Patients with persistent, recurrent, and metastatic gynecologic malignancies have poor outcomes and low cure probability (1–4). Treatment options for this population are often limited to systemic therapy (5–7) and their responses rates are relatively lower (2, 3, 8, 9). Recent studies have demonstrated that targeted agents (9–11) and immune checkpoint inhibitors (12–14) exert antitumor activity in multiple tumor types, including gynecologic malignancies. However, persistent, recurrent, or metastatic gynecological malignancies are often present in a single or isolated lesion. These patients often received multiple chemotherapy or high-dose radiation treatments, which reduced the quality of their health and result in less benefit from systemic therapy. Therefore, local therapy is more likely to be an effective strategy, in which precision radiotherapy is an important option for local therapy (15–17). Unfortunately, for the patients who had received radiotherapy before, it is difficult to achieve satisfactory prescription dose again.

Oncolytic virus (OVs) therapy is one of the most promising new anti-tumor therapies and is being increasingly used in the clinic with favorable results (18, 19). There are various modes of administration for OVs therapy, including intratumoral injection, intravenous delivery, and pleural, peritoneal, and intravesical administration (20–22), of which local intratumoral injection is the most standard delivery route. These viruses can selectively replicate in tumor cells, inducing oncolytic responses in their targets and stimulating immune response that attracts more immune cells to kill the remaining tumor cells (23, 24).

Recombinant human adenovirus type 5 (H101) is the first commercialized OVs in the world. The gene encoding the 55 kDa E1B protein responsible for p53 binding and inactivation in H101 has been deleted to confer p53-selective replication of OVs, thereby inducing p53 accumulation, resulting in direct and selective cytotoxicity in tumor cells during replication (25). In 2005, H101 was approved by the National Medical Products Administration (NMPA) of China for treating nasopharyngeal carcinoma. Moreover, the virus has also exhibited anti-cancer properties in head and neck carcinoma and gastric cancer (26, 27), but its effect on gynecologic malignancies remains unclear. Here, this study aimed to assess the efficacy and safety of H101 mono- or combination therapy in patients with persistent, recurrent, metastatic gynecologic malignancies, which provide a new strategy for the treatment of persistent, recurrent, or metastatic gynecologic malignancies.

Persistent, recurrent, and metastatic gynecological tumors are mostly treated with platinum-containing systemic therapy (3, 5, 28). However, the effective rate of treatment is limited, and the prognosis is poor (1–4). For localized and isolated lesions, LC has a significant impact on disease control and survival. Here, our study introduced a model with topical H101 as the main regimen and found that it showed anti-tumor activity with generally manageable safety in our test population. To the best of our knowledge, this study was the first to explore oncolytic viruses in gynecologic malignancies.

Of our 29 patients, 13 patients achieved LC, reaching a 44.8% rate in three months. Furthermore, 21 patients responded to treatment, achieving 72.4% ORR. These positive outcomes were consistent with previous studies in other cancers (29). Indeed, our treatment led to an even higher CR. It is worth mentioning that the single-agent application of H101 caused LC in 5 of the 29 patients in the study, and the single-agent LC rate was 17.2% without recurrence by the analysis deadline, demonstrating the effectiveness of H101 itself in this population. The LC rate increased to 44.8% after the combination of other treatments, demonstrating the necessity of combination therapy. Among the 13 patients who achieved LC, 5 of them with small residual lesions (<2 cm) received 1-2 courses of H101 treatment alone, and 5 with medium (2-4 cm) residual lesions were treated with H101 combined brachytherapy or external-beam radiotherapy (EBRT). The remaining 3 patients had large residual tumors (>4 cm) after radical chemoradiotherapy and received H101 intratumor injections. This intervention caused further tumor regression and created conditions for surgery, eventually leading to pathological CR. Our findings indicated that residual tumor size may be an important reference for choosing combination therapy. Up to the end of our follow-up period, none of the LC patients relapsed, except for 1 patient. She developed PD from pulmonary metastasis at 8.9 months follow-up. However, her local cervical lesion remained free of recurrence until the study ended (18.5 months follow-up).

All except 4 of the patients had received radiotherapy before recurrence, and 6 of them had received a second-course radiotherapy, which means that they may not be sensitive to radiotherapy. However, the ORR in our study was 72.4%, suggesting that H101 may increase the radiotherapy sensitivity. A prior study revealed that combining high doses of H101 and radiation yielded a synergistic anticancer effect in all tested cervical cancer cell lines (30). These outcomes are in line with research showing that OVs block DNA damage repair, sensitizing infected tumor cells to radiation and enhancing viral replication (22). Another in vivo test demonstrated that constant radiation combined with virotherapy eliminates cancer better than decay radiation and external beam radiation (31). In comparison, our study subjected 5 of 13 LC patients to combination H101 + brachytherapy at a relatively high radiation dose (four cases received interstitial brachytherapy). Therefore, H101 combined with radiotherapy may be a promising alternative for treating refractory gynecological malignancies. 4 patients who could no longer receive radiotherapy based on previous treatment history, local injection of H101 monotherapy may be an option. Additionally, patients with large local lesions may consider H101 injection to cause tumor regression before receiving brachytherapy (including interstitial needles); the combination of these two procedures should protect organs at risk of overdose while providing adequate radiation to the tumor, as demonstrated previously (32).

Notably, our target lesions were all accessible with the naked eye or palpation, enabling precise intratumor injection and high maneuverability. In the 21 responsive patients, we observed that tumor regression and reduction of necrotic tissue often occurred within the first five days of initial treatment. This encouraging progress led to great confidence for clinicians and patients, spurring the latter are compliance and promoting further treatment. The easily accessible tumors may thus be another possible reason for the beneficial effects observed in these patients.

Fever (70%) was the most common treatment-related side effect, occurring in a dose-depending manner consistent with other studies (33). In most patients, fever developed 1-24 h after H101 injection. Fever at 39°C was a self-limiting condition, while fevers higher than 39°C were treated with ibuprofen. 3 patients had grade 3 fever or flu-like symptoms that were effectively controlled with oral ibuprofen before injection and they generally recovered within 24 h. Other AEs included nausea/vomiting, fatigue, injection-site bleeding, and pain, but they all were transient and mild. However, 1 patient notably exhibited grade 4 thrombocytopenia after 10 days of H101 treatment. This individual had ovarian cancer and received 15 courses of chemotherapy plus two surgeries. The thrombocytopenia of grade ≥ 3 had also been reported in previous reports on treating ovarian cancer (34). Therefore, it cannot be determined whether the chemotherapy or H101 caused the grade 4 toxicity. In addition, 1 patient developed a rectovaginal fistula after H101 combined brachytherapy. This severe side-effect was first reported after OVs therapy, and radical chemoradiotherapy did not abolish the patient’s sizeable residual tumor. Although gynecological examination revealed “frozen pelvic change,” two more courses of H101 rapidly reduced the tumor. This significant tumor regression may be the main cause of fistula. Thus, chemoradiotherapy, targeted therapy, and H101 treatment together may be associated with adverse outcomes (35, 36).

Our study provided evidence that H101 monotherapy or combination therapy is safe and effective for treating patients with recurrent, refractory, metastatic gynecological malignancies. However, this study has some limitations. First, this study was a retrospective study, and there may be selection bias. Second, the sample size of this study was small. In the future, we aim to expand our sample size and collect tissue samples for fine-tuned analysis. The clinical trial has already been registered (ClinicalTrials.gov identifier: NCT05051696), aiming to evaluate the efficacy and safety of H101 intratumor injection combined with or without radiotherapy in refractory or recurrent gynecological malignancies, and further research the mechanism of H101.

The original contributions presented in the study are included in the article/supplementary material. Further inquiries can be directed to the corresponding author.

The study was approved by the Ethics Committee of The First Affiliated Hospital of Xi’an Jiaotong University, and informed consent was obtained from each participant. The patients/participants provided their written informed consent to participate in this study.

JZ and QZ conceived the study. JZ and QZ performed the literature search and writing of the manuscript. ZL, JW, and FS analyzed and interpreted the data. JS, TW, and FW collected and assembled the data. ZL submitted the manuscript and is the corresponding author. All authors contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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