Multiple myeloma is a common hematological malignancy that is usually treated with chemotherapy and immunomodulatory drugs such as Lenalidomide. In India, patients and their families often attempt dietary modification after a cancer diagnosis, influenced by traditional practices including Ayurveda. However, typical Indian diets, although predominantly plant-based, frequently do not provide adequate dietary fibre, which is important for maintaining a healthy gut microbiome. The human gut microbiome plays a crucial role in immune regulation and cancer treatment response, and its composition can be modulated by dietary intake; high-fibre diets modulate the gut microbiome, increasing the abundance of butyrate-producing bacterial species, which have anti-inflammatory and immunomodulatory effects and are associated with improved outcomes, including minimal residual disease (MRD) negativity in multiple myeloma.

This study aims to assess the feasibility of a high fibre-rich diet during initial treatment of multiple myeloma and to determine whether the intervention is tolerable and influences response to standard induction chemotherapy. Patients receiving standard induction therapy with Lenalidomide, Bortezomib, and Dexamethasone will follow a high-fibre, plant-based diet using locally available foods, and the impact of this intervention on the gut microbiome will be assessed through stool samples collected at baseline and at the end of induction therapy. Patient gastrointestinal symptoms, dietary adherence, and clinical response will be assessed at baseline and at the end of induction therapy to evaluate both the tolerability of the diet and its potential influence on treatment outcomes.If the high-fibre dietary intervention is feasible and well tolerated, it will be further evaluated in combination with chemotherapy in future phase II and phase III clinical trials to assess its potential impact on gut microbiome modulation and treatment outcomes.