Advances in precision medicine help refine – and redefine – cancer care

— Neil Osterweil

Maintenance chemo improves survival in youth with rhabdomyosarcoma

Key clinical point 6 months of maintenance chemotherapy improves survival in youth with high-risk rhabdomyosarcoma. Major finding Patients given maintenance low-dose vinorelbine and cyclophosphamide had better 5-year OS compared with those not receiving any additional treatment (86.5% vs 73.7%; HR, 0.52). Study details A phase 3 randomized controlled trial in 371 patients aged 0-21 years with high-risk rhabdomyosarcoma who had had a complete response to standard intensive therapy. Funding The study received funding from Fondazione Città della Speranza, Italy. Disclosures Dr Bisogno disclosed that he has a consulting or advisory role with Clinigen Group, and receives travel, accommodations, and/or expenses from Jazz Pharmaceuticals. Source Bisogno et al. ASCO 2018, Abstract LBA2. https://meetinglibrary.asco.org/record/161695/abstract

Six months of maintenance chemotherapy prolongs OS in youth with high-risk rhabdomyosarcoma, finds a phase 3 randomized controlled trial of the European Paediatric Soft Tissue Sarcoma Study Group (EpSSG).

Rhabdomyosarcoma is a rare but highly aggressive tumor, lead study author Gianni Bisogno, MD, PhD, a professor at the University Hospital of Padova, Italy, and chair of the EpSSG, noted in a press briefing at the meeting, where the findings were reported. In pediatric patients who achieve complete response to standard therapy, “we know that after 1 or 2 years, one-third of these children relapse, and most of them die,” he said.

The EpSSG trial, which took about 10 years to conduct, enrolled 371 patients aged 0-21 years with high-risk rhabdomyosarcoma who had had a complete response to standard intensive therapy. They were randomized evenly to stop treatment or to receive 6 months of maintenance treatment consisting of low-dose vinorelbine and cyclophosphamide.

Results reported in the meeting’s plenary session showed that giving maintenance chemotherapy improved the 5-year OS rate by an absolute 12.8%, which translated to a near halving of the risk of death. And the maintenance regimen used was generally well tolerated.

“At the end of this long, not-easy study, we concluded that maintenance chemotherapy is an effective and well tolerated treatment for children with high-risk rhabdomyosarcoma,” Dr Bisogno said.

There are three possibilities for its efficacy, he speculated. “It may be the duration, the type of drugs used, or the metronomic approach. Maybe altogether, these three different actions have a benefit to increase survival.

“Our group has decided this is the new standard treatment for patients. At least in Europe, we give standard intensive therapy and then we continue with 6 more months of low-dose chemotherapy,” Dr Bisogno concluded. “We think that this approach – a new way of using old drugs – can be of interest also for other pediatric tumors.”

The trial is noteworthy in that it shows “how to successfully conduct large and important trials in rare diseases,” said ASCO expert Warren Chow, MD.

The standard therapy for rhabdomyosarcomas is somewhat different in the United States, typically a regimen containing vincristine, actinomycin D, cyclophosphamide, and (more recently) irinotecan, he noted. “We have not been traditionally using maintenance chemo for any of the pediatric sarcomas, so this is a paradigm shift. These results will need to be tested with US-based protocols before becoming standard of care in the United States. Also, we will need to determine if these results are applicable to patients older than 21 years of age who are considered high risk based solely on their age.

“Even with these caveats, this is the first significant treatment advance in this rare cancer in more than 30 years,” concluded Dr Chow, a medical oncologist and clinical professor at City of Hope, Duarte, Calif. “No doubt, this trial was a home run.”