An open label, phase II trial of continuous low-irradiance photodynamic therapy (CLIPT) using verteporfin for the treatment of cutaneous breast cancer metastases.

TPS1121 Background: Cutaneous metastases occur in approximately 20% of patients (pts) with metastatic breast cancer (mBC) and can be highly symptomatic and distressing. Radiation is frequently offered, but progression often occurs quickly. Photodynamic therapy is a promising approach with encouraging results in small studies. Here we will evaluate a novel Continuous Low-Irradiance Photodynamic Therapy (CLIPT) system that emits 690nm LED via a handheld powerpack attached to a single-use sterile light patch to deliver a total energy level of 10J/cm2. Verteporfin (Visudyne) is a photosensitizer approved for ophthalmological use that when combined with CLIPT generates activated oxygen species which can destroy tumor cells with limited normal tissue reaction. Methods: This open label, phase 2 study will evaluate the efficacy and safety of CLIPT with verteporfin in 15 pts with cutaneous lesions from mBC. Pts will receive a single IV injection of verteporfin on day 1. The 9x9cm patch with an adhesive border is placed over the treatment site and attached to the CLIPT portable power pack. The pt turns the device on at home 6 hours after the verteprofin injection and it automatically turns off after 24 hours. The pt will remove the patch and return to clinic on day 3. The primary endpoint is objective response rate (RR) at 3 weeks following CLIPT using a modified RECIST which accounts for nodular or diffuse plaque-like lesions. Secondary endpoints include RR at 2, 8 and 12 weeks, toxicity, and quality of life (using FACT-B, a Participant Symptom Scale, and Brief Pain Inventory). Pts who derive clinical benefit may be retreated up to 3 times to the same or different region. Eligible pts will have: cutaneous metastases from mBC with measurable disease by protocol defined modified RECIST 1.1, ≥ 1 line of prior systemic or local therapy for mBC, ≥ 14 days from prior systemic therapy or 60 days from radiation to target lesion, and no expectation for systemic therapy for ≥ 14 days after CLIPT. RR will be reported with 95% CI. If ≥ 3 responses (RR ≥ 20%) are observed, the null hypothesis of RR ≤ 5% will be rejected. At the time of abstract submission, 1 patient has been accrued. Clinical trial information: NCT02939274.

Radiation Therapy Combined with Photofrin or 5-Ala: Effect on Lewis Sarcoma Tumor Lines Implanted in Mice. Preliminary Results

Aims and background Ionizing irradiation is a well-established therapeutic modality for cancer. Photodynamic therapy (PDT), especially with 5-ALA and Photofrin, is highly effective in some tumor types. Chemical modifiers, so-called radiosensitizers, are used in order to increase the efficacy of radiotherapy. Most of the known and routinely used radiosensitizers are not tumor selective, so that the normal tissue reaction toxicity is also increased. In the present study we investigated whether a porphyrin derivative that is currently used as a tumor-photosensitizing agent in photodynamic therapy (PDT) may also act as a tumor-specific radiosensitizer. Materials and methods For our investigation we used Balb/c mice implanted with Lewis sarcoma and irradiated with 3 Gy combined with injection of 5-ALA or Photofrin at various concentrations before irradiation. Results 5-ALA had no effect as a radiosensitizer at any of the concentrations examined. Photofrin at a concentration of 5 mg/kg proved to be a chemical modifier of ionizing radiation, delaying tumor growth and reducing the overall tumor volume by about 50% after six days. Conclusion Photofrin has marked efficacy as a radiosensitizer and can be used in the future as a selective tumor radiosensitizer.