Drugs, Health Technologies, Health Systems

Reimbursement Recommendation

Mosunetuzumab SC (Lunsumio SC)

Indication: As monotherapy for the treatment of adult patients with relapsed or refractory follicular lymphoma (Grades 1 – 3a) who have received at least two prior lines of systemic therapy

Sponsor: Hoffmann-La Roche Limited

Recommendation: Reimburse with conditions

Summary

What Is the Reimbursement Recommendation for Lunsumio SC?

Canada’s Drug Agency (CDA-AMC) recommends that Lunsumio subcutaneous (SC) be reimbursed by public drug plans “as monotherapy for the treatment of adult patients with relapsed or refractory follicular lymphoma (Grades 1 – 3a) who have received at least two prior lines of systemic therapy,” if certain conditions are met.

Why Did CDA-AMC Recommend Reimbursement?

The pan-Canadian Oncology Drug Review Expert Review Committee (pERC) determined that it is uncertain whether Lunsumio SC demonstrates acceptable clinical value in “adult patients with relapsed or refractory follicular lymphoma (Grades 1 – 3a) who have received at least two prior lines of systemic therapy.” Given that Lunsumio SC is expected to be an alternative option for third-line and beyond therapy, acceptable clinical value refers to at least comparable value relative to other third-line and beyond therapies relevant in the context in Canada. Direct evidence from 1 clinical trial (GO29781) showed that treatment with Lunsumio SC resulted in response rate benefits considered clinically meaningful and durable by the CDA-AMC consulted experts and suggested potential survival benefits. Evidence from an indirect treatment comparison (ITC) suggested that overall survival (OS) and response outcomes with Lunsumio SC may be broadly comparable to other third-line and beyond therapies, although results were uncertain and mixed across comparisons. Uncertainty remains due to the single-arm study design, limited comparative evidence, and imprecision in indirect estimates. pERC concluded that, although the evidence suggests mosunetuzumab SC monotherapy has uncertain clinical value, given the rarity and severity of the condition the drug may address a significant unmet clinical need to a degree that justifies a positive recommendation despite the uncertainty in the clinical value.

pERC discussed the direct and indirect evidence and the clinical experts’ input and noted that the overall evidence suggested that Lunsumio SC may address a significant unmet clinical need, offering a chemotherapy-free, fixed-duration treatment with manageable safety profile that can be given in an outpatient setting, and is readily available, particularly for patients with limited access to existing therapies.

pERC noted significant unmet nonclinical needs and health inequities among patients with relapsed or refractory follicular lymphoma (r/r FL). pERC also noted that Lunsumio SC may improve access to care, as it can be provided off the shelf and administered outside specialized centres, potentially reducing travel, clinic visits, and reliance on tertiary care services, particularly for patients in rural or underserved settings. The committee considered the IV and SC formulations of Lunsumio to have comparable efficacy and safety and therefore preferred the SC formulation, while allowing flexibility based on patient preference and for individuals who may require IV administration due to substantial injection site reactions.

Based on all of the preceding considerations, pERC recommended that Lunsumio SC be reimbursed.

Which Patients Are Eligible for Coverage?

Lunsumio SC should only be covered for adults with histologically confirmed r/r FL (grades 1 to 3a) who have received at least 2 prior lines of systemic therapy, including an anti-CD20 therapy and an alkylating agent, and who have good performance status. Lunsumio SC should not be covered for patients with nonfollicular indolent lymphoma or a disease with central nervous system involvement.

What Are the Conditions for Reimbursement?

Lunsumio SC should be prescribed by clinicians experienced in managing hematologic malignancies and bispecific antibody-related complications, and given in settings with access to tocilizumab and appropriate supportive care. Reimbursement should be for a fixed duration of 8 or 17 cycles as per the drug’s product monograph and should be discontinued upon the occurrence of complete response, unacceptable toxicity, or disease progression. Re-treatment may be considered for patients whose disease relapses after a treatment-free interval of at least 6 months following completion of the initial treatment course.

The total cost of Lunsumio should not exceed the total cost of treatment with the least costly relevant chemotherapy comparator for the same indication.

Important budget impact considerations and organizational implications must be addressed for health systems to be able to adopt Lunsumio.

Review Background

Highlights of Input From Interested Parties

The patient group (Lymphoma Canada) noted the following regarding impacts of the disease, unmet needs, and important outcomes:

The clinician groups (Leukemia and Lymphoma Society Nurses Network, Ontario Health [Cancer Care Ontario] Hematology Cancer Drug Advisory Committee, and Lymphoma Canada) and the clinical experts consulted by CDA-AMC noted the unmet needs arising from the disease as follows:

Mosunetuzumab SC is anticipated to be used primarily as a later-line outpatient treatment option for adults with r/r FL, including patients who are ineligible for, unable to access, or prefer to avoid CAR T-cell therapy, and as a potential option following disease relapse after CAR T-cell treatment.

The participating public drug programs raised potential implementation issues related to relevant comparators, considerations for initiation and prescribing of therapy, generalizability of trial populations to broader populations, potential need for a provisional funding algorithm, care provision issues, and system and economic issues.

Recommendation

With a vote of 12 in favour to 4 against, pERC recommends that mosunetuzumab SC be reimbursed “as monotherapy for the treatment of adult patients with relapsed or refractory follicular lymphoma (Grades 1 – 3a) who have received at least two prior lines of systemic therapy” only if the conditions listed in Table 1 are met.

Table 1: Reimbursement Conditions and Reasons

Reimbursement condition

Reason

Implementation guidance

Initiation

1. Mosunetuzumab SC should be reimbursed in adults with r/r FL (grades 1 to 3a) who meet all the following criteria:

1.1. histologically confirmed FL (grades 1 to 3a)

1.2. r/r to 2 or more previous lines of treatment, including an anti-CD20 therapy and an alkylating agent

1.3. have a good performance status.

Evidence from the GO29781 study demonstrated (and clinical experts consulted by CDA-AMC indicated) that treatment with mosunetuzumab SC may provide a clinical benefit in patients with the characteristics listed in this condition.

The GO29781 study enrolled patients who had an ECOG PS score of 0 or 1.

Condition 1.2:

  • pERC confirmed that jurisdictions can use the existing definition of rituximab refractory, which is defined as having no response to or progression during or within 6 months after treatment with rituximab or a rituximab-containing regimen.

  • pERC confirmed that single-agent rituximab, with or without maintenance, should be counted as 1 line of therapy.

  • pERC agreed with the clinical experts that patients who have previously received CAR T-cell therapy may be eligible for mosunetuzumab SC if they meet the criteria in the first column. As mosunetuzumab and CAR T-cell therapies target different antigens, prior CAR T-cell therapy should not be considered a basis for exclusion.

Condition 1.3:

Based on the clinical experts’ input, selected patients with an ECOG PS score of 2 could be considered for treatment with mosunetuzumab SC at the discretion of the treating physician.

2. Patients are ineligible for treatment with mosunetuzumab if they have any of the following criteria:

2.1. nonfollicular indolent lymphoma

2.2. CNS involvement.

Patients with nonfollicular indolent lymphoma or CNS involvement were not included in the GO29781 study. The clinical experts noted that conditions such as marginal zone lymphoma and chronic lymphocytic leukemia have biological behaviour that differs from FL, and that FL rarely involves the CNS. As a result, these patient populations were excluded from the study, and the evidence is therefore not generalizable to these groups.

pERC considered mosunetuzumab appropriate for patients who are ineligible for, unable to access, or decline CAR T-cell therapy, but not as a preferred alternative for eligible patients with adequate access to CAR T-cell therapy.

Renewal

3. Reimbursement of re-treatment with mosunetuzumab SC could be considered if a patient experiences r/r FL after a treatment-free interval of at least 6 months following the initial 8 or 17 cycles of treatment.

Re-treatment after a complete response and discontinuation at 8 cycles was allowed in the GO29781 study. pERC confirmed that a minimum disease-free interval (remission) of at least 6 months is required. The clinical experts emphasized that CD20 expression should be reassessed at disease relapse, as a biopsy is standard practice and CD20 down regulation may occur under selective pressure from CD20 targeted therapies. Re-treatment after completing 17 cycles may also be considered, depending on clinical context and prior tolerability.

The clinical experts noted that response should be assessed using imaging (CT or PET) after 8 cycles and again at the end of therapy, consistent with trial practice and routine standards in Canada. Interim imaging before the end of cycle 8 is recommended to determine whether treatment should stop at 8 cycles for patients who achieve a complete response or continue to 17 cycles for patients who achieve a partial response. The clinical experts indicated that these assessments align with the clinical practice in Canada and are feasible to implement.

Discontinuation

4. Reimbursement of mosunetuzumab SC should be discontinued upon occurrence of any of the following:

4.1. complete response

4.2. unacceptable toxicity

4.3. disease progression.

In the GO29781 study, mosunetuzumab SC treatment was discontinued if a patient experienced disease progression or intolerable AEs.

Per the drug’s product monograph, for patients who achieve a complete response, no further treatment beyond 8 cycles is required, and for patients who achieve a partial response or have disease stability in response to treatment with mosunetuzumab SC after 8 cycles, an additional 9 cycles of treatment (17 cycles total) could be administered, unless a patient experiences unacceptable toxicity or disease progression.

Prescribing

5. Mosunetuzumab SC should only be prescribed by clinicians experienced in managing hematologic malignancies and the complications of bispecific antibody therapy (e.g., CRS and ICANS) and administered in a setting with access to tocilizumab and appropriate supportive care.

This is meant to ensure that mosunetuzumab SC is prescribed for appropriate patients and that adverse effects are managed in an optimized and timely manner.

pERC considered that the IV and SC formulations of mosunetuzumab have comparable efficacy and safety. The committee discussed clinical experts' input indicating that SC administration is generally preferred by patients and health care systems due to reduced health system resource use (e.g., chair time, compounding time) and a more favourable safety profile. Accordingly, pERC determined that the mosunetuzumab SC be prioritized over the IV formulation, with flexibility for patients’ preference and the occasional patient who may experience significant injection site reactions, for whom IV administration may be more suitable.

6. Mosunetuzumab SC should be administered as monotherapy.

In the GO29781 study, mosunetuzumab SC was administered as a monotherapy.

Pricing

7. The total cost of mosunetuzumab SC should be negotiated so that it does not exceed the total cost of treatment with the least costly relevant chemotherapy comparator for the same indication.

Based on the committee’s assessment of the evidence, mosunetuzumab SC is expected to have similar clinical benefits and harms compared with relevant comparators. Therefore, the total cost of mosunetuzumab SC should be no more than the least costly relevant chemotherapy regimen.

Feasibility of adoption

8. The economic feasibility of adoption of mosunetuzumab SC must be addressed.

At the submitted price, the magnitude of uncertainty in the budget impact must be addressed to ensure the feasibility of adoption, given the difference between the sponsor’s estimate and the estimate from CDA-AMC.

AE = adverse event; CDA-AMC = Canada’s Drug Agency; CNS = central nervous system; CRS = cytokine release syndrome; ECOG PS = Eastern Cooperative Oncology Group Performance Status; FL = follicular lymphoma; ICANS = immune effector cell associated neurotoxicity syndrome; pERC = pan-Canadian Oncology Drug Review Expert Review Committee; r/r = relapsed or refractory; SC = subcutaneous.

Rationale for the Recommendation

Clinical Value

Based on the totality of the clinical evidence, pERC noted that it is uncertain whether mosunetuzumab SC monotherapy demonstrates acceptable clinical value in “adult patients with relapsed or refractory follicular lymphoma (Grades 1 – 3a) who have received at least two prior lines of systemic therapy.” Given that mosunetuzumab SC is expected to be an alternative option for third-line and beyond therapy, acceptable clinical value refers to at least comparable value relative to other third-line and beyond therapies relevant in the context in Canada. pERC concluded that, although the evidence suggests mosunetuzumab SC monotherapy has uncertain clinical value, given the rarity and severity of the condition the drug may address a significant unmet clinical need to a degree that justifies a positive recommendation despite the uncertainty in the clinical value

One phase I (1b)/II, single-arm, open-label study (GO29781, N = 94) provided evidence regarding the efficacy and safety of mosunetuzumab SC monotherapy in “adult patients with relapsed or refractory follicular lymphoma (Grades 1 – 3a) who have received at least two prior lines of systemic therapy.” In a median observation time of 20.7 months, the complete response rate (CRR) was 58.5% (95% confidence interval [CI], 47.9% to 68.6%), and the overall response rate (ORR) (partial or complete response) was 74.5% (95% CI, 64.4% to 82.9%). The clinical experts consulted by CDA-AMC considered the response rates observed in the GO29781 study to be clinically meaningful in the context of expected outcomes for adult patients with r/r FL (grades 1 to 3a) undergoing third-line and beyond therapy. Mosunetuzumab SC was associated with potential benefits in survival outcomes. At the clinical data cut-off of February 2024, median OS was not reached, and the Kaplan-Meier survival probability at 18 months was 89.6% (95% CI, 82.5% to 96.6%). At the clinical data cut-off of July 2024, the median progression-free survival (PFS) was 23.7 months (95% CI, 14.6 months to not estimable). Cytokine release syndrome was among the notable harms and aligned with the known safety profile of mosunetuzumab. Overall, the safety findings from the GO29781 study were consistent with the established risks of the bispecific antibody drug class, with no unexpected signals identified.

Evidence from the sponsor-submitted ITC evaluating the effects of mosunetuzumab monotherapy versus relevant comparators, indicated some uncertainty in the OS and ORR results across comparisons, with estimates suggesting that outcomes may be comparable between treatments. Results for PFS, CRR, and treatment discontinuation due to adverse events (AEs) showed mixed results across comparisons, with some analyses favouring comparator therapies (e.g., axicabtagene ciloleucel, tisagenlecleucel, or obinutuzumab plus bendamustine for PFS; axicabtagene ciloleucel for CRR), others favouring mosunetuzumab (e.g., compared to rituximab plus lenalidomide and obinutuzumab plus bendamustine for CRR, and compared to obinutuzumab plus bendamustine for treatment discontinuation due to AEs), and several comparisons remaining uncertain. Overall, the ITC evidence was very uncertain due to imprecision, limited sample size, and limitations in the assumptions underlying the model.

pERC acknowledged that patients identified a need for more effective, well-tolerated, and accessible treatment options in later lines of therapy, particularly those that reduce cumulative toxicity, treatment burden, and barriers related to travel and availability. The committee also noted clinicians emphasized the need for novel, noncross-resistant therapies that can provide durable responses, are chemotherapy-free, and can be delivered conveniently in outpatient or community settings in an SC formulation, given the limitations and restricted accessibility of CAR T-cell therapy. pERC considered the uncertainties in the evidence due to the limitations in the studies, including the single-arm design of the GO29781 trial. The committee also considered the clinical experts’ observation that the CRR and ORR were clinically meaningful for the population of patients, especially those with limited access to or unable to receive certain therapies. Therefore, pERC determined that mosunetuzumab SC represents an alternative immunotherapy option for “adult patients with relapsed or refractory follicular lymphoma (Grades 1 –3a) who have received at least two prior lines of systemic therapy” that may address some of these unmet needs by offering a fixed-duration, outpatient treatment with a manageable safety profile.

Further information on the committee’s discussion around clinical value is provided in the Summary of Deliberation section.

Considering Significant Unmet Clinical Need

pERC acknowledged that there is a significant unmet clinical need for patients with r/r FL (grades 1 to 3a), particularly in the third-line setting and beyond. This reflects the incurable and relapsing nature of the disease, diminishing effectiveness and durability of available treatments with successive lines, cumulative toxicities, and limited access to certain therapies (e.g., CAR T-cell therapy) due to eligibility, logistical, and geographic constraints. Patients and clinicians emphasized the need for effective, well-tolerated, chemotherapy-free, and accessible outpatient treatment options that can provide durable disease control and reduce treatment burden.

Further information on the committee’s discussion around unmet clinical need is provided in the Summary of Deliberation section.

Considering Significant Unmet Nonclinical Need or Health Inequity

pERC noted that there are significant unmet nonclinical needs and health inequities for patients with r/r FL. These include barriers to accessing specialized treatments (e.g., CAR T-cell therapy), particularly for patients who are older, experiencing frailty, or living in rural or remote areas, as well as the logistical burden of frequent clinic visits, travel to tertiary centres, and prolonged treatment administration. The committee observed that socioeconomic factors and geographic distance disproportionately limit access for marginalized populations who face barriers to care or are at increased risk for r/r FL.

pERC considered that the fixed-duration, outpatient administration, an SC formulation, and off the shelf availability of mosunetuzumab SC may help address unmet nonclinical needs and inequities by reducing treatment burden and improving access, particularly for patients in rural or remote areas.

Further information on the committee’s discussion around unmet nonclinical need is provided in the Distinct Social and Ethical Considerations domain in the Summary of Deliberation section.

Developing the Recommendation

Due to the uncertainty in clinical value, pERC could not recommend whether to reimburse mosunetuzumab SC or not based on clinical value alone. Therefore, they also considered whether mosunetuzumab SC addresses a significant unmet clinical need. pERC concluded that mosunetuzumab SC addresses a significant unmet clinical need with an acceptable level of certainty. Based on the preceding considerations, pERC recommended that mosunetuzumab SC be reimbursed. As part of the deliberation on whether to recommend reimbursement or not, the committee also considered unmet nonclinical need and health inequity. Information on this discussion is provided in the Distinct Social and Ethical Considerations domain in the Summary of Deliberation section.

Because pERC recommended that mosunetuzumab SC be reimbursed, the committee also deliberated on whether reimbursement conditions should be added to address important economic considerations, health system impacts, or social and ethical considerations, or to ensure clinical value is realized. The resulting reimbursement conditions, with accompanying reasons and implementation guidance, are stated in Table 1.

Summary of Deliberation

pERC considered all domains of value of the deliberative framework before developing its recommendation: clinical value, unmet clinical need, distinct social and ethical considerations, economic considerations, and impacts on health systems. For further information on the domains of value, refer to Expert Committee Deliberation at Canada’s Drug Agency.

The committee considered the following key discussion points, organized by the 5 domains of value.

Clinical Value

Unmet Clinical Need

Distinct Social and Ethical Considerations

Economic Considerations

Impacts on Health Systems

Sources of Information Used by the Committee

To make its recommendation, the committee considered the following information (links to the full documents for the review can be found on the project webpage):

All feedback received in response to the draft recommendation is available on the CDA-AMC website.

pERC Information

Members of the Committee

Dr. Catherine Moltzan (Chair), Dr. Kelvin Chan (Vice-Chair), Paul Agbulu, Dr. Phillip Blanchette, Dr. Matthew Cheung, Dr. Michael Crump, Annette Cyr, Dr. Jennifer Fishman, Dr. Jason Hart, Terry Hawrysh, Dr. Yoo-Joung Ko, Dr. Aly-Khan Lalani, Amy Peasgood, Dr. Anca Prica, Dr. Michael Raphael, Dr. Adam Raymakers, Dr. Patricia Tang, Dr. Pierre Villeneuve, and Danica Wasney.

Meeting date: May 13, 2026

Regrets: One expert committee member did not attend.

Conflicts of interest: None