Abstract PD2-03: Final results of a first-in-human phase I study of the tamoxifen (TAM) metabolite, Z-Endoxifen hydrochloride (Z-Endx) in women with aromatase inhibitor (AI) refractory metastatic breast cancer (MBC) (NCT01327781)

Background: AI's are more effective than TAM in ER+ breast cancer. In AI refractory MBC, the response rate to TAM is 0% (Osborne 2011). Z-Endx is an active metabolite of TAM and among TAM treated women in the adjuvant and metastatic settings, reduced CYP2D6 metabolism and low Endx concentrations (Css <20 nM) have been associated with increased likelihood of disease recurrence. Preclinical studies have demonstrated greater Z-Endx exposure and anti-tumor activity with oral Z-Endx compared to equivalent doses of oral TAM (Reid 2014)

Methods: We conducted a phase I trial to determine the maximum-tolerated dose (MTD) and evaluate the toxicities, clinical activity, and pharmacokinetics (PK) of Z-Endx in patients (pts) with ER+, AI refractory MBC. Unlimited prior endocrine regimens were allowed. An accelerated titration schedule was applied (2 pts/dose level) until moderate toxicity or DLT, followed by a 3+3 design and then to expansion cohorts (40, 80, and 100 mg/day). Z-Endx was administered orally once daily (28 day cycle). Eye exams were performed at baseline, and end of cycles 2 and 6. PK was performed during cycle 1 and prior to subsequent cycles. For pts in the expansion cohorts, tumor biopsies were obtained at baseline for DNA sequencing (Foundation Medicine). Plasma cholesterol levels were obtained at baseline and after 1 cycle.

Results: From March 2011 to Dec 2014, 41 pts (38 evaluable), median age 60, received Z-Endx once daily encompassing 7 dose levels (20-160 mg/daily). The median number of prior hormonal regimens was 2 and 3 for the dose escalation and expansion cohorts, respectively. Dose escalation was stopped at 160 mg/day given MTD not reached and attainment of mean Endx Css of 3.6 uM. Cycle 1 DLT (PE) was observed in one patient (60 mg). No eye toxicity was observed. PK demonstrated mean Endx Css of > 1 uM at all dose levels ≥ 40 mg/day. Antitumor activity was observed at multiple dose levels including 3 confirmed partial responses and an additional 7 with stable disease for ≥6 cycles. Of these 10 pts, 9 had prior progression on both AI and fulvestrant and 3 additionally on TAM. After 1 cycle, total and LDL cholesterol decreased > 20 points in 54% and 40% of pts, respectively. Tumor sequencing in the expansion cohorts (n=14) did not identify ESR1 mutations; however, ESR1 amplification was identified in 1 pt with prolonged stable disease (>200 days). Of 6 pts with rapid progression (≤2 cycles), 4/6 had either CCND1 amplification (n=1) or at least one of the following activating mutations: ERBB2 L755S (n=1), AKT1 E17K (n=1), MTOR E1799K (n=1).

Conclusions: The direct administration of Z-END provides substantial drug exposure, acceptable toxicity, and "proof of principle" antitumor activity in endocrine resistant MBC. While the MTD was not determined, the goal of achieving Endx Css concentrations of > 1 uM was achieved. Tumor sequencing identified pts with predicted and confirmed endocrine resistance. A randomized phase II comparing endoxifen (80 mg/day) with TAM in AI refractory MBC was recently activated (NCT02311933). Supported in part by CA 133049, CA186686, CA15083, CA116201, and CA15083.

Citation Format: Goetz MP, Suman VJ, Reid JM, Northfelt DW, Mahr MA, Dockter T, Kuffel M, Buhrow SA, Safgren SL, McGovern RM, Collins JM, Streicher H, Hawse JR, Haddad TC, Erlichman C, Ames MM, Ingle JN. Final results of a first-in-human phase I study of the tamoxifen (TAM) metabolite, Z-Endoxifen hydrochloride (Z-Endx) in women with aromatase inhibitor (AI) refractory metastatic breast cancer (MBC) (NCT01327781). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD2-03.

[Causes and calculated predictors of a Duchenne gait in adolescents and young adults with cerebral palsy]

BACKGROUND

Adolescents with cerebral palsy often complain about a Duchenne gait, which increases the load on the spine, the energy consumption and therefore decreases gait efficiency. However the underlying causes of a Duchenne gait in patients with CP are not clearly researched yet. Nevertheless there is an assumption that excessive trunk lean might assist foot clearance to compensate for muscle weakness or contractures of the legs. In particular weakness, secondary to surgical soft tissue muscle tendon lengthening in childhood, might predispose patients to greater compensatory movements of the trunk. Therefore the aim of this study was to estimate the prevalence, underlying causes and calculated predictors for a Duchenne gait on CP patients with and without previous muscle tendon lengthening.

PATIENTS, MATERIALS AND METHODS

50 CP patients between 12 and 22 years with diplegia and GMFCS II (GMFCS: Gross Motor Function Classification System) participated in this study. 25 patients had no previous surgeries (CP-0). 25 patients had previous calf, hamstrings and/or adductor muscle tendon lengthening surgeries (CP-1). Data of 20 typically developed adolescents served as controls (TD). Gait was analysed using an instrumented gait analysis system (Vicon, Oxford, UK) The parameter "thorax obliquity range" (TOR) investigated the dimension of Duchenne gait.

RESULTS

CP-0 showed a prevalence of 72 %, CP-1 of 66 % for Duchenne gait. TOR was 5 ± 2°, 16 ± 8° and 16 ± 8°, for TD, CP-0 and CP-1, respectively. CP-0 and CP-1 showed significant differences in TOR between TD (both p < 0.001), but not between CP-0 and CP-1 (p = 1.0). Passive hip abduction range of motion (ROM) showed no significant correlation to TOR in both groups, whereas hip abduction muscle strength revealed significant correlation (rs = - 0.37) in CP-0. Best gait predictors in CP-0 patients were increased hip generation work (stance = st) and ankle dorsi flexion (swing = sw), together explaining 47 % of the variance in TOR. In CP-1 best gait predictors were increased hip generation work (st) as well as reduced knee flexion (sw) and ankle generation work (st), explaining 31 % of the variance in TOR.

CONCLUSION

With a prevalence of 66 % or higher Duchenne gait is a serious gait pathology in CP. Neither the hypothesis that previous muscle tendon lengthening nor that hip adductor contractures increase Duchenne gait could be confirmed in this study. Weak hip abductor muscle strength only showed a small correlation in CP-0. Best predictor in both groups was hip generation work (st). Certain hip abductors (M. gluteus medius ventral; M. gluteus minimus; M. tensor fasciae latae) function also as hip flexors and internal rotators. This leads to the hypothesis that during stance the Duchenne gait unloads the hip abductor muscles and therefore decreases the effect of internal rotation and hip flexion which leads to improved dynamic power of the hip for propulsion. In consequence the resultant hip extension moment increases by reducing the hip flexion moment. Presumably this is due to the fact that patients with CP show a reduced selective muscle control. For CP patients the negative effects of the common pelvis drop and internal rotation of the hip during gait decrease.

Consensus guidelines for the conduct and reporting of clinical trials in systemic light-chain amyloidosis

This manuscript summarizes the recommendations that emerged from the first Roundtable on Clinical Research in Immunoglobulin Light-chain Amyloidosis (AL), a meeting sponsored by the Amyloidosis Foundation (Clarkston, MI, USA) to develop a consensus of experts on a modern framework for clinical trial design and drug development in AL. Recent diagnostic and technical advances in AL, and updated consensus guidelines for assessing hematologic and organ responses, enable us to define study populations, appropriate end points, and other criteria for all phases of clinical research. This manuscript provides a framework for the design and conduct of systematic collaborative clinical research in AL to encourage more rapid testing of therapies and to expedite new drug development and approval.

Synthesis and binding to plant lectins of sulfur-containing analogues of betaGal1,3 alphaGalNAc (T-antigen)

Analogues of the tumor-associated T-antigen (betaGal1,3 alphaGalNAc) containing 4,6-epidithio and 4,6-thietan modifications were synthesized from the alpha-allyl glycoside of betaGal alpha1,3GlcNAc via suitable thiocyanate derivatives. Binding to three leguminous lectins as model systems was investigated in an enzyme-linked lectin assay (ELLA) and IC50 values comparable to the corresponding natural disaccharides T-antigen, lactose and N-acetyllactosamine were found.

Structural features of the combining site region of Erythrina corallodendron lectin: role of tryptophan 135

The role of Trp 135 and Tyr 108 in the combining site of Erythrina corallodendron lectin (ECorL) was investigated by physicochemical characterization of mutants obtained by site-directed mutagenesis, hemagglutination-inhibition studies, and molecular modeling, including dynamics simulations. The findings demonstrate that Trp 135 in ECorL: (1) is required for the tight binding of Ca2+ and Mn2+ to the lectin because mutation of this residue into alanine results in loss of these ions upon dialysis and concomitant reversible inactivation of the mutant; (2) contributes to the high affinity of methyl alpha-N-dansylgalactosaminide (MealphaGalNDns) to the lectin; and (3) is solely responsible for the fluorescence energy transfer between the aromatic residues of the lectin and the dansyl group in the ECorL-MealphaGalNDns complex. Docking of MealphaGalNDns into the combining site of the lectin reveals that the dansyl moiety is parallel with the indole of Trp 135, as required for efficient fluorescence energy transfer, in one of the two possible conformations that this ligand assumes in the bound state. In the W135A mutant, which still binds MealphaGalNDns strongly, the dansyl group may partially insert itself into the place formerly occupied by Trp 135, a process that from dynamics simulations does not appear to be energetically favored unless the loop containing this residue assumes an open conformation. However, a small fraction of the W135A molecules must be able to bind MealphaGalNDns in order to explain the relatively high affinity, as compared to galactose, still remaining for this ligand. A model for the molecular events leading to inactivation of the W135A mutant upon demetallization is also presented in which the cis-trans isomerization of the Ala 88-Asp 89 peptide bond, observed in high-temperature dynamics simulations, appears not to be a required step.

Synthesis of soybean agglutinin in bacterial and mammalian cells

The cDNA of soybean agglutinin (SBA), a glycoprotein lectin, obtained from the mRNA of soybean seeds at mid-maturation, was cloned in a lambda gt 10 phage and subcloned in a pUC-8 plasmid. Probing with a fragment of the lectin gene [Vodkin, L. O., Rhodes, P. R. & Goldberg, R. B. (1983) Cell 34, 1023-1031] afforded a clone of 1012 nucleotides containing the complete coding region of 858 nucleotides for the precursor to soybean agglutinin. The deduced amino acid sequence contains the 253 residues of the mature lectin and an hydrophobic N-terminal signal peptide of 32 amino acids. Expression in Escherichia coli of the cDNA coding for the precursor to the lectin or for the mature lectin led to the accumulation of large quantities of inclusion bodies, from which mature SBA was isolated in small yield (up to 1 mg/l). It was identical with the native lectin in the hemagglutinating activity and carbohydrate specificity, N-terminal sequence and oligomeric structure, but, because it was not glycosylated, its subunit mass was lower by 2 kDa. Our findings show that pre-SBA is processed into the mature form in the bacteria, and that, contrary to what has been suggested [Nagai, K. & Yamaguchi, H. (1993) J. Biochem. (Tokyo) 113, 123-125], glycosylation is not essential for the folding of the lectin, nor for its subunit assembly into a biologically active tetramer. To obtain recombinant SBA in secreted form, the pre-SBA cDNA was subcloned in pTM1 vector and the construct inserted into vaccinia virus. When monkey BS-C-1 cells were infected by the virus, using a double expression protocol, recombinant lectin was secreted into the growth medium, from which it was isolated by immunoaffinity chromatography at a yield similar to that from the bacteria. Except for its lower hemagglutinating activity, the product was indistinguishable from native SBA in all properties tested. It was also susceptible to digestion by endo-beta-N-acetylglucosaminidase H or N-glycanase which caused a decrease of 2 kDa in its subunit mass and gave the same results on lectin blot analysis, indicating that it too is a glycoprotein with a single oligomannose unit.

The myrosinase-glucosinolate interaction mechanism studied using some synthetic competitive inhibitors

Using synthetic deoxy-glucotropaeolins (6d-GTL, 4d- GTL, 3d-GTL, 2d-GTL) as substrates, myrosinase activity was studied in comparison to that determined on native glucotropaeolin (GTL) isolated from ripe Lepidium sativum seeds. When the deoxy substrates were used, in addition to an overall strong reaction rate decline, a significant decrease in the reaction rate was observed in going from 6d- to 2d-GTL. This finding allows us to propose a mechanism of catalysis which appears to be similar in many respects to that established for beta-glucosidases. Finally, 2d-GTL was shown to be the first strong competitive inhibitor of myrosinase ever reported.

Human T-cell leukaemia virus

HTLV-I has a complex and finely regulated mechanism of replication, which can be used as a model to study both cellular and viral regulation pathways in T-cells. Understanding of the underlying mechanisms involved in the pleiotropic effects of HTLV-I in the host represents a real challenge. Immunological regulation likely plays a central role in HTLV-I induced neurological disease, uveitis, and perhaps arthritis, implicating the importance of host factors as well. Viral proteins, including tax and p12' might play a role in T-cell proliferation, but the event(s) that result in the late leukaemic phase are unknown. The lack of effective therapy against HTLV-I-induced leukaemia renders prevention of viral infection the best means to eliminate HTLV-I associated diseases. Elimination or reduction of breast feeding from seropositive mothers in Japan has already produced encouraging results. In developing countries, probably only a vaccine will prevent the spread of HTLV-I infection. The molecular epidemiology of HTLV and STLV will help understand not only the phylogeny of these viruses but also the migration of human populations in the past. Episodes of horizontal transmission in the past and probably the present, indicates that nonhuman primates are the natural reservoir of HTLVs. New related viruses will likely be discovered in monkeys (and humans) in the future.

Human retroviruses and their associated diseases. Biology, pathophysiology, and clinical consequences of human retroviral infection

The discovery of the group of human retroviruses and their associated diseases has had a profound impact on the way we think of viral-associated human diseases and their social, medical, economic, and even ethical aftereffects. This article discusses the biology, pathophysiology, and clinical consequences of human retroviral infection, with particular emphasis on the human immunodeficiency virus type 1, the causative agent of AIDS.

Transmission of human immunodeficiency virus from parents to only one dizygotic twin

The acquired immunodeficiency syndrome-related complex was identified in a mother and one of her nonidentical twins. Generalized lymphadenopathy was first noted in the infant at age 17 months, and that of the mother was incidentally discovered 6 months later. The father, who had had homosexual contacts before the conception of the twins, appeared to be in good health. No one in the family had constitutional symptoms or showed signs of opportunistic infection. Both parents and the patient had hypergammaglobulinemia, low T-helper-to-suppressor-cell ratio, and positive serum antibody to human immunodeficiency virus. Attempts to isolate the virus from all family members were unsuccessful. The twin brother was in good health with a normal immunologic profile and negative antibody to human immunodeficiency virus.

Human chromosome identification by differential staining: G goup (21-22-Y)

Arrighi and Hsu (1971) have described a method of differential staining of chromosomes based on the localization of repetitive DNA associated with heterochromatin. We have employed this method in an attempt to identify human chromosomes, especially the G group, Nos. 21 and 22 and the Y. Metaphases from a patient with 47,XY,21+ were examined. In addition to the Y chromosome, which shows dense staining in its long arm, three of the five G-group chromosomes show centromeric regions that stain much more densely than those of the other two. This indicates that it is possible to differentiate chromosome 21 from 22 and the Y. The possibility of identifying other chromosomes by similar differences is a likely one.