ALBERT

Description: Recent first principles calculations have predicted that boron arsenide (BAs) can possess an unexpectedly high thermal conductivity that depends sensitively on the crystal size and defect concentration. However, few experimental results have been obtained to verify these predictions. In the present work, we report four-probe thermal and thermoelectric transport measurements of an individual BAs microstructure that was synthesized via a vapor transport method. The measured thermal conductivity was found to decrease slightly with temperature in the range between 250 K and 350 K. The temperature dependence suggests that the extrinsic phonon scattering processes play an important role in addition to intrinsic phonon-phonon scattering. The room temperature value of (186 ± 46) W m −1  K −1 is higher than that of bulk silicon but still a factor of four lower than the calculated result for a defect-free, non-degenerate BAs rod with a similar diameter of 1.15  μ m. The measured p-type Seebeck coefficient and thermoelectric power factor are comparable to those of bismuth telluride, which is a commonly used thermoelectric material. The foregoing results also suggest that it is necessary to not only reduce defect and boundary scatterings but also to better understand and control the electron scattering of phonons in order to achieve the predicted ultrahigh intrinsic lattice thermal conductivity of BAs.

Description: Background: The near ubiquity and persistence of CD20 expression in B-cell malignancies provides a strong rationale for novel CD20-directed therapies. MT-3724 is a novel engineered toxin body comprised of an anti-CD20 single chain variable fragment genetically fused to Shiga-like toxin A subunit, which forces internalization of CD20-bound MT-3724, irreversibly inactivating ribosomes and triggering apoptosis. As MT-3724 competes with rituximab (RTX) for the same CD20 binding domain, undetectable or low (〈 500 ng/mL) RTX levels (RTX-neg) allow potential response to MT-3724. We present final safety and efficacy results from dose escalation to maximum tolerated dose (MTD) in Non-Hodgkin Lymphoma (NHL) subjects (subj) and dose expansion in RTX-neg DLBCL subj. Methods: In Part 1, MT-3724 dose was escalated in 21 subj with B-cell NHL according to the 3+3 design based on ≤1 subj exhibiting DLT during Cycle 1 (28 days) in 6 sequential dose cohorts (5, 10, 20, 50, 75, and 100 μg/kg/dose IV over 2 hours 3 times per week for 2 of 4 consecutive weeks) for up to 5 cycles. In Part 2, the safety and efficacy of MT-3724 was further evaluated in 6 RTX-neg subj with DLBCL. Tumor response was assessed by the International Working Group Response Criteria for Clinical Trials (Cheson 2007). Results: Twenty-seven subj with NHL (DLBCL:16, composite DLBCL/Follicular Lymphoma (FL): 3, FL: 6, Mantle Cell Lymphoma: 2 were enrolled. Seventeen (63%) were female, mean age was 65 yrs (34-78). Performance status was ECOG 0: 44%, 1: 44%, 2: 11%; median follow-up was 50 (11-372) days; median cycles 2 (1-11). The most common AEs (%) of all grades were peripheral edema (63), fatigue (41), diarrhea (41), myalgia (41), muscle weakness (33), insomnia (30); 27 subj had AEs (%) with related causality, the most common were: peripheral edema (41), myalgia (33), fatigue (26). The most common related grade (G) ³3 AEs included neutropenia, myalgia, and infections (all 11%); There were 9 related SAEs among 6 subj. One subj died on study from disease progression. MT-3724 was not tolerated at 100 µg/kg/dose (DLTs: G3 pneumonia, G2 ileus). After 2 obese (BMI 〉35) subj treated at 75 µg/kg/dose in the expansion cohort had G2 capillary leak syndrome (CLS), the MTD was set at 50 µg/kg/dose with a 6000 mg/dose cap. Innate immune responses such as CLS or manifestations thereof (hypotension, hypoalbuminemia, peripheral edema) were noted with increasing frequency with higher doses of MT-3724. No cases of 〉G2 CLS have been observed. Of the 13 RTX-neg DLBCL subj, 5 (38%) responded across the range of 5 to 50 μg/kg/dose. All responses were partial responses (PRs) including 1 subj with composite DLBCL/FL post autologous stem cell transplantation (SCT) who had a complete metabolic response of a large mesenteric mass and proceeded to allogeneic SCT. Three subj had stable disease (SD) including two with 49% and 47% tumor reductions, one of whom had FL transformed from DLBCL post autologous SCT; another 5 had progressive disease. Given a limited prescribed period of treatment with MT-3724, duration of response cannot be calculated, however, generally the tumor burden in responders decreased with repeat treatment. Among the responders, mean age was 61 (50-76) yrs, and the median number of prior lines of NHL therapy received was 3 (1-8). Subj with detectable baseline RTX levels did not benefit from MT-3724. Of all 20 subj measured, 6 developed anti-drug antibodies (ADAs) during the first cycle of therapy; 5 developed ADAs at a later timepoint; 6 did not develop ADAs. ADAs were observed in all subj who showed a response, and in 4 of 5 subj with SD. Increasing MT-3724 dose was associated with a dose-dependent peripheral B-cell depletion, evidenced by decreasing CD19+ cells. Conclusions MT-3724 is the first CD20 targeted immunotoxin to enter clinical trials. Safety events were mostly mild-moderate, and DLTs were in line with the mechanism of action of MT-3724. A tolerable dose and schedule have been identified: 50 μg/kg/dose up to a maximum of 6000 μg/dose infused over 1 hour on days 1, 3, 5, 8, 10, and 12 of a 21-day cycle. A 38% objective response rate has been observed with monotherapy in a heavily pretreated, RTX-neg DLBCL population; of these subj, 5 were treated at 50 ug/kg (MTD) and 3 of whom responded. The development of ADAs did not preclude benefit of MT-3724. An ongoing phase 2 monotherapy study to confirm efficacy and safety in RTX-neg subj with DLBCL (NCT02361346) is open for recruitment. Disclosures Musteata: Institute of Oncology: Employment; Arensia EM: Other: Principal Investigator. Park:BMS: Consultancy, Research Funding; Rafael Pharma: Membership on an entity's Board of Directors or advisory committees; G1 Therapeutics: Consultancy; Teva: Consultancy, Research Funding; Gilead: Speakers Bureau; Seattle Genetics: Research Funding, Speakers Bureau. Burnett:Molecular Templates, Inc.: Employment. Dabovic:Molecular Templates, Inc.: Employment. Williams:Molecular Templates, Inc.: Employment. Higgins:Molecular Templates, Inc.: Employment, Equity Ownership. Persky:Sandoz: Consultancy; Morphosys: Other: Member, Independent Data Monitoring Committee; Debiopharm: Other: Member, Independent Data Monitoring Committee; Bayer: Consultancy.