The FDA has granted a fast-track designation to the STRO-002 antibody-drug conjugate (ADC) as a potential treatment for with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer.1
Precision cancer medicine uses targeted drugs and immunotherapies engineered to directly attack ovarian cancer cells with specific genetic abnormalities, leaving normal cells largely unharmed and can often be used instead of chemotherapy.
In order to identify which precision cancer medicines can be used molecular diagnostic testing, including DNA sequencing is necessary to identify cancer-driving abnormalities in a cancer’s genome. Once a genetic abnormality is identified, a specific targeted therapy that attacks a specific mutation or other cancer-related change in the DNA programming of the cancer cells can be selected for treatment. Cancer cells may differ from one another based on what genes have mutations. Precision cancer medicine utilizes molecular diagnostic testing, including DNA sequencing, to identify cancer-driving abnormalities in a cancer’s genome. This “genomic testing” is performed on a biopsy sample of the cancer and increasingly in the blood using a “liquid biopsy”
For example, the poly ADP-ribose polymerase (PARP) enzyme plays a role in DNA repair, including the repair of DNA damage from chemotherapy. Precision cancer medicines that target and inhibit this enzyme may contribute to cancer cell death and increased sensitivity to chemotherapy and are called PARP inhibitors. By blocking this enzyme, DNA inside the cancerous cells is less likely to be repaired, leading to cell death and possibly a slow-down or stoppage of tumor growth. PARP inhibitors are the first precision cancer medicine developed for ovarian cancer and many others are undergoing evaluation. PARP inhibitors are the single greatest advance in the management of ovarian cancer in a generation.
STRO-002 is a novel precision cancer medicine known as an antibody drug conjugate, a type of therapy that combines an antibody that targets a specific protein on the surface of tumor cells with a payload of powerful chemotherapy. STRO-002 targets the Folate receptor alpha (FRalpha) with SP8166, which is conjugated to a cleavable DBCO-3-aminophenyl-hemiasterlin drug-linker. The dually conjugated immunostimulant and cytotoxic drug on a single ADC molecule is intended to deliver two different drugs directly to the tumor, and not only kill tumor cells but also locally prime an immune response to the cancer cells.1-4
The most recently released data from the phase I dose trial showed that 10 of 31 evaluable patients responded to treatment with a disease control rate of 58% at 16 weeks, and 4 patients were on treatment for 52 weeks, with 3 patients continuing treatment for longer than 64 weeks. To be eligible, patients needed to have recurrent platinum-resistant or -refractory ovarian cancer and have previously received at least 2 platinum regimens and they were enrolled irrespective of their level of FRalpha expression, and no limit was set regarding the number of prior lines of chemotherapy received. The study has expanded and is now enrolling participants from clinical sites throughout the United States and Spain.
- Sutro Biopharma announces STRO-002 FDA fast track designation for patients with advanced ovarian cancer. News release. Sutro Biopharma, Inc. August 18, 2021. Accessed August 18, 2021. https://prn.to/2UuhmLR
- Sutro Biopharma announces encouraging interim data on STRO-002 phase 1 dose-escalation study for patients with ovarian cancer. News release. Sutro Biopharma, Inc. December 3, 2020. Accessed August 18, 2021. https://prn.to/3gdpzvD
- Naumann RW, Braiteh FS, Diaz JP, et al. Phase 1 dose-escalation study of STRO-002, an anti-folate receptor alpha (FRα) antibody-drug conjugate (ADC), in patients with advanced platinum-resistant/refractory epithelial ovarian cancer. Presented at: 2020 International Gynecologic Cancer Society Virtual Healthcare Conference; September 10-13, 2020; Virtual. https://bit.ly/3iAhP65.
- Naumann RW, Uyar D, Moroney JW, et al. STRO-002-GM1, a first in human, phase 1 study of STRO-002, an anti-folate receptor alpha (FRα) antibody drug conjugate (ADC), in patients with advanced platinum-resistant/refractory epithelial ovarian cancer (OC), including fallopian tube or primary peritoneal cancers. Presented at: 2020 AACR Virtual Annual Meeting I; April 27-28, 2020. Abstract CT125.