 19% (106/546) in weeks 2-3. In pts not receiving G-CSF, the start of 1st-cycle FN events was more equally distributed: 41% (190/462) started in week 1 vs. 59% (272/462) in weeks 2-3. Results were robust to sensitivity analyses restricted to pts receiving ≥ 2 of T, A, and/or C. The rates of 1st-cycle FN events starting in weeks 1 and 2-3 with and without G-CSF following chemo initiation is shown below. Conclusions: Prophylactic G-CSF was highly effective for the prevention of FN in weeks 2-3, but relatively ineffective in week 1 of cycle 1 in the real-world setting, leaving pts largely unprotected during the first week. This represents an unmet medical need in week 1 of the cycle, despite use of G-CSF. Clinical trial information: NCT03294577. [Table: see text]

Abstract PS11-15: Plinabulin and pegfilgrastim (Plin+Peg) versus peg monotherapy (Peg) after TAC: A comparison of efficacy, safety, relative dose intensity (RDI) and bone pain

Introduction:Prevention of Chemotherapy Induced Neutropenia (CIN) through primary or secondary prophylaxis is indicated in breast cancer (BC) chemotherapy (chemo) which is administered with curative intent. Granulocyte colony stimulating factors (G-CSFs), including Peg are standard of care in this context. In typical every three-week chemo regimens with primary G-CSF prophylaxis, absolute neutrophil count (ANC) nadir occur approximately day (D) 7, which reduces but does not eliminate febrile neutropenia risk in the first week. However, plinabulin (Plin), a novel non-G-CSF agent, protects against the nadir and CIN in the 1st week after chemo (Blayney ASCO 2019). These findings provided the rationale to combine Plin with Peg after chemo with a high febrile neutropenia risk. Both Plin and Peg act on the neutrophil precursor. Both agents mobilize bone marrow-derived CD34+ progenitor stem cells (Blayney ASH 2018). Plin has also anti-cancer efficacy in an animal BC model (Bertelsen, Int J Rad Biol 2011). Here we summarize the efficacy and safety data with combining Peg with Plin in potentially curable BC patients treated with TAC.

Methods: In the randomized phase 2 portion of Study 106 (NCT0329457), BC patients were treated with TAC (docetaxel 75, doxorubicin 50 and cyclophosphamide 500 mg/m2) and either 6 mg Peg alone (Peg6; n=22), or Peg 6mg+Plin 20 mg/m2 (Plin+Peg; n=16). Grade (Gr) 3/4 neutropenia frequency, duration of Gr 3 and 4 neutropenia (DSMN), and neutrophil nadir was calculated from absolute neutrophil counts obtained on days 0, 1, 3, 6, 7, 8, 9, 10, 11, 12, 13, 15. Bone pain was assessed by a validated questionnaire. Percentage of pts with RDI &lt;85% and adverse event rate (Grades 1-5) was calculated.

Results: Gr 3 or 4 neutropenia with Plin/Peg vs Peg was 50% vs 81.1% (p&lt;0.04). Median DSMN with Plin/Peg vs Peg was 0.5 day vs 1 day. ANC nadir [mean (95% CI)] with Plin/Peg vs Peg was 1.15 (0.66;1.65) vs 0.80 (0.37;1.22).

In the Plin+Peg vs Peg group, Gr 4 AE frequency was 37.3% vs 54.5%, Gr 3 AE frequency was 18.8% vs 27.3%, Gr 2 AE frequency was 25% vs 9.1% and Gr 1 AE frequency was 18.8% vs 4.5%. No Gr 5 AEs occurred in either group. Bone pain was significantly less (P&lt;0.001) with Plin+Peg vs Peg.

Conclusion: Addition of Plin to Peg has superior prevention of CIN, superior safety, superior RDI and superior protection against bone pain compared to standard dose Peg alone in this randomized phase 2 trial. A confirmatory global Phase 3 trial comparing Plin+Peg vs Peg alone is underway.

RDI&lt;85%Cycle 1Cycle 2Cycle 3Cycle 4Peg0 %13.6 %19.1 %19.1 %Plin+Peg0 %6.25 %6.25 %6.25 %

Citation Format: Douglas W. Blayney, Greg Ginn, Lan Huang, Ramon W. Mohanlal. Plinabulin and pegfilgrastim (Plin+Peg) versus peg monotherapy (Peg) after TAC: A comparison of efficacy, safety, relative dose intensity (RDI) and bone pain [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS11-15.

Head-to-head comparison of the non-G-CSF small molecule single agent (SA) plinabulin with SA pegfilgrastim for the prevention of docetaxel chemotherapy (chemo)-induced neutropenia (CIN) in the protective-1 trial

TPS7087

Background: Plinabulin (Plin) is a small molecule with anti-cancer activity and CIN effects. The Phase (Ph) 2 clinical trial NPI-2358-101 ( NCT00630110 ) evaluated Plin at 20 or 30 mg/m2 on Day (D) 1 and D8) plus D1 Docetaxel (Doc) 75 mg/m2 combination versus D1 Doc alone in patients (pts) with non-small cell lung cancer(NSCLC). In a large ( > 70%) subset of pts with a measurable lung lesion in the lung (per RECIST 1.1) receiving 30 mg/m2 Plin + Doc (n = 38), mOS was 4.6 months longer vs Doc alone (n = 38) (Mohanlal ASCO-SITC 2018). An unexpected post-hoc finding was a CIN benefit with adding at 20 or 30 mg/m2 Plin to Doc: 33% of pts in the Doc arm had grade 4 neutropenia, whereas in the Plin +Doc group 4% of pts (P < 0.0003) (Blayney ASH 2018). Plin boost the number the number of hematopoietic/progenitor cells in bone marrow. We subsequently initiated two global Ph3 programs with Plin: 1. A Ph 3 trial confirming its anticancer activity in NSCLC (study BPI-2358-103; NCT02504489; this trial is ongoing) and 2. An evaluation of Plin for CIN prevention through studies BPI-2358-105 (NCT03102606; PROTECTIVE-1), and study 106 (NCT03294577; PROTECTIVE-2). We previously reported from the Ph 2 portion of study 105, that SA Plin and Pegfigrastim (Peg) had comparable protection against CIN induced by Doc, however in contrast to Peg, Plin did not cause bone pain or thrombocytopenia (Blayney IASLC 2018, ESMO 2018). Plin is given by 30 min IV infusion on the same day of Chemo, 30 min after Chemo. The Ph3 portion of Study 105 in ongoing. Methods: In the Ph 3 portion of PROTECTIVE-1, pts with NSCLC, HRPC or BC are randomized (1:1) to either Plin 40 mg (over 30 minutes on D1; n = 75) or Peg 6mg (on D2, n = 75), and the primary endpoint is Duration of Severe Neutropenia (DSN). Plin 20 mg/m2 is similar to a 40 mg fixed dose. Absolute neutrophil counts (ANC) is determined on D 0, 1,2,3,6,8,9,10, 15 in Cycle 1 The trial aims to demonstrate non-inferiority of Plin vs Peg. Non-inferiority will be declared if the non-inferiority margin (NIM) of 0.65 day will be met, which NIM is more conservative than the 1 day NIM, typically employed for G-CSG biosimilar trials. Pts should have at least 1 risk factor as per NCCN guidelines.The trial is double-blinded to enable reliable PRO, Bone Pain and QoL assessments through validated questionnaires (EQ-5D-5L; EORTC QLQ-C30; Wang Baker Faces Pain Rating Scale). Following an Interim Analysis, the trial will continue without modifications. Clinical trial information: NCT03102606 .

A comparison of CD34+ mobilization effects of standard dose pegfilgrastim (Peg) versus low-dose peg combined with plinabulin (Plin)

e20000

Background: Plin is a novel, small molecule immune-enhancing agent with in vitro anticancer activity currently in Phase (Ph) 3 clinical trials for NSCLC treatment and Chemotherapy (Chemo)-Induced Neutropenia (CIN). Single agent (SA) Plin is equally effective as Peg for the prevention of CIN, however does not cause bone pain and is given on the same day of Chemo by 30 min IV infusion, 30 min after Chemo (Blayney ASH 2018). SA Plin also mobilizes CD34+ cells to clinically relevant levels (Blayney ASH 2019). Plin has been administered to > 600 patients (pts) and has a favorable safety/tolerability profile. In clinical practice, Peg dose is often reduced to 3 mg in patients (pts) experiencing side effects with standard dose (6 mg) Peg, such as bone pain, myalgia and leucocytosis (Kim ASCO 2010; Goodman Oncology Times 2008; Lacovelli JHOP 2012; Lower Cancer Chemother Pharmacol 2018). We evaluated CD34+ cell counts and adverse events (AE) with low dose Peg combined with Plin vs full dose Peg. Methods: In a subset of Breast Cancer pts in the CIN Ph 2 trial BPI-2358-106 (NCT0329457) receiving TAC (taxotere (75), doxorubicin (50 ) and cyclophosphamide (500) mg/m2, pts also received either Peg 6mg (n = 7) or low dose peg ( n = 9, of which 7pts received 3mg and 2 pts 1.5 mg Peg) combined with Plin (20 mg/m2). CD34+ counts were obtained by central laboratory FACS analysis (Covance) at screening (SC), Day (D) 6,8 and 21 cycle 1 (see table below) and AE frequency was collected. Results: Clinical trial information: NCT0329457 . Frequency of bone pain, myalgia and leukocytosis was numerically lower with low dose Peg/Plin vs 6mg Peg. Conclusions: Under highly myelosuppressive TAC Chemo conditions, CD34+ counts increased significantly (p < 0.03) vs predose SC in cycle 1 in the low dose Peg/Plin goup. CD34+ counts were not different for full dose Peg vs low dose Peg/Plin in cycle 1. Adverse Events were fewer with the low dose Peg/Plin. The Peg/Plin combination is worthy of test in hematopoietic stem cell mobilization regimens. [Table: see text]

Effect of plinabulin, a novel late-clinical stage immunotherapeutic agent on the adaptive and innate immune system

8

Background: Plinabulin (Plin) is a small molecule Dendritic Cell modulator, which in the presence of antigen, increases T-cell proliferation in an antigen-dependent manner marrow. The addition of Plin to Docetaxel (Doc) improved mOS with 4.6 months vs Docetaxel monotherapy, and prolonged DoR with more than 1 year (p < 0.05), which is indicative of an immune-mediated mechanism of action (Mohanlal, ASCO-SITC 2017). Neutrophils are our first line of innate immune defense against foreign invaders. We previously reported that Plinabulin prevents chemotherapy (Chemo) Induced Neutropenia (CIN) in patients receiving Doc or TAC throughout the cycle (Doc, Doxorubicin, Cyclophosphamide) (Blayney ASH 2018, St Gallen 2019). Here we analyzed the onset time of neutrophil increase following Plin administration. In addition, we analyzed the impact of Plin on plasma haptoglobin, which is an acute phase protein with anti-inflammatory effects together with immune-enhancing effects and is an integral part of innate immunity (Kristiansen Nature 2001). Methods: Absolute neutrophil count (ANC) and haptoglobin data were analyzed from Phase 2 study BPI-2358-106 (NCT03294577) with 10 (n = 15), 20 (n = 15) and 30 mg/m2 (n = 12) Plin in Breast Cancer patients receiving TAC. Plin was administered on Day 1. ANC and Haptoglobin were analyzed by a Central Laboratory (Covance), from blood draws at predose, and post-dose Plin at Day 2,3,6,7,8,9,10,11,12,13 and 15, and changes relative to predose value were evaluated. Results: Plin dose-dependently increased ANC within 1 day (P < 0.001) and Haptoglobin within 3 days (P < 0.03) of dosing. Mean haptoglobin (P < 0.0005) and ANC (P < 0.001) levels increased with ~two-fold vs baseline levels. ANC levels remained increased for approximately 1 week and haptoglobin levels for > 3 weeks. Conclusions: Based on Plinabulin’s ability to stimulate the innate system, together with its previously reported evidence as a potent activator of the adaptive immune system (Mohanlal, ASCO-SITC 2017), it is concluded that Plinabulin is a potent stimulator of the adaptive and innate immune system. Clinical trial information: NCT03294577.

Abstract 1254: Predictive models for tumor cell targeting with plinabulin, derived from in vitro screening and Affymetrix mRNA expression data

Tubulin binding drugs are approved for the treatment of many cancer types, without the use of molecular markers to select patients likely to respond. Plinabulin binds β-tubulin in a differentiated pocket and is being tested in a Phase 3 clinical study for the treatment of NSCLC. Additional indications are being considered for plinabulin and an algorithm for selecting especially responsive cancers and patient subgroups would be of significant value. With this in mind, Affymetrix HG-U133 Plus 2.0 array mRNA expression data for 43 human breast, lung, prostate, ovarian or CNS cancer cell lines were utilized to develop mathematical models to predict in vitro plinabulin potency against the same cell lines. Cells were treated for only 24 hours with plinabulin and then cultured for another 48 hours without plinabulin. Viable cell number was then measured with a Cell Titer-Blue Assay, and the plinabulin concentration causing a 70% reduction in viable cells (IC70) versus vehicle treated controls was derived. Cell lines were clearly separable into plinabulin Active (21 cell lines with IC70&lt;1.0 μM) and Inactive (IC70&gt;9.5 μM) groups. Log2 transformed Affymetrix gene probeset signal values, preprocessed with the GeneChip robust multi-array average analysis algorithm, were selected and ranked as predictors of plinabulin activity with a bootstrap forest partitioning technique, utilizing JMP 14.1 statistical software. 56 HIT probesets were identified that also had significantly different expression in responding versus non-responding cell lines (p&lt;0.01, uncorrected t-test). For probesets with gene annotation, only the probeset for each gene with the highest Jetset score was utilized (Li et al., 2011). Top HIT predictor genes include CTNNB1 (β-catenin; oncogene), CALD1 (caldesmon; inhibits myosin ATPase activity), ERI1 (RNA processing), LGR5 (adult stem cell biomarker), SECISBP2L (SLAN; prolongs mitosis), and TRAK1 (mitochondrial/endosome trafficking). Models were constructed from HIT gene probesets in JMP to identify plinabulin responding cell lines, utilizing either one-layer TanH multimode fit neural networks or binary logistic regression. Surprisingly, models incorporating approximately 4-10 probeset values were derived that perfectly predicted plinabulin activity. Importantly, the cell lines tested in the above analyses were not those known to express high levels of multi-drug resistant (MDR) transporters. The importance of MDR status was therefore evaluated separately. Plinabulin activity, unlike that of taxanes, was not significantly affected by the MDR transporter inhibitor verapamil (10 μM), in ovarian cancer cell lines with a known MDR phenotype. To conclude, our work provides novel algorithms that may be of value in selecting cancer patients with tumor cells that are particularly susceptible to the direct cytotoxic effects of plinabulin.

Citation Format: James R. Tonra, Hagen Klett, Chenghao Shen, Gerhard Kelter, Ramon W. Mohanlal, G. Kenneth Lloyd, Lan Huang. Predictive models for tumor cell targeting with plinabulin, derived from in vitro screening and Affymetrix mRNA expression data [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 1254.

A phase I trial combining plinabulin and nivolumab for metastatic NSCLC: Trial in progress

TPS128

Background: Plinabulin (Plin) is a microtubule-destabilizing agent (MDA) that inhibits the polymerization of tubulin monomers and leads to disruption of the tumor vasculature. It has been shown in clinical studies of advanced NSCLC to produce a significantly longer duration of response when combined with docetaxel versus docetaxel alone (NCT00630110). MDAs were also shown to trigger the maturation of dendritic cells and the production of pro-inflammatory cytokines, thereby enhancing T-cell proliferation. Pre-clinical studies have shown that MDAs in combination with immune checkpoint inhibitors (ICI) demonstrated a superior response rate and survival when compared to ICI alone. Nivolumab is an anti-PD-1 antibody that is FDA approved for previously treated metastatic NSCLC regardless of PD-L1 expression. We hypothesized that the combination of Plin and Nivolumab will enhance the immune response, resulting in a higher response rate and longer overall survival. Methods: This is an open label single center phase I trial. The Dose Escalation Portion (Part 1) employs a 3+3 design with dose escalation of Plin starting at 13.5mg/m2 (biologically effective dose as single agent), combined with the FDA approved dose of Nivolumab 240mg. Plin is given on days 1,8, and 15 of 28- day cycles and Nivolumab is given on days 1 and 15. The dose of Plin will be escalated to 20mg/m2, 30 mg/m2, and 40mg/m2 until the maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D) is determined. The Expansion Cohort (Part 2) will enroll 20 patients with NSCLC to be treated at the RP2D, including the patients who will have received this dose in Part 1. Treatment will continue until disease progression, development of unacceptable toxicity, or a protocol-defined reason for discontinuation. Eligible patients include metastatic NSCLC who have failed platinum-based doublet and regardless of prior anti-PD-1/PD-L1 antibody treatment. Part 1 is enrolling in an expanded cohort 2 due to one dose-limiting toxicity (DLT) in this group. Clinical trial information: NCT02812667.

Extrinsic Activation of Human Coagulation Factors IX and X on the Endothelial Surface

In previous kinetic studies, the catalytic efficiency of the activation of human coagulation factors IX and X by factor VIIa in the presence of purified tissue factor apoprotein was found to be essentially equal. These activation reactions were now studied on the surface of human umbilical vein endothelial cells. The cells were stimulated with endotoxin to express tissue factor. This tissue factor activity was saturable with factor VIIa and could be inhibited by rabbit antibodies against human tissue factor apoprotein. Only stimulated cells supported factor VIIa activity. No difference in the reactivity of factor VII and VIIa was observed in the presence of factor X, due to rapid feedback activation of factor VII by factor Xa. However, the activation of factor IX by factor VII shows a 10 min lag-phase, which reflects that the activation of factor VII by factor IXa is a less efficient process. The kinetic parameters for the factor VIIa dependent activation of factor IX and factor X on the endothelial surface were: Km 0.09 εM, Vmax 0.13 pmol/min, and Km 0.071 εM, Vmax 0.41 pmol/min, respectively. The same ratio between the Vmax for factor X and factor IX activation was observed as in a cell free system. However, the Km of factor IX was 4-fold higher on the endothelial surface than in the cell free system. Together, these kinetic parameters will favour factor X activation 5-fold over factor IX activation at physiological concentrations of these proteins.

The activation of factor X by factor VIIa on the endothelial surface was characterized by a short lag-phase, which was absent in factor IX activation. Further, both the activation of factor X and factor IX were down regulated by factor Xa.

Plinabulin, a novel small molecule clinical stage IO agent with anti-cancer activity, to prevent chemo-induced neutropenia and immune related AEs

126

Background: Plinabulin (Plin) is a small molecule with tumor-inhibiting and immune-enhancing effects by targeting Dendritic Cells (DCs). In preclinical studies, Plin induces DC maturation and the production of MHCII, CD40, CD80 and CD86 and related antigen-specific T-cell activation. Plin had synergistic anticancer efficacy with PD1+CTLA4inhibitors in animal models. In addition, Plin increases expression of IL-1β, IL-6, IL-12 in DC cell, which cytokines protect neutrophils against apoptosis. In a Phase 2 (Ph2) trial, the addition of Plin to Docetaxel (Plin+Doc; n = 38) in NSCLC patients (pts) with a measurable lesion, improved mOS with 4.6 mo vs Doc alone (n = 38). DOR (a marker of immune effect) was ~1 yr longer (P < 0.05) with Plin+Doc vs Doc alone. Plin exerted immune-enhancing effects (DOR), without increasing Immune-Related AEs (IR-AEs). This may suggest that Plin exerts immune-enhancing and anti-inflammatory effects. Methods: Prospective, randomized Ph2 clinical trial (NCT00630110) and non-clinical studies. Results: In-vitro screens showed that Plin is a PDE4-inhibitor, and clinical evidence (p < 0.03; n = 90) of PDE4-inhibition with Plin was observed in Ph2. PDE4-inhibitors have steroid-like effects and are approved for the treatment of Inflammatory disorders, and thus have the potential to prevent IR-AEs. In addition, Plin prevented chemo-induced Neutropenia (CIN), through a mechanism, different from G-CSF, in non-clinical (with various chemotherapies) and Ph2. In Ph2, Gr 4 Neutropenia occurred in 5% with Plin+Doc vs 33 % off pts with Doc (p < 0.0003) in Cycle 1, day 8. Plin is given 30 min after chemo (on the same day of chemo), and does not cause bone pain. G-CSF is given 24 hr after chemo, and causes bone pain in most pts. Conclusions: Plin exerts anticancer immune-enhancing effects, combined with anti-inflammatory effects, due to PDE4-inhibition. Plin holds the promise of an agent with anti-cancer efficacy, while also mitigating IR-AEs and CIN. Therefore, Plin is an attractive candidate for combination therapy with PD1-inhibitors (or PD-L1 inhibitors), PD1+CTLA-inhibitor, or PD1-inhibitor/chemotherapy.

Plinabulin as a novel small molecule clinical stage immuno-oncology agent for NSCLC

139

Background: Plinabulin (Plin) is a small molecule with tumor-inhibiting and immune-enhancing effects. In preclinical studies, Plin induces dendritic cell maturation and related IL-1β, IL-6 and IL-12 release, enhances antigen-specific CD4 T-cell proliferation, reduces regulatory T-cells and M2 macrophages in tumor tissue. Plin had synergistic efficacy with checkpoint inhibitors (PD-1 +/- CTLA-4) in animal models of tumor growth. Plin is targeting critical steps in the immune-cascade, independent from that of PD-1/PD-L1 binding. Methods: In a Phase 2 clinical trial, patients (pts) with and without measurable lung lesion were randomized to docetaxel (D) alone at 75 mg/m2 or Plin with D (Plin+D), in 30 mg/m2 or 20 mg/m2 Plin cohorts, given every 3 weeks (NCT00630110). The primary efficacy endpoint was mOS. Secondary endpoints were safety assessments, DOR, PFS, ORR. PD-L1 tumor status was not characterized. Results: In the 30 mg/m2 cohort, n=50 patients received 30 mg/m2 Plin+ D and n=55 patients received D alone; 72% had measurable lung lesion. In pts with a measurable lung tumor, Plin+D (n=38) was numerically more effective vs. D alone (n=38). mOS, PFS and ORR were 11.3 mo, 3.7 mo, and 18% respectively for Plin+ Doc, and 6.7 mo, 2.9 mo, and 10.5% resp for D alone. DOR (a marker of immune effect) with the Plin+D vs. D alone was 12.7 mo vs. 1 mo (p<0.05). Plin+D did not induce immune-related adverse events (IR-AEs), but prevented D- induced neutropenia (p<0.0002), and D-dose-reduction due to toxicity. The 30 mg/m2 Plin cohort was more effective than the 20 mg/m2 cohort as an anticancer agent. Conclusions: Plin added to D increases efficacy vs. D alone most likely through an immune-related mechanism independent from PD1/PD-L1 intervention and mitigates the known D-related safety concerns, without increasing IR-AEs. The Plin+D combination might represent an effective and cost-effective alternative to Nivolumab, in particular in PD-L1 negative NSCLC. A global phase 3 trial with Plin+D vs. D alone is underway in pts with at least one measurable NSCLC lesion. Clinical trial information: NCT00630110.

Efficacy and safety of continued zoledronic acid every 4 weeks versus every 12 weeks in women with bone metastases from breast cancer: Results of the OPTIMIZE-2 trial

LBA9500^

Background: Zoledronic acid (ZOL, 4 mg) every (q) 4 wk reduces the risk of skeletal-related events (SREs) in patients (pts) with bone metastases from breast cancer (BC). The OPTIMIZE-2 trial examined whether ZOL q12 wk was non-inferior to ZOL q4 wk in pts who had previously received monthly IV bisphosphonate (BP) therapy for ~1 year or longer. Methods: This was a prospective, randomized, double-blind, multicenter trial in female pts with bone metastases from BC who previously received ≥9 doses of IV BP (ZOL or pamidronate) during the first 10-15 months of therapy. Pts were randomized (1:1) to receive ZOL 4 mg IV q4 wk or q12 wk (placebo between ZOL doses to maintain blind) for 1 year. The primary endpoint was the proportion of pts with ≥1 SRE on study (SRE rate). Primary analysis was non-inferiority (pre-defined margin of 10%) for the difference in SRE rates. Secondary endpoints included time to first SRE, skeletal morbidity rate (SMR), bone pain score, change in bone turnover markers, and safety. Results: 403 pts were randomized to ZOL q4 wk (n = 200) or q12 wk (n = 203). Median age was 59 years, and baseline characteristics were similar between arms. The SRE rate was 22% and 23.2% in the ZOL q4 and q12 wk arms, respectively. The difference in SRE rate between arms was 1.2% (95% CI, –7.5% to 9.8%; P = .724). The upper limit of this 95% CI (9.8%) is less than the predefined margin of 10%, which indicates non-inferiority of ZOL q12 wk vs q4 wk. Times to first on-study SRE (HR, 1.06; 95% CI, 0.70 to 1.60; P = .792) were similar in the ZOL q4 and q12 wk arms, and mean SMRs were also similar (0.46 vs 0.50, respectively; P = .854). Overall, changes from baseline in bone turnover markers, and the incidence of treatment-emergent adverse events (TEAEs), were similar in the 2 arms. Numerically more renal TEAEs were reported in the ZOL q4 wk vs q12 wk arm (9.6% vs 7.9%, respectively). Two cases (1.0%) of osteonecrosis of the jaw (ONJ) were reported in the q4 wk arm. Conclusions: Among pts who had received monthly IV BP therapy for 1 year or longer, the efficacy of continuing ZOL for an additional year at q12 wk was non-inferior to ZOL q4 wk. Fewer renal AEs and none of the ONJ events were observed in the ZOL q12 wk vs ZOL q4 wk arm. Clinical trial information: NCT00320710.

Anticipatory anxiety in moderately to highly-anxious oral surgery patients as a screening model for anxiolytics: evaluation of alprazolam

Alprazolam, a benzodiazepine anxiolytic, was evaluated in anxious patients prior to oral surgery. This population represents a possible acute screening model for novel anxiolytic agents. Healthy subjects, preselected for a moderate to high degree of dental anxiety based upon Corah's Dental Anxiety Scale, were enrolled in a three-arm parallel design study and randomly assigned to receive double-blind placebo (N=15), alprazolam 0.25 mg (N=16) or alprazolam 1 mg (N=16). Subjective self-reported anxiety was rated using the State Anxiety Inventory and visual analog scales. Objective measures included galvanic skin conductance, heart rate variability, blood pressure, pulse rate, and respiration. At 90 minutes after dosing, there were statistically significant (p<0.05) reductions compared with placebo in subjective anxiety and skin conductance mean level for the alprazolam-treated subjects. Changes from pre-dose (mean +/- SEM) at 90 minutes in the placebo, alprazolam 0.25 mg, and alprazolam 1 mg groups were -4.73 +/- 2.79, -13.75 +/- 2.49, and -12.81 +/- 2.32 for the State Anxiety Inventory and 5.44 +/- 6.71, -31.88 +/- 5.88, and -32.34 +/- 5.32 mm for analog anxiety scores. Corresponding skin conductance mean level at 100 minutes in the three groups (respectively) changed 0.64 +/- 0.24, -0.53 +/- 0.21, -0.71 +/- 0.22 microSiemens. The 0.25 mg and 1 mg dosages of alprazolam were not differentiated. Changes in heart rate variability, blood pressure, pulse rate, and respiration did not reflect subjective anxiety. Overall, the oral surgery anticipation anxiety model was found to be a sensitive test for benzodiazepine anxiolytic activity and may represent a potential screening model for evaluation of investigational agents.

Gadolinium-DTPA-enhanced magnetic resonance imaging of the isolated rat heart after ischemia and reperfusion

The objective of this study was to assess the potential of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) to identify myocardial ischemia and reperfusion in the isolated rat heart model. Ischemia was induced by reducing the perfusion pressure from 80 to 30 mm Hg for 2 hours. Hearts were not reperfused, or were reperfused for 20 minutes or for 2 hours. Perfusion was performed with Evans blue dye and/or Gd-DTPA for 3 minutes. Twenty isolated rat hearts were perfused according to the Langendorff method, and divided into five groups according to the perfusion status and the use of Gd-DTPA and/or Evans blue as perfusion markers. The Evans blue distribution in the hearts was assessed by point-counting volumetry. The Gd-DTPA distribution was assessed by magnetic resonance microimaging at 6.3 T field strength. Evans blue staining clearly identified areas with "no flow" or "no reflow." Perfusion with Gd-DTPA enhanced signal intensity significantly, both in ischemic and reperfused myocardium. Signal intensity in hearts reperfused for 2 hours was increased significantly compared to nonreperfused ischemic hearts, but not to ischemic hearts reperfused for 20 minutes. Magnetic resonance imaging with the aid of Gd-DTPA can identify ischemia and reperfusion in the isolated rat heart, dependent on residual perfusion.

Extrinsic activation of human coagulation factors IX and X on the endothelial surface

In previous kinetic studies, the catalytic efficiency of the activation of human coagulation factors IX and X by factor VIIa in the presence of purified tissue factor apoprotein was found to be essentially equal. These activation reactions were now studied on the surface of human umbilical vein endothelial cells. The cells were stimulated with endotoxin to express tissue factor. This tissue factor activity was saturable with factor VIIa and could be inhibited by rabbit antibodies against human tissue factor apoprotein. Only stimulated cells supported factor VIIa activity. No difference in the reactivity of factor VII and VIIa was observed in the presence of factor X, due to rapid feedback activation of factor VII by factor Xa. However, the activation of factor IX by factor VII shows a 10 min lag-phase, which reflects that the activation of factor VII by factor IXa is a less efficient process. The kinetic parameters for the factor VIIa dependent activation of factor IX and factor X on the endothelial surface were: Km 0.09 microM, Vmax 0.13 pmol/min, and Km 0.071 microM, Vmax 0.41 pmol/min, respectively. The same ratio between the Vmax for factor X and factor IX activation was observed as in a cell free system. However, the Km of factor IX was 4-fold higher on the endothelial surface than in the cell free system. Together, these kinetic parameters will favour factor X activation 5-fold over factor IX activation at physiological concentrations of these proteins. The activation of factor X by factor VIIa on the endothelial surface was characterized by a short lag-phase, which was absent in factor IX activation.(ABSTRACT TRUNCATED AT 250 WORDS)

Delayed recovery of homogeneous perfusion distribution in isolated rat heart after vasodilatation induced by alpha 1 adrenoceptor blockade during postischaemic reperfusion

The purpose of this study was to investigate whether vasodilatation induced by doxazosin, an alpha 1 adrenoceptor blocker, during postischaemic reperfusion was able to accelerate reflow in unperfused myocardium. Isolated isovolumetrically beating rat hearts were exposed to global ischaemia by perfusion at 15 mm Hg for 2 h, resulting in an end ischaemic coronary flow rate of 2.3 (SD 1.7)% of preischaemic value, and an unperfused myocardial volume of 71.8(4.3)% of total myocardial volume. Subsequent reperfusion at 80 mm Hg for 2 h produced a partial recovery of coronary flow rate of 41(6)% in the absence of doxazosin and a complete recovery [97(28)%] in the presence of doxazosin 2 mumol.litre-1. Surprisingly, doxazosin induced vasodilatation retarded the disappearance of "no reflow" during reperfusion: after 3 h of reperfusion the volume of unperfused myocardium was 14.3(5.5)% v 1.5(1.7)% in the control group (p less than 0.005). Assessed histologically the regions of "no-reflow" were localised predominantly in the subendocardium. In the presence of doxazosin, left ventricular end diastolic pressure during reperfusion was twice as high as in the control group, indicating pronounced subendocardial compression. The mechanism underlying prolonged subendocardial "no-reflow" in the presence of doxazosin during postischaemic reperfusion is a compressive action of dilated (sub)epicardial vessels on the vasculature in the unperfused subendocardial regions ("hydraulic" or "erectile" effect of increased vascular volume). Thus coronary vasodilatation induced by alpha 1 adrenergic receptor blockade during postischaemic reperfusion delays the recovery of homogeneous transmural perfusion distribution.

Diltiazem (0.5 mg/l) decreases coronary vascular resistance during reperfusion, but not during low flow ischemia, in the isolated perfused rat heart

Isolated rat hearts underwent low flow perfusion with a perfusion pressure of 15 mmHg for two hours followed by reperfusion at a perfusion pressure of 80 mmHg for two hours. In these severely damaged hearts we tested whether diltiazem (0.5 mg/l) administered during ischemia or during reperfusion had vasodilatory effects. Ischemia-induced progressive vasoconstriction was not influenced by the presence of diltiazem: during ischemia coronary vascular resistance (CVR) rose from 3.3 +/- 0.1 to 46.4 +/- 17.6 mmHg.ml-1.min in the diltiazem group and from 3.5 +/- 0.1 to 42.4 +/- 5.3 mmHg.ml-1.min in the control group (n.s.). If diltiazem was administered during reperfusion only CVR dropped from 45.7 +/- 9.2 to 4.4 +/- 1.1 mmHg.ml-1.min in the presence of diltiazem, and from 47.1 +/- 11.6 to 9.3 +/- 1.5 mmHg.ml-1.min in the control group (P less than 0.025). The disparity between diltiazem's effects during ischemia and reperfusion suggests a different mechanism of Ca2+-influx in vascular smooth muscle cells in ischemic and reperfused hearts: in reperfusion through the Ca2+-channels which are sensitive to calcium antagonists, and in ischemia through other channels, like the Na+/Ca2+ exchanger, or from intracellular calcium stores.

Reperfusion induced enzyme release: washout effect or manifestation of reperfusion damage?

Isolated isovolumically contracting rat hearts were subjected to ischaemia and subsequent reperfusion to determine whether reperfusion induced release of lactate dehydrogenase from the heart was due to washout of previously unperfused areas by reflow or a manifestation of myocardial damage occurring during reperfusion. Hearts were exposed to 2 h of ischaemia alone or to 2 h of ischaemia followed by reperfusion for at least 2 h. Below an ischaemic coronary flow rate of 40% of the preischaemic value drainage of enzymes liberated from irreversibly damaged myocytes was impaired owing to the presence of unperfused myocardium. The lactate dehydrogenase activity released during 2 h of ischaemia was maximally 60 U per heart and during 2 h of reperfusion maximally 251 U per heart (comprising together 89% of cardiac lactate dehydrogenase content). Lactate dehydrogenase activity released during reperfusion correlated with ischaemic coronary flow rate (r = -0.93). Reperfusion induced reflow of previously unperfused regions resulted in washout of liberated but trapped lactate dehydrogenase, predominantly responsible for lactate dehydrogenase release if ischaemia was severe (ischaemic flow rate below 40%). After the onset of reperfusion there was partial initial recovery of left ventricular developed pressure, with a gradual decline thereafter. In experiments in which ischaemia induced unperfused areas could be excluded--that is, at ischaemic flow rates of 40% or higher--reperfusion gave rise to lactate dehydrogenase release closely associated in time with the decline of left ventricular developed pressure. It is concluded that in this rat heart preparation reperfusion --takes place in previously underperfused (low flow) myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)