Gene therapy for people with hepatocellular carcinoma

Gene therapy for people with hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma is the most common type of liver cancer, accounting for 70% to 85% of individuals with primary liver cancer. Gene therapy, which uses genes to treat or prevent diseases, holds potential for treatment, especially for tumours. Trials on the effects of gene therapy in people with hepatocellular carcinoma have been published or are ongoing.

OBJECTIVES

To evaluate the benefits and harms of gene therapy in people with hepatocellular carcinoma, irrespective of sex, administered dose, and type of formulation.

SEARCH METHODS

We identified randomised clinical trials through electronic searches in The Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE, Embase, LILACS, Science Citation Index Expanded, and Conference Proceedings Citation Index-Science. We searched five online clinical trial registries to identify unpublished or ongoing trials. We checked reference lists of the retrieved studies for further trials. The date of last search was 20 January 2023.

SELECTION CRITERIA

We aimed to include randomised clinical trials assessing any type of gene therapy in people diagnosed with hepatocellular carcinoma, irrespective of year, language of publication, format, or outcomes reported.

DATA COLLECTION AND ANALYSIS

We followed Cochrane methodology and used Review Manager to prepare the review. The primary outcomes were all-cause mortality/overall survival (whatever data were provided), serious adverse events during treatment, and health-related quality of life. The secondary outcomes were proportion of people with disease progression, adverse events considered non-serious, and proportion of people without improvement in liver function tests. We assessed risk of bias of the included trials using RoB 2 and the certainty of evidence using GRADE. We presented the results of time-to-event outcomes as hazard ratios (HR), dichotomous outcomes as risk ratios (RR), and continuous outcomes as mean difference (MD) with their 95% confidence intervals (CI). Our primary analyses were based on intention-to-treat and outcome data at the longest follow-up.

MAIN RESULTS

We included six randomised clinical trials with 364 participants. The participants had unresectable (i.e. advanced inoperable) hepatocellular carcinoma. We found no trials assessing the effects of gene therapy in people with operable hepatocellular carcinoma. Four trials were conducted in China, one in several countries (from North America, Asia, and Europe), and one in Egypt. The number of participants in the six trials ranged from 10 to 129 (median 47), median age was 55.2 years, and the mean proportion of males was 72.7%. The follow-up duration ranged from six months to five years. As the trials compared different types of gene therapy and had different controls, we could not perform meta-analyses. Five of the six trials administered co-interventions equally to the experimental and control groups. All trials assessed one or more outcomes of interest in this review. The certainty of evidence was very low in five of the six comparisons and low in the double-dose gene therapy comparison. Below, we reported the results of the primary outcomes only. Pexastimogene devacirepvec (Pexa-Vec) plus best supportive care versus best supportive care alone There is uncertainty about whether there may be little to no difference between the effect of Pexa-Vec plus best supportive care compared with best supportive care alone on overall survival (HR 1.19, 95% CI 0.78 to 1.82; 1 trial (censored observation at 20-month follow-up), 129 participants; very low-certainty evidence) and on serious adverse events (RR 1.42, 95% CI 0.60 to 3.33; 1 trial at 20 months after treatment, 129 participants; very low-certainty evidence). The trial reported quality of life narratively as "assessment of quality of life and time to symptomatic progression was confounded by the high patient dropout rate." Adenovirus-thymidine kinase with ganciclovir (ADV-TK/GCV) plus liver transplantation versus liver transplantation alone There is uncertainty about whether ADV-TK/GCV plus liver transplantation may benefit all-cause mortality at the two-year follow-up (RR 0.39, 95% CI 0.20 to 0.76; 1 trial, 45 participants; very low-certainty evidence). The trial did not report serious adverse events other than mortality or quality of life. Double-dose ADV-TK/GCV plus liver transplantation versus liver transplantation alone There is uncertainty about whether double-dose ADV-TK/GCV plus liver transplantation versus liver transplantation may benefit all-cause mortality at five-year follow-up (RR 0.40, 95% CI 0.22 to 0.73; 1 trial, 86 participants; low-certainty evidence). The trial did not report serious adverse events other than mortality or quality of life. Recombinant human adenovirus-p53 with hydroxycamptothecin (rAd-p53/HCT) versus hydroxycamptothecin alone There is uncertainty about whether there may be little to no difference between the effect of rAd-p53/HCT versus hydroxycamptothecin alone on the overall survival at 12-month follow-up (RR 3.06, 95% CI 0.16 to 60.47; 1 trial, 48 participants; very low-certainty evidence). The trial did not report serious adverse events or quality of life. rAd-p53/5-Fu (5-fluorouracil) plus transarterial chemoembolisation versus transarterial chemoembolisation alone The trial included 46 participants. We had insufficient data to assess overall survival. The trial did not report serious adverse events or quality of life. E1B-deleted (dl1520) adenovirus versus percutaneous ethanol injection The trial included 10 participants. It did not report data on overall survival, serious adverse events, or health-related quality of life. One trial did not provide any information on sponsorship; one trial received a national research grant, one trial by the Pedersen foundation, and three were industry-funded trials. We found five ongoing randomised clinical trials.

AUTHORS' CONCLUSIONS

The evidence is very uncertain about the effects of gene therapy on the studied outcomes because of high risk of bias and imprecision of outcome results. The trials were underpowered and lacked trial data on clinically important outcomes. There was only one trial per comparison, and we could not perform meta-analyses. Therefore, we do not know if gene therapy may reduce, increase, or have little to no effect on all-cause mortality or overall survival, or serious adverse events in adults with unresectable hepatocellular carcinoma. The impact of gene therapy on adverse events needs to be investigated further. Evidence on the effect of gene therapy on health-related quality of life is lacking.

Modified dietary fat intake for treatment of gallstone disease in people of any age

BACKGROUND

The prevalence of gallstones varies between less than 1% and 64% in different populations and is thought to be increasing in response to changes in nutritional intake and increasing obesity. Some people with gallstones have no symptoms but approximately 2% to 4% develop them each year, predominantly including severe abdominal pain. People who experience symptoms have a greater risk of developing complications. The main treatment for symptomatic gallstones is cholecystectomy. Traditionally, a low-fat diet has also been advised to manage gallstone symptoms, but there is uncertainty over the evidence to support this.

OBJECTIVES

To evaluate the benefits and harms of modified dietary fat intake in the treatment of gallstone disease in people of any age.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials in the Cochrane Library, MEDLINE ALL Ovid, Embase Ovid, and three other databases to 17 February 2023 to identify randomised clinical trials in people with gallstones. We also searched online trial registries and pharmaceutical company sources, for ongoing or unpublished trials to March 2023.

SELECTION CRITERIA

We included randomised clinical trials (irrespective of language, blinding, or status) in people with gallstones diagnosed using ultrasonography or conclusive imaging methods. We excluded participants diagnosed with another condition that may compromise dietary fat tolerance. We excluded trials where data from participants with gallstones were not reported separately from data from participants who did not have gallstones. We included trials that investigated other interventions (e.g. trials of drugs or other dietary (non-fat) components) providing that the trial groups had received the same proportion of drug or other dietary (non-fat) components in the intervention.

DATA COLLECTION AND ANALYSIS

We intended to undertake meta-analysis and present the findings according to Cochrane recommendations. However, as we identified only five trials, with data unsuitable and insufficient for analyses, we described the data narratively.

MAIN RESULTS

We included five trials but only one randomised clinical trial (69 adults), published in 1986, reported outcomes of interest to the review. The trial had four dietary intervention groups, three of which were relevant to this review. We assessed the trial at high risk of bias. The dietary fat modifications included a modified cholesterol intake and medium-chain triglyceride supplementation. The control treatment was a standard diet. The trial did not report on any of the primary outcomes in this review (i.e. all-cause mortality, serious adverse events, and health-related quality of life). The trial reported on gallstone dissolution, one of our secondary outcomes. We were unable to apply the GRADE approach to determine certainty of evidence because the included trial did not provide data that could be used to generate an estimate of the effect on this or any other outcome. The trial expressed its finding as "no significant effect of a low-cholesterol diet in the presence of ursodeoxycholic acid on gallstone dissolution." There were no serious adverse events reported. The included trial reported that they received no funding that could bias the trial results through conflicts of interest. We found no ongoing trials.

AUTHORS' CONCLUSIONS

The evidence about the effects of modifying dietary fat on gallstone disease versus standard diet is scant. We lack results from high-quality randomised clinical trials which investigate the effects of modification of dietary fat and other nutrient intakes with adequate follow-up. There is a need for well-designed trials that should include important clinical outcomes such as mortality, quality of life, impact on dissolution of gallstones, hospital admissions, surgical intervention, and adverse events.