Cost-effectiveness of maintenance rituximab treatment after second line therapy in patients with follicular lymphoma in Sweden

Figures & data

Figure 1.  Model design.

Figure 2.  Extrapolation of progression-free survival data.

Figure 3.  Extrapolation of overall survival data.

Table I.  Cost of maintenance therapy.

Parameter
Rituximab cost per 100 mg vial (€)	285
Rituximab dose (mg/m^2)	375
Rituximab dispensed dose (mg)	759
Rituximab drug costs per dose (€)	2 159
Mean number of rituximab doses per patient (SD = 2.74)	5.9
Total rituximab drug costs per patient* (€)	12 637
Mean cost per administration (Out-patient visit Haematology) (€)	90
Total rituximab administration cost per patient* (€)	526
Total cost of maintenance therapy (€)	13 163

*Total costs have been discounted as the maintenance therapy encompassed two years.

Table II.  Cost of serious adverse events during the maintenance phase.

Rituximab maintenance	Unit cost (€)	No of SAEs	% of SAEs
Blood Cell Disorders	3 729	1	3.3%
Minor Infections (including Immune Disorders)	2 892	2	6.7%
Bronchopneumonia, w/o cc	2 700	6	20.0%
Septicaemia	6 983	1	3.3%
Other Gastrointestinal or Metabolic Disorders	1 814	3	10.0%
Kidney or Urinary Tract Infections, w/o cc	2 324	2	6.7%
Nervous System Disorders	2 554	2	6.7%
Other unassigned condition	2 458	1	3.3%
Pulmonary Embolis, w/o cc	4 435	1	3.3%
Skin, Musculoskeletal, or Connective Tissue Disorders	9 992	1	3.3%
Intermediate Pain Procedures	2 685	1	3.3%
Heart Failure or Shock, w/o cc	3 893	2	6.7%
Ischaemic Heart Disease without intervention, w/o cc	3 263	1	3.3%
Upper Respiratory Tract Disorders	2 267	1	3.3%
Acute Liver Disorders	2 715	1	3.3%
Acute Myocardial Infarction, w/o cc	4 529	2	6.7%
Asthma, w/o cc	1 724	1	3.3%
Malignant Breast Disorders, w/o cc	3 718	1	3.3%
Average cost per event	3 267	30	100.0%
Average cost per patient (n = 167)	587
Observation	Unit cost (€)	No of SAEs	% of SAEs
Heart Failure or Shock, w/o cc	3 893	1	100.0%
Average costs per patient (n = 167)	23

Table III.  Unit costs of treatments received upon relapse [15], [18–20].

		Proportion of patients receiving therapy
Treatment	Cost (€)	Rituximab	Observation
Chemotherapy	3 547	0.63	0.44
Rituximab single agent	13 533	0.05	0.23
Rituximab chemotherapy combination	16 540	0.06	0.09
Radiotherapy	3 008	0.09	0.12
Allogeneic stem cell transplantation (ASCT)	84 089	0.05	0.04
Autologous stem cell transplantation (ASCT)	39 259	0.05	0.03
Rituximab + ASCT	74 520	0.00	0.01
Chemoradiotherapy	6 554	0.01	0.02
Interferon maintenance	10 366	0.03	0.00
Other	0	0.02	0.04
Average total costs per patient for treatment upon relapse		€11 249	€11 117

Table IV.  Base case results

	Result per QALY gained			Result per life-year gained
	Rituximab maintenance	Observation	Incremental	Rituximab maintenance	Observation	Incremental
Total cost (€)	39 617	28 156	11 461	39 617	28 156	11 461
Total effect (QALY/LYG)	4.29	3.38	0.91	5.96	4.94	1.02
ICER* (Δcost/Δeffect)	€12 584/QALY			€11 187/LYG

* Incremental cost-effectiveness ratio

Table V.  Cost data (€).

	Rituximab maintenance	Observation	Incremental
Study drug costs (including administration)	13 163	0	13 163
Adverse events	767	186	582
Treatment costs upon relapse	15 399	17 776	−2 377
Routine management	10 288	10 195	94
Total cost	39 617	28 156	11 461

Table VI.  One-way sensitivity analysis.

Description of variable tested	Value in base case	Description of sensitivity analysis	Value in senstivity analysis	Incremental cost per QALY gained (€)	Incremental cost per LYG (€)
Base case				12 584	11 187
Duration of follow-up in the model	30 years	Range of values	4 years	24 836	30 346
			7 years	12 798	12 349
			10 years	12 551	11 360
			50 years	12 584	11 187
Duration of treatment benefit	5 years	Observation arm applied hazards for PFS and OS in both arms from the end of the treatment benefit	2 years	29 124	29 460
			3 years	19 170	18 520
			10 years	10 619	8 508
			30 years	10 789	8 339
Distribution used for extrapolation of PFS & OS	Weibull	Log-logistic	Log-logistic	9 904	8 552
Unit cost of non serious adverse event (€)	112	Value halved	56	12 574	11 179
		Value doubled	225	12 604	11 205
Adverse events	Included	Excluded	–	11 946	10 620
Unit cost per line of treatment upon relapse (€)	OBS = 11 117	Double cost in OBS arm only	OBS = 22 234	RIT dominant	RIT dominant
	RIT = 11 249		RIT = 11 249
		Double cost in RIT arm only	OBS = 11 117	29 492	26 219
			RIT = 22 499
		Double cost in both arms	OBS = 22 234	9 975	8 867
			RIT = 22 499

Figure 4.  Probabilistic sensitivity analysis.

Figure 5.  Acceptability curve.

Läkemedelsportalen (Swedish national pharmaceuticals price list) [Online]. [cited 2007 April]; Available from: www.fass.se.

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