Where to Go Now With V-Go?

Abstract

V-Go™ is a mechanical continuous insulin delivery device releasing a basal amount of rapid acting insulin that also allows the user the ability to deliver discrete meal time or correction doses. This analysis reviews available published literature on the technology, and discusses a recent article comparing the V-Go system with multiple daily insulin injection therapy. Finally, suggestions for future studies are provided.

V-Go (www.V-Go.com) is a disposable, mechanical device containing rapid acting insulin which can deliver both continuous basal and on-demand insulin boluses over a 24-hour period. It is available in preset basal rates of 20, 30, or 40 units and can provide an additional 36 units for bolus administration in 2 unit increments. It is affixed to the skin with adhesive and activated with the press of a button, which inserts a 30-gauge needle perpendicular to the skin surface. The device can be manipulated through clothing to allow patients a discreet method to bolus insulin throughout the day. A new device has to be prefilled with insulin and applied every day.

Published experience with V-Go technology is limited. In a single-center, single-arm, open-label study where 6 subjects were transitioned from subcutaneous glargine injections to a V-Go device, V-Go maintained glycemic control compared to that achieved during the baseline glargine treatment period and no significant safety issues were noted. ¹ A retrospective study of 23 patients showed similar results with a hemoglobin A1c (HbA1c) reduction (8.8% to 7.6%, P = .005) after 3 months of therapy. ² Generally, patient satisfaction with this technology was high, as reported in this study (average scores 8.7/10 with 10 being the most positive for V-Go). ² Another retrospective analysis of 60 patients on the V-Go demonstrated a 0.9% reduction in HbA1c after 2-4 months of therapy. ³ There have been no significant safety concerns with the V-Go, and no reported increased episodes of hypoglycemic events among users. Device malfunction is generally low, and the greatest side effect remains skin irritation secondary to the adhesive. However, it is important to realize that these published studies are small and mostly retrospective in nature, and although they support the safety and efficacy of the V-Go, they still harbor significant limitations.

There are no large prospective studies comparing V-Go to more conventional insulin treatment algorithms. Winter and colleagues, therefore, should be commended for conducting a prospective comparison study of V-Go technology to standard insulin therapy. ⁴ Patients with type 2 diabetes and poor glycemic control (HbA1c over 8%) were allowed to choose their preferred method of insulin delivery (V-Go versus multiple daily insulin injection therapy) and followed for 3 months. Subjects were seen on a weekly basis until they reached therapeutic goals based on self-reported home blood glucose readings and then monthly thereafter. Pre- and postintervention HbA1c and total daily insulin doses were compared. Secondary outcome measures included weight, blood pressure, hypoglycemic events, and quality of life. In the V-Go group, 1 patient dropped out due to skin irritation from the adhesive, and another was lost to follow-up, leaving only 3 patients in the V-Go group.

All subjects in Winter V-Go study group experienced a decrease in HbA1c level, with an average change of 1.5%. In the standard therapy group, 2 of 3 patients experienced a decrease in HbA1c, with the third seeing an increase. All patients in the V-Go group decreased their total daily doses (TDD) of insulin with an average decrease of 26.3 units. All patients in the standard therapy group experienced an increase in TDD with an average of 15 units. There was no significance between the groups with regard to weight or blood pressure. Hypoglycemia was more common in the V-Go group. Patient satisfaction improved over the 3-month study period, and patients generally reported good adherence and the perception of improved glycemic control.

However, no conclusions can be derived from the study because of its nonrandomized nature and the small sample size. With regard to HbA1c, 5 of the 6 study patients achieved a reduction in their HbA1c levels. The significant increase in 1 patient in the standard therapy group greatly skews the overall results. It is also difficult to conclude anything from these results given the distinct differences between patients in each treatment group. All the patients in the V-Go group were on basal-bolus regimens at baseline, whereas all the patients in the standard therapy group were on only basal insulin at baseline. It may not be unexpected that TDD insulin dose increased in the standard therapy group given that bolus insulin was added to poorly controlled patients already on basal insulin. Even within the same treatment group, patients were distinctly different. In the standard therapy group; the 3 patients being compared included a relatively insulin sensitive patient (TDD of 26 units with HbA1c of 8.1% at baseline) and a very insulin resistant patient (TDD of 120 units with an HbA1c of 8.7% at baseline).

Despite its limitations, the Winter study does raise an important question. In an era of expanding insulin delivery options, which include conventional insulin injections, an expanding market of electronic continuous subcutaneous insulin infusion (CSII) devices, and now inhaled insulin, where does V-Go technology fit in the treatment paradigm? Can V-Go serve as a bridge to multiple daily insulin injections in relatively insulin sensitive patients with type 2 diabetes? Given the maximum allowable insulin amount of 76 units, V-Go technology would not be applicable to more insulin resistant type 2 diabetes patients. Or can V-Go act as a transition to electronic CSII therapy? Can the V-Go device be used safely in the hospital or during surgery? Does V-Go have any utility in the management of patients with type 1 diabetes? Although FDA approved the device in 2010, and while initial data suggest some promise to this new technology, V-Go’s place in diabetes management has yet to be determined. There is not enough data to know whether this technology offers any benefit in terms of glycemic control, cost, or patient satisfaction above and beyond currently available insulin delivery options. Simply put, where do we go with V-Go? Larger, prospective studies are needed and are warranted to answer these questions.