Memorandum

Full Results from Tandem’s Control-IQ Pivotal Published in NEJM with Accompanying Editorial – October 17, 2019

Data from six-month, n=168 study first read out at ADA 2019; Control-IQ currently under FDA review, expected launch in 4Q19

Yesterday, full results from Tandem/Dexcom’s Control-IQ pivotal were published in NEJM – a prestigious publication win for automated insulin delivery and a lightning quick turnaround after the six-month pivotal trial data read out at ADA 2019. Tandem’s press release confirmed plans to launch the system in the US this year, pending FDA approval (submitted mid-summer). Kudos to NIH for funding this study (the first large-scale, six-month AID trial with a control group), Tandem/Dexcom for creating a highly usable and effective product (+2.6 hours/day in-range, 90%+ time in closed loop, no fingersticks), the investigators for 100% study retention (!), and NEJM for recognizing the clinical importance.

There were no surprises on the adverse effect front, as reported at ADA. Control-IQ also achieved near-perfect scores on user surveys: ease of use was 4.7/5, usefulness was 4.6/5, trust was 4.5/5, and desire to continue using was an impressive 4.8/5. Every single participant also completed the entire study and Control-IQ users spent a remarkable 92% with closed loop active.

  • The study, which is prominently featured on NEJM’s home page, was accompanied by a 1.5-page editorial from the University of Padova’s Dr. Daniela Bruttomesso. She calls the results “impressive and clinically relevant,” though also notes that the baseline use of CGM (70%) and insulin pumps (79%) were significantly higher than that of the general type 1 population. As a counterpoint, we’d note that this study was much, much more representative and much longer than the average closed loop study – often, participants come into studies with 65%+ time-in-range; here, time-in-range was 59% at baseline, and Control-IQ showed time-in-range improvement in every A1c subgroup. (For further context, Medtronic’s MiniMed 670G pivotal study in the same age group started with a much higher baseline time-in-range of 67%, and had no control group; it compared two weeks of baseline manual therapy to three months of closed loop). She also points out a few remaining barriers to a fully automated closed loop system, “including slow subcutaneous absorption of insulin, low stability of current glucagon formulations, insufficient sensor accuracy, and algorithms that are not yet flexible enough for every day needs.”

SAP at baseline (n=56)

Closed loop at baseline (n=112)

SAP at six months (n=56)

Closed loop at six months (n=112)

Adjusted Difference

p-value

Time-in-range (70-180 mg/dl)

59%

61%

59%

71%

+11%

p<0.001

A1c

7.4%

7.4%

7.4%

7.1%

-0.3%

p=0.001

Time >180 mg/dl

38%

36%

38%

27%

-10%

p<0.001

Mean CGM

169 mg/dl

166 mg/dl

170 mg/dl

156 mg/dl

-13 mg/dl

p<0.001

Time <70 mg/dl

2.8%

3.6%

2.3%

1.6%

-0.9%

p<0.001

Time <54 mg/dl

0.6%

0.9%

0.4%

0.3%

-0.1%

p=0.02

 

 

--by Albert Cai and Kelly Close