A comparison of the efficacy of trastuzumab deruxtecan in advanced HER2-positive breast cancer: active brain metastasis versus progressive extracranial disease alone

BACKGROUND

Trastuzumab deruxtecan (T-DXd) has demonstrated efficacy in patients with brain metastasis (BM), a group historically with poor outcomes. The prevalence of BMs in patients commencing T-DXd is currently unknown. No direct comparisons have been made of the activity of T-DXd in patients with active BM versus those with extracranial progression alone. This real-world study explored the prevalence of BMs in patients commencing T-DXd, the efficacy of T-DXd in active BM versus extracranial progression alone and the safety of T-DXd.

PATIENTS AND METHODS

Patients with human epidermal growth factor receptor 2-positive advanced breast cancer treated with T-DXd between June 2021 and February 2023 at our specialist cancer hospital were identified and notes reviewed. Clinicopathological information, prior treatment, the presence or absence of central nervous system (CNS) disease, outcomes and treatment-emergent adverse events (TEAEs) were recorded.

RESULTS

Twenty-nine female patients, with a median age of 52 years (interquartile range 44-62 years), were identified; the prevalence of BM was 41%. Median number of lines of prior therapy was 2 (range 2-6). At a median follow-up of 13.8 months, median progression-free survival (PFS) for the overall population was 13.9 months [95% confidence interval (CI) 12.4 months-not estimable (NE)], 16.1 months (95% CI 15.1 months-NE) for active BMs and 12.4 months (95% CI 8.3 months-NE) for progressive extracranial disease alone. The 12-month overall survival (OS) rate was 74% (95% CI 59% to 95%) in the overall population, and 83% (95% CI 58% to 100%) and 66% (95% CI 45% to 96%) for active BMs and extracranial disease only, respectively. Most common TEAEs were fatigue, alopecia, and constipation. In nine patients (31%, including two deaths), pneumonitis occurred.

CONCLUSION

In this real-world population, we demonstrate T-DXd to be effective in patients with active BMs and those with progressive extracranial disease alone. PFS and OS were numerically longer in those with active BMs. These data demonstrate that patients with active BM treated with T-DXd have at least comparable outcomes to those with extracranial disease alone. The high rate of pneumonitis warrants further consideration.

Sperm interaction with bacteria induces the spontaneous acrosome reaction

Bacterial contamination in the semen deteriorates spermatozoa function. One mechanism through which this may occur is by inducing a premature form of the acrosome reaction (spontaneous acrosome reaction (sAR)) which has been shown to abrogate fertilization. To understand the mechanism by which bacteria affect sperm functions, we determined the effects of bacteria on sperm sAR and on other parameters involved in sperm capacitation. Sperm cells undergo biochemical changes in the female reproductive tract collectively called capacitation. Only capacitated sperm can undergo the physiological acrosomal exocytosis process near or on the oocyte, which allows the spermatozoon to penetrate and fertilize the egg. Bovine sperm incubated with the bacteria Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) or Pseudomonas aeruginosa (P. aeruginosa), revealed a sperm-bacteria interaction, however only E. coli and P. aeruginosa caused an increase in sperm sAR. This effect was seen only when the bacteria were present with the sperm during the full incubation under capacitation conditions but not when the bacteria were added to capacitated sperm. These results indicate that bacteria affect sperm during capacitation and not at the AR step. In addition, Ca²⁺ influx, protein kinase A, and protein tyrosine phosphorylation activities, three essential processes that promote capacitation, were inhibited by the bacteria. Moreover, increasing intracellular cAMP, which also occur during sperm capacitation, caused significant reverse of sAR induced by the bacteria.

The state of bariatric dental care in Australia: a silent disability crisis?

In the absence of dental related guidelines available in Australia specific to obesity and minimal awareness of the clinical implications on local dental practice, bariatric dental care can be perceived as a 'silent disability crisis'. This opinion piece and brief clinical note aims to question and raise awareness amongst dental professionals surrounding the current limited availability of bariatric dental chairs, difficulties in access, the safety of dental care delivery and ethical considerations for the dental management of people with obesity.

Addition of docetaxel to hormonal therapy in low- and high-burden metastatic hormone sensitive prostate cancer: long-term survival results from the STAMPEDE trial

BACKGROUND

STAMPEDE has previously reported that the use of upfront docetaxel improved overall survival (OS) for metastatic hormone naïve prostate cancer patients starting long-term androgen deprivation therapy. We report on long-term outcomes stratified by metastatic burden for M1 patients.

METHODS

We randomly allocated patients in 2 : 1 ratio to standard-of-care (SOC; control group) or SOC + docetaxel. Metastatic disease burden was categorised using retrospectively-collected baseline staging scans where available. Analysis used Cox regression models, adjusted for stratification factors, with emphasis on restricted mean survival time where hazards were non-proportional.

RESULTS

Between 05 October 2005 and 31 March 2013, 1086 M1 patients were randomised to receive SOC (n = 724) or SOC + docetaxel (n = 362). Metastatic burden was assessable for 830/1086 (76%) patients; 362 (44%) had low and 468 (56%) high metastatic burden. Median follow-up was 78.2 months. There were 494 deaths on SOC (41% more than the previous report). There was good evidence of benefit of docetaxel over SOC on OS (HR = 0.81, 95% CI 0.69-0.95, P = 0.009) with no evidence of heterogeneity of docetaxel effect between metastatic burden sub-groups (interaction P = 0.827). Analysis of other outcomes found evidence of benefit for docetaxel over SOC in failure-free survival (HR = 0.66, 95% CI 0.57-0.76, P < 0.001) and progression-free survival (HR = 0.69, 95% CI 0.59-0.81, P < 0.001) with no evidence of heterogeneity of docetaxel effect between metastatic burden sub-groups (interaction P > 0.5 in each case). There was no evidence that docetaxel resulted in late toxicity compared with SOC: after 1 year, G3-5 toxicity was reported for 28% SOC and 27% docetaxel (in patients still on follow-up at 1 year without prior progression).

CONCLUSIONS

The clinically significant benefit in survival for upfront docetaxel persists at longer follow-up, with no evidence that benefit differed by metastatic burden. We advocate that upfront docetaxel is considered for metastatic hormone naïve prostate cancer patients regardless of metastatic burden.

Volumetric laser endomicroscopy and its application to Barrett's esophagus: results from a 1,000 patient registry

Volumetric laser endomicroscopy (VLE) uses optical coherence tomography (OCT) for real-time, microscopic cross-sectional imaging. A US-based multi-center registry was constructed to prospectively collect data on patients undergoing upper endoscopy during which a VLE scan was performed. The objective of this registry was to determine usage patterns of VLE in clinical practice and to estimate quantitative and qualitative performance metrics as they are applied to Barrett's esophagus (BE) management. All procedures utilized the NvisionVLE Imaging System (NinePoint Medical, Bedford, MA) which was used by investigators to identify the tissue types present, along with focal areas of concern. Following the VLE procedure, investigators were asked to answer six key questions regarding how VLE impacted each case. Statistical analyses including neoplasia diagnostic yield improvement using VLE was performed. One thousand patients were enrolled across 18 US trial sites from August 2014 through April 2016. In patients with previously diagnosed or suspected BE (894/1000), investigators used VLE and identified areas of concern not seen on white light endoscopy (WLE) in 59% of the procedures. VLE imaging also guided tissue acquisition and treatment in 71% and 54% of procedures, respectively. VLE as an adjunct modality improved the neoplasia diagnostic yield by 55% beyond the standard of care practice. In patients with no prior history of therapy, and without visual findings from other technologies, VLE-guided tissue acquisition increased neoplasia detection over random biopsies by 700%. Registry investigators reported that VLE improved the BE management process when used as an adjunct tissue acquisition and treatment guidance tool. The ability of VLE to image large segments of the esophagus with microscopic cross-sectional detail may provide additional benefits including higher yield biopsies and more efficient tissue acquisition. Clinicaltrials.gov NCT02215291.

Abstract P6-18-32: Profiling the early haematological dynamics and treatment modifications with palbociclib when used as first line treatment for ER-positive, HER2-negative metastatic breast cancer

Background: Palbociclib plus endocrine therapy (ET) significantly increases progression free survival compared to ET alone. Within PALOMA2 neutropenia was the most common AE and reason for dose reductions. No real data exists regarding dose reductions (DRs), dose interruptions (DIs), toxicities and benefits of palbociclib. Objective: To describe the early haematological dynamics, DRs/DIs with 1st line palbociclib in the context of a routine UK clinical practice. Methods: A prospective record was maintained of all patients with ER-positive, HER2-negative metastatic BC registered on the Pfizer patient programme at the Clatterbridge Cancer Centre NHS Foundation Trust. The clinical records of all patients commenced on treatment between April and December 2017 were reviewed, and clinico-pathological information, haematological data & toxicity data recorded. Data lock was 31st March 2018. Results: 48 patients received at least one cycle of treatment. The median age was 58, 29% (14/48) premenopausal & 71% (34/48) postmenopausal. 43% (21/48) had bone only disease with 42% (20/48) having visceral disease. The median number of cycles delivered 8 (range 2-11). DRs: 18/48 (38%) patients had a total of 21 DRs; 14/18 (78%) had 1 DR to 100mg; 1/18 (5%) 1 DR to 75mg; & 3/18 (17%) 2 DRs to 75mg. Reasons for DRs: 13 neutropenia, 2 leukopenia, 1 thrombocytopenia, 2 fatigue, 1 poor appetite, 1 sore mouth & 1 non-specially unwell. DIs: occurred in 24/48 patients (50%). Details of DRs/DIs by cycle will be presented. 85% (41 of 48) patients remain on treatment with 59% (24/41) on 125mg; 34% (14/41) on 100mg & 7% (3/41) on 75mg. FBC were available for 41/48 (85%) cases & dynamics considered over the first 6 cycles using FBC at the time of planned treatment delivery. Hb Baseline all patients (AP):129 (121 – 138), patients; patients with no dose reductions (NDR) 127 (123 – 139) & patient dose reduction (DR): 130 (118 – 136). Hb changes to cycles 2, 4 and 6 AP: 122 (115 – 131), 121 (116 – 127) and 125 (116 – 134); NDR:122 (110 - 135), 125 (117 - 127) and 131 (116 – 135); DR: 115 (112 - 120), 120 (115 - 124) and 122 (115 – 129). WCC Baseline AP: 6.8 (5.6 – 7.7); NDR: 7.2 (6.3 – 7.7); DR: 6.7 (5.2 – 7.7). WCC changes to cycles 2, 4 and 6 AP: 3.7 (2.9 – 4.4), 3.7 (3.1 – 4.4) and 3.3 (3 – 3.9); NDR: 3.5 (2.9 – 4.1), 3.6 (3.2 – 4.3) and 3.6 (3.1 – 4.1); DR: 2.1 (1.7 – 2.5), 4.3 (3 – 4.6) and 3.3 (2.8 – 3.5). ANC Baseline AP: 4.0 (3.2 – 5.1); NDR: 4.4 (3.4 – 5.0); DR: 3.6 (2.9 – 5.2). ANC changes to cycles 2, 4 and 6 AP: 1.5 (1.2 – 2.1), 1.7 (1.3 – 2.0) and 1.4 (1.2 – 1.9) NDR: 1.5 (1.1 – 2.1), 1.7 (1.4 – 2.0) and 1.3 (1.2 – 2.0); DR: 0.8 (0.6 – 0.8), 1.7 (1.2 – 2.3) and 1.4 (1.3 – 1.6). Plts Baseline AP: 298 (226 – 339), NDR: 252 (211 – 336); DR: 299 (253 – 339). Plt changes to cycles 2, 4 and 6 AP: 252 (198 – 310), 221 (186 – 259) and 200 (169 – 243). NDR: 249 (185 – 334), 229 (171 – 267) and 205 (177 – 263);DR: 208 (199 – 210), 216 (199 – 243) and 194 (162 -210). Conclusion: These initial real world data are consistent with the PALOMA2 data. Baseline WCC & ANC show no significant difference between NDR and DR cases. Updated data will be presented as well as outcome data for first time.

Citation Format: Bhojwani A, Flint H, Hall B, Wong H, Innes H, Cliff J, Ahmed E, Malik Z, O'Hagan J, Tolan S, Hall A, Hyatt K, Errington D, Alam F, Robson P, Thorp N, O'Reilly S, Law A, Cicconi S, Jackson R, Palmieri C. Profiling the early haematological dynamics and treatment modifications with palbociclib when used as first line treatment for ER-positive, HER2-negative metastatic breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-32.

Abstract P6-17-27: Real world experience of the medical and surgical management of HER2 positive early breast cancer treated with neoadjuvant trastuzumab and pertuzumab via the NHS England cancer drug fund

Background: Studies of neoadjuvant (NA) dual HER2 blockade with trastuzumab (T) and pertuzumab (P) in combination with chemotherapy (CT) for early breast cancer (BC) have reported pathological complete response (pCR) rates of 39 to 62%. These studies also report manageable toxicity with diarrhoea reported in up to 73% of cases. To date no real-world studies have explored the efficacy and toxicity of this treatment. The objective of this study was to describe the medical and surgical management of women treated with neoadjuvant T-P in combination with CT (NAT-P-CT). As well as to determine the efficacy toxicity of NAT-P-CT in the context of a routine UK NHS clinical practice.

Methods: Patients with HER2+ BC treated neoadjuvantly with T-P accessed via the NHS England Cancer Drug Fund (CDF) at the Clatterbridge Cancer Centre NHS Foundation Trust between October 2016 and January 2018 were retrospectively identified. Clinico-pathological information, treatment data, nurse led toxicity review and echocardiographic were reviewed. Data lock was 19th June 2018.

Results: 78 female patients were identified with a median age of 50 years (IQR: 44.4-60.2). At diagnosis: median tumour size 30mm (23.0-47.5mm), 62% (48/78) were LN positive & 56% (44/78) ER+. CT regimens: 81% (63/78) FEC-DHP of these 30% (19/63) switched to weekly paclitaxel (wP). or nab-paclitaxel; 5% (4/78); AC/EC-DHP; 9% (8/78) TCHP with 13% (1/8) switched to wP. At time of analysis, 88% (69/78) had undergone definitive surgery. Surgical details: Breast: 52% (36/69) mastectomy & 48% (33/69) WLE, Axillary management: 51% (35/69) axillary dissection (Ax Dx) & 49% (34/69) sentinel node biopsy (4 performed prior to NA treatment). 91% (32/35) of those undergoing Ax Dx were LN+ at presentation, of these 59% (19/32) had no evidence of axillary involvement at surgery. pCR rate (ypT0/is, N0) was 46% (32/69) [pCR by HR: ER+ 43% (21/49) & ER- 55% (11/20]. pCR for 20 patients switched to wP was 60% (12/20). 7% (5/69) achieved pCR in the breast alone (in these LN status ITCx1, micrometsx3 & macrometsx1). Of the 54% (37/69) with residual breast tumour median size was 13mm (1-22mm). Toxicity Data: Ejection fraction (EF) did not decline beyond 10% of baseline in any patients. Diarrhoea (any grade) occurred in 74% of cases, and CTCAE grade 3-4 toxicity occurring in &gt;2% of patients: diarrhoea, fatigue, and infection. Updated analysis regarding pCR rate and toxicity, as well as initial outcome data will be presented.

Conclusion: These results (1) confirm the efficacy of NA T-P in a real world population; (2) support the use of NA wP; (3) indicate significant proportion of patients axilla are downstaged & (4) reveal diarrhoea rates in keeping with the literature. Currently, NHS England rules do not allow wP to be used routinely in NA setting with T-P this should be reviewed in light of these data and those of the BERENICE study. Measures to identify patients who can avoid axillary dissection as well as to mitigate diarrhoea should be considered.

Citation Format: Hall B, Bhojwani A, Innes H, Ahmed E, Cliff J, Malik Z, O'Hagan J, Tolan S, Hall A, Hayat K, Errington D, Alam F, Thorp N, Flint H, Law A, Wong H, O'Reilly S, Jackson R, Cicconi S, Palmieri C. Real world experience of the medical and surgical management of HER2 positive early breast cancer treated with neoadjuvant trastuzumab and pertuzumab via the NHS England cancer drug fund [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-27.

Pyloric sphincter characteristics using EndoFLIP® in gastroparesis

INTRODUCTION AND AIMS

Pyloric sphincter abnormalities may be detected in gastroparesis. Botulinum toxin A (BoNT/A) injection into the pylorus has been used to treat gastroparesis with varying results. The aim of the present article was to assess whether pyloric sphincter characteristics using the endoscopic functional lumen imaging probe (EndoFLIP^®) with impedance planimetry in patients with gastroparesis correlated with symptoms, gastric emptying, and therapeutic response to pyloric sphincter BoNT/A injection.

METHODS

EndoFLIP^® study was performed on patients undergoing gastroparesis treatment with BoNT/A. The gastroparesis cardinal symptom index (GCSI) was applied prior to treatment and at post-treatment weeks 2, 4, 8, and 12.

RESULTS

Forty-four patients were enrolled (30 with idiopathic gastroparesis, 14 with diabetic gastroparesis). Smaller pyloric diameter, cross-sectional area (CSA), and distensibility correlated with worse vomiting and retching severity at baseline. Greater gastric retention tended to correlate with decreased CSA and pyloric distensibility. BoNT/A treatment resulted in a significant decrease in the GCSI score at 2 and 4 weeks after treatment, but not at post-treatment weeks 8 or 12. Nausea, early satiety, postprandial fullness, and upper abdominal pain improved up to 12 weeks, whereas loss of appetite, stomach fullness, and stomach visibly larger improved only up to 4 weeks. Retching and vomiting failed to improve. Greater pyloric compliance at baseline correlated with greater improvement in early satiety and náusea at 8 weeks and greater pyloric distensibility correlated with improvement in upper abdominal pain.

CONCLUSIONS

EndoFLIP^® characteristics of the pylorus provided important pathophysiologic information in patients with gastroparesis, in relation to symptoms, gastric emptying, and predicting the response to treatment directed at the pylorus.

Bone Morphogenetic Protein 2 Coordinates Early Tooth Mineralization

Formation of highly organized dental hard tissues is a complex process involving sequential and ordered deposition of an extracellular scaffold, followed by its mineralization. Odontoblast and ameloblast differentiation involves reciprocal and sequential epithelial-mesenchymal interactions. Similar to early tooth development, various Bmps are expressed during this process, although their functions have not been explored in detail. Here, we investigated the role of odontoblast-derived Bmp2 for tooth mineralization using Bmp2 conditional knockout mice. In developing molars, Bmp2LacZ reporter mice revealed restricted expression of Bmp2 in early polarized and functional odontoblasts while it was not expressed in mature odontoblasts. Loss of Bmp2 in neural crest cells, which includes all dental mesenchyme, caused a delay in dentin and enamel deposition. Immunohistochemistry for nestin and dentin sialoprotein (Dsp) revealed polarization defects in odontoblasts, indicative of a role for Bmp2 in odontoblast organization. Surprisingly, pSmad1/5/8, an indicator of Bmp signaling, was predominantly reduced in ameloblasts, with reduced expression of amelogenin ( Amlx), ameloblastin ( Ambn), and matrix metalloproteinase ( Mmp20). Quantitative real-time polymerase chain reaction (RT-qPCR) analysis and immunohistochemistry showed that loss of Bmp2 resulted in increased expression of the Wnt antagonists dickkopf 1 ( Dkk1) in the epithelium and sclerostin ( Sost) in mesenchyme and epithelium. Odontoblasts showed reduced Wnt signaling, which is important for odontoblast differentiation, and a strong reduction in dentin sialophosphoprotein ( Dspp) but not collagen 1 a1 ( Col1a1) expression. Mature Bmp2-deficient teeth, which were obtained by transplanting tooth germs from Bmp2-deficient embryos under a kidney capsule, showed a dentinogenesis imperfecta type II-like appearance. Micro-computed tomography and scanning electron microscopy revealed reduced dentin and enamel thickness, indistinguishable primary and secondary dentin, and deposition of ectopic osteodentin. This establishes that Bmp2 provides an early temporal, nonredundant signal for directed and organized tooth mineralization.

The synergistic effect of PDT and oxacillin on clinical isolates of Staphylococcus aureus

BACKGROUND

Staphylococcus aureus is a major pathogen in clinical microbiology. It is known to cause infections at various body sites and can be life-threatening. The development of resistance to many well-established antibiotic treatments and the prevalence of methicillin-resistant S. aureus (MRAS) among hospital patients and the general community pose challenges in treating the pathogen. The antimicrobial effect of photodynamic therapy (PDT) has been a subject of study for a long time and can offer new strategies for dealing with resistant strains.

OBJECTIVE

In our study, we searched for a positive synergistic relationship between PDT and the standard antibiotics used to treat S. aureus and MRSA infections.

MATERIALS AND METHODS

The phototoxic profile of deuteroporphyrin (DP) in both resistant and susceptible clinical strains of S. aureus was determined by plating of treated and untreated broth cultures. Electron microscopy imaging was done to explore possible sites of damage and free-radical accumulation in the cells during DP-PDT. Minimal inhibitory concentration (MIC) of oxacillin, gentamicin, vancomycin, rifampin, and fusidic acid was determined using the broth dilution method, and the checkerboard method was used to detect and evaluate the synergistic potential of DP-PDT and antibiotic combinations. A synergistic combination was further characterized using broth cultures and plating.

RESULTS

DP-PDT using a light dose of 15 J/cm² showed a bactericidal effect even with a small concentration of 17 μM DP. Transmission electron microscopy indicated profound damage in the cell wall and cell membrane, and the appearance of mesosome-like structures. Free radicals tend to localize in the cell membrane and inside the mesosome. No synergistic effect was detected by combining PDT with gentamicin, vancomycin, rifampin, and fusidic acid treatments. A positive synergistic effect was observed only in DP-PDT-oxacillin combined treatment using the checkerboard method. The effect was observed in clinical antibiotic-resistant isolates after DP-PDT using a light dose of 46 J/cm² and small concentrations of DP. Oxacillin MIC decreased below 2 μg/ml in resistant strains under such conditions. Cultures which did not undergo new cycles of DP-PDT recovered their original oxacillin resistance after a few generations.

CONCLUSIONS

PDT with porphyrins shows possible new therapeutic options in treating drug-resistant S. aureus at body sites suitable for irradiation. The synergistic effect of DP-PDT with oxacillin on clinical strains illustrates the potential of PDT to augment traditional antibiotic treatment based on cell wall inhibitors. Lasers Surg. Med. 50:535-551, 2018. © 2018 Wiley Periodicals, Inc.

l-phenylalanine modulates gut hormone release and glucose tolerance, and suppresses food intake through the calcium-sensing receptor in rodents

OBJECTIVE

High-protein diets (HPDs) are associated with greater satiety and weight loss than diets rich in other macronutrients. The exact mechanisms by which HPDs exert their effects are unclear. However, evidence suggests that the sensing of amino acids produced as a result of protein digestion may have a role in appetite regulation and satiety. We investigated the effects of l-phenylalanine (L-Phe) on food intake and glucose homeostasis in rodents.

METHODS

We investigated the effects of the aromatic amino-acid and calcium-sensing receptor (CaSR) agonist l-phenylalanine (L-Phe) on food intake and the release of the gastrointestinal (GI) hormones peptide YY (PYY), glucagon-like peptide-1 (GLP-1) and ghrelin in rodents, and the role of the CaSR in mediating these effects in vitro and in vivo. We also examined the effect of oral l-Phe administration on glucose tolerance in rats.

RESULTS

Oral administration of l-Phe acutely reduced food intake in rats and mice, and chronically reduced food intake and body weight in diet-induced obese mice. Ileal l-Phe also reduced food intake in rats. l-Phe stimulated GLP-1 and PYY release, and reduced plasma ghrelin, and also stimulated insulin release and improved glucose tolerance in rats. Pharmacological blockade of the CaSR attenuated the anorectic effect of intra-ileal l-Phe in rats, and l-Phe-induced GLP-1 release from STC-1 and primary L cells was attenuated by CaSR blockade.

CONCLUSIONS

l-Phe reduced food intake, stimulated GLP-1 and PYY release, and reduced plasma ghrelin in rodents. Our data provide evidence that the anorectic effects of l-Phe are mediated via the CaSR, and suggest that l-Phe and the CaSR system in the GI tract may have therapeutic utility in the treatment of obesity and diabetes. Further work is required to determine the physiological role of the CaSR in protein sensing in the gut, and the role of this system in humans.

Dronabinol increases pain threshold in patients with functional chest pain: a pilot double-blind placebo-controlled trial

Noncardiac chest pain is associated with poor quality of life and high care expenditure. The majority of noncardiac chest pain is either gastresophageal reflux disease related or due to esophageal motility disorders, and the rest are considered functional chest pain (FCP) due to central and peripheral hypersensitivity. Current treatment of FCP improves 40-50% of patients. Cannabinoid receptors 1 (CB1) and 2 (CB2) modulate release of neurotransmitters; CB1 is located in the esophageal epithelium and reduces excitatory enteric transmission and potentially could reduce esophageal hypersensitivity. We performed a prospective study to evaluate its effects on pain threshold, frequency, and intensity in FCP. Subjects with FCP received dronabinol (5 mg, twice daily; n = 7; average age, 44 years; mean body mass index, 26.7) or placebo (n = 6; average age, 42 years; mean body mass index, 25.9) for 28 days (4 weeks). Chest pain, general health, and anxiety/depression questionnaires were assessed at baseline and at 4 weeks. Subjects underwent an esophageal balloon distention test prior to treatment and on last day of the study. Dronabinol increased pain thresholds significantly (3.0 vs. 1.0; P = 0.03) and reduced pain intensity and odynophagia compared to placebo (0.18 vs. 0.01 and 0.12 vs. 0.01, respectively, P = 0.04). Depression and anxiety scores did not differ between the groups at baseline or after treatment. No significant adverse effects were observed. In this novel study, dronabinol increased pain threshold and reduced frequency and intensity of pain in FCP. Further, large scale studies are needed to substantiate these findings.