Chemotherapy improves distant control in localized high-grade soft tissue sarcoma of the extremity/trunk

Background

Soft tissue sarcomas (STS) are rare and heterogeneous tumors making chemotherapy use controversial. Our goal was to identify a subset of patients with primary STS that benefit with the addition of chemotherapy.

Methods

A retrospective chart review included intermediate to high-grade localized primary STS of the extremity/trunk, and tumor size > 5 cm. The effect of chemotherapy was evaluated for local control (LC), distant control (DC), progression free survival (PFS), and overall survival (OS).

Results

In this cohort (n = 273), patients were treated with surgery (98%), radiation (81%), and chemotherapy (24.5%). With a median follow-up of 51 months, the entire cohort’s 5-year LC, DC, PFS, and OS are 79.1%, 59.9%, 43.8%, and 68.7%, respectively. The addition of chemotherapy did not provide a DC benefit (p = 0.238) for the entire cohort. High-grade disease (n = 210) experienced a 5-year benefit in DC (68% vs. 54.4%, p = 0.04), which was more pronounced with MAI (Mesna, Adriamycin, Ifosfamide) based regimens (74.2%, p = 0.016), and a 5-year PFS (50.8% vs 45%, p = 0.025) and OS benefit (76.2% vs 70%, p = 0.067) vs. no chemotherapy. On multivariate analysis of the high-grade subset, chemotherapy independently predicted for a DC benefit (HR 0.48 95% CI 0.26–89, p = 0.019). The benefit of chemotherapy was more pronounced with MAI, showing a significant benefit in DC (HR 0.333 95% CI 0.145–0.767, p = 0.01) and PFS (HR 0.52 95% CI 0.28–0.99, p = 0.047).

Conclusion

In patients with localized STS > 5 cm, the high-grade subset had a distant control benefit with the addition of chemotherapy, leading to improved progression free survival. This is more pronounced with the use of MAI and should be considered in patients eligible for this regimen.

Overall responses with coordinated pembrolizumab and high dose IL-2 (5-in-a-row schedule) for therapy of metastatic clear cell renal cancer: A single center, single arm trial

657

Background: Ligation of IL-2 receptor or blockade of PD-1 receptor may change lymphocytes to induce regression of cancers with diverse histology or site of origin. Single agent objective response rates of 14-25% have been reported for IL-2 therapy of metastatic clear cell RCC (ccRCC). A response rate of 33% was observed in pembrolizumab treated ccRCC patients. Nivolumab treated ccRCC patients were observed to have early intratumoral migration of lymphocytes. A case report of IL-2 induced major regression right after no change on nivolumab therapy suggested that combining the two means of lymphocyte stimulation could be effective. Other trials combining IL-2 receptor agonists (NKTR-214) and PD-1 blockade have also reported regression of ccRCC. Distinctive attributes of high dose IL-2 therapy are the required inpatient stay and the durability of the complete responses. Methods: This single-institution, single arm study addresses the safety and feasibility of the combination of IL-2 and pembrolizumab in the treatment of metastatic ccRCC. Subjects are treated on four nine-week blocks, as follows: Pembrolizumab is given on weeks 1, 4, and 7 of each block. Patients are admitted for 5 doses of high dose IL-2 (given over ~ 33 hours/3 days) on weeks 2, 3, 5, and 6 of blocks 2 and 3. Safety is monitored by a Pocock boundary of .05 likelihood of 0.15 dose limiting toxicity rate. The Simon 2-stage alternative hypothesis for the sample size was a 45+% major response rate vs null hypothesis < 20%, at alpha = 0.10, 90% power. Results: No accrual stop for safety was triggered. Thirteen of the first 18 patients responded, substantially exceeding the requirement of 8+/24 combination-treated patients to reject the null. Seven patients responded after receiving pembrolizumab alone, six after starting combination therapy in block 2. Accrual is completed; at 27. Kaplan-Meier analysis projects ORR of 69%, with ORR 90%-lower confidence bound of 55%. Conclusions: The combination of high dose IL-2 and pembrolizumab is feasible, with a high response rate, justifying further exploration of this dual immune treatment of metastatic ccRCC. Clinical trial information: NCT02964078.

Surface plasmon resonance analysis of antifungal azoles binding to CYP3A4 with kinetic resolution of multiple binding orientations

The heme-containing cytochrome P450s (CYPs) are a major enzymatic determinant of drug clearance and drug-drug interactions. The CYP3A4 isoform is inhibited by antifungal imidazoles or triazoles, which form low-spin heme iron complexes via formation of a nitrogen-ferric iron coordinate bond. However, CYP3A4 also slowly oxidizes the antifungal itraconazole (ITZ) at a site that is approximately 25 A from the triazole nitrogens, suggesting that large antifungal azoles can adopt multiple orientations within the CYP3A4 active site. Here, we report a surface plasmon resonance (SPR) analysis with kinetic resolution of two binding modes of ITZ, and the related drug ketoconazole (KTZ). SPR reveals a very slow off-rate for one binding orientation. Multiphasic binding kinetics are observed, and one of the two binding components resolved by curve fitting exhibits "equilibrium overshoot". Preloading of CYP3A4 with the heme ligand imidazole abolishes this component of the antifungal azole binding trajectories, and it eliminates the conspicuously slow off-rate. The fractional populations of CYP3A4 complexes corresponding to different drug orientations can be manipulated by altering the duration of the pulse of drug exposure. UV-vis difference absorbance titrations yield low-spin spectra and K(D) values that are consistent with the high-affinity complex resolved by SPR. These results demonstrate that ITZ and KTZ bind in multiple orientations, including a catalytically productive mode and a slowly dissociating inhibitory mode. Most importantly, they provide the first example of a SPR-based method for the kinetic characterization of binding of a drug to any human CYP, including mechanistic insight not available from other methods.

Preclinical detection of Alzheimer's disease: hippocampal shape and volume predict dementia onset in the elderly

Structural deformity of the hippocampus is characteristic of individuals with very mild and mild forms of dementia of the Alzheimer type (DAT). The purpose of this study was to determine whether a similar deformity of the hippocampus can predict the onset of dementia in nondemented elders. Using high dimensional diffeomorphic transformations of a neuroanatomical template, hippocampal volumes and surfaces were defined in 49 nondemented elders; the hippocampal surface was subsequently partitioned into three zones (i.e., lateral, superior and inferior-medial), which were proximal to the underlying CA1 subfield, CA2-4 subfields plus dentate gyrus, and subiculum, respectively. Annual clinical assessments using the Clinical Dementia Rating scale (CDR), where CDR 0 indicates no dementia and CDR 0.5 indicates very mild dementia, were then performed for a mean of 4.9 years (range 0.9-7.1 years) to monitor subjects who converted from CDR 0 to CDR 0.5. Inward variation of the lateral zone and left hippocampal volume significantly predicted conversion to CDR 0.5 in separate Cox proportional hazards models. When hippocampal surface variation and volume were included in a single model, inward variation of the lateral zone of the left hippocampal surface was selected as the only significant predictor of conversion. The pattern of hippocampal surface deformation observed in nondemented subjects who later converted to CDR 0.5 was similar to the pattern of hippocampal surface deformation previously observed to discriminate subjects with very mild DAT and nondemented subjects. These results suggest that inward deformation of the left hippocampal surface in a zone corresponding to the CA1 subfield is an early predictor of the onset of DAT in nondemented elderly subjects.

Timing Noise in SGR 1806-20

We have phase-connected a sequence of Rossi X-Ray Timing Explorer Proportional Counter Array observations of SGR 1806-20 covering 178 days. We find that a simple secular spin-down model does not adequately fit the data. The period derivative varies gradually during the observations between 8.1x10-11 and 11.7x10-11 s s(-1) (at its highest, approximately 40% larger than the long-term trend), while the average burst rate as seen with the Burst and Transient Source Experiment drops throughout the time interval. The phase residuals give no compelling evidence for periodicity, but more closely resemble timing noise as seen in radio pulsars. The magnitude of the timing noise, however, is large relative to the noise level typically found in radio pulsars (Delta8=4.8; frequency derivative average power approximately 7x10-20 cycles(2) s(-3)). Combining these results with the noise levels measured for some anomalous X-ray pulsars, we find that all magnetar candidates have Delta(8) values larger than those expected from a simple extrapolation of the correlation found in radio pulsars. We find that the timing noise in SGR 1806-20 is greater than or equal to the levels found in some accreting systems (e.g., Vela X-1, 4U 1538-52, and 4U 1626-67), but the spin-down of SGR 1806-20 has thus far maintained coherence over 6 yr. Alternatively, an orbital model with a period Porb=733 days provides a statistically acceptable fit to the data. If the phase residuals are created by Doppler shifts from a gravitationally bound companion, then the allowed parameter space for the mass function (small) and orbital separation (large) rule out the possibility of accretion from the companion sufficient to power the persistent emission from the SGR.

A hydrophobic cluster forms early in the folding of dihydrofolate reductase

The rapid kinetic phase that leads from unfolded species to transient folding intermediates in dihydrofolate reductase from Escherichia coli was examined by site-directed mutagenesis and by physicochemical means. The absence of this fluorescence-detected phase in the refolding of the Trp-74Phe mutant protein strongly implies that this early phase in refolding can be assigned to just one of the five Trp residues in the protein, Trp-74. In addition, water-soluble fluorescence quenching agents, iodide and cesium, have a much less significant effect on this early step in refolding than on the slower phases that lead to native and native-like conformers. These and other data imply that an important early event in the folding of dihydrofolate reductase is the formation of a hydrophobic cluster which protects Trp-74 from solvent.