Antibody-Drug Conjugate Combo Delivers 92.6% Complete Response Rate in Low-Risk Lymphoma Patients

A landmark real-world study from China has delivered striking news for patients with one of the most common forms of blood cancer: an antibody-drug conjugate-based regimen, when deployed as a first treatment in people with low-risk diffuse large B-cell lymphoma, produced complete responses in more than nine out of ten patients. The multicenter retrospective study, published in Clinical Cancer Bulletin, followed 118 previously untreated patients across 17 tertiary hospitals and found that the combination of polatuzumab vedotin with rituximab, cyclophosphamide, doxorubicin, and prednisone—known as Pola-R-CHP—achieved a complete response rate of 92.6 percent at the end of treatment. The finding matters because this specific patient group, those scoring 0 or 1 on the international prognostic index, was deliberately excluded from the pivotal clinical trial that made the regimen famous, leaving clinicians worldwide without direct evidence for roughly a third of everyone they treat.

Diffuse large B-cell lymphoma, or DLBCL, is the most frequent subtype of non-Hodgkin lymphoma, accounting for approximately 30 to 40 percent of all cases. For two decades, the frontline standard of care was R-CHOP, a five-drug immunochemotherapy combining the monoclonal antibody rituximab with three chemotherapeutic agents and a corticosteroid. Despite countless attempts to improve upon it with novel agents, R-CHOP remained essentially unchallenged until the POLARIX trial demonstrated that swapping vincristine for polatuzumab vedotin—a targeted antibody-drug conjugate directed against CD79b, a signaling component of the B-cell receptor—produced significantly superior outcomes. That result transformed Pola-R-CHP into the new global standard for previously untreated DLBCL, and the regimen was approved in China in April 2023 for adult patients.

Yet the POLARIX trial enrolled only patients with international prognostic index scores of 2 through 5, meaning patients considered to have intermediate or high-risk disease. The IPI is a well-established scoring system that predicts prognosis in DLBCL using five factors: age, tumor stage, number of extranodal sites involved, performance status, and serum lactate dehydrogenase levels. Patients scoring 0 or 1 are conventionally labeled low-risk and represent approximately 30 percent of newly diagnosed cases. Because they were excluded from the pivotal trial, this substantial population became a critical evidence gap. The problem is compounded by the fact that low IPI scores do not guarantee biological simplicity. Many of these patients carry molecular and pathological features known to undermine standard therapy, including bulky tumors, double-expressor lymphoma, and abnormalities of the TP53 gene, the so-called guardian of the genome.

The new study, led by Yuhong Ren and Peng Liu of Zhongshan Hospital, Fudan University, together with colleagues across China, set out to fill that gap using real-world data. Between June 2023 and July 2025, the researchers enrolled 118 consecutive previously untreated DLBCL patients with IPI scores of 0 or 1 who received at least one cycle of Pola-R-CHP. The median age was 53.5 years, with patients ranging from 17 to 87 years old. Despite their formally low-risk classification, the cohort was biologically heterogeneous and carried a surprising burden of adverse features: 51.7 percent had the non-germinal center B-cell-like subtype, 24.6 percent had double-expressor lymphoma, 9.3 percent had double-hit or triple-hit lymphoma, 25.4 percent showed high P53 expression, 12.7 percent had bulky disease, and 62.7 percent had extranodal involvement.

The treatment protocol followed a well-defined structure. Each 21-day cycle comprised polatuzumab vedotin at 1.8 milligrams per kilogram of body weight, rituximab at 375 milligrams per square meter, cyclophosphamide at 750 milligrams per square meter, doxorubicin at 50 milligrams per square meter or epirubicin at 70 milligrams per square meter, and prednisone at 100 milligrams orally for five consecutive days. Patients received a median of six cycles. Efficacy was assessed using whole-body fluorodeoxyglucose PET/CT or contrast-enhanced CT imaging after three to four cycles and again at the end of treatment, with responses graded according to the 2014 Lugano classification, the international standard for lymphoma response assessment.

The results were remarkable. Among the 68 patients who had completed end-of-treatment evaluation at the data cut-off of August 2025, 63 achieved a complete response, yielding a complete response rate of 92.6 percent. The overall response rate reached 98.5 percent at end of treatment and 98.9 percent at interim assessment, with 78.2 percent of interim-evaluated patients already in complete remission after just three to four cycles. Only two patients experienced disease progression during follow-up, both of whom had central nervous system involvement, and no deaths occurred at a median follow-up of 7.1 months. Importantly, the 50 patients without end-of-treatment assessment had not progressed, died, or been lost to follow-up; they were simply still undergoing treatment or awaiting imaging, meaning the missing data reflected short follow-up rather than treatment failure.

Perhaps most striking was the consistency of responses across molecular subgroups. Exploratory analyses showed broadly similar response rates at both interim and end-of-treatment time points among elderly patients, those with the non-germinal center subtype, extranodal disease, double-expressor lymphoma, and double-hit or triple-hit lymphoma. The one exception was the high P53 expression subgroup, where the complete response rate was numerically lower at 78.6 percent compared with 96.9 percent in patients with low or absent P53 expression. This finding aligns with the well-documented biology of TP53 alterations, which are associated with genomic instability and chemoresistance in lymphoma. However, the researchers caution that the small number of evaluable patients in this subgroup prevents definitive conclusions, and they suggest that the bystander effect of antibody-drug conjugates—the ability of the drug payload to diffuse into neighboring tumor cells that may not express the target antigen—could theoretically help overcome the clonal heterogeneity that drives resistance.

Safety data from all 118 patients showed a tolerable profile without unexpected toxicity compared with the POLARIX trial. Any grade 3 or 4 adverse event occurred in 24.6 percent of patients. The most common adverse events overall were anemia in 68.6 percent, leukopenia in 47.5 percent, and decreased neutrophil count in 39.8 percent, the vast majority of which were mild to moderate. The most frequent severe toxicity was neutropenia, affecting 21.2 percent of patients at grade 3 or 4—a manageable side effect routinely addressed with dose adjustments and growth factor support in clinical practice. No new safety signals emerged, reinforcing the regimen’s established risk-benefit profile in a broader and more diverse population than the original trial captured.

The study’s authors place their findings in context by comparing them with other real-world cohorts and historical R-CHOP data. Published complete response rates for frontline Pola-R-CHP and R-CHOP in low-risk patients range from 80.6 to 96.5 percent, and the current results sit comfortably at the upper end of that spectrum. Notably, the Chinese cohort carried a heavier burden of adverse features than a comparable R-CHOP cohort from a Chinese phase 3 trial, with higher rates of impaired performance status, advanced stage disease, and double-expressor lymphoma, yet still achieved outstanding responses. The researchers acknowledge the inherent limitations of a retrospective, single-arm design conducted exclusively in China, including potential selection bias and immature survival data, and they emphasize that a conservative sensitivity analysis counting all unevaluated patients as non-responders still yielded a complete response rate of 85.1 percent.

The implications reach beyond the numbers. Roughly a third of DLBCL patients worldwide fall into the IPI 0-1 category, yet they remain underrepresented in clinical trials and continue to experience late relapses even in limited-stage disease, a pattern that contrasts with the survival plateau seen in advanced-stage patients. This study provides the first multicenter real-world evidence that Pola-R-CHP is both effective and tolerable in this population, even when adverse biological features are present. The authors call for prospective randomized trials to precisely define the magnitude of benefit, and for molecular subtyping strategies to better identify which low-risk patients harbor hidden resistance mechanisms. For now, the message for clinicians is clear: the antibody-drug conjugate revolution in lymphoma treatment appears to extend to nearly every patient who walks through the door, not just those who fit the narrow criteria of a registration trial.

Subject of Research: Frontline Pola-R-CHP treatment of low-risk diffuse large B-cell lymphoma

Article Title: Pola-R-CHP in previously untreated DLBCL with international prognostic index score 0–1: a multicenter real-world retrospective study in China

Article References: Ren, Y., Liu, J., Lin, Z., Shou, L., Zeng, H., Wu, D., Zeng, Z., Zhou, F., Bao, L., Jing, H., Jiang, S., Liu, H., Shen, J., Yu, W., Zhou, H., Xu, J., Zhang, Y., Wang, T., Huang, H., … Liu, P. (2026). Pola-R-CHP in previously untreated DLBCL with international prognostic index score 0–1: a multicenter real-world retrospective study in China. Clinical Cancer Bulletin, 5(1), Article 21. https://doi.org/10.1007/s44272-026-00073-3

Image Credits: AI Generated

DOI: 10.1007/s44272-026-00073-3

Keywords: diffuse large B-cell lymphoma, Pola-R-CHP, polatuzumab vedotin, antibody-drug conjugate, international prognostic index, real-world study, R-CHOP, double-expressor lymphoma, TP53, complete response, non-Hodgkin lymphoma, immunochemotherapy