Abstracts

HspE7 Treatment of High-Grade Anal Dysplasia: Final Results of an Open-Label Trial and Interim Long-Term Follow-up

Abstract presented at HPV 2002 - Paris, France

Palefsky J (1), Goldstone S (2), Neefe J (3)

1) University of California at San Francisco, San Francisco, CA, USA
2) Mt. Sinai School of Medicine, New York City, NY, USA
3) Stressgen Biotechnologies, Inc., Collegeville, PA, USA

Background:
We update previously reported interim results with HspE7, a recombinant fusion protein of Hsp65 from BCG and E7 protein from HPV 16, for the treatment of high-grade anal dysplasia (HSIL).

Methods:
82 patients (pts) (80 evaluable) with HSIL received open-label treatment with HspE7 500 mcg subcutaneously (SC) monthly x3 (Study 9902). Response was taken as the highest-grade dysplasia after cytology and high-resolution anoscopy with biopsy. 57 evaluable pts gave informed consent for additional periodic biopsies and anoscopy (Study 0003).

Results:
At 6 months (m) in 9902, 61/80 (76%) pts responded with improvement to low-grade SIL (LSIL). No complete responses (CR, absence of HSIL or LSIL) were observed at 6 m. HspE7 was well tolerated. 78/82 (95%) pts in 9902 reported adverse experiences related to HspE7, most commonly mild injection site reactions and asthenia. In Study 0003, 54/57 (95%) pts showed CR or partial response (PR) by 15 m; median time to first reduction in disease state was 96 days. 25/57 pts (44%) showed CR by 15 m. The median time to CR could not be estimated; 15 CR occurred within 9 m. 16/25 (64%) CRs were maintained throughout the observation period (up to 2 years).

Conclusions:
Our data suggest that HspE7 500 mcg SC x3 is active in the treatment of anal HSIL, converting most pts from HSIL to LSIL within 3-6 m of starting therapy. CRs were observed within 9-15 m; 64% of CRs were durable through the observation period of up to 2 years. Elucidation of the full extent and duration of the CRs requires additional long-term follow-up.