First-in-human phase I study of the microtubule inhibitor plocabulin in patients with advanced solid tumors

Background Plocabulin (PM060184) is a novel marine-derived microtubule inhibitor that acts as an antitumor agent. This first-in-human study evaluated dose-limiting toxicities (DLT) to define the maximum tolerated dose (MTD) and phase II recommended dose (RD) of plocabulin given as a 10-min infusion on Day (D) 1, D8 and D15 every four weeks. Patients and methods Forty-four patients with advanced solid tumors received plocabulin following an accelerated titration design. Results Plocabulin was escalated from 1.3 mg/m² to 14.5 mg/m², which was defined as the MTD. No RD was confirmed, because frequent dose delays and omissions resulted in low relative dose intensity (66%) at the 12.0 mg/m² expansion cohort. The main DLT was grade 3 peripheral sensory neuropathy (PSN); other DLTs were grade 4 tumor lysis syndrome, grade 4 cardiac failure and grade 3 myalgia. Toxicities were mainly mild to moderate, and included abdominal pain, myalgia, fatigue, nausea, and vomiting. Myelosuppression was transient and manageable. Plocabulin had a half-life of ~4 h and a wide diffusion to peripheral tissues. Antitumor response was observed in cervix carcinoma and heavily pretreated metastatic non-small cell lung cancer patients, and disease stabilization (≥3 months) in patients with colorectal, thymic, gastrointestinal stromal and breast tumors, among others. The clinical benefit rate was 33%. Conclusion The main DLT of plocabulin was PSN, as anticipated for a tubulin-binding agent. Since encouraging antitumor activity was observed, efforts to improve toxicity and to find the RD were planned in other trials evaluating D1&D8 and D1-D3 plus D15-D17 schedules.

CORALLEEN: A phase 2 clinical trial of chemotherapy or letrozole plus ribociclib as neoadjuvant treatment for postmenopausal patients with luminal B/HER2-negative breast cancer

TPS594

Background: Dysregulation of cyclin D-CDK4/6-Rb pathway is associated with endocrine resistance in hormone receptor–positive (HR+) breast cancer. Recently, a CDK4/6 inhibitor has shown unprecedented efficacy in metastatic disease, leading to its regulatory approval. Several others are currently in clinical development for the management of HR+ breast cancer in the early and advanced settings. However, it is vital to gain insights into the molecular and biological effects of this class of agents and could identify patients who can benefit the most, delaying or avoiding the use of chemotherapy.The neoadjuvant setting provides an ideal scenario to carry out these investigations. Hence, we propose to conduct an exploratory study to evaluate the biological effects and the efficacy of ribociclib in patients with primary luminal B tumors.We hypothesize that the combination of ribociclib plus letrozole may offer clinical benefit in the preoperative setting. Methods: This is a parallel, multicenter, two-arm, randomized exploratory study in postmenopausal women with primary operable HR+/HER2-negative Luminal B breast cancer designed to evaluate the clinical benefit of ribociclib plus letrozole. Eligibility includes stage I-III operable breast cancer, Luminal B by PAM50, ECOG 0-1. They will be randomized 1:1 to receive either six 28-days cycles of ribociclib (600mg; 3-weeks-on/1-week-off) plus daily letrozole (2.5mg) or chemotherapy: four cycles of AC (doxorubicin 60 mg/m2, cyclophosphamide 600 mg/m2 every 21 days) followed by weekly paclitaxel during 12 weeks. Baseline, Day 15 on-treatment, and surgical specimens will be collected for molecular characterization and evaluation of response (decrease in Ki67, change to ROR low disease) The primary endpoint is the rate of Residual Cancer Burden (RCB) per MD Anderson Cancer Center procedures. A rate of RCB 0 and 1 score at surgery, with a rank between 20% to 25% with 47 evaluable patients by group of treatment will offer a precision between 11.5% and 12.4%, respectively (95%CI). Ninety-four patients will be enrolled in 20 sites across Spain.

Abstract OT1-01-04: VENTANA (SOLTI-1501): Oral metronomic vinorelbine combined with endocrine therapy in luminal/HER2-negative early breast cancer: A window of opportunity trial

BACKGROUND

The CDK4/6 inhibitor palbociclib, in combination with endocrine therapy (ET), has been approved for patients (pts) with HR+/HER2- metastatic breast cancer (BC), suggesting that inhibition of the cell cycle in combination with ET is a strategy to keep exploring. In this context, vinorelbine (VNB) inhibits chromosome segregation during mitosis and blocks cells at G2/M. Interestingly, several metronomic schedules of VNB are being used in the clinical setting, a strategy that might not only affect cell-cycle but also aims to target tumor angiogenesis.

VENTANA is a “window-of-opportunity” trial designed to explore whether, similarly to CDK4/6 and mTOR inhibitors, oral metronomic VNB in combination with endocrine therapy induces a superior anti-proliferative effect than ET alone, as suggested by preclinical and clinical studies. We believe that a biological synergy of the combined treatment could open the door to include this treatment strategy in pts with BC as an alternative to CDK4/6 inhibitors.

METHODS

VENTANA is a phase 0 multicenter, three-arm, randomized clinical trial of oral metronomic VNB and letrozole (LET) versus either treatment alone in postmenopausal women with newly diagnosed, untreated HR+ and HER2-, stage I-III operable BC. Other eligibility criteria include primary tumor size ≥1 cm (cT1-3) and N0-1, ECOG PS 0-1 and evaluable diagnostic tumor sample. Pts are randomized (1:1:1) to receive LET 2.5mg daily, oral VNB 50mg 3 days a week, or LET 2.5mg daily and oral VNB 50mg 3 times a week. After 3 weeks of treatment, pts will undergo surgery, and both pre-treatment and post-treatment surgical samples will be analyzed for gene expression. Primary objective is to test if oral metronomic VNB and LET induce a superior anti-proliferative effect than either drug alone in pts with early BC defined as Luminal by PAM50. This will be evaluated by the expression of 11 proliferative genes contained in the PAM50 subtype predictor (BIRC5, CCNB1, CDC20, CDCA1, CEP55, KNTC2, MKI67, PTTG1, RRM2, TYMS and UBE2C) as surrogate signature biomarker of its anticancer activity.

VENTANA is a proof-of-concept study to describe the change in the expression of a proliferation-related gene signature in all 3 treatment arms. Changes in the proliferation signature will be determined by following formula: Mean suppression of proliferation signature score = 100 − [geometric mean (post treatment proliferation score / pre-treatment proliferation score · 100)]. By evaluating other BC-related gene signatures (560 genes), the antiangiogenic and immunogenic potential of the treatment arms will also be compared and genes regulated in a treatment-specific manner identified. All analyses will be performed within the different PAM50-defined subtypes (Luminal, Luminal A or Luminal B).

As the primary endpoint is continuous and there are no previous data to make assumptions about the degree of suppression of these genes, the sample size has not been determined by statistical calculations. A sample size of 20 pts per arm is considered appropriate to support our hypothesis. The targeted accrual of 60 pts will be enrolled in 10 sites across Spain (EudraCT Number 2015-004714-24).

Citation Format: Adamo B, Vidal M, Gomez Pardo P, Zaragoza K, Ciruelos E, Virizuela JA, Blanch Tormo S, Pérez-Fidalgo JA, Murillo L, Lopez-Gonzalez A, Amillano Parraga K, Martinez Jañez N, Gonzàlez Farré X, Prat A. VENTANA (SOLTI-1501): Oral metronomic vinorelbine combined with endocrine therapy in luminal/HER2-negative early breast cancer: A window of opportunity trial [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT1-01-04.

Abstract P4-21-05: Neoadjuvant non-pegylated liposomal doxorubicin plus paclitaxel, trastuzumab and pertuzumab in patients with HER2+ breast cancer – Final results of the SOLTI OPTI-HER HEART study

INTRODUCTION

Targeting HER2 by dual blockade with trastuzumab (T) and pertuzumab (P) in a taxane-based regimen is an active neoadjuvant treatment (NAT) of HER2+ early breast cancer (EBC). Addition of an anthracycline could further enhance this response, but potential cardiac toxicity is a concern. The Opti-HER HEART trial (NCT01669239) aims to optimize neoadjuvant treatment while minimizing cardiac risk, by combining T+P with a taxane and non-pegylated liposomal doxorubicin (NPLD).

MATERIAL AND METHODS

Phase II open-label, single-arm study of six 21-day cycles of NPLD (50mg/m2 D1), paclitaxel (80mg/m2 D1,8,15), T (4mg/kg C1D1, followed by 2mg/kg weekly), and P (840mg C1D1, followed by 420mg C2-6D1) as NAT for patients (pts) with stage II-IIIB HER2+ BC. Primary objective was to evaluate cardiac safety of the combination, measured by the incidence of type A (symptomatic congestive heart failure ) or type B [asymptomatic reduction of Left Ventricular Ejection Fraction (LVEF) value: ≥10% absolute decrease and LVEF<50%, LVEF<40% or any absolute decrease ≥20%] events, during NAT. Eighty-three pts were required to reject with 80% confidence the null hypothesis that the combination increases the incidence of cardiac events above the historical control of 18% (3% type A; 15% type B).

RESULTS

Between June 2013 and January 2015, 83 pts with HER2+ EBC (stage II 78%, stage III 22%) and adequate cardiac function (LVEF≥55%) were enrolled. Mean age was 50 years, N+ 47%, hormone receptor (HR) positive 71% and median baseline LVEF 66%. Eighty-five percent of pts completed 6 cycles of NAT, whereas 15% discontinued NAT due to toxicity. Adverse events (AEs) leading to dose adjustments/temporary interruptions and discontinuation of at least 1 drug occurred in 70% and 21% of pts, respectively. Primary objective was met with an incidence of cardiac events during NAT of 4% (95%CI 1-10, 3pts, all type B). Cardiac events until study completion (1 year) were 8% (all type B). All (but 2 cases with no follow-up data) were reversible and only 1 pt presented an asymptomatic LVEF<40%. Neutropenia (45%) was the most frequent hematological toxicity (G3/4 34%; febrile neutropenia 6%), less frequent in the 71% of pts that received primary G-CSF prophylaxis (G3/4 25% vs. 67%). Common non-hematological toxicities were diarrhea (74%; G3 7%), asthenia (78%; G3 11%) and neurotoxicity (52%; G3/4 10%). Pathological complete response (pCR) in breast+axilla (ypT0/is ypN0) was 60% (87% in HR-) and 69% in breast (91% in HR-).

 TOTALHR-HR+% ypT0/is (95% CI)69 (58-79)91 (72-99)61 (47-74)% ypT0/is ypN0 (95% CI)60 (46-71)87 (66-97)50 (36-64)

CONCLUSIONS

The neoadjuvant combination of T+P, paclitaxel and NPLD does not increase the risk for cardiac events in HER2+ BC pts. Since cardiac toxicities may present later, long-term cardiac monitoring is essential. Efficacy in terms of pCR was remarkable, being higher to historical values of combinations with dual anti-HER2 blockade and one of the highest reported among HR-HER2+ BC. This regimen administered with primary G-CSF prophylaxis and cardiac function monitoring may be an effective and secure option for early and locally advanced HER2+ pts with good cardiac function.

Citation Format: Gavilá J, Perez-Garcia J, Calvo I, Ciruelos E, Muñoz M, Virizuela JA, Ruiz I, Andrés R, Morales S, Perelló A, Sánchez P, Garcia-Saenz JA, Quero Guillen JC, González-Santiago S, Garau Llinas I, González-Martín A, Cantos Sánchez de Ibargüen B, Zaragoza K, de la Peña L, Llombart-Cussac A, Oliveira M. Neoadjuvant non-pegylated liposomal doxorubicin plus paclitaxel, trastuzumab and pertuzumab in patients with HER2+ breast cancer – Final results of the SOLTI OPTI-HER HEART study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-21-05.

Drosophila melanogaster linker histone dH1 is required for transposon silencing and to preserve genome integrity

Histone H1 is an intrinsic component of chromatin, whose important contribution to chromatin structure is well-established in vitro. Little is known, however, about its functional roles in vivo. Here, we have addressed this question in Drosophila, a model system offering many advantages since it contains a single dH1 variant. For this purpose, RNAi was used to efficiently deplete dH1 in flies. Expression-profiling shows that dH1 depletion affects expression of a relatively small number of genes in a regional manner. Furthermore, depletion up-regulates inactive genes, preferentially those located in heterochromatin, while active euchromatic genes are down-regulated, suggesting that the contribution of dH1 to transcription regulation is mainly structural, organizing chromatin for proper gene-expression regulation. Up-regulated genes are remarkably enriched in transposons. In particular, R1/R2 retrotransposons, which specifically integrate in the rDNA locus, are strongly up-regulated. Actually, depletion increases expression of transposon-inserted rDNA copies, resulting in synthesis of aberrant rRNAs and enlarged nucleolus. Concomitantly, dH1-depleted cells accumulate extra-chromosomal rDNA, show increased γH2Av content, stop proliferation and activate apoptosis, indicating that depletion causes genome instability and affects proliferation. Finally, the contributions to maintenance of genome integrity and cell proliferation appear conserved in human hH1s, as their expression rescues proliferation of dH1-depleted cells.

Impact of the introduction of rapid HIV testing in the Voluntary Counselling and Testing sites network of Catalonia, Spain

Summary

Rapid HIV antibody tests, which provide results within 15–60 minutes, can help reduce the number of unrecognized infections by improving access to testing facilities and increase the number of people tested who know their results. After an acceptability study, rapid HIV testing was first implemented in Catalonia in 2007 within the community-based Voluntary Counselling and Testing sites network. One year after implementation, an increase of 102.9% has been observed in the number of tests performed, ranging from 8.4% to 328.3% according to the site. Despite the important immediate impact of rapid HIV testing on the number of tests performed, there was no significant change in the proportion of tests that were positive. Rapid HIV testing can help increase access to testing, but it should be complemented with specific outreach programmes targeting the most vulnerable subgroups.

C/EBPbetaDeltauORF mice--a genetic model for uORF-mediated translational control in mammals

Upstream ORFs (uORFs) are translational control elements found predominantly in transcripts of key regulatory genes. No mammalian genetic model exists to experimentally validate the physiological relevance of uORF-regulated translation initiation. We report that mice deficient for the CCAAT/enhancer-binding protein beta (C/EBPbeta) uORF initiation codon fail to initiate translation of the autoantagonistic LIP (liver inhibitory protein) C/EBPbeta isoform. C/EBPbeta(DeltauORF) mice show hyperactivation of acute-phase response genes, persistent repression of E2F-regulated genes, delayed and blunted S-phase entry of hepatocytes after partial hepatectomy, and impaired osteoclast differentiation. These data and the widespread prevalence of uORFs in mammalian transcriptomes suggest a comprehensive role of uORF-regulated translation in (patho)physiology.

Sexual risk behaviour and its determinants among men who have sex with men in Catalonia, Spain

To evaluate the prevalence of sexual risk behaviours among men who have sex with men (MSM) in Catalonia and to identify sociodemographic, psychosocial, and behavioural factors associated with unprotected anal intercourse (UAI) with casual partners a convenience sample of 850 MSM was recruited in 2006. An anonymous questionnaire was used to explore risk behaviours during the previous 12 months. Logistic regression models were used to examine the variables associated with UAI. Mean age was 41 years and 20.4% were immigrants. Among those with casual partners (91.7% of all respondents), 31.4% had UAI. The multivariate analysis revealed that the likelihood of UAI was higher in men who were HIV-positive (OR: 1.77), used more than four drugs before sex (OR: 4.90 for +6), were not from Spain (OR: 2.10 for Latin American; OR: 1.86 for other immigrants), had more than 20 sexual partners (OR: 1.56), met casual sex partners on the Internet (OR:1.45) and presented a high level of internalised homophobia (OR: 2.40). HIV/STI prevention programmes for MSM in Catalonia should incorporate activities that strengthen self-esteem, take into account the impact of internalised homophobia, and adapt to the sociocultural reality of immigrants. Furthermore, these programmes should also address substance abuse and alert HIV-positive men about the risk of HIV re-infection and transmission of other STI.

Role for histone deacetylase 1 in human tumor cell proliferation

Posttranslational modifications of core histones are central to the regulation of gene expression. Histone deacetylases (HDACs) repress transcription by deacetylating histones, and class I HDACs have a crucial role in mouse, Xenopus laevis, zebra fish, and Caenorhabditis elegans development. The role of individual class I HDACs in tumor cell proliferation was investigated using RNA interference-mediated protein knockdown. We show here that in the absence of HDAC1 cells can arrest either at the G(1) phase of the cell cycle or at the G(2)/M transition, resulting in the loss of mitotic cells, cell growth inhibition, and an increase in the percentage of apoptotic cells. On the contrary, HDAC2 knockdown showed no effect on cell proliferation unless we concurrently knocked down HDAC1. Using gene expression profiling analysis, we found that inactivation of HDAC1 affected the transcription of specific target genes involved in proliferation and apoptosis. Furthermore, HDAC2 downregulation did not cause significant changes compared to control cells, while inactivation of HDAC1, HDAC1 plus HDAC2, or HDAC3 resulted in more distinct clusters. Loss of these HDACs might impair cell cycle progression by affecting not only the transcription of specific target genes but also other biological processes. Our data support the idea that a drug targeting specific HDACs could be highly beneficial in the treatment of cancer.

A novel and essential mechanism determining specificity and activity of protein phosphatase 2A (PP2A) in vivo

Protein phosphatase 2A (PP2A) is an essential intracellular serine/threonine phosphatase containing a catalytic subunit that possesses the potential to dephosphorylate promiscuously tyrosine-phosphorylated substrates in vitro. How PP2A acquires its intracellular specificity and activity for serine/threonine-phosphorylated substrates is unknown. Here we report a novel and phylogenetically conserved mechanism to generate active phospho-serine/threonine-specific PP2A in vivo. Phosphotyrosyl phosphatase activator (PTPA), a protein of so far unknown intracellular function, is required for the biogenesis of active and specific PP2A. Deletion of the yeast PTPA homologs generated a PP2A catalytic subunit with a conformation different from the wild-type enzyme, as indicated by its altered substrate specificity, reduced protein stability, and metal dependence. Complementation and RNA-interference experiments showed that PTPA fulfills an essential function conserved from yeast to man.