Prospective experimental treatment of colorectal cancer patients based on organoid drug responses.

BACKGROUND: Organoid technology has recently emerged as a powerful tool to assess drug sensitivity of individual patient tumors in vitro. Organoids may therefore represent a new avenue for precision medicine, as this circumvents many of the complexities associated with DNA- or transcriptional-profiling. MATERIALS AND METHODS: The SENSOR trial was a single-arm, single-center, prospective intervention trial to evaluate the feasibility of patient-derived organoids to allocate patients for treatment with off-label or investigational agents. The primary endpoint was an objective response rate of ≥20%. Patients underwent a biopsy for culture before commencing their last round standard of care. Organoids were exposed to a panel of eight drugs and patients were treated after progression on standard-of-care treatment and when a clear signal of antitumor activity was identified in vitro. RESULTS: Sixty-one patients were included and we generated 31 organoids of 54 eligible patients. Twenty-five cultures were subjected to drug screening and 19 organoids exhibited substantial responses to one or more drugs. Three patients underwent treatment with vistusertib and three with capivasertib. Despite drug sensitivity of organoids, patients did not demonstrate objective clinical responses to the recommended treatment. CONCLUSIONS: Organoid technology had limited value as a tool for precision medicine in this patient population because a large fraction of patients could not undergo treatment or because the recommended treatment did not elicit an objective response. We identified several essential parameters, such as the culture success rate, clinical deterioration of patients during standard of care, and rational design of drug panels that need to be accounted for in organoid-guided clinical studies.

The emerging roles of DOT1L in leukemia and normal development.

Methylation of lysines within histone proteins represents a posttranslational modification system that can have profound effects on gene expression. An evolutionarily conserved, but poorly understood, histone methylation mark occurs on lysine 79 on histone H3 (H3K79). The H3K79 methyltransferase, DOT1L, is involved in a number of key processes ranging from gene expression to DNA-damage response and cell cycle progression. Recently, DOT1L has also been implicated in the development of mixed lineage leukemia (MLL)-rearranged leukemia, where mistargeting of DOT1L causes aberrant H3K79 methylation at homeobox genes. As DOT1L is essential for leukemic transformation, small-molecule inhibitors of DOT1L function are an attractive therapeutic target for this type of leukemia. However, in order to develop safe treatments, it is necessary to also understand the biological functions of DOT1L. Here we review the various functions of DOT1L in normal mammalian development. Dot1L knockout is embryonic lethal in mice and is important for processes as diverse as proliferation of mouse embryonic stem cells, induced and natural reprogramming, cardiac development and chondrogenesis. Additionally, while an important role for DOT1L in embryonic hematopoiesis is clear, its role in postnatal hematopoiesis is less so. Establishing the precise function of DOT1L in normal adult hematopoiesis and understanding its mode of action will aid in our understanding of the use of DOT1L as a therapeutic target in MLL-rearranged leukemia.

Whole-genome sequencing of bladder cancers reveals somatic CDKN1A mutations and clinicopathological associations with mutation burden.

Bladder cancers are a leading cause of death from malignancy. Molecular markers might predict disease progression and behaviour more accurately than the available prognostic factors. Here we use whole-genome sequencing to identify somatic mutations and chromosomal changes in 14 bladder cancers of different grades and stages. As well as detecting the known bladder cancer driver mutations, we report the identification of recurrent protein-inactivating mutations in CDKN1A and FAT1. The former are not mutually exclusive with TP53 mutations or MDM2 amplification, showing that CDKN1A dysfunction is not simply an alternative mechanism for p53 pathway inactivation. We find strong positive associations between higher tumour stage/grade and greater clonal diversity, the number of somatic mutations and the burden of copy number changes. In principle, the identification of sub-clones with greater diversity and/or mutation burden within early-stage or low-grade tumours could identify lesions with a high risk of invasive progression.

Capecitabine combined with oxaliplatin (CapOx) in clinical practice: how significant is peripheral neuropathy?

BACKGROUND: There is speculation that peripheral neuropathy (PN) with capecitabine and oxaliplatin (CapOx; 130 mg/m(2), day 1, every 21 days) may be more common than with FOLFOX4 (5-fluorouracil and oxaliplatin 85 mg/m(2), day 1, every 14 days). We aimed to determine PN incidence and associations during CapOx, and 6 and 12 months after CapOx. PATIENTS AND METHODS: Retrospective audit of 188 oxaliplatin-naive colorectal cancer patients (87 adjuvant, 101 palliative) who received at least one cycle of CapOx. Neurosensory Common Toxicity Criteria Adverse Events version 3 were applied. RESULTS: Overall, 94% experienced acute PN. Worst severities for adjuvant and palliative patients, respectively, were grade 1, 44% and 54%; grade 2, 35% and 32%; grade 3, 16% and 3%; grade 4, 0% and 1% and grade unclear 1% and 1%. Two patients developed PN after CapOx completion despite no symptoms during treatment. Chronic PN at 6 months affected 57% and 18% of adjuvant and palliative patients, respectively. At 12 months, 35% and 16% were affected. Chronic PN at 12 months was associated with cumulative oxaliplatin dose but not age, gender, acute myotonia, pseudolaryngospasm or grade 2 or more PN during treatment. CONCLUSION: Incidence of acute PN during CapOx appears similar to FOLFOX4 but chronic PN in adjuvant patients may be more common with CapOx.