Oncolytic Virus Wins FDA Fast Track Designation in Soft Tissue Sarcoma

The U.S. Food and Drug Administration (FDA) has granted fast track designation to treatment with CLD-201 (SuperNova), an allogeneic adipose stem-cell loaded oncolytic virus, for patients with soft tissue sarcoma, according to a news release from Calidi Biotherapeutics, Inc.

“FDA investigational new drug clearance and fast track designation represents an important milestone in the development of CLD-201,” Dr. Guy Travis Clifton, chief medical officer of Calidi stated in the news release. “This designation underscores the unmet medical need in sarcoma and provides scientific and regulatory validation of CLD-201. We believe CLD-201 has the potential to provide durable and transformational treatment to patients with sarcoma as well as patients with other advanced tumor types. We want to thank the FDA for its support and partnership and look forward to continued collaboration with the agency.”

A fast track designation from the regulatory agency is granted to therapeutic agents that are being developed to treat serious or life-threatening conditions, such as (in this case) soft tissue sarcoma. Moreover, the product in question must demonstrate the potential to address unmet medical needs.

The intent of this designation is to facilitate development and expedite review of qualifying drugs, like CLD-201, which will benefit from this designation. Frequent interactions with the FDA, as well as eligibility for priority review and accelerated approval are all benefits to come out of a fast track designation from the U.S. FDA.

More Information CLD-201 and Its Clinical Designations

On April 17, 2025, the U.S. FDA granted investigational new drug clearance to CLD-201, and in turn, Calidi Biotherapeutics is planning a phase 1 first-in-human, open-label, multicenter clinical trial to evaluate the safety, tolerability and efficacy of CLD-201 in sarcoma, triple-negative breast cancer, and head and neck squamous cell carcinoma

“This allogeneic virotherapy product can transform how we treat cancer. It’s a one-of-a-kind product that has never been manufactured before using adipose tissue-derived stem cells in combination with oncolytic vaccinia virus. Its versatility in being able to treat solid tumors is remarkable,” Allan Camaisa, CEO and chairman at Calidi, stated in a previous news release, on the topic of the investigational new drug clearance. “I am proud of our executives and staff that have worked tirelessly to make this application possible.”

CLD-201 consists of adipose-derived mesenchymal stem cells (AD-MSCs) engineered to carry an oncolytic vaccinia virus for the treatment of advanced solid tumors, including sarcoma, triple-negative breast cancer, and head and neck squamous cell carcinoma. Loading the oncolytic virus into stem cells shields the virus from immune system clearance and enables it to replicate within the stem cells.

This approach has demonstrated increased potency, immune activation, and improved efficacy in preclinical animal models.

What is an Oncolytic Vaccine?

Oncolytic virotherapy is an emerging cancer treatment that uses specially modified viruses to target and destroy cancer cells, according to research published in Frontiers in Immunology. Researchers wrote that these viruses multiply inside the cancer cells, causing them to break apart, and also help the immune system recognize and attack the tumor. In addition to killing cancer cells directly, these viruses can change the environment around the tumor to support a longer-lasting immune response.

Although early research has shown encouraging results, only a few oncolytic viruses are currently approved for use in patients. One notable option is the vaccinia virus, like what is used in CLD-201, which can infect many different types of cancer cells.

References

1. “Calidi Biotherapeutics Receives FDA Fast Track Designation For CLD-201 (Supernova), A First-in-class Stem-cell Loaded Viral Therapy For The Treatment Of Patients With Soft Tissue Sarcoma.” News release. Calidi Biotherapeutics, Inc. July 29, 2025.
2. “Calidi Biotherapeutics Announces Fda Clearance Of Ind Application For Cld-201 In Solid Tumors.” News release. Calidi Biotherapeutics, Inc. April 17, 2025.
3. “Oncolytic vaccinia virus and cancer immunotherapy,” by Dr. Lihua Xu, et al. January 11, 2024. Frontiers in Immunology.

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