Siplizumab Starts Two Trials in Honeymoon T1D (DESIGNATE and STRIDE)

Siplizumab (MEDI-507, TCD601) is an monoclonal antibody which targets CD2 cells in the immune system.  It is being developed by ITB-MED.  It has an active research program for several different diseases with about 20 clinical trials in process.  There are currently two clinical trials targeting Type 1 Diabetes, so I'll discuss each in turn.

Part of the motivation to test Siplizumab was a previously good result from Alefacept.  I blogged about that result here:
https://cureresearch4type1diabetes.blogspot.com/2016/02/alefacept-reports-on-phase-ii-results.html
You can read my conclusions in the previous blog posting, but the company that made Alefacept stopped marketing the drug, which had been approved for Psoriasis, because of newer drugs in the field.  The hope is that Siplizumab will work in the same way and have similar results.

DESIGNATE: Phase-IIΔ Siplizumab in [Mostly] Honeymooners

This trial was started by the US government (National Institutes of Health, National Institute of Allergy and Infectious Diseases) and is being run by the Immune Tolerance Network.  It started in April-2023 and they are enrolling 120 people, which is a lot.

Initially adults were enrolled, but later the study started enrolling children as young as 8.  Everyone is within 18 months of diagnosis.  This is an open label trial, where each person will get one of four different doses of Siplizumab.  No placebo or control group.

The primary end points for this study look at changes in immune cells, so they are measuring how the treatment changes the immune system.  The secondary end points include adverse effects, C-peptides, and insulin use, and so cover both safety and effectiveness.

This study is in a pause right now.  They are evaluating the results from the first couple of people, and may change the study slightly based on what they learn.  When it moves forward, they will be recruiting at 20 locations all over the US, which will be listed in the links below:

Trial Web Page: https://www.designate-study.org/
Clinical trial registry: https://clinicaltrials.gov/study/NCT05574335

STRIDE: Phase-IIΔ Siplizumab in Honeymooners

This trial was started by a company (ITB-Med LLC), and is run by INNODIA.  It started in Jan-2023 and expects to finish in Jan-2025.  They are enrolling 96 adults. 

People must be within 100 days of diagnosis to be enrolled.  I think that there are four treatment groups, with one getting a placebo and the other three each getting a different dose of Siplizumab.  Nowhere are the doses listed.  Patients will get the treatment for 12 weeks; I think 1 dose per week, and will be followed for a year total. 

Although the description is a little vague, I think this study measures C-peptide as its primary end point, and adverse reactions as its secondary end point.  The first covers effectiveness and the second covers safety.

This study is still recruiting in Europe (Belgium, Germany, Italy, Poland, UK).  You can see the exact locations in the clinical trial registry: https://clinicaltrials.gov/study/NCT06025110

Eudract number: https://www.clinicaltrialsregister.eu/ctr-search/trial/2022-001713-39/SE

Discussion

These clinical trials have a lot in common.  The differences I do see are:

1. The STRIDE study recruits people within 100 days of diagnosis, while DESIGNATE recruits people within 18 months of diagnosis.
2. The STRIDE study recruits adults only, while DESIGNATE started out recruiting adults, but later added children.
3. STRIDE is single blind, DESIGNATE is open label. 
4. My understanding is that the two studies use different dosing techniques. 
   

An obvious question is: why did two different studies start at almost the same time, which are so similar?  I don't know the answer.  Both studies were motivated by the same company, the one producing the drug, and I'm always in favor of doing more studies, more quickly.  I'm happy they are moving forward along two separate paths at the same time.

One issue in the DESIGNATE trial is the recruitment cut off of 18 months after diagnosis.  I don't understand that.  The honeymoon time period is generally accepted to end after 12 months or a little earlier, so this means that DESIGNATE will include some honeymooners and some non-honeymooners.  I can only hope that they will analyze the data for both people recruited in their honeymoon phrase and separately for people who are not, just in case it works at one time but not at the other.

I'm not sure of the details of the history of Siplizumab, but I think it was originally developed by MedImmune,which was later bought by AstraZeneca.  However, the rights were later bought by ITB-Med, who are responsible for testing the drug on people with T1D. 

The Immune Tolerance Network, which is running DESIGNATE, is a collaborative network for clinical research, funded by the National Institute of Allergy and Infectious Diseases, part of the [United States] National Institutes of Health (especially through the special type 1 diabetes appropriation), and JDRF.

INNODIA, which is running STRIDE is a European non-profit network dedicated to preventing and curing type 1 diabetes.  It is funded by the European Commission’s Innovative Medicines Initiative (IMI-JU Joint Undertaking), The Hemsley Charitable Trust, JDRF, and EFPIA partners.

Joshua Levy

http://cureresearch4type1diabetes.blogspot.com

publicjoshualevy at gmail dot com

All the views expressed here are those of Joshua Levy, and nothing here is official JDRF or JDCA news, views, policies or opinions. My kid has type-1 diabetes and participates in clinical trials, which might be discussed here. My blog contains a more complete non-conflict of interest statement. Thanks to everyone who helps with the blog!