Psilocybin-Assisted Psychotherapy in Cancer Patients With Adjustment Disorder

This is a randomized, double-blind, low-dose comparator-controlled Phase IIb study to investigate the efficacy and safety of PAP with 25 mg, 10 mg and 1 mg \[low-dose comparator) NPX-5, for the treatment of adjustment disorder symptoms in participants diagnosed with cancer. The referring oncologist will indicate that the participant is physically capable of undergoing psychedelic encounter and is likely to have a minimum life expectancy of 6 months. At least 87 adult participants (age 18 to 80 at screening) with a diagnosis of AjD due to cancer diagnosis will be enrolled in this study. Participants will be randomly assigned with a ratio of 1:1:1 to receive Psilocybin-Assisted Psychotherapy (PAP) with either 25 mg, 10 mg or 1 mg NPX-5. Both the site staff treating participants and the participants themselves will be blinded to the treatments being administered. The study consists of a combination of clinic visits and telehealth phone calls to support this vulnerable participant population. The clinic will have experience with conducting PAP. All study visits be carried out by suitably qualified individuals and wherever possible, the same therapist will meet with study participants for in-person and telehealth appointments. Participants will undertake a screening visit between Day -45 and Day -2 to determine eligibility to participate in the study. Those participants that meet the eligibility criteria will attend the study site on Day 1 when continued eligibility will be assessed and baseline assessments performed. Participants must complete three preparation sessions with the therapist prior to dosing session. Two of these sessions can be completed remotely via telehealth and have flexible timing, provided there is at least one day between each session. One preparation session must be done in person in the dosing room, ideally during a site visit on Day 13. Additionally, at least one preparation session must include the sitter or secondary therapist. The primary therapist has the discretion to include the sitter or secondary therapist in more preparation or integration sessions based on their assessment. The clinic site visits will comprise Day 1, Day 13 (day prior dosing session), Day 14 (dosing session), Day 15 (integration session) and Day 70/Week 10 (follow-up) post-randomization. There will be ± 3 days for a dosing session allowed. Subsequently, all relevant visits will be adjusted accordingly. In addition, participants will be required to attend following telehealth appointments: * Two telehealth appointments for preparatory sessions within 2 weeks prior to dosing session. * One telehealth appointment for integration therapy session in the two weeks following the dosing session. * Follow up telehealth appointments on Day 28 (Week 4), Day 42 (Week 6). * Final study follow-up telehealth appointment at 3 months post the Day 70 (Week 10) visit of the final PAP cycle for final safety assessments. Non responders (for criteria see Section 5.5.2) at Day 70 (Week 10) that continue to meet the study eligibility criteria, may commence an additional PAP cycle (at 25 mg NPX-5). These participants will repeat the schedule described above, including the visit the day prior to dosing session, the actual dosing session, and the integration sessions. A maximum of 2 PAP cycles may be administered.