A randomized phase 2 trial compared two breast-cancer regimens, finding a higher complete pathological response in the concurrent treatment group. METIS enrolled 156 women at 11 Chinese centres. The regimens differed in chemotherapy formulation as well as timing, so the difference cannot be assigned to scheduling alone. This single peer-reviewed trial leaves longer-term survival benefit uncertain and requires larger confirmation.
In METIS, a breast-cancer trial of preoperative treatment, complete pathological response occurred in 67.5 per cent of the concurrent group and 48.7 per cent of the sequential group. The endpoint assesses tumour response in tissue examined at surgery. This single peer-reviewed phase 2 study enrolled 156 women across 11 centres in China, all with HER2-positive breast cancer at stages II–III. Treatment allocation was randomized and open-label.[1]
Both treatment groups received chemotherapy and agents targeting HER2, a protein involved in the growth of these tumours. The concurrent regimen uses a liposomal form of doxorubicin with targeted treatment, while the sequential comparison starts with epirubicin-based chemotherapy. Because the anthracycline formulation changes too, the comparison evaluates complete regimens and cannot isolate the contribution of timing alone.[1]
The median follow-up lasted 37.5 months; the concurrent regimen had three events affecting event-free survival, compared with eight under sequential treatment. The small number leaves a survival advantage uncertain. Longer survival cannot be inferred directly from a better tissue response.[1]
No symptomatic cardiac dysfunction was reported. Eight participants receiving concurrent treatment experienced serious adverse events; two did so under the sequential regimen. The modest sample and open-label design constrain interpretation of benefits and risks. Larger confirmatory studies remain necessary for evaluating this treatment strategy beyond the response measured at surgery.[1]
