SUMMARY

• The phase 3 GRIPHON trial was conducted to evaluate the long-term safety and efficacy of UPTRAVI in patients with symptomatic pulmonary arterial hypertension (PAH). In this event-driven study, UPTRAVI significantly reduced the risk of a morbidity/mortality event by 40% compared with placebo. The most common adverse events (AEs) in GRIPHON that occurred with higher frequency on UPTRAVI compared with placebo were headache, diarrhea, jaw pain, nausea, myalgia, vomiting, pain in extremity, and flushing.¹
• At baseline, 334 patients (29%) were classified as PAH associated with connective tissue disease (PAH-CTD) in GRIPHON. A subgroup analysis showed that the treatment effect of UPTRAVI was consistent with the overall PAH study population among patients with PAH-CTD. The treatment effect in patients with different forms of connective tissue disease (CTD), including systemic sclerosis (SSc), systemic lupus erythematosus (SLE), and mixed CTD (MCTD), was also consistent across the subtypes.²
• Overall, in the PAH-CTD subgroup, 15 (9.1%) placebo-treated patients and 32 (19.2%) UPTRAVI-treated patients discontinued their study regimen prematurely because of an AE. The frequencies of AEs and serious AEs (SAEs) reported in the treatment groups were similar for the PAH-CTD subgroup and for the CTD subtypes.²
• SPHERE (NCT03278002), a United States (US)-based multicenter, prospective, observational, real-world registry study (November 2016 to March 2020), assessed the real-world outcomes of UPTRAVI in routine clinical practice and provided information on patient demographics and disease characteristics in the enrolled population.³
  • In the interim analysis of the SPHERE study (data cutoff date, December 20, 2019; N=500)⁴, 132 (26.4%) patients had PAH-CTD, 246 (49.2%) had idiopathic PAH (IPAH), and 122 (24.4%) had other diagnoses. The mean individualized maintenance dose of UPTRAVI in the PAH-CTD and IPAH subgroups was 1200 mcg twice daily (BID). More patients in the PAH-CTD subgroup (15.2%) vs the IPAH subgroup (11.0%) discontinued treatment due to AEs related to PAH disease progression.⁵
• A search of the scientific literature retrieved 2 real-world studies that described the use of UPTRAVI in patients with PAH-CTD; relevant information from these studies is summarized in this letter.^6,7
• Additional citations identified during a literature search is included in the REFERENCES section for your review.^8-10

CLINICAL DATA

Phase 3 Study: GRIPHON

The GRIPHON phase 3 study (Prostacyclin [PGI₂] Receptor Agonist In Pulmonary Arterial HypertensiON; AC-065A302) was a multicenter, double-blind, parallel group, placebocontrolled event-driven trial evaluating the efficacy and safety of oral UPTRAVI in adult patients with WHO group 1 PAH.

Study Design/Methods

GRIPHON completed enrollment in May 2013 with 1156 patients from 181 centers in 39 countries. Patients received UPTRAVI (n=574) or placebo (n=582). The median treatment duration was 63.7 and 70.7 weeks for patients receiving placebo and UPTRAVI, respectively, and the study was completed in April 2014, with 397 blinded, adjudicated primary endpoint events.¹

Efficacy: Primary Endpoint

UPTRAVI decreased the risk of a morbidity/mortality event vs placebo (risk reduction) by 40% (hazard ratio [HR], 0.60; 99% confidence interval [CI], 0.46-0.78; P<0.001).¹ The beneficial effect of UPTRAVI was primarily attributable to a reduction in hospitalization for worsening of PAH and a reduction in disease progression events, with death from any cause, initiation of parenteral prostanoid or chronic oxygen therapy and PAH worsening resulting in need for lung transplantation or atrial septostomy representing fewer events.

Safety and Tolerability

The most common AEs in GRIPHON that occurred with higher frequency (≥5%) on UPTRAVI compared to placebo were headache, diarrhea, jaw pain, nausea, myalgia, vomiting, pain in extremity, and flushing. The proportion of patients discontinuing treatment due to an AE was 14.3% on UPTRAVI and 7.1% on placebo.

Subgroup Analyses of PAH-CTD Patients From the GRIPHON Study

The PAH-CTD population was a prespecified subgroup for evaluation of the primary endpoint, however, the more detailed analyses described were post hoc and exploratory in nature. Therefore, sample size should be considered, and results should be interpreted with caution.²

Patients and Treatment Exposure

Of the 1156 patients enrolled in GRIPHON, 334 were diagnosed with PAH-CTD. This comprised 170 with PAH associated with SSc (PAH-SSc), 82 with PAH associated with SLE (PAH-SLE), 37 with PAH associated with MCTD (PAH-MCTD), and 45 in whom the underlying CTD was not further defined (PAH-CTD-other). Due to smaller patient numbers, and corresponding number of primary endpoint events, the PAH-MCTD and PAH-CTD-other groups are presented as a single group (PAH-MCTD/CTD-other). Baseline characteristics of the PAH-CTD subgroup and the 3 CTD subtypes are shown in Table: Patient Characteristics at Baseline.

Of the 334 patients with PAH-CTD, 167 received placebo and 167 received UPTRAVI. The median treatment durations for placebo and UPTRAVI were 62.0 and 67.1 weeks, respectively, similar to the treatment duration in the overall study population.

UPTRAVI Dose

In the PAH-CTD subgroup, 40 patients (24.0%) had their individualized maintenance dose in the low-dose group (200 or 400 mcg BID), 45 (26.9%) in the medium-dose group (600, 800, or 1000 mcg BID) and 75 (44.9%) in the high-dose group (1200, 1400, or 1600 mcg BID). These proportions were similar to those observed in the overall GRIPHON population and there were no notable differences between CTD subtypes and the overall PAH-CTD subgroup.

Response to UPTRAVI Treatment

Among patients with PAH-CTD, UPTRAVI reduced the risk of a morbidity/mortality event by 41% vs placebo (HR=0.59; 95% CI, 0.41-0.85) (Figure: Effect of UPTRAVI on the Primary Composite Endpoint of Morbidity/Mortality by PAH Therapy at Baseline and CTD Subtype and Figure: Effect of UPTRAVI on the Primary Composite Endpoint of Morbidity/Mortality in Patients With PAH-CTD). This response was consistent with that observed in the overall GRIPHON population. The treatment effect was consistent in patients with PAH-CTD irrespective of PAH therapy at baseline (interaction P=0.87) and across the CTD subtypes (interaction P=0.89) (Figure: Effect of UPTRAVI on the Primary Composite Endpoint of Morbidity/Mortality by PAH Therapy at Baseline and CTD Subtype). The risk reduction of UPTRAVI vs placebo was 44% (HR, 0.56; 95% CI, 0.34-0.91) in patients with PAH-SSc and 34% (HR, 0.66; 95% CI, 0.30-1.48) in patients with PAH-SLE (Figure: Effect of UPTRAVI on the Primary Composite Endpoint of Morbidity/Mortality by PAH Therapy at Baseline and CTD Subtype).

In the PAH-CTD subgroup, the 6-minute walk distance (6MWD) decreased by a median of 10.0 m from baseline in the placebo group and 2.0 m from baseline in the UPTRAVI group (treatment effect, 12 m [95% CI, -4 to 27]). With respect to N-terminal pro b-type natriuretic peptide (NT-proBNP), a median (quartile [Q]1-Q3) decrease of -55.5 ng/L (282.5 to 48.0) from baseline to week 26 was observed with UPTRAVI compared with a median increase of 13 ng/L (-99.0 to 404.0) with placebo (treatment effect, -140.0 [95% CI, -265 to -51]).

Overall, in the PAH-CTD subgroup, 15 (9.1%) placebo-treated patients and 32 (19.2%) UPTRAVI-treated patients discontinued their study regimen prematurely because of an AE (Table: Most Frequent AEs Among Patients With PAH-CTD). The frequencies of AEs and SAEs reported in the treatment groups were similar for the PAH-CTD subgroup and for the CTD subtypes. The most frequent AEs are listed in Table: Most Frequent AEs Among Patients With PAH-CTD. The most frequent AEs associated with therapies that target the prostacyclin (PGI₂) pathway, which occurred during the titration and maintenance periods, are provided in Table: PGI₂-Associated AEs Reported in the Study Titration and Maintenance Periods Among Patients With PAH-CTD. Irrespective of the underlying CTD, these AEs were generally reported more frequently during the 12-week titration period, when they were used to define the highest tolerated dose.

SPHERE Registry

SPHERE (SelexiPag: tHe usErs dRug rEgistry; NCT03278002) was a USbased, multicenter, prospective, observational, real-world registry study (November 2016 to March 2020) that assessed the real-world outcomes of UPTRAVI in routine clinical practice. The study also provides information regarding patient demographics and disease characteristics in the enrolled population.³

Of the total 829 adult (≥18 years of age) patients with pulmonary hypertension (WHO group 1-5) enrolled in SPHERE, 759 had PAH (WHO group 1), of whom 387 and 372 were newly (starting UPTRAVI ≤60 days before enrollment) and previously (starting UPTRAVI >60 days before enrollment) initiated on UPTRAVI, respectively.³

Of the 759 patients with PAH, 205 (27.0%), 106 (27.4%), and 99 (26.6%) were with PAHCTD in the overall, newly initiated, and previously initiated groups, respectively. However, the treatment outcomes specific to the PAH-CTD population among the overall PAH population enrolled in SPHERE (N=759) are not available.³

SPHERE Registry Interim Data

The first 500 patients enrolled as of the data cutoff date of December 20, 2019, were analyzed. Patients previously initiated on UPTRAVI continued treatment until enrollment and were required to have a documented titration schedule. Data were collected at baseline (initiation of UPTRAVI) and study enrollment and then quarterly until the end of follow-up (18 months after enrollment).^4,5

Of the first 500 patients enrolled, 132 (26.4%) had PAH-CTD, 246 (49.2%) had IPAH, and 122 (24.4%) had other diagnoses. Median (interquartile range [IQR]) time from PAH diagnosis to UPTRAVI initiation was 3.3 (1.2-7.8) years for patients with PAH-CTD vs 3.0 (1.1-6.3) years for patients with IPAH.⁵

In previously initiated patients, median (IQR) duration of UPTRAVI treatment prior to enrollment was 5.6 (1.5-11.5) months for the PAH-CTD subgroup vs 6.9 (1.812.1) months for the IPAH subgroup. Compared to patients with IPAH, patients with PAH-CTD were more likely to be female, functional class (FC) III, have a shorter 6MWD and higher brain-type natriuretic peptide (BNP) level (See Table: Patient and Disease Characteristics at UPTRAVI Initiation).⁵

UPTRAVI Dosing and Titration

Dose titration pattern and time to maintenance dose of UPTRAVI were similar in the PAHCTD and IPAH subgroups (See Figure: UPTRAVI Dosing Throughout the Study). The median individualized maintenance dose in both subgroups was 1200 mcg BID.⁵

Safety

More patients in the PAH-CTD subgroup (15.2%) vs the IPAH subgroup (11.0%) discontinued treatment due to AEs related to PAH disease progression (See Table: AEs Leading to Treatment Discontinuation in >2% of Patients in Any Group).⁵

Real-world Evidence

Gaine et al (2024)⁶ described the characteristics, treatment patterns, tolerability, and outcomes from the ongoing observational, multicenter, prospective EXPOSURE (EXPloratory Observational Study of Uptravi in Real-lifE) study in patients with PAH-CTD treated with UPTRAVI in clinical practice.

The analysis included PAH-CTD (n=178) patients newly initiated on UPTRAVI with follow-up information reported from September 2017 to November 2022. Of the PAH-CTD patients, 71% had SSc, 8% had MCTD, 7% had SLE, 6% had rheumatoid arthritis, 4% had Sjogren’s syndrome, and 3% had undifferentiated CTD. The median age of the PAH-CTD population was 68 years and 88% were females, with a median time since diagnosis of 1.7 years. At baseline, 1%, 33%, 63%, and 3% had WHO FC I, II, III, and IV, respectively.

The median titration duration for PAH-CTD patients was 1.5 months. Of the 151 PAH-CTD patients who completed titration, the median UPTRAVI individualized dose was 600 mcg BID. By distribution, the dose group comprised of 30% as low (200 or 400 mcg BID), 41% as medium (600, 800, or 1000 mcg BID), and 23% as high (1200, 1400, or 1600 mcg BID) in comparison to the low (24%), medium (27%), and high (45%) dose groups of PAH-CTD patients in the GRIPHON study. Eleven patients did not receive a dose consistent with the dosing groups.

UPTRAVI was initiated as a triple oral therapy in 142 (80%) PAH-CTD patients, with 131 (92%) taking UPTRAVI in combination with both an endothelin receptor antagonist and a PDE-5i and 11 (8%) taking UPTRAVI in combination with an endothelin receptor antagonist and sCG stimulator. Among the 13% of PAH-CTD patients initiating double therapy, UPTRAVI was initiated as combination therapy with ERA in 13 (57%) patients and with PDE-5i in 10 (43%) patients. Majority of the PAH-CTD patients (56%) initiating triple oral combination therapy escalated from double oral combination therapy. Most of the PAH-CTD patients were on double therapy for at least 1 year before treatment escalation with UPTRAVI. Of the 91 (61%) PAH-CTD patients on triple therapy at 6 months postbaseline, 89 patients remained on triple therapy from baseline, and 2 patients escalated from double therapy at baseline. At 6 months postbaseline, 21/143 (15%) patients de-escalated from triple to double combination therapy, whereas 89/143 (62%) remained on triple therapy. At 12 months postbaseline, majority of the PAH-CTD patients (n=122) maintained the treatment regimen with fewer follow-up observations (15% patients on double therapy; 56% patients on triple therapy).

One-year Kaplan-Meier (KM) estimates for PAH-CTD patients free from hospitalization were 63% (95% CI, 46-76). The 1-year and 2-year KM estimates for IPAH patients free from hospitalization were 76% (95% CI, 66-83) and 66% (95% CI, 54-76), respectively. The 1-year and 2-year KM survival estimates were 85% (95% CI, 69-93) and 71% (95% CI, 49-84), respectively. The 1-year, 2-year, and 3-year KM survival estimates for IPAH patients were 93% (95% CI, 85-97), 87% (95% CI, 75-93), and 82% (95% CI, 67-90), respectively. The incidence rates, mortality rates, and hospitalizations are reported in Table: Hospitalizations and Mortality During the UPTRAVI Exposure Period.

UPTRAVI discontinuation occurred in 79 (44%) PAH-CTD patients, with a median time to discontinuation of 4.3 months. The reasons for discontinuation were due to tolerability/AEs (20%), death (16%), PAH disease progression (4%), administrative reasons (2%), treatment non-compliance (<1%), and unknown reasons (<1%). There were 70 (39%) patients who experienced an AE while on UPTRAVI. The most frequent AEs occurring in ≥5% of patients were diarrhea (11%), headache (7%), and dyspnea (5%).

Limitation of the study:⁶

• There was a lack of diversity of CTD subtypes within the EXPOSURE study as the underlying disease was mainly SSc (71%).

Tsang et al (2023)⁷ presented results from a retrospective cohort study using the USbased Optum’s de-identified Clinformatics^® Data Mart database that evaluated the effect of oral UPTRAVI on clinical outcomes in patients with PAH (N=317) with (15.2% [n=80]) and without (74.8% [n=237]) CTD comorbidities. At baseline, patients in the PAH-CTD vs PAH non-CTD group were younger (62.7 vs 64.8 years; P=0.221), consisted of proportionately more female (82.5% vs 72.0%; P=0.065), and had a lower mean Charlson Comorbidity Index score (2.3 vs 3.1; P=0.013). The most common comorbidities in PAH-CTD cohort were hypertension (91.3%), coronary artery disease (42.5%), and interstitial lung disease (40%). The most common comorbidities in PAH without CTD cohort were hypertension (84.4%), chronic obstructive pulmonary disease (55.7%) and apnea (48.5%). After adjusting for the baseline demographics and clinical characteristics, among patients with PAH-CTD and PAH non-CTD, no statistically significant difference was reported in time to PAH-related hospitalization, time to all cause hospitalization, and time to disease progression (Table: Adjusted Outcomes for Patients With PAH-CTD Compared to PAH NonCTD Patients Prescribed UPTRAVI).

Limitations of the study:⁷

• There was lack of specificity of ICD codes in the WHO PAH clinical classification and PAH etiology, and no specific ICD codes for PAH.
• The diagnosis code on a medical claim does not indicate the positive presence of a disease and a claim for filled prescription does not imply that the medication was consumed or taken as prescribed.
• The varying definition of PAH disease progression across different studies may result in conflicting information on PAH disease progression.
• Undifferentiated CTD was not considered in the study, which could have introduced misclassification of PAH patients in some cases.
  • Due to the small sample size of PAH-CTD cohort, the study did not examine CTD subtype and CTD medications used.
• The analysis may be underpowered to detect small differences between PAH with and without CTD, due to the small sample size.

Literature Search

A literature search of MEDLINE^®, EMBASE^®, BIOSIS Previews^®, DERWENT^® (and/or other resources, including internal/external databases) was conducted on 03 July 2024.