CD200AR-L and Allogeneic Tumor Lysate Vaccine Immunotherapy for Recurrent HGG and Newly Diagnosed DMG/DIPG in Children and Young Adults

Description

A previous pediatric trial using GBM6-AD vaccine was found to be safe, and an appropriate pediatric dose of GBM6-AD was determined, but the efficacy of the vaccine was diminished due to secretion of CD200 by the patient’s HGG or DMG/DIPG cells. CD200 is known to binds to CD200 inhibitory receptor (CD200R1) on immune cells and suppress the immune cell response. Laboratory studies have shown that administering agents that bind to the CD200 activation receptor (CD200-AR) on immune cells results in activation of immune cells and overcomes any inhibitory signals caused by CD200.

CD200AR-L is a newly developed agent that binds to CD200-AR. This trial will assess the combination of CD200AR-L with GBM6-AD vaccine, imiquimod cream and a single dose of radiation given on day 15 for the treatment of recurrent HGG and newly diagnosed DMG/DIPG.

This study has the following primary goals:

1. To determine the maximum tolerated dose and side-effects of the experimental medicine, CD200AR-L, when given with a fixed dose of GBM6-AD vaccine in combination with imiquimod cream and a single dose of radiation on Day 15 for patients with recurrent HGG or newly diagnosed DMG/DIPG in children.
2. To use the information from this study to design a larger study of the GBM6-AD vaccine and CD200AR-L treatment to assess the effectiveness of this combination vaccine in pediatric HGG and newly diagnosed DMG/DIPG.

Study treatment consists of CD200AR-L, GBM6-AD vaccine and imiquimod, along with a single dose of radiation on day 15. Study treatment will begin approximately 14 days after the completion of standard of care radiation therapy for patients with newly diagnosed DMG/DIPG and at the time of recurrence for patients with HGG. The study will enroll patients between the ages of 2 – 25 years, but it will initially enroll and treat 3 patients age > 12 years in the first dosing cohort in order to acquire safety data before enrolling patients 2-11 years of age. Up to 3 dose levels of CD200AR-L will be tested, with dose reduction in the event of toxicity.

Each vaccine treatment is given as an outpatient visit on two consecutive days. Imiquimod cream is applied to the supraclavicular site followed by 2 supraclavicular injections of CD200AR-L each day for 2 consecutive days. On the second day, following application of Imiquimod cream and CD200AR-L injection, 2 supraclavicular injections of GBM6-AD vaccine will be given. All CD200AR-L and GBM6-AD vaccine administrations must be done at Children’s Minnesota. Two-day injection series will be administered every week for the first 3 weeks, then every 4 weeks starting at week 7 for the next 8 weeks, then every 8 weeks starting at week 19 for 2 years. On day 15, a single dose of 300 cGy radiation will be given to help sensitize the tumor to immune attack. The patient will undergo a series of MRIs to follow the status of their tumor, blood work for immune characterization, and pediatric functional performance assessments. Treatment will continue for 2 years, unless disease progression is noted on MRI, unacceptable toxicity develops, a greater than 8-week treatment delay occurs during the maintenance phase, or the patient withdraws from the study. The patient will have an option of continuing therapy beyond 2 years if they are tolerating the treatment and if their tumor is controlled by the treatment.