# Doublet, triplet and quadruplet regimens

Source: https://onco.cc/terms/doublet-triplet/  
OnCo record `doublet-triplet` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Shorthand for how many active drugs are combined: a doublet is two, a triplet three, a quadruplet four. More drugs usually mean more responses and more side effects, and trials test whether the extra drug earns its place.

## Summary

Platinum doublets (cisplatin or carboplatin plus a partner) are the chemotherapy standard in lung, bladder and ovarian cancer. FOLFOXIRI is a chemotherapy triplet; quadruplet induction (daratumumab, bortezomib, lenalidomide, dexamethasone) is now standard in myeloma; IO-TKI doublets (pembrolizumab-axitinib) and IO-IO doublets (nivolumab-ipilimumab) compete in kidney cancer; prostate cancer moved from ADT alone to doublets and triplets (ADT + ARPI + docetaxel, PEACE-1, ARASENS). The question in each case is whether the combination beats sequential use of the same drugs, which is rarely tested directly.

## Fields

- Kind: Term
- Last checked: 2026-09-09
- Also known as: doublet; doublets; triplet; triplets; quadruplet; quadruplets; quad; two-drug; three-drug; four-drug; IO-TKI doublet; IO-IO; IO/IO; chemo-doublet; dual blockade; IO-TKI doublets

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Combination_therapy
- Wikipedia: https://en.wikipedia.org/wiki/Combination_therapy

## Connected records

- terms: [Backbone, add-on and monotherapy](https://onco.cc/terms/backbone-add-on/), [Platinum-sensitive / platinum-resistant](https://onco.cc/terms/platinum-sensitivity/), [Regimen and cycles](https://onco.cc/terms/chemotherapy-regimen/), [Taxanes (paclitaxel, docetaxel, nab-paclitaxel)](https://onco.cc/terms/taxane/), [VRd and Dara-VRd (myeloma induction regimens)](https://onco.cc/terms/vrd/)
- fronts: [Chemotherapy](https://onco.cc/fronts/chemotherapy/)

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