Pathological response in children and adults with large unresected intermediate-grade or high-grade soft tissue sarcoma receiving preoperative chemoradiotherapy with or without pazopanib (ARST1321): a multicentre, randomised, open-label, phase 2 trial

A phase II study on the neo-adjuvant combination of pazopanib and radiotherapy in patients with high-risk, localized soft tissue sarcoma

PURPOSE

A prior phase I study showed that the neo-adjuvant combination of pazopanib and radiotherapy was well tolerated, and induced promising pathological responses in soft-tissue sarcoma patients. Results of the subsequent prospective, multicenter phase II, PASART-2 trial are presented here, further investigating the efficacy and safety of this combination.

PATIENTS AND METHODS

Patients with high-risk, localized soft-tissue sarcoma received neo-adjuvant radiotherapy, 50 Gy in 25 fractions (PASART-2A) or with a subsequent dose de-escalation to 36 Gy in 18 fractions (PASART-2B). This was combined with 800 mg once daily pazopanib, which started one week before radiotherapy and finished simultaneously. After an interval of 4-8 weeks, surgical resection was performed. The primary endpoint was the rate of pathological complete responses (pCR), defined as ≤5% viable cells.

RESULTS

25 patients were registered in the study, 21 in PASART-2A and 4 in PASART-2B. After central pathology review, the combination treatment led to a pCR in 5 patients (20%). 17 patients (68%) experienced grade 3+ toxicities during neo-adjuvant treatment, of which the most common were alanine aminotransferase (ALT) elevation, aspartate aminotransferase (AST) elevation, and hypertension, all asymptomatic. Grade 3+ acute post-operative toxicities occurred in 5 patients (20%), of which the most common was wound infection. All patients completed the full radiotherapy regimen and underwent surgery. Pazopanib was discontinued before completion in 9 patients (36%), due to elevated ALT and/or AST, and shortly interrupted in 2 patients (8%), due to hypertension.

CONCLUSION

Apart from asymptomatic hepatotoxicity, the study regimen was well tolerated. Although the pre-specified efficacy endpoint (30% pCR) was not met, a more than doubling of historical pCR rates after neo-adjuvant radiotherapy alone was observed, which warrants further investigation.

Synovial Sarcoma in Children, Adolescents, and Young Adults: A Report From the Children's Oncology Group ARST0332 Study

PURPOSE

Synovial sarcoma (SS) is the second most common malignant soft tissue tumor in children. ARST0332 evaluated a risk-based treatment strategy for young patients with soft tissue sarcoma designed to limit therapy for low-risk (LR) disease and to test neoadjuvant chemoradiotherapy for unresected higher-risk disease.

METHODS

Newly diagnosed patients with SS age < 30 years were assigned to four treatment arms based on disease features: A (surgery only), B (55.8 Gy radiotherapy [RT]), C (ifosfamide and doxorubicin [ID] chemotherapy plus 55.8 Gy RT), and D (neoadjuvant ID and 45 Gy RT, then surgery and RT boost based on margins followed by adjuvant ID). Patients treated in Arms A and B were considered LR, arms C and D without metastases as intermediate-risk (IR), and those with metastases as high-risk (HR).

RESULTS

Of the 146 patients with SS enrolled, 138 were eligible and evaluable: LR (46), IR (71), and HR (21). Tumors were 80% extremity, 70% > 5 cm, 70% high-grade, 62% invasive, 95% deep, and 15% metastatic. Treatment was on arm A (29.7%), B (3.6%), C (16.7%), and D (50%). There were no toxic deaths and four unexpected grade 4 adverse events. By risk group, at a median follow-up of 6.8 years, estimated 5-year event-free survival was LR 82%, IR 70%, and HR 8%, and overall survival was LR 98%, IR 89%, and HR 13%. After accounting for the features that defined risk category, none of the other patient or disease characteristics (age, sex, tumor site, tumor invasiveness, and depth) improved the risk stratification model.

CONCLUSION

The risk-based treatment strategy used in ARST0332 produced favorable outcomes in patients with nonmetastatic SS relative to historical controls despite using RT less frequently and at lower doses. The outcome for metastatic SS remains unsatisfactory and new therapies are urgently needed.

The Evolving Role of Radiotherapy for Pediatric Cancers With Advancements in Molecular Tumor Characterization and Targeted Therapies

Ongoing rapid advances in molecular diagnostics, precision imaging, and development of targeted therapies have resulted in a constantly evolving landscape for treatment of pediatric cancers. Radiotherapy remains a critical element of the therapeutic toolbox, and its role in the era of precision medicine continues to adapt and undergo re-evaluation. Here, we review emerging strategies for combining radiotherapy with novel targeted systemic therapies (for example, for pediatric gliomas or soft tissue sarcomas), modifying use or intensity of radiotherapy when appropriate via molecular diagnostics that allow better characterization and individualization of each patient’s treatments (for example, de-intensification of radiotherapy in WNT subgroup medulloblastoma), as well as exploring more effective targeted systemic therapies that may allow omission or delay of radiotherapy. Many of these strategies are still under investigation but highlight the importance of continued pre-clinical and clinical studies evaluating the role of radiotherapy in this era of precision oncology.

Identified Enrollment Challenges of Adolescent and Young Adult Patients on the Nonchemotherapy Arm of Children's Oncology Group Study ARST1321

ARST1321, a trial of patients with advanced soft tissue sarcoma, was the first National Clinical Trials Network study codeveloped by pediatric and adult consortia with two treatment cohorts. We report on the findings of a survey to identify barriers to enrolling adolescent and young adult patients (15-39 years) onto the nonchemotherapy arm. The survey response rate was 31% with a 70% completion rate. Common identified reasons for low accrual in order of decreasing frequency included insufficient funding, lack of study awareness or interest, competing trials, toxicity concerns, philosophical differences in the therapy backbone, and regulatory and infrastructure barriers. Clinical Trials.gov ID: NCT02180867.

Targeted and immuno-based therapies in sarcoma: mechanisms and advances in clinical trials

Sarcomas represent a distinct group of rare malignant tumors with high heterogeneity. Limited options with clinical efficacy for the metastatic or local advanced sarcoma existed despite standard therapy. Recently, targeted therapy according to the molecular and genetic phenotype of individual sarcoma is a promising option. Among these drugs, anti-angiogenesis therapy achieved favorable efficacy in sarcomas. Inhibitors targeting cyclin-dependent kinase 4/6, poly-ADP-ribose polymerase, insulin-like growth factor-1 receptor, mTOR, NTRK, metabolisms, and epigenetic drugs are under clinical evaluation for sarcomas bearing the corresponding signals. Immunotherapy represents a promising and favorable method in advanced solid tumors. However, most sarcomas are immune "cold" tumors, with only alveolar soft part sarcoma and undifferentiated pleomorphic sarcoma respond to immune checkpoint inhibitors. Cellular therapies with TCR-engineered T cells, chimeric antigen receptor T cells, tumor infiltrating lymphocytes, and nature killer cells transfer show therapeutic potential. Identifying tumor-specific antigens and exploring immune modulation factors arguing the efficacy of these immunotherapies are the current challenges. This review focuses on the mechanisms, advances, and potential strategies of targeted and immune-based therapies in sarcomas.

Receptor tyrosine kinase inhibitors for the treatment of osteosarcoma and Ewing sarcoma

Adjuvant chemotherapy for osteosarcoma and Ewing sarcoma consists of conventional cytotoxic regimens that have changed little over the past decades. There is an urgent need for agents that are more effective and have less long-term toxicity. Receptor tyrosine kinases regulate cell growth and proliferation of these tumors, and small-molecule inhibitors for many of these kinases are now available. In this article, we review published phase II trials for patients with recurrent disease and highlight the pathways targeted by available agents, as well as the toxicity and efficacy results seen to date. We also discuss the difficulties in identifying biomarkers to facilitate rational patient selection, as well as published and proposed strategies for how these inhibitors can be combined with conventional chemotherapy or other targeted agents. It is hoped future trials can capitalize on this growing experience to optimize the use of this exciting class of agents.

Pursuing Precision: Receptor Tyrosine Kinase Inhibitors for Treatment of Pediatric Solid Tumors

Receptor tyrosine kinases are critical for the growth and proliferation of many different cancers and therefore represent a potential vulnerability that can be therapeutically exploited with small molecule inhibitors. Over forty small molecule inhibitors are currently approved for the treatment of adult solid tumors. Their use has been more limited in pediatric solid tumors, although an increasing number of single-agent and combination studies are now being performed. These agents have been quite successful in certain clinical contexts, such as the treatment of pediatric tumors driven by kinase fusions or activating mutations. By contrast, only modest activity has been observed when inhibitors are used as single agents for solid tumors that do not have genetically defined alterations in the target genes. The absence of predictive biomarkers has limited the wider applicability of these drugs and much work remains to define the appropriate patient population and clinical situation in which receptor tyrosine kinase inhibitors are most beneficial. In this manuscript, we discuss these issues by highlighting past trials and identifying future strategies that may help add precision to the use of these agents for pediatric extracranial solid tumors.

What is the standard indication of adjuvant or neoadjuvant chemotherapy in localized soft-tissue sarcoma?

PURPOSE OF REVIEW

The aim is to bring latest evidence of the role of perioperative chemotherapy in localized soft-tissue sarcomas (STS) of limbs and to review the risk classification systems of retroperitoneal and extremity STS.

RECENT FINDINGS

High-risk subset of localized STS of limbs and trunk-wall, defined with classic prognostic factors, consistently obtained 5-year overall survival ranging from 69 to 76% in randomized patients treated with full-dose of anthracycline and ifosfamide. Validated nomograms accurately predict, on individual basis, the risk of death and recurrence in localized STS of retroperitoneum and limbs, enabling a better selection of high-risk patients (usually those with death risk of ≥40%) that potentially could benefit with perioperative systemic treatment. Nomograms have virtually converted a negative large perioperative trial into a positive, favouring chemotherapy arm in the high-risk selection.

SUMMARY

Perioperative three cycles of full-dose of anthracycline and ifosfamide should be proposed on an individual basis, in reference sarcoma centres, to high-risk localized STS of limbs or trunk-wall in certain histologies.

Paediatric non-rhabdomyosarcoma soft tissue sarcomas: the prospective NRSTS 2005 study by the European Pediatric Soft Tissue Sarcoma Study Group (EpSSG)

BACKGROUND

A standardised approach to treatment of paediatric non-rhabdomyosarcoma soft tissue sarcomas (NRSTS), which account for about 4% of childhood cancers, is still lacking. We report the results of the NRSTS 2005 protocol developed specifically by the European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) to determine a risk-adapted multimodal standard of care for this group of tumours.

METHODS

The EpSSG NRSTS 2005 study included two prospective, non-randomised, historically controlled trials (one on localised adult-type NRSTS and the other on localised synovial sarcoma) done at 100 academic centres and hospitals in 14 countries. Patients younger than 21 years with a pathologically proven diagnosis of synovial sarcoma or an adult-type NRSTS, no evidence of metastatic disease, no previous treatment other than primary surgery, and diagnostic specimens available for pathological review were included. Patients were stratified by surgical stage, tumour size, nodal involvement, tumour grade (for adult-type NRSTS), and tumour site (for synovial sarcoma). Patients were then divided into four treatment groups: surgery alone, adjuvant radiotherapy, adjuvant chemotherapy (with or without radiotherapy), or neoadjuvant chemotherapy (with or without radiotherapy). The main chemotherapy regimen was ifosfamide (3·0 g/m² intravenously per day for 3 days) plus doxorubicin (37·5 mg/m² intravenously per day for 2 days); only ifosfamide (3·0 g/m² intravenously per day for 2 days) was given concomitantly with radiotherapy (delivered with three-dimensional conformal external beam technique, using conventional fractionation [1·8 daily fractions, 5 days per week] at a dose of 50·4 Gy or 54·0 Gy, to a maximum of 59·4 Gy). The number of chemotherapy cycles ranged from three to seven depending on the stage of the disease. The primary outcomes were event-free survival and overall survival. This study has been completed, and is registered under EudraCT, 2005-001139-31.

FINDINGS

Between May 31, 2005, and Dec 31, 2016, 1321 patients were enrolled, of whom 569 (206 with synovial sarcoma and 363 with adult-type NRSTS), with a median age of 12·6 years (IQR 8·2-14·9), were included in this analysis. With a median follow-up of 80·0 months (IQR 54·3-111·3) for the 467 patients alive, 5-year event-free survival was 73·7% (95% CI 69·7-77·2) and 5-year overall survival was 83·8% (95% CI 80·3-86·7). 5-year event-free survival was 91·4% (95% CI 87·0-94·4) and 5-year overall survival was 98·1% (95% CI 95·0-99·3) in the surgery alone group (n=250); 75·5% (46·9-90·1) and 88·2% (60·6-96·9) in the adjuvant radiotherapy group (n=17); 65·6% (54·8-74·5) and 75·8% (65·3-83·5) in the adjuvant chemotherapy group (n=93); and 56·4% (49·3-63·0) and 70·4% (63·3-76·4) in the neoadjuvant chemotherapy group (n=209). Reported severe adverse events included one case of generalised seizures (probably related to ifosfamide) and six cases of secondary tumours.

INTERPRETATION

Findings from the EpSSG NRSTS 2005 study help to define the risk-adapted standard of care for this patient population. Adjuvant treatment can be safely omitted in the low-risk population (classified here as the surgery alone group). Improving the outcome for patients with high-risk, initially resected adult-type NRSTS and those with initially unresectable disease remains a major clinical challenge.

FUNDING

Fondazione Città della Speranza.

Apatinib with doxorubicin and ifosfamide as neoadjuvant therapy for high-risk soft tissue sarcomas: a retrospective cohort study

BACKGROUND

There is a need to establish an effective neoadjuvant therapy for soft tissue sarcomas (STSs). We previously showed that apatinib, administered in combination with doxorubicin-based chemotherapy, improves the efficacy of treatment. This study aimed to clarify the effectiveness and safety of apatinib combined with doxorubicin and ifosfamide (AI) neoadjuvant chemotherapy for STSs.

METHODS

This retrospective study included patients with STS who received neoadjuvant therapy and surgery between January 2016 and January 2019. The patients were divided into two treatment groups: AI + apatinib group and AI group (doxorubicin + ifosfamide).

RESULTS

The study included 74 patients (AI + apatinib: 26, AI: 48) with STS. There were significant between-group differences in objective response rates (53.85% vs. 29.17%, p = 0.047) and the average change in target lesion size from baseline (-40.46 ± 40.30 vs. -16.31 ± 34.32, p = 0.008). The R0 rate (84.62% vs. 68.75%; p = 0.170) and 2-year disease-free survival (73.08% vs. 62.50%, p = 0.343) were similar across groups. Finally, the rates of neoadjuvant therapy-related adverse effects and postoperative complications were similar in both groups (p > 0.05).

CONCLUSION

Apatinib plus doxorubicin and ifosfamide regimen is safe and effective as neoadjuvant therapy for patients with STS. However, the significantly improved preoperative ORR observed after neoadjuvant therapy did not translate into a significantly improved R0 rate and 2-year DFS. Prospective, well-powered studies are warranted to determine the long-term efficacy and optimal application of these protocols.

Rationale for the use of tyrosine kinase inhibitors in the treatment of paediatric desmoid-type fibromatosis

In children with desmoid-type fibromatosis (DTF) in whom disease progression occurs after an initial watch-and-wait strategy, prolonged low-dose chemotherapy using vinblastine and methotrexate (VBL-MTX) is currently the standard of care. These conventional drugs have been prospectively evaluated but their efficacy and safety profiles are limited, and alternative therapeutic options are therefore essential. Based on the results of clinical trials, the use of tyrosine kinase inhibitors (TKIs) in the treatment of DTF is currently considered only in adult patients. TKIs such as imatinib show superior therapeutic efficacy to VBL-MTX and tolerable short-term side effects for the treatment of adult DFT, supporting the concept of the use of TKIs for the treatment of paediatric DFT. Moreover, new-generation TKIs, such as pazopanib and sorafenib, have shown improved therapeutic efficacy compared to imatinib in adult non-comparative studies. A tolerable safety profile of TKI therapy in children with disease entities other than DTF, such as leukaemia, has been reported. However, the efficacy and, in particular, the long-term safety of TKIs, including childhood-specific aspects such as growth and fertility, for the treatment of children with DTF should be investigated prospectively, as DFT therapy requires long-term drug exposure.

Neoadjuvant hypofractionated radiotherapy and chemotherapy for extremity soft tissue sarcomas: Safety, feasibility, and early oncologic outcomes of a phase 2 trial

BACKGROUND AND PURPOSE

Optimal treatment of extremity soft tissue sarcomas (ESTS) is controversial. The aim of this study was to evaluate neoadjuvant chemotherapy (ChT) plus concomitant hypofractionated RT (hypo-RT) in local and distant disease relapse. Here we report safety, feasibility and early outcomes.

MATERIALS AND METHODS

This was a prospective, single arm study with a goal accrual of 70 patients. Between 2015 and 2018, 18 patients with histologically confirmed nonmetastatic ESTS were assigned to receive doxorubicin and ifosfamide for three neoadjuvant cycles, concomitant with hypo-RT (25 Gy in 5 fractions) followed by surgery. The primary endpoint was disease-free survival (DFS). Secondary outcomes were pathologic response, wound complications (WC), and morbidity rates.

RESULTS

Median follow-up was 29 months. At last follow-up, 13/18 patients were alive without evidence of local or systemic disease (DFS 72%), 1 had died due to metastatic disease, and 3 were alive with distant metastasis. One patient presented with local relapse within the irradiated field. Mean DFS time was 48.6 months (95% CI: 37.3-59.9). Six patients (33%) had no residual viable tumor detected in pathologic specimens (3 of these myxoid liposarcomas). There was a significant difference in WC among patients with acute RT skin toxicity. Six patients (33%) developed major WC. No grade 3 or 4 ChT adverse events were reported.

CONCLUSION

Despite the limited sample size, these early outcomes demonstrate that this treatment regimen is feasible and well tolerated with high rates of limb preservation, local control, and pathologic complete response, supporting further investigation in a multi-institutional setting.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02812654; https://clinicaltrials.gov/ct2/show/NCT02812654.

The in-vitro effect of famotidine on sars-cov-2 proteases and virus replication

The lack of coronavirus-specific antiviral drugs has instigated multiple drug repurposing studies to redirect previously approved medicines for the treatment of SARS-CoV-2, the coronavirus behind the ongoing COVID-19 pandemic. A recent, large-scale, retrospective clinical study showed that famotidine, when administered at a high dose to hospitalized COVID-19 patients, reduced the rates of intubation and mortality. A separate, patient-reported study associated famotidine use with improvements in mild to moderate symptoms such as cough and shortness of breath. While a prospective, multi-center clinical study is ongoing, two parallel in silico studies have proposed one of the two SARS-CoV-2 proteases, 3CLpro or PLpro, as potential molecular targets of famotidine activity; however, this remains to be experimentally validated. In this report, we systematically analyzed the effect of famotidine on viral proteases and virus replication. Leveraging a series of biophysical and enzymatic assays, we show that famotidine neither binds with nor inhibits the functions of 3CLpro and PLpro. Similarly, no direct antiviral activity of famotidine was observed at concentrations of up to 200 µM, when tested against SARS-CoV-2 in two different cell lines, including a human cell line originating from lungs, a primary target of COVID-19. These results rule out famotidine as a direct-acting inhibitor of SARS-CoV-2 replication and warrant further investigation of its molecular mechanism of action in the context of COVID-19.

Pathologic Response Rates after Neoadjuvant Therapy for Sarcoma: A Single Institution Study

(1) Background: Pathologic necrosis of soft tissue sarcomas (STS) has been used to determine treatment response, but its relationship to neoadjuvant treatments remains indeterminate. In this retrospective, single institution study, we hypothesized that neoadjuvant chemoradiation (NA-CRT) yields higher rates of pathologic complete response (pCR) than neoadjuvant radiation (NA-XRT) or chemotherapy (NA-CT) alone. (2) Methods: Patients with extremity STS between 2011-2020 who received neoadjuvant treatment were included. pCR was defined as percent necrosis of the surgical specimen greater than or equal to 90%. (3) Results: 79 patients were analyzed. 51.9% of the population were male with a mean age of 58.4 years. 49.4% identified as Non-Hispanic White. Twenty-six (32.9%) patients achieved pCR while 53 (67.1%) did not. NA-CT (OR 15.82, 95% CI = 2.58-96.9, p = 0.003 in univariate (UVA) and OR 24.7, 95% CI = 2.88-211.2, p = 0.003 in multivariate (MVA), respectively) and NA-XRT (OR 5.73, 95% CI = 1.51-21.8, p = 0.010 in UVA and OR 7.95, 95% CI = 1.87-33.7, p = 0.005 in MVA, respectively) was significantly associated with non- pCR when compared to NA-CRT. The analysis also demonstrated that grade 3 tumors, when using grade 2 as reference, also had significantly higher odds of achieving pCR (OR 0.23, 95% CI = 0.06-0.80, p = 0.022 in UVA and OR 0.16, 95% CI = 0.04-0.70, p = 0.015 in MVA, respectively). (4) Conclusion: NA-CRT yields superior pCR compared to other neoadjuvant regimens. This extends to higher grade tumors.

Use of Antiangiogenic Therapies in Pediatric Solid Tumors

Cancer is an important cause of death in childhood. In recent years, scientists have made an important effort to achieve greater precision and more personalized treatments against cancer. But since only a few pediatric patients have identifiable therapeutic targets, other ways to stop the neoplastic cell proliferation and dissemination are needed. Therefore, the inhibition of general processes involved in the growth and behavior of tumors can be a relevant strategy for the development of new cancer therapies. In the case of solid tumors, one of these processes is angiogenesis, essential for tumor growth and generation of metastases. This review summarizes the results obtained with the use of antiangiogenic drugs in the main pediatric malignant solid tumors and also an overview of clinical trials currently underway. It should be noted that due to the rarity and heterogeneity of the different types of pediatric cancer, most studies on antiangiogenic drugs include only a small number of patients or isolated clinical cases, so they are not conclusive and further studies are needed.