Modified DHAP Versus Standard DHAP in Relapsed/Refractory Diffused Large B-cell Lymphoma.

This study is a randomized controlled trial designed to compare the effectiveness and toxicity profile of a modified DHAP regimen versus the standard DHAP regimen in adult patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL).

DLBCL is the most common subtype of non-Hodgkin lymphoma, with a significant proportion of patients experiencing relapse or refractory disease after initial therapy. The standard DHAP regimen (cisplatin, cytarabine, dexamethasone) has been widely used as salvage therapy, achieving response rates of up to 70%. However, its use is limited by severe toxicities, including renal dysfunction, infections, and profound myelosuppression.

The modified DHAP regimen alters the administration schedule of cisplatin and cytarabine. Cisplatin is fractionated into smaller doses over multiple days rather than a single 24-hour continuous infusion, and cytarabine is administered over two consecutive days. This modification is hypothesized to reduce nephrotoxicity, improve tolerability, and allow outpatient administration, while maintaining or enhancing cytotoxic synergy between cisplatin and cytarabine.

A total of 74 patients will be enrolled and randomized into two arms (37 per arm):

• Arm A (Modified DHAP): Dexamethasone 40 mg PO/IV days 1-4; Cisplatin 50 mg/m² over 6 hours days 1-2; Cytarabine 2 g/m² IV over 3 hours days 1-2.
• Arm B (Standard DHAP): Dexamethasone 40 mg PO/IV days 1-4; Cisplatin 100 mg/m² continuous infusion over 24 hours day 1; Cytarabine 2×2 g/m² IV over 3 hours day 2.

Primary endpoint: Overall response rate (ORR), defined as complete or partial response per RECIL 2017 criteria.

Secondary endpoints: Progression-free survival (PFS), toxicity incidence and severity graded by CTCAE, and quality of life (QoL) assessed using the EORTC QLQ-C30 questionnaire.

Patients will be followed for treatment response, adverse events, and QoL changes. Toxicities will be documented using CTCAE forms, with particular attention to hematological toxicities (anemia, neutropenia, thrombocytopenia) and non-hematological toxicities (renal dysfunction, hepatotoxicity, mucositis, neuropathy).

The study anticipates that the modified DHAP regimen will demonstrate comparable or superior efficacy with a reduced incidence of severe toxicities, shorter hospital stays, and improved patient satisfaction. If successful, this regimen could support the transition of DHAP into outpatient administration, optimizing healthcare resource utilization in Pakistan and improving access to therapy for patients with poor prognoses.

Inclusion criteria

• Histologically confirmed relapsed or refractory DLBCL
• Adults ≥ 18 years
• At least one prior line of therapy for lymphoma
• ECOG performance status 0-2
• Ability to provide informed consent and comply with study requirements
• Adequate organ function:
• Hematologic: ANC ≥ 1,000 cells/mm³, Platelets ≥ 75,000 cells/mm³
• Renal: Serum creatinine ≤ 1.5 × ULN
• Hepatic: Total bilirubin ≤ 1.5 × ULN, AST/ALT ≤ 2.5 × ULN (if no liver metastases)

Exclusion criteria

• History of other malignancies within last 5 years (except non-melanoma skin cancer or localized prostate cancer)
• Pregnant or breastfeeding women
• Significant uncontrolled medical conditions (e.g., cardiovascular disease, uncontrolled diabetes)
• Receipt of investigational agents within 30 days prior to enrollment
• Known severe allergic reactions to DHAP components (dexamethasone, cytarabine, cisplatin)
• Concurrent anti-cancer treatments (chemotherapy, radiotherapy) during study period