[Edaily Reporter NA EUN-KYUNG ] FutureChem Co., Ltd.(220100)announced on the 23rd the topline results of the U.S. Phase 2a clinical trial for its prostate cancer drug candidate “FC705.” Among the 18 patients with measurable lesions, tumor shrinkage or disappearance was observed in 7 patients.

FC705 is a radiopharmaceutical currently under development for metastatic castration-resistant prostate cancer. Castration-resistant prostate cancer refers to a condition in which the disease progresses despite treatment that suppresses male hormones. For patients whose cancer has metastasized to other organs, subsequent treatments are selected based on their prior treatment history and overall health status.

In May 2022, FutureChem Co., Ltd. received approval from the U.S. Food and Drug Administration (FDA) for the Investigational New Drug (IND) application for FC705’s Phase 1 and 2a clinical trials. Following the Phase 1 trial, the company announced the start of the Phase 2a trial in July 2023 and reported the first patient dosing in May 2024. This top-line data release comes approximately 4 years and 5 months after the approval of the clinical trial plan and approximately 2 years and 5 months after the announcement of the first patient dosing.

This Phase 2a trial was conducted at three institutions, including the University of Maryland Medical Center, and enrolled 20 patients. All enrolled patients had prior experience with taxane-based chemotherapy. Patients received FC705 at a dose of 100 mCi (3.7 GBq) per administration, up to six times at 8-week intervals.

The objective response rate (ORR), determined based on RECIST 1.1 criteria—which assess treatment response through changes in tumor size—was 38.9%. Among the 18 evaluable patients, 5 achieved a complete response (CR) and 2 achieved a partial response (PR). A complete response, as defined by these criteria, indicates the disappearance of lesions and is distinct from a cure of the cancer.

The disease control rate (DCR), which includes patients who achieved a complete or partial response as well as those whose disease remained stable without progression, was recorded at 83.3% (15 out of 18 patients). However, the company noted that this announcement is based on preliminary analysis results and that some figures may change during the preparation of the final results report (CSR).

FC705 is a drug in which the radioactive isotope lutetium-177 is attached to a substance that binds to prostate-specific membrane antigen (PSMA), which is abundantly expressed on the surface of cancer cells. The mechanism involves the PSMA-binding substance delivering the radioactive isotope to the cancer cells, where the radiation emitted then attacks the cancer cells. Unlike treatments that use external equipment to irradiate specific areas, this drug is administered directly into the body.

FutureChem Co., Ltd. has incorporated a structure into FC705 that binds to albumin, a protein found in the blood. This design is intended to increase the drug’s residence time in the bloodstream, thereby ensuring it reaches the tumor. The company explained that it is developing the drug to reduce the proportion of unbound drug that could be non-specifically absorbed by normal organs, such as the salivary glands. Actual safety must be confirmed through clinical analysis.

Novartis’ PSMA-targeted radiopharmaceutical “Flubicto” has already entered this market. Flubicto’s sales last year totaled $1.994 billion (approximately 2.6 trillion won), a 43% increase from the previous year. In the United States, the indication was expanded last March to include certain patients for whom chemotherapy can be deferred. FC705 now faces competition from a first-mover drug that has secured approval and a prescription base while expanding its scope of use.

The dose used in this FC705 trial is half of Fluvicto’s standard single dose of 200 mCi. However, the lower radiation dose alone does not necessarily indicate superior therapeutic efficacy or safety. FutureChem Co., Ltd. also stated that direct comparative clinical trials are needed to determine which drug is superior.

The company plans to utilize the data obtained from this U.S. clinical trial, along with existing domestic clinical results, for technology transfer negotiations and follow-up development. In the domestic Phase 2 clinical trial, tumor response was evaluated using PSMA positron emission tomography (PET), and this time, additional data based on the RECIST 1.1 criteria was obtained.

Safety analyses were not included in these topline results. FutureChem Co., Ltd. plans to disclose the relevant findings in a final results report later this year. A FutureChem Co., Ltd. official stated, “We are currently conducting a Phase 3 clinical trial in Korea, and we will prepare an application for conditional approval by compiling the clinical data.”