The correct brand name of the drug is Mabthera (not Mapthara). It contains a medicine called rituximab. The medicine is used in Follicular Lymphoma Stage 3 to 4. The dose is 375mg per square meter of the body. The usual dose for a normal adult is 500mg weekly for 4 weeks.
It costs 873.15 British pounds per dose of 500mg that comes to approximately Rs. 65,000 (not Rs. 100,000 mentioned in your communication). Due to counterfeit drugs in the market, it must invariably and always be directly procured from Britain and/or Australia where it costs 2456.83 Australian dollars (per dose). Buying locally is hazardous.
The efficacy of treatment depends on individual patients. The overall response rate (ORR) is 48% (6% complete response and 42% partial response). Within this response rate, patients with bone marrow involvement respond less (40%) compared with others with no involvement (59%). Furthermore those patients who have undergone bone marrow transplant respond better (78%) than others who have not undergone this treatment (43%). Kindly keep in mind that these statistics are for information only to give you an idea of the efficacy of this drug in trials.
You may wish to obtain 2nd or even 3rd opinion to ensure that correct clinical decision is taken to the satisfaction of family members.