Is short-course radiotherapy and total neoadjuvant therapy the new standard of care in locally advanced rectal cancer? A sensitivity analysis of the RAPIDO clinical trial

BACKGROUND

The results of the RAPIDO trial have been accepted as evidence in favour of short-course radiotherapy (SC-RT) followed by chemotherapy before total mesorectal excision in high-risk locally advanced rectal cancer. A noteworthy concern is that the RAPIDO trial did not ensure that all patients in the control arm received adjuvant chemotherapy. This may bias statistical estimates in favour of the experimental arm if adjuvant chemotherapy is active in rectal cancer. Moreover, the 5-year update revealed an increase in the risk of local relapse in the experimental arm.

MATERIALS AND METHODS

We carried out sensitivity analyses to determine how plausible effects of adjuvant chemotherapy, adjusted by the proportion of patients in the standard arm receiving adjuvant treatment, would have influenced the observed treatment effect estimate of the RAPIDO trial. The most plausible values for the benefit of adjuvant chemotherapy were determined by Bayesian re-analysis of a prior meta-analysis.

RESULTS

The meta-analysis suggested that oxaliplatin/fluorouracil-based adjuvant chemotherapy may improve disease-free survival (DFS) in rectal cancer although the signal is weak [hazard ratio (HR) 0.84, 95% credible interval, 0.57-1.15]; probability of benefit (HR <1) was 91.2%. In the sensitivity analysis, the HR for disease-related treatment failure would remain <1, thus favouring total neoadjuvant therapy (TNT), on most occasions, but the null hypothesis would not have been rejected in various credible settings. For the RAPIDO data to be consistent with the null effect, a moderate benefit of adjuvant chemotherapy (HR for DFS between 0.75 and 0.80) and 70%-80% of exposed participants would suffice.

CONCLUSION

The decision to make adjuvant chemotherapy optional in the standard arm may have biased the results in favour of the experimental arm, in a scenario in which TNT does not offset the increase in local recurrences after SC-RT.

Outcomes of patients with metastatic clear-cell renal cell carcinoma treated with second-line VEGFR-TKI after first-line immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) are being increasingly utilised in the front-line (1L) setting of metastatic clear-cell renal cell carcinoma (mccRCC). Limited data exist on responses and survival on second-line (2L) vascular endothelial growth factor-receptor tyrosine kinase inhibitor (VEGFR-TKI) therapy after 1L ICI therapy.

PATIENTS AND METHODS

This is a retrospective study of mccRCC patients treated with 2L VEGFR-TKI after progressive disease (PD) with 1L ICI. Patients were treated at MD Anderson Cancer Center or Memorial Sloan Kettering Cancer Center between December 2015 and February 2018. Objective response was assessed by blinded radiologists' review using Response Evaluation Criteria in Solid Tumours v1.1. Descriptive statistics and Kaplan-Meier method were used.

RESULTS

Seventy patients were included in the analysis. Median age at mccRCC diagnosis was 59 years; 8 patients (11%) had international metastatic database consortium favourable-risk disease, 48 (69%) had intermediate-risk disease and 14 (20%) had poor-risk disease. As 1L therapy, 12 patients (17%) received anti-programmed death ligand-1 (PD-(L)1) monotherapy with nivolumab or atezolizumab, 33 (47%) received nivolumab plus ipilimumab and 25 (36%) received combination anti-PD-(L)1 plus bevacizumab. 2L TKI therapies included pazopanib, sunitinib, axitinib and cabozantinib. On 2L TKI therapy, one patient (1.5%) achieved a complete response, 27 patients (39.7%) a partial response and 36 patients (52.9%) stable disease. Median progression-free survival (mPFS) was 13.2 months (95% confidence interval: 10.1, NA). Forty-five percent of subjects required a dose reduction, and twenty-seven percent of patients discontinued treatment because of toxicity.

CONCLUSIONS

In this retrospective study of patients with mccRCC receiving 2L TKI monotherapy after 1L ICI, we observed 2L antitumour activity and tolerance comparable to historical data for 1L TKI.

Inhibition of Rho-associated coiled-coil-forming kinase increases efficacy of measles virotherapy

RhoA and its downstream effector Rho-associated coiled-coil-forming kinase (ROCK) are known regulators of the formation of actin cytoskeleton in cells. Actin cytoskeleton is involved in paramyxovirus infection; we, therefore, examined the effect of ROCK inhibition on measles virus (MV) cytopathic effect and replication. Treatment with the ROCK inhibitor, Y27632, significantly increased syncytia size in tumor cell lines following MV infection, associated with cytoskeleton disruption as demonstrated by actin staining. Treatment of prostate cancer, breast cancer and glioblastoma tumor cell lines with Y27632 following MV infection resulted in increased cytopathic effect, as assessed by trypan blue exclusion assays. In addition, there was a significant increase in viral proliferation by at least one log or more as tested in one-step viral growth curves. Increased viral replication was also observed in athymic nude mice bearing MDA-MB-231 xenografts following combination treatment with MV and Y27632. In summary, inhibition of the ROCK kinase by Y27632 enhanced the oncolytic effect of MV and viral proliferation; this approach merits further translational investigation.

Attenuated oncolytic measles virus strains as cancer therapeutics

Attenuated measles virus vaccine strains have emerged as a promising oncolytic vector platform, having shown significant anti-tumor activity against a broad range of malignant neoplasms. Measles virus strains derived from the attenuated Edmonston-B (MV-Edm) vaccine lineage have been shown to selectively infect, replicate in and lyse cancer cells while causing minimal cytopathic effect on normal tissues. This review summarizes the preclinical data that led to the rapid clinical translation of oncolytic measles vaccine strains and provides an overview of early clinical data using this oncolytic platform. Furthermore, novel approaches currently under development to further enhance the oncolytic efficacy of MV-Edm strains, including strategies to circumvent immunity or modulate immune system responses, combinatorial approaches with standard treatment modalities, virus retargeting as well as strategies for in vivo monitoring of viral replication are discussed.

KISS1/KISS1R expression in eutopic and ectopic endometrium of women suffering from endometriosis

BACKGROUND

The KISS1/KISS1R system has been implicated in the physiology of reproduction and many studies have documented the stimulatory effect of kisspeptin on Gonadotropin-releasing Hormone (GnRH) and gonadotropin secretion. In addition, the KISS1/KISS1R system has been implicated in several pathophysiological processes, including cancer.

MATERIALS AND METHODS

We examined the pattern of KISS1 and KISS1R expression in eutopic and ectopic endometrium tissues which were obtained from 24 women suffering from endometriosis and 16 control women who underwent laparoscopic excision for other benign gynecological diseases.

RESULTS

Significant KISS1R expression was detected in 10 out of the 24 samples of eutopic endometrial biopsies of women suffering from endometriosis, while their matched biopsies of ectopic endometrial lesions did not reveal any KISS1R expression. KISS1R expression was not detected in the endometrial biopsies of control women. In addition, KISS1 expression was not detected in practically any the endometrial tissues of either control women or women with endometriosis.

CONCLUSION

The expression of KISS1R in 10/24 samples of human endometrial biopsies of women suffering from endometriosis and the loss of its expression in the samples of matched ectopic endometrial tissues, suggests that the KISS1/KISS1R system may play a role in the pathophysiology of endometriosis only for a particular group of patients. Since KISS1 is not expressed by the endometrium and endometriotic tissue, it is conceivable that the activation of KISS1R in this particular group is mediated by KISS1 expression by non-endometrial tissues (endocrine action).

The role of kisspeptin/GPR54 in the reproductive system

The Kiss-1 gene encodes a secreted protein that is proteolytically cleaved to produce a number of structurally related peptides, with high interspecies conservation, globally termed kisspeptins. The original niche for the role of kisspeptin in human physiology is derived from cancer biology, with the loss of Kiss-1 expression being associated with poor prognosis in several malignancies. However, kisspeptin has recently emerged as a fundamental player in the field of reproductive biology. Genetic analysis of large consanguineous pedigrees by two independent groups led to the association of inactivating mutations of GPR54, the receptor which mediates kisspeptin action, with idiopathic hypogonadotropic hypogonadism. In the present paper the most salient aspects of the multifaceted role of kisspeptin in the reproductive system are reviewed, including the association of kisspeptin with the gonadal steroid feedback loop and the triggering of puberty onset.

Evaluation of Sperm Chromatin Quality and Screening of Y Chromosome Microdeletions in Greek Males with Severe Oligozoospermia

Normal (n = 20) and abnormal (n = 21) semen samples were explored for possible relationships between conventional semen parameters, chromatin status, and microdeletions in the Y chromosome. DNA fragmentation was detected by the terminal deoxynucleotidyl trasferase-mediated dUTP-nick end labelling (TUNEL) assay, chromatin condensation, and DNA packaging quality were assessed by chromomycin A3 (CMA(3)) staining. All men were investigated for Y chromosome microdeletions using polymerase chain reaction (PCR). No deletions were detected in 21 severely oligozoospermic men for the three screened regions (AZFa, AZFb, and AZFc). Men with normal semen parameters showed better chromatin condensation. Spermatozoa with low motility were more likely to contain loosely packaged chromatin. In the abnormal semen group, DNA fragmentation (TUNEL) correlated significantly with sperm motility, concentration, and chromatin packaging assessed by chromomycin A3. However sperm morphology did not correlate significantly with TUNEL and CMA(3) staining.

Crossover analysis using immunofluorescent detection of MLH1 foci in frozen–thawed testicular tissue

To date, the effects of freezing on spermatogenesis have not yet been fully investigated at a molecular level. Antibody localization studies have identified the MutL homolog 1 (MLH1) protein, a mis-match repair protein, at the prophase I stage of meiosis, which allows the detection of recombination foci during pachytene. This study investigated the effect of long-term testicular tissue cryopreservation on meiotic prophase I, identified by recombination foci frequency and synaptonemal complex (SC) integrity. Frozen-thawed testicular tissues from 12 males who had each fathered a child were used. Because vasectomy or reverse vasectomy procedures are rare in the locale of the investigation, it was not possible to obtain fresh testicular tissue and use the males as their own controls. Immunocytogenetic analysis of 612 spermatocytes at the pachytene stage was performed. The results indicated a mean number of MLH1 foci of 49.2 (SD +/- 5.9), and no correlation was found between the freezing period, the MLH1 frequency and the SC integrity. The results suggest that freezing of testicular tissue taken post-puberty does not appear to be detrimental to the crossover process as identified by occurrence of MLH1 loci.

Evaluation of gram stain as an alternative in the assessment of human spermatozoa quality

INTRODUCTION

During spermiogenesis, protaminosis and sperm chromatin condensation are important prerequisites for the preservation of DNA integrity in spermatozoa. The aim of this study is to assess Gram stain as an alternative technique for the evaluation of human sperm chromatin condensation status.

PATIENTS AND METHODS

Aniline blue and Gram staining were applied to semen samples from 34 donors in order to determine the relationship between sperm chromatin condensation and infertility. In addition, the possible correlation between morphology and vitality (eosin-Y staining) of spermatozoa compared with their nuclear status (aniline blue and Gram staining) was studied.

RESULTS

Chromatin condensation and sperm vitality were significantly higher in fertile men compared to the subfertile. A significant correlation was found between chromatin condensation and (a) sperm vitality (p < 0.01), and (b) nuclear protein status (p < 0.01).

CONCLUSIONS

Gram staining may be used as a routine method in assisted reproduction laboratories and could assist in the evaluation of sperm quality as well as in the selection of the appropriate fertilization technique.

Extracellular calcium sensing receptor: an overview of physiology, pathophysiology and clinical perspectives

The identification and cloning of the extracellular calcium sensing receptor (CaR) has provided a new conceptual framework in which we can better understand the interactions between extracellular calcium and the many cell types which express the CaR. The role of the CaR in regulating extracellular calcium ion homeostasis has been well established, as has its role in genetically determined disorders such as Familial Hypocalciuric Hypercalcaemia (FHH). This recently acquired knowledge has incited the discovery of new compounds which function as positive allosteric modulators of the CaR (named calcimimetics) and which are under clinical investigation for potential use in primary and secondary hyperparathyroidism. Research into the properties of the CaR produced an overwhelming influx of data but key questions have remained unanswered. We summarize the currently available information about the function of the CaR, underlining the significant progress which has been made in deciphering its role in pathological disorders and in drug development.