Clarithromycin

證據等級: L5

預測適應症: 10 個

Clarithromycin: From Bacterial Infections to Monoclonal Gammopathy

One-Sentence Summary

Clarithromycin is a macrolide antibiotic with well-established use in treating respiratory tract infections, skin and soft tissue infections, and Helicobacter pylori eradication. The TxGNN model predicts it may be effective for Monoclonal Gammopathy (encompassing the Multiple Myeloma and MGUS spectrum), with 1 registered clinical trial and 19 publications — including Phase 2 trials, a Phase 3 RCT, and a systematic review — currently supporting this direction.

Note: The Evidence Pack contains 10 TxGNN-predicted indications. This report focuses on Monoclonal Gammopathy (ranked 7th by TxGNN score, evidence level L2) as the most clinically actionable prediction. The top-ranked prediction by TxGNN score (hyperamylasemia) carries only a single case report and a “Hold” recommendation; focusing the report on that indication would not serve clinical decision-making.

Quick Overview

Item	Content
Original Indication	Bacterial infections (respiratory tract, skin/soft tissue, H. pylori eradication, Mycobacterium avium complex)
Predicted New Indication	Monoclonal Gammopathy (Multiple Myeloma / MGUS spectrum)
TxGNN Prediction Score	98.81%
Evidence Level	L2
South Africa Market Status	Registration data not available in current pack — verify via SAHPRA online register
Number of SAHPRA Registrations	Not available in current pack
Recommended Decision	Proceed with Guardrails

Why Is This Prediction Reasonable?

Currently, detailed mechanism of action data was not captured in this Evidence Pack. However, based on well-established pharmacological knowledge, clarithromycin is a 14-membered ring macrolide antibiotic that inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit. Beyond antimicrobial activity, clarithromycin has demonstrated clinically relevant immunomodulatory and anti-inflammatory effects, including suppression of pro-inflammatory cytokines (IL-6, IL-8, TNF-α) and inhibition of the NF-κB signalling pathway — a critical plasma cell survival signal that is constitutively activated in multiple myeloma.

Monoclonal gammopathy spans a spectrum from asymptomatic MGUS through to symptomatic Multiple Myeloma (MM) and Waldenström’s Macroglobulinaemia. Clarithromycin’s mechanistic contribution in this context is multi-pronged: (1) NF-κB inhibition undermines a key plasma cell survival axis; (2) modulation of the autophagosome-lysosomal pathway appears to overcome resistance to immunomodulatory drugs (IMiDs) such as lenalidomide and pomalidomide; and (3) broad immunoregulatory effects potentiate host anti-tumour immunity. These effects are additive rather than overlapping with standard myeloma therapies, explaining why combination regimens incorporating clarithromycin have shown enhanced efficacy.

The BiRD regimen (Biaxin + Revlimid + Dexamethasone) has become a well-recognised combination in myeloma practice over two decades of investigational use, and clarithromycin has been studied across the full MM treatment continuum — from MGUS chemoprevention through to relapsed/refractory disease — providing a broad and internally consistent evidence base that corroborates this TxGNN prediction.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT00006219	Phase 2	Completed	N/A	Randomised Phase 2 comparing DHEA vs clarithromycin (Biaxin) in MGUS patients at high risk of progression to multiple myeloma; evaluated clarithromycin as a chemopreventive agent against myeloma development

Literature Evidence

PMID	Year	Type	Journal	Key Findings
34021118	2021	Randomised Controlled Trial (Phase 3)	Blood Cancer Journal	Phase 3 RCT (n=286, transplant-ineligible MM); Rd ± clarithromycin until progression — no significant PFS difference, but provides definitive data on the addition of clarithromycin to continuous Rd
36394758	2022	Systematic Review / Meta-analysis	Eur Rev Med Pharmacol Sci	Meta-analysis of pomalidomide + dex-based triplet regimens in relapsed/refractory MM; comparative safety and efficacy of clarithromycin-containing arms assessed
30792190	2019	Phase 2 Trial	Blood Advances	Phase 2 ClaPd study (clarithromycin + pomalidomide + dex, n=120) in RRMM with prior lenalidomide exposure; demonstrated meaningful responses in heavily pre-treated patients (median 5 prior lines)
34424561	2021	Phase 2 Trial	Am J Hematology	Car-BiRd regimen: carfilzomib/dex induction followed by lenalidomide + clarithromycin + dex consolidation and lenalidomide maintenance in newly diagnosed MM; achieved high response rates with reduced toxicity profile
17989313	2008	Phase 2 Trial	Blood	BiRD (clarithromycin + lenalidomide + dex) as first-line therapy in treatment-naive symptomatic MM; established high complete and overall response rates that underpinned subsequent BiRD research
24723438	2014	Cohort Study	Am J Hematology	Addition of clarithromycin to Rd at time of progression in 24 patients (median 3 prior therapies); 48% response rate, demonstrating ability to overcome established lenalidomide/dex resistance
24576165	2014	Phase 2 Trial	Leukemia & Lymphoma	T-BiRD (thalidomide + clarithromycin + lenalidomide + dex) in 26 newly diagnosed symptomatic MM patients; high overall response rate reported
27804150	2017	Clinical Study	Am J Hematology	Addition of clarithromycin to IMiD-based therapy in 31 MM and 17 AL amyloidosis patients refractory to IMiDs; 48% haematological response in MM group — suggests clarithromycin can re-sensitise resistant disease
12685831	2002	Phase 2 Trial	Leukemia & Lymphoma	BLT-D (clarithromycin + low-dose thalidomide + dex) in previously untreated or treated MM and Waldenström’s macroglobulinaemia; earliest formal Phase 2 evaluation establishing anti-myeloma activity of clarithromycin
33138750	2021	Review	Curr Med Chemistry	Comprehensive review of drug repositioning in haematological malignancies; clarithromycin’s mechanistic rationale and clinical evidence in MM detailed with signalling pathway context

South Africa Market Information

SAHPRA registration data was not available in this Evidence Pack (0 licences returned). This is likely a data capture gap, as clarithromycin is a widely used antibiotic available in many countries.

Required action before proceeding: Verify the current SAHPRA registration status, registered formulations (tablet, oral suspension, IV), and approved indications via the SAHPRA medicines register. Cross-reference with the National Essential Medicines List (EML) for relevant dosage forms.

Safety Considerations

Detailed SAHPRA-registered warnings and contraindications were not available in this Evidence Pack. The following safety considerations are drawn from published clinical experience in the myeloma setting and are not exhaustive:

QT prolongation: Clarithromycin prolongs the QTc interval. Many myeloma regimens (e.g., combinations with carfilzomib, bortezomib, or azole antifungals) carry additive QT risk. Baseline and on-treatment ECG monitoring is recommended.
CYP3A4 inhibition: Clarithromycin is a potent CYP3A4 inhibitor. Dose adjustments may be required for co-administered agents metabolised by CYP3A4 that are commonly used in myeloma regimens (e.g., carfilzomib, ixazomib, certain corticosteroids, calcineurin inhibitors).
Neurological effects: Auditory toxicity (hearing loss, tinnitus) and sensory disturbances have been reported, particularly at higher doses or with prolonged treatment. Clarithromycin itself may cause peripheral neuropathy symptoms, which is particularly relevant when combined with neurotoxic agents such as thalidomide or bortezomib.
Gastrointestinal: Nausea, diarrhoea, abdominal discomfort, and taste disturbances are common and may compound IMiD-related GI side effects.

Please refer to the SAHPRA-approved Professional Information (PI) for complete safety information. Report adverse drug reactions to SAHPRA via the MedSafety reporting system.

Conclusion and Next Steps

Decision: Proceed with Guardrails

Rationale: Clarithromycin has a coherent mechanistic basis for activity in plasma cell dyscrasias (NF-κB inhibition, IMiD potentiation, immunomodulation), supported by multiple Phase 2 trials, one Phase 3 RCT, and a systematic review. However, the only Phase 3 RCT (PMID 34021118) did not demonstrate a statistically significant PFS benefit for adding clarithromycin to continuous Rd in transplant-ineligible patients, which tempers enthusiasm despite consistently positive Phase 2 signals. The drug has a well-characterised safety profile accumulated over decades of infectious disease use.

To proceed, the following is needed:

Confirm SAHPRA registration status, available formulations, and approved indications via the SAHPRA online register
Obtain the SAHPRA-approved Professional Information (PI) to complete a full safety and contraindication review
Consult a South African haematologist or oncologist experienced in myeloma management before initiating off-label use in plasma cell dyscrasias
Establish a formal drug interaction assessment for the intended combination regimen, particularly regarding CYP3A4-mediated interactions and QTc additive risk
Implement a baseline and on-treatment ECG monitoring protocol for QTc interval surveillance
Consider whether the use case is newly diagnosed MM (where Phase 2 data are stronger) or relapsed/refractory disease (where resistance-overcoming evidence is promising but Phase 3 data are lacking)
Identify applicable South African clinical trial registrations via SANCTR or PACTR should a formal investigational pathway be pursued

This report is generated for research purposes only and does not constitute medical advice. All drug repurposing candidates require clinical validation before therapeutic application. This document should be reviewed by a qualified South African healthcare professional familiar with the relevant patient population and local treatment guidelines.

Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.