OBJECTIVE
To evaluate the efficacy and safety of recombinant adenovirus-p53 (Adp53, SBN-1) combined with radiotherapy in treatment of head and neck squamous cell carcinoma (HNSCC).
METHODS
Forty-two patients with HNSCC were randomly divided into 2 groups: gene therapy + radiotherapy group (GTRT group. n = 20, SBN-1 solution 1 x 10(12) VP was injected intratumorally once a week for 8 weeks and radiotherapy was begun since the 3rd day of gene therapy 5 fractions a week with the with the fraction dosage of 2 Gy and total dosage of 70 GY) and radiotherapy group (RT group. n = 22, the above regimen of radiotherapy was conducted). CT was conducted 5 weeks and 8 weeks after the beginning of treatment and 2 months after the finish of treatment (validation point) to calculate the size of tumor. Patients were monitored for adverse event and serum level of anti-adenoviral antibody. A comparative study was also performed on the immediate response rate by CT at the times when the dosages of 40 Gy and 70 Gy had been given.
RESULTS
The average tumor reduction rates were (63 +/- 17)%, (82 +/- 18)%, and (90 +/- 16)% at the 40 Gy time point, 70 Gy time point, and validation point respectively in the GTRT group, all higher than those in the RT group (37 +/- 26)%, (62 +/- 39)%, and (70 +/- 34)% respectively, all P < 0.05. Random control study showed that the radio-sensitized enhancement rate was 1.72 at 40 Gy time point and the CR rate of the GRTR group at the validation point was 1.68 times higher than that of the RT group. Self-controlled study showed that the SBN-1 radio-sensitized enhancement ratio in the 4 GTRT group was 1.69 at 40 Gy time point and the CR rate of the GTRT group at validation point was 253% that of the RT group (P < 0.01). No dose-limiting toxicity and adverse events were noted, except transient fever after SBN-1 administration.
CONCLUSION
A potentially effective gene therapeutic agent for HNSCC treatment, intratumoral injection of SBN-1 is safe.