Purpose: Human papillomavirus (HPV) is found in 90% of squamous cell carcinomas of the anal canal (SCCA). We investigated the clinical validity of HPV circulating tumor DNA (ctDNA) detection in patients enrolled in the Epitopes-HPV02 trial that demonstrated the efficacy of docetaxel, cisplatin, and 5-FU as first-line chemotherapy in advanced SCCA. Experimental Design: According to the protocol, serum samples were collected before chemotherapy and on completion of chemotherapy. HPV16 ctDNA was quantified by droplet digital PCR (ddPCR) and correlated with prospectively registered patient characteristics and outcomes. A landmark was set at the time of chemotherapy completion for postchemotherapy progression-free survival (PFS) analyses. Results: Among 57 patients with HPV16-related advanced SCCA, HPV ctDNA was detected in 91.1% (95% confidence interval, 81.1–96.2) of baseline samples. Baseline HPV ctDNA levels were not associated with any patient characteristics; baseline ctDNA level below the cutoff obtained by AUC (area under the curve) was associated with a longer PFS (HR = 2.1; P = 0.04). Among the 36 patients who completed 5 months of chemotherapy, residual HPV ctDNA was detected after chemotherapy in 38.9% of patients. Residual HPV ctDNA detected at chemotherapy completion was associated with shorter postchemotherapy PFS (median PFS 3.4 months vs. not reached; HR = 5.5; P < 0.001) and a reduction of 1-year overall survival rate (OR = 7.0; P = 0.02). Conclusions: This prospective study in advanced SCCA demonstrated a significant prognostic impact of HPV ctDNA level before first-line chemotherapy and HPV ctDNA negativity after chemotherapy completion. With a limited cost and short turnaround, this assay is a promising tool to optimize the therapeutic management of SCCA. See related commentary by Morris, p. 2030

Cisplatin/gemcitabine association has been a standard of care for first‐line regimen in advanced biliary tract cancer nevertheless oxaliplatin/gemcitabine regimen is frequently preferred. Because comparative effectiveness in clinical outcomes of cisplatin‐ versus oxaliplatin‐containing chemotherapy is not available, a systematic review of studies assessing cisplatin/gemcitabine or oxaliplatin/gemcitabine chemotherapies in advanced biliary tract cancer was performed. Published studies evaluating cisplatin/gemcitabine or oxaliplatin/gemcitabine in advanced biliary tract cancer were included. Each study was weighted according to the number of patients included. The primary objective was to assess weighted median of medians overall survival (mOS) reported for both regimens. Secondary goals were to assess weighted median of medians progression‐free survival (mPFS) and toxic effects were pooled and compared within each arm. Thirty‐three studies involving 1470 patients were analyzed. In total, 771 and 699 patients were treated by cisplatin/gemcitabine and oxaliplatin/gemcitabine, respectively. Weighted median of mOS was 9.7 months in cisplatin group and 9.5 months in oxaliplatin group. Cisplatin‐based chemotherapy was significantly associated with more grade 3 and 4 asthenia, diarrhea, liver toxicity, and hematological toxicity. Sensitivity analysis including only the studies with the standard regimen of cisplatin (25–35 mg/m² administered on days 1 and 8) showed that the weighted median of mOS increased from 9.7 to 11.7 months but Gem/CDDP regimen remained more toxic than Gemox regimen. These results suggest that the Gem/CDDP regimen with cisplatin (25–35 mg/m²) administered on days 1 and 8 is associated with survival advantage than Gemox regimen but with addition of toxicity.

Locally advanced or metastatic squamous carcinoma of the anal canal (SCAC) has poor prognosis following platinum-based chemotherapy. Retifanlimab (INCMGA00012), a humanized monoclonal antibody targeting programmed death protein-1 (PD-1), demonstrated clinical activity across a range of solid tumors in clinical trials. We present results from POD1UM-202 (NCT03597295), an open-label, single-arm, multicenter, phase II study evaluating retifanlimab in patients with previously treated advanced or metastatic SCAC. Patients ≥18 years of age had measurable disease and had progressed following, or were ineligible for, platinum-based therapy. Retifanlimab 500 mg was administered intravenously every 4 weeks. The primary endpoint was overall response rate (ORR) by independent central review. Secondary endpoints were duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. Overall, 94 patients were enrolled. At a median follow-up of 7.1 months (range, 0.9-19.4 months), ORR was 13.8% [95% confidence interval (CI) 7.6% to 22.5%], with one complete response (1.1%) and 12 partial responses (12.8%). Responses were observed regardless of human immunodeficiency virus or human papillomavirus status, programmed death ligand 1 (PD-L1) expression, or liver metastases. Stable disease was observed in 33 patients (35.1%) for a DCR of 48.9% (95% CI 38.5% to 59.5%). Median DOR was 9.5 months (range, 5.6 months-not estimable). Median (95% CI) PFS and OS were 2.3 (1.9-3.6) and 10.1 (7.9-not estimable) months, respectively. Retifanlimab safety in this population was consistent with previous experience for the PD-(L)1 inhibitor class. Retifanlimab demonstrated clinically meaningful and durable antitumor activity, and an acceptable safety profile in patients with previously treated locally advanced or metastatic SCAC who have progressed on or are intolerant to platinum-based chemotherapy.

Squamous cell carcinoma of the anal canal (SCCA) is a rare disease, mostly diagnosed at early stage. After concurrent chemoradiation (CRT) with mitomycin C and 5-fluorouracil (5FU), local or metastatic recurrences occur in >20% of the patients. After treatment failure, cisplatin (CDDP)-based chemotherapy is the standard option, but complete response (CR) is a rare event and the prognosis remains poor. Eight consecutive patients with advanced recurrent SCCA after CRT were treated with DCF regimen (docetaxel 75 mg/m² day 1, CDDP 75 mg/m² day 1 and 5FU at 750 mg/m²/day for 5 days every 3 weeks). Tumour samples were analysed for human papillomavirus (HPV) genotyping, as well as p16 and p53 expression. After a median follow-up of 41 months, the overall survival rate at 12 months was 62.5% (95% CI 22.9–86.1 months). Four patients achieved a complete remission and remain relapse-free at the time of analysis with a progression-free survival of 19, 33, 43 and 88 months. Three of these patients underwent surgery for all involved metastatic sites. For all of them, pathological CR was confirmed. DCF regimen appeared feasible in these patients previously exposed to pelvic CRT, and no grade IV toxicity occurred. All patients in complete remission had HPV-16-positive SCCA, while HPV could only be detected among 50% of the non-responding patients. Of interest, immunohistochemical study revealed a p16⁺/p53⁻ phenotype in these patients, while none of non-responders expressed p16. The high level of complete and long-lasting remission among SCCA patients treated with DCF regimen supports the assessment of this strategy in prospective cohorts.