Letter of Support (LOS)
Biomarker Letter of Support
- What is a Letter of Support?
- Why CDER Issues Letters of Support?
- How to Request a Letter of Support?
- FDA Issued Letters of Support
What is a Letter of Support?
This is a letter issued to a requester that briefly describes CDER’s thoughts on the potential value of a biomarker and encourages further evaluation. This LOS does not imply qualification of a biomarker and does not endorse a specific biomarker test or device. It is meant to enhance the visibility of the biomarker, encourage data sharing, and stimulate additional studies. A letter of support request should include the information listed in the Letter of Support Request: Content Elements outline.
Why CDER Issues Letters of Support?
An LOS is issued for promising biomarkers which have not yet been accepted into the CDER Biomarker Qualification Program. CDER encourages the early identification of novel biomarkers that may address drug development needs. The intent of the LOS is to enhance the visibility of these biomarkers, make public FDA’s support for continued development, and encourage data sharing and collaboration. When issued, both the LOS and the requester’s contact information are made publicly available on this website..
How to Request a Letter of Support?
An LOS request should be submitted along with a draft LOS in the format provided below. This information should be submitted via CDER’s NextGen Collaboration Portal.
For detailed instructions and video guidance on how to transmit a submission through NextGen Collaboration Portal to the Biomarker Qualification Program, please select the “Get Started with your Submission (FAQs)” button below:
GET STARTED WITH YOUR DDT SUBMISSION(FAQs)
For more information, please contact CDER-BiomarkerQualificationProgram@fda.hhs.gov.
Information for Requester:
- Letter of Support Request: Content Elements (PDF - 25 KB)
- Draft Letter of Support (DOC - 27 KB)
List of FDA Issued Letters of Support
Requester
|
Biomarker(s)
|
Area(s) for Use in Drug Development
|
Issuance Date with Link to Letter of Support
|
Requester Contact
|
---|---|---|---|---|
Critical Path Institute | Alpha-synuclein seeding amplification assay | For the application of binary assessment of α-syn SAA as an enrichment biomarker for patient selection in clinical trials investigating therapies that are intended to treat, prevent, or delay neurodegenerative disorders characterized by a common synuclein biology. | 8/19/2024: Letter of Support (PDF - 425 KB) | Diane Stephenson, PhD |
Nordic Bioscience | PRO-C3 fragment of collagen III in plasma | Prognostic biomarker for enrichment of clinical trials of solid tumors | 6/6/2023: Letter of Support (PDF - 391 KB) | Daniel Guldager Kring Rasmussen, MSc, PhD |
C-Path, PSTC | Molecular Biomarkers: miR-217, miR-216a, miR-216b, and miR-375 | Translational safety biomarkers to detect and monitor drug-induced pancreatic injury | 5/5/2023 Letter of Support (PDF - 158 KB) | Refer to Predictive Safety Testing Consortium Website |
Joint Head and Neck Radiotherapy-MRI Development Cooperative / MD Anderson Cancer Center |
Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) quantitative parameters, Ktrans and Ve, for monitoring of mandibular injury/osteoradionecrosis |
DCE-MRI Ktrans and Ve as exploratory monitoring biomarkers of osteoradionecrosis (ORN) in at risk patients with head and neck cancer (HNC) treated with radiation therapy | 11/23/21: Letter of Support (PDF - 137 KB) | Dr. Stephen Lai |
Nordic Bioscience A/S, Bristol Myers Squibb (BMS), University of Pennsylvania (UPENN) |
PRO-C6 |
Heart failure with preserved ejection fraction (HFpEF) |
8/25/21 Letter of Support (PDF - 202 KB) | Daniel Guldager Kring Rasmussen, MSc, PhD |
International Progressive Multiple Sclerosis Alliance Fluid Biomarkers Implementation Team |
Plasma/serum neurofilament light (NfL) chains |
Assess response to treatment in clinical trials |
5/25/21 Letter of Support (PDF - 241 KB) | Kathryn Smith |
sRNAlytics, Inc. | Isomicro-RNAs’ levels in blood as measured by assay | As a monitoring biomarker, indicating progression of Huntington’s Disease in patients bearing the HD mutation | 1/17/19: Letter of Support (PDF) | David W. Saltzman |
NeuroRx, Inc. | Glx (Glutamine and Glutamate) in the brain as measured by Magnetic resonance spectroscopy | As a pharmacodynamic biomarker, an objective imaging biomarker measure of depression to be used in conjunction with current measures of depression (rating scales) in clinical trials. | 4/3/18: Letter of Support (PDF) | Johnathan C. Javitt |
FLUIDDA, Inc. | Functional Respiratory Imaging (FRI) of Lung and Airway Structural and Functional Parameters Measured by Low-dose High-definition Volumetric Computerized Tomography (HDCT) Scans and Quantitative Imaging Technology | Exploratory pharmacodynamic/response (PD/R) biomarkers for use in bioequivalence (BE) studies of locally-acting orally-inhaled drug products (LAOIDP) in clinical trials of patients with conditions of the lung | 1/10/18: Letter of Support (PDF) | Jan De Backer |
TBI Endpoints Development (TED) Initiative and Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) | Glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase-L1 (UCH-L1) in blood | Exploratory prognostic enrichment biomarkers to identify patients who are likely to develop persistent disability during the course of mild traumatic brain injury (TBI) clinical trials | 1/10/18:Letter of Support (PDF) | Dr. Geoff Manley or view TED Initiative website and/or TRACK-TBI website |
Health and Environmental Sciences Institute (HESI) Genomics Committee | Genomic biomarker panel TGx-DDI | Exploratory safety biomarker panel to facilitate safety genotoxicity assessment in nonclinical studies | 10/24/17; Letter of Support (PDF) | Syril Petit or view the HESI committee website |
TBI Endpoints Development (TED) Initiative and Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) | Cortical contusions and diffuse axonal injury, as measured by magnetic resonance imaging (MRI) | Exploratory prognostic enrichment biomarkers to identify patients who are likely to develop persistent disability during the course of mild traumatic brain injury (TBI) clinical trials | 3/31/17: Letter of Support (PDF) | Dr. Geoff Manley or view TED Initiative website and/or TRACK-TBI website |
Safer and Faster Evidence-based Translation (SAFE-T) Consortium and Predictive Safety Testing Consortium (PSTC) | urinary alpha-glutathione S-transferase (α-GST), urinary clusterin (CLU), urinary cystatin C (CysC), urinary Kidney Injury Molecule-1 (KIM-1), urinary neutrophil gelatinase-associated lipocalin (NGAL), urinary osteopontin (OPN), urinary albumin (ALB) and urinary total protein (TPRO) | Exploratory safety biomarkers for monitoring drug-induced renal tubular injury in early clinical drug development | 11/23/2016: Letter of Support (PDF) | Gary Steven Friedman, Stefan Sultana, Jean-Charles Gautier, John-Michael Sauer or view either the Critical Path Institute Website or the IMI SAFE-T Consortium Website |
Safer and Faster Evidence-based Translation (SAFE-T) Consortium and Predictive Safety Testing Consortium (PSTC) | Soluble biomarkers of endothelial cell injury and inflammation: E-Selectin, P-Selectin, sICAM-1, sICAM-3, sVCAM-1, thrombomodulin VEGF, CRP, GROa, IL-6, IL-8, IP-10, I-TAC, MCP-1, MIG, SAA and MIP-1a | Exploratory safety biomarkers for monitoring drug-induced vascular injury (DIVI) in early clinical drug development | 11/7/2016: Letter of Support (PDF) |
Michael Lawton, Tanja Zabka, Brad Enerson, John-Michael Sauer or view either the Critical Path Institute Website or the IMI SAFE-T Consortium Website |
The Safer and Faster Evidence-based Translation Consortium (SAFE-T) |
Cytokeratin 18 (CK‐18), Total and Hyperacetylated High Mobility Group Protein B1 (HMGB1), Osteopontin, and Macrophage Colony-Stimulating Factor 1 Receptor (CSF1R) |
Exploratory Monitoring Biomarkers for Use in Drug Development as a Clinical Safety Assessment of the Risk of Drug-induced Liver Injury (DILI) Progression |
7/25/2016: Letter of Support (PDF) |
Drs. Gerd Kullak-Ublick, Sif Ormarsdottir, John-Michael Sauer or Douglas Keller or view either the Critical Path Institute Website or the IMI SAFE-T Consortium Website |
Mosaiques-diagnostics |
CKD273 |
Prognostic Enrichment Biomarker Panel for use in Early Stage Diabetic Kidney Disease |
6/14/2016: Letter of Support (PDF) |
|
FLUIDDA |
Functional Respiratory Imaging (FRI) of Lung and Airway Structural and Functional Parameters Measured by Low-dose High-definition Volumetric Computerized Tomography (HDCT) Scans and Quantitative Imaging Technology |
Prognostic Biomarkers of Disease Progression and Pharmacodynamic Response for use in Idiopathic Pulmonary Fibrosis (IPF) |
||
Xhale, Inc. |
2-Butanone in Human Breath |
Monitoring Biomarker to Evaluate Drug-Dosing Compliance on a Dose-by-Dose Basis |
11/19/2015:Letter of Support (PDF) |
|
Memorial Sloan-Kettering Cancer Center, Medivation Inc., and Janssen Diagnostics, LLC |
Circulating Tumor Cell (CTC) Enumeration |
Disease Activity Biomarker for use in Metastatic Castration-resistant Prostate Cancer (mCRPC) |
9/25/2015: Letter of Support (PDF) |
|
C-Path, Polycystic Kidney Disease (PKD) Outcomes Consortium |
MRI, Computerized Tomography (CT), or Ultrasound (US) Biomarker: Total Kidney Volume (TKV) |
Exploratory Prognostic Biomarker for Enrichment in Autosomal Dominant Polycystic Kidney |
4/23/2015: Letter of Support (PDF) |
Refer to Polycystic Kidney Disease Outcomes Consortium Web Site |
C-Path, CAMD |
Molecular Neuroimaging Biomarker: Dopamine Transporter (DAT) |
Exploratory Prognostic Biomarkers for Enrichment in Early Stage Parkinson's Disease Clinical Trials |
3/16/2015: Letter of Support (PDF) |
Refer to Coalition Against Major Diseases Web Site |
C-Path, CAMD |
Magnetic Resonance Imaging Biomarker: Low Baseline Hippocampal Volume |
Exploratory Prognostic Biomarkers for Enrichment in Early Stage Alzheimer's Disease Clinical Trials |
3/10/2015: Letter of Support (PDF) |
Refer to Coalition Against Major Diseases Web Site |
C-Path, Coalition Against Major Diseases Consortium (CAMD) |
Cerebral Spinal Fluid (CSF) Analyte Biomarkers: Aβ1-42, Total tau, Phosphotau |
Exploratory Prognostic Biomarkers for Enrichment in Early Stage Alzheimer’s Disease Clinical Trials |
2/26/2015: Letter of Support (PDF) |
Refer to Coalition Against Major Diseases Web Site |
C-Path, PSTC, Skeletal Muscle Working Group (SMWG) |
Serum and Plasma Biomarkers: Myosin Light Chain 3 (Myl3), Skeletal Muscle Troponin I (sTNI), Fatty Acid Binding Protein 3 (FABP3), Creatine Kinase, Muscle Type (CK-M, the Homodimer CK-MM) |
Early Clinical Drug Development |
1/22/2015: Letter of Support (PDF) |
Refer to Predictive Safety Testing Consortium Web Site |
Critical Path Institute's (C-Path) Predictive Safety Testing Consortium (PSTC), Nephrotoxicity Working Group (NWG) |
Urinary Biomarkers: Osteopontin and Neutrophil Gelatinase-associated Lipocalin (NGAL) |
Early Clinical Drug Development |
8/20/2014: Letter of Support (PDF) |
Refer to Predictive Safety Testing Consortium Web Site |