The U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation for STRO-001 for the treatment of multiple myeloma (MM).
In the United States, Orphan Drug Designation provides orphan status to drugs and biologics which are defined as those intended for the safe and effective treatment, diagnosis or prevention of rare diseases/disorders that affect fewer than 200,000 people in the U.S., or that affect more than 200,000 persons but are not expected to recover the costs of developing and marketing a treatment drug.
STRO-001, which is being developed by Sutro Biopharma, a clinical-stage drug discovery, development and manufacturing company, is a potential first-in-class antibody-drug conjugate or ADC targeting CD74, a type II transmembrane glycoprotein involved in the formation and transport of MHC class II protein which is highly expressed in B-cell malignancies such as multiple myeloma, follicular lymphoma, diffuse large B-cell lymphoma (DLBCL), chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) and other types of NH. 
“There is a growing need for new treatment options for patients with multiple myeloma,” commented Bill Newell, Sutro’s Chief Executive Officer.
“This Orphan Drug Designation is a great step towards advancing our uniquely designed STRO-001 that could bring new treatment options to patients in need.”
STRO-001 was developed with Sutro’s proprietary cell-free protein synthesis and site-specific conjugation platform, XpressCF+™, which facilitate precision design and rapid empirical optimization of ADCs.
The company’s technology platform is made possible by the separation, into an extract, of the cellular components required to produce proteins from the process of protein generation itself. The extract includes all the necessary biochemical components for energy production, transcription and translation and can be used to support cell-free biochemical protein synthesis by the addition of the specific DNA sequence for the desired protein. The process produces single proteins at g/L yields in 8-10 hours at any scale.
One of the benefits of Sutro’s technology is that it enables design and manufacture of a highly optimized single molecular species within the product, rather than the usual mixture of imprecisely conjugated antibodies that comprise an ADC development product made by conventional cell-based manufacturing platforms.
In addition, the platform helps accelerate discovery and development of potential first-in-class and best-in-class molecules through rapid and systematic evaluation of protein structure-activity relationships to create optimized homogeneous product candidates.
“STRO-001 was designed to directly target cancer cells to deliver a cytotoxic payload. Building upon our XpressCF+™ platform we plan to develop better options to treat tumors with greater precision,” Bill Newell explained.
Sutro’s proprietary and integrated cell-free protein synthesis and site-specific conjugation platform, XpressCF+™, led to the discovery of STRO-001 and STRO-002, Sutro’s first two internally-developed antibody drug conjugates
STRO-001 is currently being studied in a Phase I clinical trial enrolling separate dose escalation cohorts for myeloma and B-cell lymphoma.
The second drug being developed using Sutro’s proprietary platform, STRO-002, is a potentially best-in-class ADC targeting folate receptor alpha, a cell-surface protein highly expressed in gynecological cancers.