OK, time to beat this to death! 
First Pantethine (Coenzyme A Precursor) is a derivative of vitamin B5.
I don’t know what you think are good studies, but a couple I find compelling, are below:
Does a randomized, double-blind, multicenter study meet your criteria?
Or, a triple-blinded placebo and diet-controlled investigation.
My personal experience is that Pantethine negated rapamycin’s effects on my lipids.
Pantethine alone reduces TGs by ~ 17% adding CoA reduces to ~26%
I am a big fan of Pantethine because it works for me and I feel zero side effects.
“Moreover, unlike statins, which deplete CoQ10 to detrimental levels, both the pantethine and placebo groups significantly increased their CoQ10 levels above baseline.”
“Pantethine is known to be safe and effective33 and has been used as a medicine in Japan for over 40 years. In the US, oral pantethine (Pantesin®; Daiichi Fine Chemical Co, Ltd, Toyama, Japan) has been available as a nutritional supplement since 1992. In a recent randomized clinical study in a North American population of participants at conventional low to moderate CVD risk, pantethine produced significant and sustained reductions in LDL-C, TC, and Apo-B.34 Based on previous studies”
"To evaluate the lipid-lowering effects and safety of a natural hypolipidemic compound, coenzyme A (CoA) capsule, in Chinese patients with moderate dyslipidemia, compared with pantethine.
Overall, 216 subjects (124 males and 92 females; age, 18-75 years) with moderate dyslipidemia (triglyceride [TG], 2.3-6.5 mmol/L) were randomly divided into 2 groups administered CoA 400 U/d (n = 111) or pantethine 600 U/d (n = 105). Blood lipoproteins, liver and renal function, blood glucose, and complete blood count were measured at baseline and after 4- and 8-week treatment.
TG reduction was 26.0% with CoA and 17.4% with pantethine after 4 weeks and 33.3% and 16.5% after 8 weeks; compared with baseline, the reduction was significant (P < .01) in both groups. The difference between the 2 groups was significant at both 4 weeks (P = .0413) and 8 weeks (P < .001). Compared with baseline, total cholesterol and non-high-density lipoprotein cholesterol (non-HDL-C) were reduced, whereas HDL-C was increased with CoA after 8 weeks"
Full paper here: “Sci-Hub | Efficacy and tolerability of coenzyme A vs pantethine for the treatment of patients with hyperlipidemia: A randomized, double-blind, multicenter study. Journal of Clinical Lipidology, 9(5), 692–697 | 10.1016/j.jacl.2015.07.003”
Pantethine has a possible use in preserving brain function:
“As a natural dietary low-molecular-weight thiol, pantethine helps maintain brain homeostasis and function in Alzheimer’s disease (AD) mice”
“This study highlights the potential therapeutic effect of pantethine in AD by reducing cholesterol and lipid raft formation and regulating intestinal flora, suggesting a new option for the development of clinical drugs for AD.”