PBTC Phase 2 Study Results for Temozolomide/06-Benzylguanine

An abstract was released ahead of print for a phase 2 Pediatric Brain  Tumor Consortium study on recurrent/progressive high-grade gliomas and brainstem gliomas utilizing the combination of temozolomide and 06-benzylguanine (06 BG).  The study was initially put up on clinicaltrials.gov in January 2006.

O6-Benzylguanine and Temozolomide in Treating Young Patients With Recurrent or Progressive Gliomas or Brain Stem Tumors

http://clinicaltrial.gov/ct2/show/NCT00275002?term=06+temozolomide&rank=10

The thought was that the two agents may work differently to stop tumor growth and that combined chemotherapy might kill more cells.   Temozolomide is an alkylating agent that interferes with DNA replication.  This mechanism of action has seemed dependant on the ability to methylate DNA primarily at the N7 of 0-6 position on guanine.  Some cells were found to be able to repair this DNA damage.  The hope that O6 BG might overcome some of that repair issue.

Of the 41 children evaluated, 16 had brainstem gliomas.  There were no sustained objective responses with any in the brainstem glioma group, however, one patient had long term stable disease of more than 6 courses (28 day course). 

It was concluded that this combination “did not achieve target response rate for pediatric patients with recurrent or progressive high grade glioma or brainstem glioma.”

A phase II study of O6-benzylguanine and temozolomide in pediatric patients with recurrent or progressive high-grade gliomas and brainstem gliomas: a Pediatric Brain Tumor Consortium study   
http://www.ncbi.nlm.nih.gov/pubmed/21968943

Columbia’s new treatment for DIPG - CED Topotecan

In September, Columbia University announced that neurosurgeons Richard Anderson and Jeffrey Bruce have successfully used convection enhanced delivery (CED) with the agent topotecan for two pediatric DIPG patients.
http://www.columbianeurosurgery.org/2011/09/anderson-and-bruce-beating-the-odds-with-new-cancer-treatment/

CED requires fine catheters to be placed directly into the tumor.  This approach allows for therapy to be placed directly in the tumor avoiding systemic toxicity and higher dosages.

Dr Bruce has worked for more than a decade in development of CED for malignant gliomas.   His initial publications were in 2000 with a rat glioma model.  In 2011, Bruce has authored three publications regarding CED with topotecan for malignant glioma. 

Tissue distribution and antitumor activity of topotecan delivered by intracerebral clysis in a rat glioma model
http://www.ncbi.nlm.nih.gov/pubmed/11126910

Convection-enhanced delivery of topotecan into a PDGF-driven model of glioblastoma prolongs survival and ablates both tumor-initiating cells and recruited glial progenitors
www.ncbi.nlm.nih.gov/pubmed/21464045

Regression of Recurrent Malignant Gliomas with Convection-Enhanced Delivery of Topotecan
http://www.ncbi.nlm.nih.gov/pubmed/21562434

Prolonged intracerebral convection-enhanced delivery of topotecan with a subcutaneously implantable infusion pump
http://www.ncbi.nlm.nih.gov/pubmed/21750007

In addition to Columbia, the NIH also has a CED trial open for recurrent DIPG children utilizing a different agent -
An Open Label Dose Escalation Safety Study of Convection-Enhanced Delivery of IL13-PE38QQR in Patients With Progressive Pediatric Diffuse Infiltrating Brainstem Glioma and Supratentorial High-grade Glioma
http://clinicaltrial.gov/ct2/show/NCT00880061?term=pontine+glioma&rank=20

The NIH has piloted CED in the brainstem not only for DIPG but also for other issues.  In 2007, the NIH published technical notes on two children that received CED therapy.  One of these children had a DIPG and the other had Gaucher’s Disease.
Real-time image-guided direct convective perfusion of intrinsic brainstem lesions. Technical note.
http://www.ncbi.nlm.nih.gov/pubmed/17639894

Nimotuzumab and Vinorelbine Concomitantly to Radiation and as Maintenance for Diffuse Pontine Glioma in Childhood

On September 25^th, YM Bioscience presented a poster presentation at the ECCO-EMSO meeting in Stockholm, Sweden regarding the combined use of Nimotuzamab and vinorelbine with radiation in pediatric DIPG entitled:
"Nimotuzumab and Vinorelbine Concomitantly to Radiation and as Maintenance for Diffuse Pontine Glioma in Childhood: Promising Results on a Series of 13 Patients"
http://www.news-medical.net/news/20110927/Data-from-YM-BioSciences-nimotuzumab-clinical-trials-to-be-reported-at-ECCO-ESMO-2011.aspx

This appears to a companion to the 2011 ASCO presentation in Chicago.   In this study, the Italian researchers reported on a series of 12 children.  They noted that all children were treated on an outpatient basis and none had suffered significant treatment related side effects.  For the 12 children (ages from 3-13), the progression free survival at 9 months was 69 ± 21% and the 12 month overall survival  was 81.5 ± 12 %.  The researchers believed this combination shows promise for DIPG

http://www.asco.org/ASCOv2/Meetings/Abstracts?&vmview=abst_detail_view&confID=102&abstractID=77258

Many researchers feel that combination therapy is going to be important in combating DIPG.  It is exciting to see the combination therapy research.

DIPG Consensus Conference

On October 6 and 7^th in Bethesda, a potentially pivotal meeting took place.
http://web.ncifcrf.gov/events/DIPG/default.asp

This invitation-only conference brought together physicians that care for children with diffuse intrinsic pontine gliomas to talk about several key current issues facing DIPG research.  Some of the presentation titles include:

• A Death Sentence Without Tissue Diagnosis
• Translating Genomics Into Novel Therapeutic Strategies in Pediatric DIPG
• Using A Genetically Engineered Mouse Model of Brainstem Glioma as a Preclinical Tool
• Development of an International DIPG Registry
• Personalized Medicine in Translation: From the Tissue to Treatment in a Single trial
• Rapid Preclinical Development of Targeted Therapy Combinations for DIPG

Hopefully a Consensus Statement or White Paper will be issued as was done with the Toronto DIPG Think Tank.

http://www.ncbi.nlm.nih.gov/pubmed/21901544

The agenda and presenters can be found in the following link-
http://web.ncifcrf.gov/events/DIPG/agenda.pdf